Global Positioning System Or, Where the heck am I ???

Tri-County Ground Search and Rescue Agenda 09:00 – 10:00 Maps 10:00 – 10:15 Break 10:15 – 12:00 GPS 12:00 – 12:30 Lunch 12:30 – 13:15 GPS continued 13:15 – 14:00 Enter GPS waypoints 14:00 - ? Travel to Waypoints

Tri-County Ground Search and Rescue First things first! Need to know about maps and geographic coordinates. We will use the NB Atlas as our main map reference.

Tri-County Ground Search and Rescue Prime Meridian/Equator

Tri-County Ground Search and Rescue Lines of Lat/Long

Tri-County Ground Search and Rescue Degrees, Minutes, Seconds 60 minutes in 1 degree 60 seconds in 1 minute 360 degrees in a circle, and the earth Degree° Minute’ Second”

Tri-County Ground Search and Rescue Example – converted 40° 20’ 50” To decimal minutes: 40° 20’ 50 / 60 ’ = 40° 20.83’ To decimal degrees: / 60 ° = °

Tri-County Ground Search and Rescue First go up, then go left! To get latitude read up the right side of the map. To get longitude, read leftward from the lower right corner.

Tri-County Ground Search and Rescue Longitude and Time Moncton: 46° 06’ 57” N / 64° 48’ 11” W It is 64° west of Greenwich (0°) Every 15° of longitude = 1 hour from Greenwich, England So, at 64° W, we are 4 hours behind Greenwich time

Tri-County Ground Search and Rescue Latitudes/Longitudes for NB 69°68°67°66°65°64° 69°68°67°66°65°64° 45° 46° 47° 48° 45° 46° 47° 48°

Tri-County Ground Search and Rescue Now let’s find?? 1. What’s at: N 47° 00’ W 065° 30’ 2. What place is within 2km of grid ref: N 46° 03’ W 064° 18’ 3. Find the co-ordinates for a place called: MacDougall Reference: for NB Atlas 12.5mm = 1 minute = 1.86km (latitude) 8.6mm = 1 minute = 1.26km (longitude)

Tri-County Ground Search and Rescue Resolution of Measurement 46° 13’ 21.9 ” 1 decimal second = 3m 1 second = 31m 1 minute = 1.85km 1 degree = 111km ° (5 decimal places) 1 m 10 m 100 m 1,000 m 10,000 m Actual distance differs when stating latitude or longitude.

Now on to GPS

Tri-County Ground Search and Rescue What is the Global Positioning System? Space-based, worldwide radio- navigation system. Constellation of 24 satellites(plus spares) in geosynchronous orbits, and a network of ground control stations. Free access, highly accurate positioning data is available to GPS receivers anywhere in the world. Developed and owned by the US Dept of Defence.

Tri-County Ground Search and Rescue Many Different Receivers Garmin, Magellan, Trimble etc. Handheld, permanent mounted in vehicles.

Tri-County Ground Search and Rescue How Does GPS work? Satellites travel in predictable paths. Radio frequency signals travel at a predictable speed. GPS receivers are programmed with the general positions of the satellite constellations, and their identifier data.

Tri-County Ground Search and Rescue How Does GPS work? cont’d Satellites constantly transmit a stream of coded signals at low power. Signals include timing data that receivers can compare to predicted timing data programmed in their memory. By determining the time difference in the predicted vs. the actual signals, and multiplying by the speed of light, a distance to a satellite can be determined.

Tri-County Ground Search and Rescue How Does GPS work? cont’d The distance to: 3 satellites is known—a 2- dimensional position can be determined. 4 satellites is known—a 3- dimensional position can be determined. Note: this is what you always want to have. More satellites—more accurate position.

Tri-County Ground Search and Rescue A Little Aside! Some Satellite Facts There are some 2,500 satellites orbiting the earth There are over 8,000 foreign objects orbiting the earth consisting of items like nose cones and panels from old satellites Interactive Site: me/jtrack/3d/JTrack3d.html

Tri-County Ground Search and Rescue How Accurate is it? Depends on the type of receiver. Average handheld receive: 10 to 15 meters Graphic of person standing in a 10 m circle

Tri-County Ground Search and Rescue What can a GPS do for you? Provide your current position— anywhere, anytime. Display a line of past positions (a track) and store them. Store a large number of known locations—waypoints. Give you real-time estimates on your travel progress.

Tri-County Ground Search and Rescue What the GPS will NOT do? Will not : Give much useful data without a map. Replace map and compass. Necessarily give an accurate indication of magnetic north or current heading. Assist you in getting “home” unless you can tell it where home is. Be accurate over short distances—less than 15m. Be of any use without batteries or a clear view of sky.

Tri-County Ground Search and Rescue Hand-Held GPS Units Number and ID of satellites received. Indication of signal quality. Estimated position accuracy. All have basic satellite reception screens

Tri-County Ground Search and Rescue Hand-Held GPS Units All have system and navigation set-up screens

Tri-County Ground Search and Rescue Hand-Held GPS Units Set-up position format and map datum to match paper map. If not using same map datum—can be out 100’s of meters.

Tri-County Ground Search and Rescue The Difference in Position Entered: N W st under WGS84/true north 2 nd under NAD27/grid north Difference in position is approx. 60m

Tri-County Ground Search and Rescue True Magnetic Grid In our area the difference between True and Magnetic is approx. 19°W Hand-Held GPS Units Which way is north?

Tri-County Ground Search and Rescue Hand-Held GPS Units All have screens to set waypoints.

Tri-County Ground Search and Rescue Hand-Held GPS Units Once you have a waypoint, you can navigate to it using the “Goto” command. Normally directs you in a straight line—”as- the-crow-flies”.

Tri-County Ground Search and Rescue Hand-Held GPS Units Navigating to a waypoint: Gives compass bearing, Distance to point, Estimated time to get there, based on current rate of travel.

Tri-County Ground Search and Rescue Be Careful with “GOTO” GPS tells you to go 3.8km at a bearing of 248° true. Have to look at the map to see what terrain is between the “start” and “end” position. Need to plan your route!

Tri-County Ground Search and Rescue A Point About Accuracy Training exercise, Irishtown Nature Park: 28 Aug 2004, 9 to 11pm

Tri-County Ground Search and Rescue Position Formats Position: Map Datum: North Ref: Position: Decimal degrees Map Datum: WGS84 North Ref:True Position: Degrees, dec. minutes Map Datum: WGS84 North Ref:True Position: MGRS Map Datum: NAD27/WGS84 North Ref:Grid

Tri-County Ground Search and Rescue Tracks & Waypoints

Tri-County Ground Search and Rescue Always Remember! 1. Allow unit to lock on to 4 or more satellites. 2. ALWAYS save your starting point as a waypoint (let’s call it “home”). 3. Clear the track log before starting a task. 4. Set the odometer/trip to zero. 5. Keep extra batteries and keep GPS warm. 6. Does NOT replace a compass. 7. Always check/set (according to map reference): Position format Map datum North reference

Tri-County Ground Search and Rescue Electronic Maps Mapquest – find latitude/longitude ong&cat=&address=&city=&state=&zipcode= Google Earth: Map Source: (from Garmin) Topographic maps Metro Guide maps Service NB – NB Atlas:

Tri-County Ground Search and Rescue Downloading/Uploading Can download/upload: Waypoints Tracks Routes to/from GPS units into mapping software

Tri-County Ground Search and Rescue Hands-On! Now let’s put some waypoints into our GPS and see what we can find!

Tri-County Ground Search and Rescue Exercise From Parking Lot WP1 - N46° 13’ 21.9” W64° 30’ 17.5” Travel By Car WP2 - N46° 13’ 53.9” W64° 30’ 34.2” WP3 - N46° 14’ 24.8” W64° 30’ 28.6” WP4 - N46° 12’ 16.6” W64° 29’ 12.7” WP5 - N46° 10’ 47.0” W64° 28’ 51.0”

Tri-County Ground Search and Rescue Reference Material Two good manuals: GPSGuideforBeginners_Manual.pdf UsingaGarminGPSwithPaperLandMaps_Manual.pdf US Coast Guard service interruptions Geocache web site: Topographic map information: