Presentation on theme: "UNIT-I & II-ACCIDENT AVOIDANCE TRAINING"— Presentation transcript:
1 UNIT-I & II-ACCIDENT AVOIDANCE TRAINING Presented by the Ft. Lee Safety OfficeThis training is designed to reinforce good driving principles and to remind or make you aware of hazards associated with poor driving behaviors and practices.Bottom line: this training will help preserve the organization’s resources (personnel, equipment, and money)The course consists of videos, open discussion, and short quizes at the end of each block.I encourage all personnel to actively participate with the discussions and quiz questions.Lack of participation may result in me calling names from the attendance roster to answer questions.
2 TABLE OF CONTENTS INTRODUCTION Safe Driving ARMY Regulation Traffic SafetyVehicle SafetyDefensive DrivingNight Driving TacticsWinter Driving TacticsSafe DrivingDriving SafetyHeads Up at the Wheel: Home SafeHands on Driving InformationSAFETY ALERTS & Awareness MaterialFT LEE FORM 1082The Accident Avoidance Training is made up of these key areas:IntroductionArmy Regulations governing this trainingTraffic SafetyVehicle SafetyDefensive DrivingWinter Driving TacticsSafe DrivingDriving SafetyHeads up at the Wheel (video)Hands on Driving InformationSafety Alerts & Awareness MaterialFt. Lee Form 1082
3 INTRODUCTION Driving can lead to a false sense of security. You take most risks for granted.Driving becomes second nature.Motor vehicle accidents are the single largest cause of accidental death.Leading cause of on-the-job fatalities.Over time, driving can lead to a false sense of security. Driving becomes second nature. Chances are, you take most driving risks for granted.Motor vehicle accidents are the single largest cause of accidental death and the leading cause of on-the-job fatalities.
4 IntroductionDriving may be one of the most dangerous activities you engage in on the job.By following the Ft. Lee Accident Avoidance Training handbook, you may be surprised to find that some of your driving habits are not as harmless as you thought. After all, even a good driver can improve.No matter how hazardous your occupation, driving may be one of the most dangerous activities you engage in on the job.At the conclusion of the Fort Lee Accident Avoidance Training, you may be surprised to find that some of your driving habits are not as harmless as you thought.Even a good driver can improve.
5 ARMY REGULATION AR 385-55: Prevention of Motor Vehicle Accidents requirement every 4 yearsAR : The Army Driver and Operator Standardization Program (Selection, Training, Testing and Licensing)This training is required by AR for all personnel who operate military or government owned vehicles.At the completion of this training, personnel will be issued a Ft. Lee Form (similar to the old Defensive Driving card)Drivers are required to receive this training every 4 years.
7 TRAFFIC SAFETYWhy is it important to keep your eyes and attention on the driving task?Traffic SafetyWhy is it important to keep your eyes and attention on the driving task?
8 Avoid inside and outside distractions to the driving task. Distractions are a leading contributor tovehicle accidents.Taking your eyes and attention off the driving task will mentally leave you blind to the driving environment.At highway speeds, a one second distraction can permit you to travel blind for over 100 feet.Answer:Distractions are a leading contributor to vehicle accidents.Taking your eyes and attention off the driving task will mentally leave you blind to the driving environment.At highway speeds, a one second distraction can permit you to travel blind for over 100 feet.Avoid distractions to the driving task...looking at a passengeradjusting the radio or looking for a CD or tapereading an unrelated off road advertisementtalking on the cell phoneAvoid inside and outside distractions to the driving task.
9 What is the purpose of delaying your start at a traffic light that has just turned green? The first three seconds after a light turns green are the most dangerous.Drivers facing the newly turned red light may still be trying to make the light.What is the purpose of delaying your start at a traffic light that has just turned green?The first 3 seconds after a light turns greens are the most dangerous.Drivers facing the newly turned red light may still be trying to make the light.By delaying your start, you permit anyone who was still trying to make their light a clear space so they do not hit you.Remember………Having a green light does not give you the right to start moving immediately. Always pause to look.Remember, having a green light does not give you the right to start moving immediately.
10 Traffic Safety Discussion What is the purpose of scanning seconds ahead of your vehicle’s intended path?What is meant by the concept road management ?Discussion:What is the purpose of scanning seconds ahead of your vehicle’s intended path?Allows time to identify changing conditionsTime permits you to adjust your vehicle speed and direction to meet the changing conditionsWhat is meant by the concept “road management”?Knowing where your vehicle is in relation to other vehicles and objects at all timesMaintaining a safe cushion in all directionsHaving a clear, unobstructed field of vision
12 QUIZ 1. How far ahead should you scan your intended driving path? A seconds D secondsB seconds E secondsC seconds2. What is the recommended safety cushion for vehicles you are following?A. 3 seconds D. 6 secondsB. 4 seconds E. 7 secondsC. 5 secondsC secondsQUIZ1. How far ahead should you scan your intended driving path?A seconds D secondsB seconds E secondsC seconds2. What is the recommended safety cushion for vehicles you are following?A. 3 seconds D. 6 secondsB. 4 seconds E. 7 secondsC. 5 secondsA. 3 seconds
13 D. Rear tires of vehicle ahead touching ground 3. When stopping behind another vehicle, what should you be able to see?A. Tail lights of vehicle ahead D. Rear tires of vehicle ahead B. Bumper of vehicle ahead touching the groundC. Rear tires of vehicle ahead E. 15 feet of ground behindthe vehicle ahead4. The recommended delayed starting time at a light is?A. Delay not recommended D. 5 secondsB. 1 second E. 7 secondsC. 3 seconds5. Proper seatbelt use reduces the likelihood of fatal or serious injuries by:A. Does not reduce likelihood C. 24% E. 44%B. 14% D. 34%D. Rear tires of vehicle ahead touching groundC. 3 secondsQUIZ3. When stopping behind another vehicle, what should you be able to see?A. Tail lights of vehicle ahead D. Rear tires of vehicle aheadB. Bumper of vehicle ahead touching the groundC. Rear tires of vehicle ahead E. 15 feet of ground behindthe vehicle ahead4. The recommended delayed starting time at a light is?A. Delay not recommended D. 5 secondsB. 1 second E. 7 secondsC. 3 seconds5. Proper seatbelt use reduces the likelihood of fatal or serious injuries by:A. Does not reduce likelihood C. 24% E. 44%B. 14% D. 34%E. 44%
15 Do all vehicles handle and operate the same? Each vehicle and type of vehicle has its own handling characteristics.Drivers should be trained on the vehicle they operate.Follow the same driving rules on and off-site.Do all vehicles handle and operate the same?Each vehicle and type of vehicle has its own handling characteristics.Drivers should be trained on the vehicle they operate.Operators should basically follow the same rules of the road both on and off post; and on/off main roadways.
16 What purpose do the lights on a vehicle serve? To illuminate the path of the vehicle.To help others locate the vehicle and determine its activity (braking, turning, backing, etc.).What purpose do the lights on a vehicle serve?The main purpose is to illuminate the path the vehicle is traveling on.The secondary purpose of the vehicle lighting system is to help others locate (or see) the vehicle and determine its activitybrakingturningbacking
17 What is the role of the braking system of a vehicle? To avoid collisions with other objects in the vehicle’s path.To hold the vehicle in place while parked.To slow the vehicle so it can stop or make appropriate turns.What is the role of the braking system of a vehicle?To avoid collisions with other objects in the vehicle’s path.To hold the vehicle in place while parked.To slow the vehicle so it can stop or make appropriate turns.
19 QUIZ 1. Which statement(s) about vehicles on a facility is true? A. Each vehicle has its C. Drivers should be trainedown operating procedures on vehicles they operateB. Drivers must know & follow D. All of the aboveeach vehicle’s operating E. None of the aboveprocedures2. A vehicle’s lighting system exists for which of the following purposes?A. To help the driver see his/her path of travelB. To warn others of the vehicle’s presenceC. To inform others of the vehicle’s activityD. All of the aboveE. None of the aboveD. All of the aboveQUIZ1. Which statement(s) about vehicles on a facility is true?A. Each vehicle has its C. Drivers should be trainedown operating procedures on vehicles they operateB. Drivers must know & follow D. All of the aboveeach vehicle’s operating E. None of the aboveprocedures2. A vehicle’s lighting system exists for which of the following purposes?A. To help the driver see his/her path of travelB. To warn others of the vehicle’s presenceC. To inform others of the vehicle’s activityD. All of the aboveE. None of the aboveD. All of the above
20 A. Driver’s inability to hear warning devices 3. Based on the concept of one vehicle length per every 10 mph of travel, how many vehicle lengths should you be behind a vehicle traveling 30 mph?A. One C. Three E. FiveB. Two D. Four4. What types of problems can the noise from some industrial vehicles create?A. Driver’s inability to hear C. Driver’s inability to steer thewarning devices vehicleB. Driver’s inability to see D. All of the aboveapproaching vehicles or E. None of the abovepedestriansC. ThreeA. Driver’s inability to hear warning devicesQUIZ3. Based on the concept of one vehicle length per every 10 mph of travel, how many vehicle lengths should you be behind a vehicle traveling 30 mph?A. One C. Three E. FiveB. Two D. Four4. What types of problems can the noise from some industrial vehicles create?A. Driver’s inability to hear C. Driver’s inability to steer thewarning devices vehicleB. Driver’s inability to see D. All of the aboveapproaching vehicles or E. None of the abovepedestrians
21 5 Rules of Defensive Driving SAFE DRIVINGView Videos:5 Rules of Defensive DrivingHeads Up At the WheelSafe Driving
22 Why should you check outside the vehicle before putting the vehicle in motion? To ensure no objects will interfere with the movement of the vehicle.To ensure tires are in good condition.To ensure the windows are clean.To identify any unexpected body damage to the vehicle.Why should you check outside the vehicle before putting the vehicle in motion?To make sure there are no objects that will interfere with the movement of the vehicle. (equipment, small children, etc)To make sure the tires are in good condition. (avoid blowouts)To make sure the windows are clean. (provide clear vision)To identify any unexpected body damage to the vehicle.
23 What types of emergency equipment should be with the vehicle? If your vehicle is well maintained, what else can affect motor vehicle safety?A driver not getting proper rest; and not being alert.What types of emergency equipment should be with the vehicle?If your vehicle is well maintained, what else can affect motor vehicle safety?The driver needs to me ready to drive. This means getting proper rest prior to driving and being alert during driving.What types of emergency equipment should be with the vehicle?Warning flares or triangleJumper cablesFire extinguisherFirst aid kitTire jack and lug wrenchWarning flares or triangles, jumper cables, fire extinguisher, first aid kit, & equipment to change a flat.
24 What is meant by properly securing the driver and goods? Driver properly belted inPassengers wearing seatbeltsCargo properly secured so it can’t move around during travel.What is meant by properly securing the driver and goods?Driver is properly belted in (use of serviceable seatbelt)Passengers are wearing their seatbeltsCargo or equipment is properly secured so it can’t move around during travel.
25 How do senses other than vision help in driving? Provide warning that something is not right.smells alert you to something burningunusual engine sounds may indicate a mechanical problemyour body may alert you to bad brakes or improper tire inflation by feeling the vehicle pull to the left or right when brakingHow do your senses (other than vision) help in driving?Other senses can warn you that something is not right.Electrical shorts or oil leaks can cause start a fire; you can detect by smellingUnusual noises coming from the tires or engine may indicate a mechanical problemYour body may alert you to bad brakes or improper tire inflation by feeling the vehicle pull left or right when braking, or soft/spongy brakes.
26 Good visual driving habits: Keep eyes moving (check out your path of travel)Look 15 seconds ahead of your vehicle. (it provides a picture of what’s happening)Scan mirrors every 4-6 sec. (find out what’s happening behind and along side your vehicle)Glance at dashboard every 20 sec. (observe speed control and warning gauges)Follow vehicles ahead no closer than 3 sec. (allows for reaction time if needed)Good visual driving habits include:Keep your eyes moving (check out your path of travel)Look at least 15 seconds ahead of your vehicle. It provides you with a picture of what is happening ahead.Scan your mirrors at least every 4-6 seconds to find out what is happening behind and along side of your vehicle.Glance at your dashboard at least every 20 seconds to observe speed control and warning gauges.Follow vehicles ahead no closer than 3 seconds so that you have reaction time if you need it.
28 QUIZ 1. Outside the vehicle, you should check for: A. Objects that could interfere C. Bad tire pressure or lossin the movement of the vehicle of fluidsB. Vehicle damage not D. All of the abovepreviously reported E. None of the above2. Taking care of the vehicle and yourself means?A. The driver getting plenty of restB. The vehicle receiving proper maintenanceC. Having emergency supplies in the vehicleD. All of the aboveE. None of the aboveD. All of the aboveQUIZ1. Outside the vehicle, you should check for:A. Objects that could interfere C. Bad tire pressure or lossin the movement of the vehicle of fluidsB. Vehicle damage not D. All of the abovepreviously reported E. None of the above2. Taking care of the vehicle and yourself means?A. The driver getting plenty of restB. The vehicle receiving proper maintenanceC. Having emergency supplies in the vehicleD. All of the aboveE. None of the aboveD. All of the above
29 QUIZ 3. Good visual search patterns while driving: A. Provide the driver with needed information to safely drive from point A to point B.B. Include looking inside of the vehicle and under the hood as much as looking outside of the vehicle.C. Include maintaining a minimum 10 sec following distance.D. All of the aboveE. None of the above4. Seatbelts should be worn:A. Only when traveling short distancesB. Only when traveling long distancesC. Any time the vehicle is in motionD. Only when confronted with dangerous driving conditionsE. When your supervisor is presentA. Provides driver with needed info to safely drive from point A to point B.QUIZ3. Good visual search patterns while driving:A. Provide the driver with needed information to safely drive from point A to point B.B. Include looking inside of the vehicle and under the hood as much as looking outside of the vehicle.C. Include maintaining a minimum 10 sec following distance.D. All of the aboveE. None of the above4. Seatbelts should be worn:A. Only when traveling short distancesB. Only when traveling long distancesC. Any time the vehicle is in motionD. Only when confronted with dangerous driving conditionsE. When your supervisor is presentC. Any time the vehicle is in motion
30 QUIZ 5. When driving in bad weather, the driver should: E. A and B A. Allow more time to secure the cargoB. Allow more time to stop the vehicleC. Take fewer rest stops to get home fasterD. A and CE. A and BE. A and BQUIZ5. When driving in bad weather, the driver should:A. Allow more time to secure the cargoB. Allow more time to stop the vehicleC. Take fewer rest stops to get home fasterD. A and CE. A and B
32 Four strategies that make for a safe driver: Driver has behaviors and attitudes appropriate to the driving task.Driver follows appropriate driving behaviors.Drivers see to it that their vehicle is properly maintained and loaded/unloaded.Drivers comply with organizational policies as they relate to safe operation of a vehicle on and off the facility.There are 4 strategies that make for a safe driver:Safe drivers have behaviors and attitudes that are appropriate to the driving task.Safe drivers follow appropriate driving behaviors.Safe drivers see to it that their vehicles are properly maintained, loaded, and unloaded.Safe drivers comply with organizational policies as they relate to safe operations of a vehicle on and off the facility.
33 Driving Safety Discussion What is meant by the need to develop a high emotional tolerance level to other drivers?Driving Safety Discussion:What is meant by the need to develop a high emotional tolerance level to other drivers?A high emotional tolerance level permits one to remain in control of their own emotions when dealing with the driving mistakes of others.(Prevent Road Rage)Remember, you can not control other drivers and their behaviors, so it is important to control yourself and your driving behavior.
35 QUIZ1. Which of the following behaviors is common to a driver with an inappropriate driving attitude?A. Speeding D. Accelerating towards aB. Tailgating caution lightC. Needless risk taking E. All of the above2. The minimum distance you should maintain when following another vehicle is:A. 4 seconds D. 7 secondsB. 5 seconds E. None of the aboveC. 6 secondsE. All of the aboveQUIZ1. Which of the following behaviors is common to a driver with an inappropriate driving attitude?A. Speeding D. Accelerating towards aB. Tailgating caution lightC. Needless risk taking E. All of the above2. The minimum distance you should maintain when following another vehicle is:A. 4 seconds D. 7 secondsB. 5 seconds E. None of the aboveC. 6 seconds [3 seconds is minimum]E. None of the above
36 QUIZ3. Which of the following items should be included in a pre-drive checklist?A. Tires D. All of the aboveB. Wipers E. None of the aboveC. Brakes4. Alcohol consumption followed by driving has which of the following impacts on the driver?A. Improved visionB. Improved hearingC. Reduced concentrationD. Reduced distractionsE. All of the aboveD. All of the aboveQUIZ3. Which of the following items should be included in a pre-drive checklist?A. Tires D. All of the aboveB. Wipers E. None of the aboveC. Brakes4. Alcohol consumption followed by driving has which of the following impacts on the driver?A. Improved visionB. Improved hearingC. Reduced concentrationD. Reduced distractionsE. All of the aboveC. Reduced concentration
37 QUIZ5. Your organization’s policy on vehicle operation is intended to protect:A. You the operatorB. Your supervisorC. The organizationD. The product (equipment)E. All of the aboveE. All of the aboveQUIZ5. Your organization’s policy on vehicle operation is intended to protect:A. You the operatorB. Your supervisorC. The organizationD. The product (equipment)E. All of the above
44 INTRODUCTIONAutomobile Industry is undergoing a BIG TRANSFORMATION never seen before.Today CAR’s are not only used for personal Transport but they are ENCOMPASSED withEntertainment that vies with the fedility of your HOME THEATRESeating arrangement more comfortable than your RECLINERSAFETY FEATURES making your car safer than a TANK
45 Globally car companies Spend nearly $36 billon annually for influencing new TECHNOLOGIES into their cars.Some of the big advancement in Automotive Industry in last 10years have come in a area of SAFETY.
46 In addition to Telematics based Services like Digital Satellite RadioIn carGPS systemsRecent Advancement in Braking Technology have led toShorter stopping distanceIncreased Control in PANIC situationMore control on CURVED turns
47 Air Bags What’s the main function of the System? Material of Airbags? History
48 Actual WorkingAirbag Before CollisionAirbag After Collision
50 Effectiveness This system has proven its effectiveness In frontal crashes reduction in d rivers death reduced by nearly 14%Passenger side airbags reducing death by nearly 11%NHTSA estimated reduction in risk by nearly 85% with the combination of seat belt and airbags compared than only seatbelt i.e60%Car ModelHead Injury Risk Airbag No Airbag Holden Commodore2848Toyota Camry2044Mitsubishi Magna627Ford Falcon14N. A.This are some crash results which give the effectiveness of the system
56 Working Conventional Braking ABS Braking Whole process is controlled by driver applied break paddle pressure;ABS BrakingElectric Sensors monitor the wheel speedABS microprocessor Compares the wheel speedControl valve is energized.
58 Advantages: Disadvantages: Achives the Shortest Stopping distance Better chance on Steering around obstacleReduced risk of skiddingDisadvantages:Precautions should be taken while drivingProved less effective on gravel road or road compacted by snow
59 Traction Control Next Generation ABS Uses ABS as a Building block. Can be is a combination of ABS & Engine control
60 Mainly the system has to control some or all conditions Retard or Suppress the spark to one or more cylindersRetard fuel supply to one or main cylinderBreak one or more wheelClose the throttle, if the vehicle is fitted by wire throttle
64 Some important ECS definitions ESC augments vehicle directional stability by applying and adjusting the vehicle brakes individually to induce correcting yaw torques to the vehicle.ESC is a computer-controlled system, which uses a close-loop algorithm to limit under steer and over steer of the vehicle when appropriate
65 Case StudyA S-Class Mercedes sedan testing Bosch's ESP system
68 1. The ProblemVehicles and highways have greatly improved safety: total fatalities are down approximately 30% over the past 35 yearsEven with those improvements, there are still approximately 40,000 fatalities / year in the USPeople haven’t improved: in 90% of all accidents, the driver is a contributing cause
69 The SolutionThe Intelligent Vehicle Initiative (IVI) is a USDOT program to use advanced electronics to improve vehicles, with the dominant concern being safety.This tutorial is arranged around a series of advanced functions, such as vehicle detection, that contribute to safer and more intelligent vehicles. For each function, the tutorial discusses a set of possible technologies.The next set of slides show the “user services” for the IVI advanced vehicle control and safety systems. The following charts show which technology functions support each user service.Note the synergy: each technical function supports many user services.
70 IVI User Services categories: Safety: (directly contributing to vehicle safety);rear end collision warningroadway departure warninglane change / merge collision warningintersection collision warningrailroad crossing collision warningvision enhancementlocation-specific warningscollision notificationSafety Impacting: (potential to distract or aid the driver);navigation and routingreal-time traffic informationdriver comfort and convenience features
71 More Services Commercial Vehicle Services: Transit: vehicle stability vehicle diagnosticsdriver condition monitoringcargo identificationautomated transactionssafety recorderTransit:obstacle and pedestrian detectionprecision dockingpassenger monitoringpassenger information
72 More Services Specialty Vehicles: Supporting Services: full automation low friction warninglongitudinal controllateral control
73 Technical functionsThere is a set of common vehicle functions that underlie those user services:sensing the position of other vehiclessensing obstaclessensing the position of the lane relative to your own vehiclesensing vehicle position and motionestimating braking performancecommunicationreliabilitymiscellaneous functionssensor-friendly vehicles and roadwaysThe rest of this section shows how each of these functions supports the various user services
81 Section 1 Questions:How many accidents occurred in the most recent year for which statistics are available? Hint - andHow many fatalities?What was the dollar cost of those accidents?What kind of economic justification is there for the various AVCSS services?Are there other on-vehicle functions that would be useful?
82 2 Sensing Other Vehicles Other vehicles need to be sensed in front for adaptive cruise control and forward collision warning; on the sides, for blind spot and lane change / merge warning; and behind, for backup warning and for lane change / merge warning of overtaking vehicles.Sensing has to work in all weather, and at a variety of ranges
83 2.1 Basic GeometrySensing straight ahead is not sufficient; on a curving road, a forward-looking sensor needs to have a wide field of view, and sensed vehicle position needs to be combined with road geometry to know whether the lead vehicle is in your lane, another lane, or on the shoulder.
84 2.2 Targets and ClutterOther objects in the field of view can include roadside signs, parked cars, overpasses, guard rails, etc; this is referred to in the radar literature as “clutter”.Adaptive Cruise Control (ACC) systems, which are only concerned with moving vehicles, can reject any stopped object as clutter.Rear-end collision warning systems need to sense stopped vehicles, and so need high-acuity sensing of vehicles and lanes in order to separate targets (other vehicles) from clutter.
85 2.3 RadarRadar is an excellent choice for seeing big metal objects through fog, snow, or light rainThe currently approved frequency is 77 GHz. Radar works at the speed of light, so sensing is almost instantaneous.Simple radar is be a single spot with no information on bearing angle. More sophisticated versions sweep the beam mechanically, or use two or more beams and various processing schemes to measure bearing and rangeTypical resolution (closest objects that can be distinguised) is 1 meter in range, 3 degrees in bearing.
86 Radar DataData from a scanning radar. Top image is video of the scene, bottom is radar data, with corresponding locations marked. The radar data is range (horizontal) and bearing angle (vertical; up is left, down is right). Brightness indicates strength of return. Car A is close and he center of the radar return (the video image does not extend as far to the right as the radar); B is further and left; C is further yet and is barely visible above the roof of A; D is much further and has a bearing between A and B.ABCD
87 2.4 LadarLadar, lidar, and laser rangefinder are all synonyms. They refer to measuring distance using the travel time of a laser beam. The laser can be scanned over the scene with mirrors to produce a “range image”.Lasers can be focused to very small spots (fractions of a degree), so they have much better resolution than radar. Instead of sensing a blob with radar, a ladar can make many measurements as it scans, and can measure fine details of shape.Since ladar is near visible light, it is blocked by the same kinds of effects that impede human vision: fog, snow, and heavy rain will block the signals.
88 Ladar DataThe figures on the next page show data from a high-resolution scanning laser rangefinder. Each picture is 480,000 pixels (points), each corresponding to a separate ladar measurement.The top picture shows the reflectance data: this is the amount of laser energy returned from that point in the scene, and is roughly equivalent to a flash photo.The lower picture shows range data. Brightness encodes range: points that are further away are displayed more brightly.Note the fine details of shape and appearance visible in this data. It is possible to build a computer program that can identify which objects are cars, and which direction they are facing; this can give early warning of which vehicles may be on a collision course.
90 2.5 Sonar Sonar works by measuring the time of flight of sound. Sound travels (relatively) slowly though air and is hard to focus, so sonar is only useful for detecting objects at ranges of a few meters or less.Sonars are inexpensive, and work in a most weather conditions. The initial mass market application was in Polaroid auto-focus cameras.Sonars are commercially available for blind spot sensors and back-up warning sensors.
91 Side and Rear Sensors Sonars Radar This bus is equipped with rear and side sensors for blind spot coverage
92 2.6 CommunicationsIf all vehicles on a roadway are equipped with ITS features, inter-vehicle communications can be used to determine relative positions.Each vehicle can broadcast its current location, derived from GPS or other positioning systems.Vehicles can also broadcast other information, such as speeds, intent to change lanes, or onset of emergency braking. This is crucial in decreasing inter-vehicle spacing to increase throughput, while maintaining safety.This kind of scheme is most appropriate for high-end IVI systems, such as automated highways.The picture on the next page shows a “platoon” of tightly-spaced automated vehicles, developed by the PATH program at UC Berkeley. Platoons rely on communications 20 times a second to keep all vehicles moving smoothly together.
94 2.7 Driver modelsSensing the current location of a nearby vehicle is not all: it would be even better to predict future actions of the vehicle. Unless that vehicle is fully automated, it is necessary to model the behavior of that driver.As shown in the next slide (and as everyone knows from personal experience), there is a great deal of variability in people’s driving behavior.If a particular vehicle can be observed for some time, that driver’s behavior can be estimated, and used to predict future actions.
95 Left curve Straight Right curve Driver DifferencesThe five drivers plotted here each have different behaviors for one important component of driving: average lane position. They have different mean lane positions when the road is straight, and cut the corners by different amounts when the road curvesLeft curve Straight Right curve
96 Section 2 Questions:What are the advantages and disadvantages of using radar vs. ladar?The speed of light is about 3*10^8 m/sec, or, for a rule of thumb, a foot / nanosecond. How long does it take a radar pulse to go to and from an object 150 m away?Find two manufacturers of automotive or truck radars on the www
97 3 Sensing ObstaclesObstacle detection is much more difficult than vehicle detection: obstacles can be small, non-metallic, and much harder to seeObstacles can be stationary or moving (e.g. deer running across the road)For a passenger car at highway speeds, obstacles need to be detected 100 m ahead. For trucks, the distance is even longer.Obstacle detection is one of the most challenging tasks for an intelligent vehicle
98 3.1 Obstacles on the RoadState DOTs report cleaning up construction debris, fuel spills, car parts, tire carcasses, and so forth.State highway patrols receive reports of washing machines, other home appliances, ladders, pallets, deer, etc.A survey commissioned by a company that builds litter-retrieval machines reports 185 million pieces of litter / week.Rural states report up to 35% of all rural crashes involve animals, mostly deer but also including moose and elk as well as farm animals.A non-scientific survey of colleagues indicates that people have hit tire carcasses, mufflers, deer, dogs, even a toilet.
99 3.2 SensorsLadar, in its high-resolution scanning formats, is useful for seeing small objectsA variant is to use the reflectance channel of a ladar, and to look for bright returns, which probably come from objects sticking up out of the roadway.Sonar has insufficient rangeAdvanced radar and stereo vision systems may work
100 3.3 Polarimetric radarRadar can be polarized in the same was as light.Just as polarized sunglasses help reduce light reflected from shallow angles (glare), polarized radar transmitters and receivers can separate the return from different polarization directions; this provides cues to distinguish horizontal surfaces and from vertical surfaces.Polarimetric radars built at U of Michigan are much better than ordinary radar at separating small obstacles from ground clutter.There is also some evidence that polarimetric radar will give different returns for wet or snowy roads, giving some information on road conditions.
101 3.4 Stereo visionStereo works by finding the same point in two or more cameras. Intersecting the lines of view from the cameras gives the 3D location of the object.
102 Stereo Guided Segmentation Low-resolution stereo for detection and recognition of nearby objects, used for side-looking sensors on a bus.Left: Original image. Center: depth map from stereo; brighter is close. Right: “blobs” of pixels at the same distance. The overlays on the original image show detected objects, two pedestrians and a car.Further processing can examine each blob to separate people from fixed obstructions, and generate appropriate driver warnings
103 Long-Range StereoTop: One of three images from a stereo set. The objects on the road are 15 cm tall at a range of 100 m from the camera.Bottom: detected objects in black. Besides the obstacles on the road, the system has found the person, the sign, grass along the road, and a distant dip in the road
104 Section 3 Questions:Look up the connection between posted speeds and vertical curvature in the AASHTO handbook. Is the line of sight for a human driver, going over the crest of a hill, better or worse than for a sensor mounted in the front bumper?For extra credit, go out and run over obstacles with your car, and decide what is the largest object you would be willing to hit, and therefore the smallest object that needs to be detected.
105 4 Sensing Lane PositionKnowing lane position is necessary for automated guidance and for lane departure warning systems. It is also important for rear-end collision warning, to know which lane your vehicle is in as well as which lane preceeding vehicles are in.Requirements are somewhat different for each application.
106 4.1 Requirementsreliability: high for warning systems, extremely high for automated guidanceavailability: must be available nearly 100% for automated guidance; lower availability acceptable for warning systems provided a warning is givenweather: should operate in most weather, warn and disable if not operatingaccuracy: absolute accuracy of better than 30 cm needed; no high-frequency jitter allowed for control applicationsrange: rear-end warning requires knowing lane position of leading vehicle, to approx. 100m
107 4.2 MagneticsUC Berkeley has pioneered the use of permanent magnets, buried in the center of the road, for lateral guidance. The magnets can be inexpensive magnets, as shown here, for most applications; or more expensive but much smaller magnets for bridge decks where drilling large holes would damage the structure. The magnets are sensed by magnetometers underneath the front and rear bumpers of the vehicle to provide lateral position information.The magnets can be installed north pole up or down, providing a simple binary code that can indicate e.g. map location.
108 More MagnetsAn obvious advantage of magnets is that they are not affected by weather. Here, they are used to mark the edge of the shoulder, to provide a visual indicator to the snow plow operator.Besides buried magnets, there are also efforts to place magnets in lane marking tape. This would be less expensive to install, but requires more sophisticated sensing, since the magnets are not directly underneath the vehicle’s sensors.
109 4.3 Buried cablesThe oldest way to perform automated guidance, going back to the 1950’s, is to follow a buried cable. The automated trucks at the Westrack pavement test site use two cables for redundancy, with pickup coils mounted in triangular frames at both front and back of the truck. Buried cables are all-weather, and the signal on the cable can be used to send messages (e.g. “speed limit change”). But cable installation and maintenance are difficult.
110 4.4 Radar reflective surfaces Collision avoidance radar can be used for lateral control with modified lane-marking tape.Frequency-dependent tape properties can provide distance and other informationConventional lane marking tape (3M Corp.) punched with specific hole pattern to provide frequency-selective retro-reflection
111 4.5 Vision Typical vision system for lane tracking. The detected position of the solid line is shown by the blue dots; the detected dashed line by dark and light blue dots. Overlayed on the image is data from other sensors, showing the location of radar targets: yellow X for right lane, red X for current lane. Experimenter interface shown at bottom.
112 Section 4 Questions:What would be the relative advantages of magnetics vs. vision?What is the disadvantage of buried cables?
113 5 Sensing vehicle position and motion An estimate of vehicle motion, and position on a map, can be used in several ways, depending on the resolution. For example:coarse position (10s of meters) can be used to predict that a corner is coming upmedium position (meters) can be used to warn a driver to slow down, based on the design speed of the upcoming curvefine positioning (cm) can be used to tell if the driver is drifting out of their lane through the curveSeveral different technologies provide ways of measuring absolute position and motion, at a variety of resolutions.
114 5.2 GPSThe Global Positioning System is a satellite-based navigation system, originally developed by the US military. It works by broadcasting very accurate time signals from a constellation of orbiting satellites. A ground-based receiver can compare the times from several satellites; the different in apparent times gives the difference in time-of-flight of the signals from the satellites, and therefore the difference in distance to each satellite. Simple geometry gives the location of the ground-based unit and an accurate time.
115 More GPS This simple picture is distorted by two phenomena The US government deliberately introduces distortions into the civilian version of the signal, in order to reduce the accuracy of the system for potential enemiesLocal atmospheric effects refract the signals by varying amountsThe result is that raw GPS has an accuracy of only 10’s of meters
116 Differential GPSIn Differential GPS, a base station has a GPS receiver at a known location. It continually compares its known position with the GPS reported position. The difference is the error caused by selective availability and atmospheric distortion. The base station broadcasts the correction terms to mobile units. By applying the correction, the mobile units can reduce their errors.The accuracy of DGPS is on the order of a few meters.
117 Carrier Phase GPSIn carrier phase systems, the base station and the mobile units watch both the broadcast time code, and the actual waveforms of the carriers. By counting waveforms, they can synchronize their positions with each other to a fraction of a wavelength.A good carrier-phase system, with good conditions, can achieve accuracies of 2 cm or better.
118 GPS DifficultiesGPS requires a clear view of at least 4 satellites. For aircraft applications, or in flat, open terrain, this is not a problem.In mountainous terrain, or in urban canyons, GPS signals can be blocked or (worse) can reflect from tall objects and cause mistaken readings.Carrier-phase GPS is very sensitive to losing lock on the satellites, and can become confused even going under a large road sign.
119 Bottom line on GPS GPS is very useful for many applications. It is not yet 100% reliable, so is not ready for control applications.Research continues on filling in gaps in GPS coverage, and integrating GPS with other sensors, so there is hope for the future.
120 MapsAccurate position is not useful unless combined with accurate maps.The first generation of digital maps were produced from paper maps, and therefore are no more accurate than the paper products. Typical quoted accuracies are 14 meters. This is sufficient for in-vehicle navigation systems; until more sophisticated uses arise, there is little market demand for high accuracy.The next generations of maps will be produced directly from aerial photos and verified by driving selected routes with accurate GPS, so the accuracies will improve.To be completely useful, maps should have additional information, such as design speed of curves, grade of slopes, etc. This would aid e.g. in warning drivers of excessive speed when entering a curve.
121 5.3 InertialInertial sensing measures acceleration, then integrates acceleration to give velocity and again to give position.Since position is doubly-integrated, small errors in acceleration build up rapidly.Inertial measurement is good for sensing braking forces or for comparing wheel speed with ground speed and calculating slip during braking.High-precision inertial navigation is not yet affordable for the automotive market.Inertial measurement is useful to fill in short-term gaps in GPS or other measurements.
122 5.4 Other sensors“Dead reckoning” uses estimates of distance travelled and direction of travel.Odometry uses wheel encoders to measure distance traveled. It is susceptible to errors due to tire slip, incorrect estimates of wheel circumference due to changes in tire inflation, etc. Road Rally enthusiasts can calibrate their odometry to 0.1%; this is not practical for most vehicles.Standard compasses are affected by nearby metallic objects, such as bridges or buildings.
123 More SensorsImage correlators directly measure vehicle motion by watching the ground move by under the vehicle. These systems are accurate to better than 0.1%Doppler radar is used in precision agriculture applications, where it is important to measure the speed of farm equipment even with significant tire slip.
124 Section 5 Questions:Why can’t you just use a magnetic compass for heading?What’s the cheapest GPS unit you can find on the web?Why would Japan have a higher market penetration of GPS and moving map displays than the US?
125 6 Predicting Braking Performance Braking performance is key to setting many parameters in automated control and in driver warning systems.To set safe following distance, ideally the system should know its own braking capability; the braking capability of the lead car; and the reaction time of the automated system or of theBraking performance of vehicles on identical roadways can vary by a factor of 4
126 6.1 Basic formulasThe basic formulas for the time and distance required to bring a car to a stop areTime = reaction time + speed / decelerationDistance = speed * reaction time + ½ speed2 / decelerationTypical highway speeds are approximately 30 meters / second; typical reaction times range from 100 milliseconds for a fast computer-controlled sensor and brake actuator, to up to 2 seconds for a human driver. The dominant unknown factor is deceleration, or braking performance.
127 6.2 Wheel speeds and slipTypical force vs. slip curve. As the brakes are applied, the tires begin to slip, which results in deceleration force. As the slip increases, the force increases to some maximum. After that point, the wheels begin to lock and skid, and the braking force decreases. Note that the curves for wet and dry pavement start off very close to each other, but reach different peaks. This means that gently tapping the brakes is not enough to tell surface type, and therefore it is difficult to predict maximum braking performance without attempting hard braking.Force (g)Slip (%)Dry surfaceWet surface
128 6.3 Surface condition sensing Several methods have been attempted to sense current surface conditions:infrared spectrophotometers, tuned to detect differences between ice, water, and dry pavementmicrophones in the wheel wells listening for water splash soundsroadside mini-weather stations with sensors built into the pavementcareful instrumentation of all wheels of a car, looking for incipient slip on the driving wheelsNone of the methods is completely successful yet.
129 Section 6 Questions:Have you ever encountered “black ice” that you couldn’t tell was there?Calculate stopping distance for the following parameters:Truck with 1.0 sec reaction time and 0.3 g brakingSedan with 1.0 sec reaction time and 0.7 g brakingSedan with sleepy driver, 1.5 sec reaction time and 0.7 g brakingSedan with poor brakes, 1.0 sec reaction and 0.5 g brakingSports car with professional driver, 0.5 sec and 1.0 gWhich factors dominate stopping distance?
130 7 ReliabilityReliability engineering in intelligent vehicles is difficult. Several characteristics of automobiles are much different than, e.g., aircraft:Cost sensitivity: Usual practices that involve triplex redundancy of critical components may not be affordable in automobiles.Equipment used until end-of-life: In most safety- critical tasks, preventive maintenance schedules call for replacing electronics before the end of their design life. In the automotive environment, many components are never replaced until they fail.
131 More ReliabilityOperation in uncontrolled environment: Vehicles operate in harsh environments, with relatively unskilled and untrained operators.Very large scale of deployment: An extremely improbable event, one that occurs once in 109 hours, would cause one failure in 73 years in the US commercial air fleet. That same probability would cause a failure once every 4.5 days in the US automotive fleet, due to the much higher number of vehicles. Even though the risk to a passenger might be the same in both cases, the public perception of risk could be much higher for cars.
132 7.1 RedundancyDuplex redundancy refers to having two copies of a subsystem (e.g. computer). If a failure is detected in one system, the other can be used.Triplex redundancy has three copies. for computers, the output of all three can be compared, and the majority wins; this provides automatic detection and correction of single errors.Heterogeneous redundancy refers to doing the same function with different means. For instance, if a steering actuator fails on an automated vehicle, some steering authority is available by differentially applying the right or left brakes.
133 7.2 System-level solutions System level solutions build safety into the system by considering the entire system. In automated highways, the California PATH approach of Platoons is designed to mitigate the effects of an (unlikely) crash by having vehicles so closely spaced that any collision would be at a small relative velocity.
134 Questions:How reliable is your car? Your computer? Would you trust your life to them?Describe heterogeneous redundancy, and give an example.
135 8 Emerging technologies A number of other technologies are being developed that will support intelligent vehicles.Some, such as electronic controls, are being developed for other purposes (e.g. handling), but will be useful for intelligent vehicles.As drivers become more accustomed to electronics in vehicles, prices will fall, consumer acceptance will increase, and the pace of adoption of new technology could accelerate.
136 8.1 ControlCurrent IVI applications are focused on driver assistance rather than vehicle control; nevertheless, partial and full automation will eventually be important.A wide variety of standard and advanced controls techniques are being applied to road vehiclesVehicles to date have been designed for human control, not automated control. For example, current steering system geometry is designed for “good handling”, i.e. predictable response for humans. The underlying hardware may need to be modified for optimal automatic control.
137 DifficultiesAutomated control is especially difficult in some situations:Emergency maneuvers: Control systems optimized for smooth performance at cruise will not work for abrupt maneuvers in emergency situations.Equipment failure: Special controllers need to be designed to cope with tire blowout or loss of power brakes or power steering.Heavy vehicles: The load, and the distribution of the load, vary much more for a heavy truck than for a passenger car. Truck controllers need to be much more adaptable than light vehicle controllers.
138 More DifficultiesLow speeds: Engine and transmission dynamics are hardest to model at slow speeds. Applications such as automated snow plows or semi-automated busses will require careful throttle control design.Low-friction surfaces: As addressed above, it is difficult to predict the effective coefficient of friction on a particular road surface. This affects not only braking performance but also the design of throttle and steering controllers.
139 8.2 ActuationFull or partial automation will require actuators, i.e. computer-controlled motors that can move the throttle, brake, and steering.The state of the art is rapidly improving: vehicles are available on the market with electronic fuel injection, electronic power steering, and electronic power brakes, all driven by performance and weight improvements for manually-driven cars. This makes it much easier to add computer control.Special-purpose actuators will still be needed in some applications, such as quick-response throttles for closely-spaced platoons of cars.
140 8.3 Driver conditionIt is important to assess driver alertness, both in a drowsy driver warning system, and in an automated system that is preparing to return control to the driver.Alertness can be sensed indirectly, by watching lane-keeping performance; or directly, by watching for eye blink rate and closure.
141 PercloseMeasuring percentage of time eyes are closed. This system illuminates the face with two IR wavelengths, one of which reflects from the retina. Subtracting the images will create a blank image (if the eyes are closed) or an image with two bright spots (if the eyes are open).Top left: image with retinal reflectionsTop right: no retinal reflectionsBottom left: difference image, note two bright dots for reflections
142 8.4 CommunicationsInfrastructure-based ITS projects are building roadway-to-vehicle communications for traffic and routing information.Dedicated Short Range Communication (DSRC) is being developed for warning of local conditions, such as ice, sharp curves, changes in speed limit, or stopped traffic out of sight around a bend.Vehicle-vehicle communications will be increasingly important for collision warning systems. The lead vehicle can communicate speed, braking, intent to change lanes, traffic status ahead, etc.In the platoon version of full automation, vehicles need to communicate with low latency, e.g. 20 times / second. This creates interesting research questions on creating local nets, on managing both inter- and intra-platoon communication, and on reliable communications in urban canyons and other difficult environments.
143 Communications Technologies Most communications schemes rely on radio, using a variety of bands.Schemes currently under research include:modulating the radar reflectivity of a surface, so radar-equipped trailing vehicles can get information as well as rangepowering a transponder with radar energy, again to communicate to a following radar-equipped vehiclemodulating LED brake lights so trailing vehicles equipped with detectors tuned to that particular wavelength can pick up information
144 Section 8 Questions: What makes vehicle control difficult? What makes communications difficult?
145 9 Sensor-friendly roadways and vehicles On-board sensing would work better if the environment were designed for sensing.Current roadways have significant variability (Bott’s dots, painted lines, thermoplastic stripes, etc).Current roadways have many objects that cause radar “clutter” (returns from objects that are not of interest), such as guard rails, roadside signs, bridge overpasses
146 9.2 Path prediction“Path Prediction” refers to estimating where the vehicle’s current lane goes, so an obstacle detection system knows where to look for stopped cars and other obstructions.Sensor friendly systems will improve path prediction by enhancing lane visibility.They will also improve obstacle detection by reducing clutter from off-road objects and increasing returns from other vehicles.
147 9.1 Dealing with clutter Clutter can be: Moved: Sign posts could be placed farther from the travel lanes.Masked: Radar Absorbing Material (RAM) could be applied to objects such as bridge abutmentsMarked: Polarizing reflectors, or filters that absorb only a narrow frequency band, could be applied to large objects. They would then still appear in a radar return, but would be marked in the radar signal as known fixed objectsMapped: The locations and signatures of fixed objects could be stored in a map, and provided to individual vehicles.
148 Sensor-Friendly Features Besides clutter suppression, sensor-friendly systems can improve visibility:Lane markings can be improved with pigments that reflect radar or near-visible wavelengthsVehicle visibility can be improved with radar reflectors, either fixed or modulated for communications
149 Microstrip patch retroreflector antenna Without a stable aiming point, radar-based vehicle tracking is difficult. Lead vehicle appears to wanderOSU patch retro-reflector provides a distinctive, wideband, vehicle marker. Compact form factor is easily attached to vehicles.AngleAngle-invariant return provides aim-point stability.Wide bandwidth permits good range resolution.Freq. [GHz]
150 Section 9 Questions: List four ways of handling clutter. How can sensor-friendly features help with the path prediction problem?
151 10 Comments and conclusions Many of these technologies work best in combination: e.g. lane tracking aids both lane departure and rear-end warnings.Many of these work best with some infrastructure assistance: e.g. lane departure systems need at least good road delineation, and can take advantage of better markings.In many cases, the technology is approaching readiness; the remaining obstacles to deployment are legal and institutional.
152 AcknowledgementsMy thanks to the CMU Navlab group, and the Automated Highways Tech Team. Much of the research described here was supported by NHTSA and FHWA.Photo credits: thanks to Liang Zhao (stereo), Todd Williamson (stereo), Richard Grace (perclose), Gerald Stone and California PATH (magnets and snowplow), Bill Stone and California PATH (platoon), Colin Ashmore (buried wire), Umit Ozguner, Jon Young, and Brian A. Baertlein (radar reflective surfaces and microstip antenna), K2T Inc (ladar), Dirk Langer (radar), Parag Batavia (driver differences chart), Assistware Technologies (vision system) and Todd Jochem (bus). All pictures copyright by their owners; reproduced by permission.
154 UNIT-V-Vehicle network systems A primary purpose of automotive networked systems is to reduce the amount of wire that is used.15 kg of wire can be eliminated by the use of networking on a single vehicleFor example, systems such as traction control and engine management that make use of the engine speed sensor can make use of a single engine speed sensor by placing the reading on the data bus as required (i.e. the sensor is multiplexed), instead of having a separate sensor for each system. Similar economies are possible with a range of systems and this can result in a reduction in the total number of sensors on a vehicle.
156 There are several areas of vehicle control where data buses can be used to advantage. Some of these, such as lighting and instrumentation systems, can operate at fairly low speeds of data transfer, e.g bits per second. Others such as engine and transmission control require much higher speeds, probably bits per second, and these are said to operate in ‘real time’. To cater for these differing requirements the Society of Automotive Engineers (SAE) recommends three classes known as Class A, Class B and Class C.Class A. Low speed data transmission, up to bits/s, used for body wiring such as exterior lamps etc.Class B. Medium speed data transmission, bits/s up to bits/s, used for vehicle speed controls, instrumentation, emission control etc.Class C. High speed (real time) data transmission, bits/s up to bits/s (or more), used for brake by wire, traction and stability control etc.
158 The system comprises four subsystems. 1. The Lucas EPIC (Electronically-programmed injection control ) system.2. The Lucas flow valve anti-lock braking system.3. A clutch management system (CMS). This replaces the normal clutch pedal linkage with a computer controlled, hydraulically actuated system.4. Adjustable rate dampers are fitted. The damping rate is adjusted by the computer (ECM) to provide optimum damping during rapid steering input, braking and acceleration.
159 Master controllerEach of the above systems has a CAN interface, which permits them to be connected to the master controller. A network of twisted pair cables connects each of the above subsystems to the master controller and this allows the transfer of sensor information and control signals with reliable safety checking and minimal wiring. The master controller thus receives information from the subsystems via the CAN bus (cables).The master controller is directly connected to a switch pack (for cruise and damper control), two accelerometers and an inclinometer (for hill detection). This means that the master controller ‘knows’ the complete status of the vehicle and the driver’s requirements. The vehicle status information is processed by the master controller to generate control signals which are sent to the subsystems. These “Master” signals over-ride the normal operation of the subsystems to operate another tier of systems known as the integrated systems. In the event of CAN failure, each subsystem defaults to stand-alone operation.
160 The integrated systems The four subsystems, i.e. EPIC, ABS, damper control and clutch management, are integrated (made to work together) to provide seven additional functions of vehicle management. The computer programs that do this controlling are executed by the master controller. These seven integrated systems are:traction and stability controlcruise controlpower shiftengine drag controlhill holddamper controlcentralized diagnostics.
161 These use one or more serial networks to achieve the following objectives: • Reduction of the number of wires within the wiring looms of a vehicle;• Improved system failure diagnosis;• Distributed control centers in or off the vehicle which can talk and interact with one another;• Improved manufacturing techniques and increased reliability due to a reduction in the number of wires and connectors
163 Space Segment: The space segment of GPS consists of 24 satellites fielded in nearly circular orbits with a radius of 26,560 km, period of nearly 12 hours and stationary ground tracks. The satellites are arranged in six orbital planes inclined at 55° relative to the equatorial plane, with four satellites distributed in each orbit. With this constellation, almost all users with a clear view of the sky have a minimum of four satellites in view. Each satellite receives and stores information from the control segment; maintain very accurate time through on board precise atomic clocks.Control Segment: The control segment of GPS consists of five tracking stations distributed around the earth of which one, located in Colorado Springs, is a Master Control Station. The control segment tracks all satellites, ensures they are operating properly and computes their position in space. The computed positions of the satellites are used to predict where the satellite will be later in time. These parameters are uploaded from the control segment to the satellites and referred to as broadcast ephemeredes.User Segment: The GPS user segment consists of the GPS receivers and the user community. Almost all GPS tracking equipment have the same basic components: an antenna, an RF (Radio Frequency) sections a microprocessor, a control and display unit (CDU), recording device and a power supply. Usually all component, with the exception of the antenna, are grouped together and referred to as a receiver. GPS receivers convert SV signals into position, velocity, and time estimates. Four satellites are required to compute the four dimensions of X, Y, Z (position) and time. GPS receivers are used for navigation, positioning, time dissemination, and other research.GPS Signals: Each GPS satellite continuously broadcasts ranging signals containing wealth of information. The information contained in GPS signals includes the carrier frequencies (L1 & L2), codes (coarse acquisition [C/A] & Precise [P]) and the navigational message. These allow users to measure their pseudo ranges and to estimate their positions in passive, listen only mode.
164 Basic principle of GPS.The basic principle of determining the position by using GPS satellites is based on measurement of distances from the point of observations to the satellite. This is done by comparing the reading of transmitter antenna time with the receiver antenna time. It cannot be assumed that the two clocks will be strictly in synchronization since the clocks used in the present type of receivers are quartz clocks to reduce the cost of the receiver. The observed signal time will have a systematic synchronization error. Since the measured range has got this systematic error in it, the computed distances will also be biased, and therefore, these are called pseudo-range. To compute the position based on this pseudo-range, the error due to time bias has to be corrected and therefore, this is also taken as an unknown and determined before deriving the true range. As we know from the simple formulate of distance computation thatR = Ö ((X – Xi) 2 + (Y –Yi) 2 + (Z –Zi)) 2Where X, Y & Z are the co-ordinate of the station, therefore unknown and Xi, Yi & Zi are the co-ordinates of the satellite, which is broadcast information.To find the true range the time bias t is also has to be considering, thereforeR = ((X – Xi) 2 + (Y –Yi) 2 + (Z –Zi)) 2 + TCWhere C is the velocity of light, R is pseudo-range and T is travel time.Now in this equation, there are four unknown therefore, to solve this at least 4 satellites will have to be observed. The minimum requirement in this case isTo know the co-ordinates of satellite antennaTo know the satellite time at the time of emission of the signalMinimum 4 satellites, 4th one required to determine the time bias.
169 1.Location Verification 2.Route Analysis 3.Mobile Navigation GPS APPLICATIONS:MOVING BEYOND AUTOMATIC VEHICLE LOCATION TO FULL ENTERPRISE INTEGRATION1.Location Verification2.Route Analysis3.Mobile Navigation
170 Vehicle Navigation System (VNS) A Vehicle Navigation System (VNS) is a driving assist system that combines digital maps, vehicle position, route optimization, route guidance, and other technologies.It is one of the most important components of advanced traffic and traveler information systems in Intelligent Transportation Systems (ITS) and is an important application and research field in Geographic Information Systems for Transportation (GIS-T).
171 A Framework for Network based VNS A framework for network based VNS is illustrated in Figure. Four components are encompassed in the proposed framework, namely, the content supported layer, the service center, the communication layer, and navigation terminals.The Content Supported LayerThe Service CenterThe Communication LayerNavigation Terminals
175 MESSAGE – Mobile Environmental Sensing System Across a Grid Environment Heterogeneous fixed and mobile sensors on infrastructure, vehicles and peopleSensors communicate via wireless and wired networksPositioning via GPS + wireless rangingIntegration of processing along the data pathMultiple application studies in different local contextsMESSAGE focusses on pollution but could be any form of dataProject shows a range of new technologies and, most importantly, how they can come together to create a very different data environmentSensing: Developing a new pollution sensor (GUSTO) into a form that can be mounted on vehicleUsing existing sensors combined with location, local processing and wireless networking<Show Mote> Pollution temp noise, count payloadGPS location in acquiescent modeZigbee (802.15) Wireless Sensor comms – peer to peer to “super peer” with GPRS linkBattery powered with anticipated lifetime of 1 yearLinks to GRID computing environment – use of internet to partition data processing across available computing resourcesResources may not be owned but dynamically called up through a service provider.Links to other data, traffic and weatherWill be able to interact with UTMC databasesMESSAGE shows that the technical environment is very rich but and evolving rapidlyCamden Town, LondonProcessing175
177 Sensor Network for Traffic Accident Detection and Notification Designing a sensor network that will inform incoming vehicles of these accidents/congestions well in advance so that the drivers of the vehicles may take appropriate actions.Present traffic monitoring systems use expensive devices such as video cameras, magnetic loop detectors that are expensive, difficult to deploy and not very scalableVehicular network solutions differ greatly in their design, protocol and implementation. As such a vehicle that uses one vehicular solution will not be able to communicate with other vehicles along the road unless they all implement the same solution. This can be a very grave problem
178 ChallengesSensors are very resource-constrained: power, memory, computation.- minimizes resource consumption.Vehicles on highways usually travel at high speeds between 65 to 70 mph. They need to be informed of the accident/congestion up ahead as quickly as possible before it is too late.- designed to sense accidents as soon as they occur and communicate this information to the rest of the relevant network very quickly.Users are often unwilling to learn (or just plain lazy) how to use new systems.- requires minimal interaction with the user and will be perceived as very uncomplicated by the user
179 Sensor Network for Traffic Accident Detection and Notification 1. It integrates an ad-hoc sensor network with a vehicular network to create an effective, energy-efficient traffic accident detection and notification system without all of the problems mentioned above.2. BY introduce the new concept of Virtual Group and Watchdog Group of sensors that will track the motion of a car and will greatly increase the reliability of the network while decreasing the energy-consumption of the sensors.
180 Sensors placed along-side highway roads will detect a traffic accident and will communicate this message to sensors further down the road, which will in turn notify incoming vehicles of the accident up-ahead.Assumptions:1. Highways2. Unidirectional traffic3. Vehicles are equipped with bi-directional radios that can do two things:i. Transmit alarm message when accident occurs.ii. Receive notification of accident broadcast by sensor.
181 1. Watchdog Groups: Sensors are divided into groups of n each, say three sensors S1, S2 and S3. When there is no traffic on the highway, in each group one sensor (S1) will be on for a certain fixed period of time while the other two (S2 and S3) remain off. After this fixed period S2 will wake up and S1 and S3 will sleep and so on. Synchronized timers will be used to control the sleep/wake cycle of sensors in each group.
182 Watchdog Group n = 3 Watchdog group 1 Watchdog group 2 asleep awake
183 2. Virtual Groups: Sensors are again divided into groups of n each 2. Virtual Groups: Sensors are again divided into groups of n each. But in this case, the group is not “fixed” but rather “moves” along the highway following the motion of the vehicle being sensed.
185 Normal Operation:- Car approaches junction.- Special sensor (always on) at junction detects car, alerts closest neighboring sensor, S1.- S1 will alert S2, S2 will alert S3. Now S1, S2 and S3 will be awake (Virtual Group 1).
187 Accident Occurs:Detection of accident: Air-bag trigger in cars that detects the accident will trigger the car radio to broadcast accident alarm message.uses air-bag triggers because:i. It provides greater accuracy in detecting actual accidents and not just false alarms.ii. It simplifies the work of the sensors (lesser sensing, lesser computation).ii. Air-bag triggers are already present in vehicles; does not require additional add-ons.The sensor closest to the car that receives the alarm message will wake up the sensors behind it (if they are already not awake).The sensor will then broadcast an Event Notification message with the TTL field set to a fixed value so that the message does not propagate further than is required.
189 Special Cases 1. Very long stretch of highway with no exits: - Accident occurs.- Vehicle must be informed before it leaves all exits behind.To relay message from one sensor to next until it reaches car will be too slow.Use access point to convey message directly to sensor closest to next-to-last exit (as far in advance as feasible).Sensor will inform vehicle before it reaches last exit and looses all chances to re-route.
190 Very long stretch of road w/no exit Long stretch of road with no exit
191 Special Cases contd. 2. Backup Case - In case of sensor failure: Normally sensors communicate with each other on a per-hop basis.If a sensor goes down, its immediately neighboring sensors on both sides will increase their sensing and communication range.The increase in power consumption is a small price to pay for greater reliability.