Concepts of operation Design of UAV Systems

Name: Concepts of operation Design of UAV Systems
Uploaded: 2017-07-17T16:43:19+00:00
Duration: PTM45S23
Channel: Marvin Carr
Description: Concepts of operation Design of UAV Systems

Concepts of operation Design of UAV Systems
c LM Corporation Lesson objective – to discuss Concepts of operation including … Basic concepts Area coverage Combat air patrol Response time Example problem 5-1

Concept of operations (ConOps) definition(s)
Design of UAV Systems Concepts of operation c LM Corporation Review Concept of operations (ConOps) definition(s) How something is used or operated Typically associated with military systems but also applicable to commercial systems. The name of a document used to describe how a system should be operated, e.g. …describes the approach to deployment, employment, and operation of a new or upgraded system or capability being advocated to meet identified tasks or missions. CONOPS are not limited to single systems but can rely on other systems and organizations, as required. We will use the first definition – determining how something is used or operated vs. a ConOps document 5-2

No physical constraints Size, endurance, maneuvers, etc.
Design of UAV Systems Concepts of operation c LM Corporation How UAVs are used Although it is tempting to consider UAVs as straight-forward replacements for manned aircraft, this does not take advantage of their inherent capabilities No physical constraints Size, endurance, maneuvers, etc. No mental/physiological constraints Memory, errors, training, etc. No work rules, arguments, sick days or vacations Fewer survivability concerns But they also have inherent limitations (today) On board intelligence is either simple or easily spoofed Off board intelligence is bandwidth limited UAV missions, therefore, tend to require or involve Small size Long endurance, high altitude or physiological constraints Simple rules of engagement and ConOps High risk Continuous operations 5-3

Examples Design of UAV Systems HeliWing
Concepts of operation c LM Corporation Examples HeliWing Helios – Altitude record holder (air breathing aircraft) Global Hawk - 38 hour endurance MicroStar Lockheed Martin Aeronautics Company Tom Cat Predator A – Hellfire missiles DarkStar 5-4

Preplanned missions are scheduled well in advance
Design of UAV Systems Concepts of operation c LM Corporation Air operations Whether, manned or unmanned, there are two general types of missions, preplanned and on-demand Preplanned missions are scheduled well in advance On demand missions can be launched quickly (within minutes) if an aircraft is ready and a crew is on site - The military does “strip alert” and “standby alert” missions - Strip alert pilots are in the cockpit, ready to go There are two basic types of loiter missions - standoff and over flight (or “penetration”) Standoff missions generally are flown when over flight is not allowed or is considered too risky Exceptions are missions flown with sensors that do not look straight down such as synthetic aperture radar (SAR) Although missions can takeoff from one base and land at another, typically we design for fixed base operations 5-5

Typical mission profile
Design of UAV Systems Concepts of operation c LM Corporation Typical mission profile 0 Engine start 1 Start taxi 2 Start takeoff 3 Initial climb 4 Initial cruise 5 Start pre-strike refuel 6 End pre-strike refuel Start cruise 7 Start loiter 8 End loiter, start cruise 9 Start ingress 10 Combat 11 Weapon release 12 Turn 13 Start egress 14 End egress, start cruise 15 Start post-strike refuel 16 End post-strike refuel 17 End cruise 18 Start hold 19 End hold Notation Border - Standoff Loiter/Penetrate Penetrate/Loiter 2 3 4 5 6 7 8 10 11 12 13 15 16 17 18 19 Standoff - Distance from loiter or combat to border (+/-) Standback - Distance from refuel to border Ingress - To target at penetration speed Egress - From target at penetration speed Range (Rge) = 2*Radius(R) Terminology 1 14 9 5-6

Target area coverage from base
Design of UAV Systems Concepts of operation c LM Corporation Target area coverage from base Target area Rp Target coverage Area (Ap) Base Db p Xmax Platform only Ap = (p)*Rp^2 -Tan(p)*Db^2 (10.1) where p (radians) = ArcCos(Db/Rp) (10.2) Rp = Platform radius Db = Distance to border 5-7

Coverage area example Design of UAV Systems For Db = 250 nm
Concepts of operation c LM Corporation Coverage area example Rp Rp = 500 nm Target coverage Area (Ap) Base Db p Int’l waters For Db = 250 nm Rp = 500 nm Platform only coverage p = ArcCos(250/500) = 60 deg Xmax = 433 nm Ap = (60*/180)*500^2-250*433 = nm^2 5-8

UAV vs. manned operations
Design of UAV Systems Lesson Concepts of operation c LM Corporation UAV vs. manned operations Military UAV missions can be planned and operated like manned aircraft if they stay in military air space Flights can be scheduled one day and flown the next or, in time critical situations, launched on demand But manned aircraft operations sometimes cease during UAV launch and recovery operations If UAVs have to fly in non-military airspace, flights may have to be planned days to weeks in advance - To allow time for coordination with local civilian air traffic control and VFR traffic Most manned military missions are for training - Pilots need proficiency flying (20+ hrs/month) Reconnaissance UAVs operate differently, after initial training, most missions are operational UCAVs are more different, plans are to keep most in storage until needed for combat (train on simulators) 5-9

Some sensors are fixed (called “staring” sensors)
Design of UAV Systems Concepts of operation c LM Corporation Sensor coverage Some sensors are fixed (called “staring” sensors) - Photo reconnaissance cameras are often fixed - Staring sensors also used for self defense Others are essentially fixed (e.g. “line-scanners”) - The sensor rotates, target coverage is in thin strips which can be integrated over time to form an “image” - They can provide horizon-to-horizon coverage Some sensors are fixed in one direction and can be “slewed” in another (e.g. side looking radar) - Horizontal coverage controlled by vehicle flight path, elevation controlled independently Other sensors can be slewed in azimuth and elevation but only within limits (e.g. SAR) The most flexible sensors are fully “gimbaled”in azimuth and elevation and can cover an entire hemisphere (or more) 5-10

There are a wide variety of weapons types, both powered and unpowered
Design of UAV Systems Concepts of operation c LM Corporation Weapon coverage There are a wide variety of weapons types, both powered and unpowered - Powered weapons can extend target coverage from a little (free fall bombs) to a lot (cruise missiles) Almost all weapons are launched forward - Sonabouys and parachute delivered weapons are exceptions Guided weapons can attack targets well off of the flight patch axis Some weapons can be aimed like sensors - Machine guns and grenade launchers Some future weapons will also be aimed Lasers 5-11

Manned military reconnaissance missions loiter over friendly territory
Design of UAV Systems Lesson Concepts of operation c LM Corporation Loiter missions Manned military reconnaissance missions loiter over friendly territory - Sensors can look into neighboring territory without endangering the crew (in general) Manned strike missions are flown both ways - Stealth aircraft are designed for over flight but they seldom loiter over hostile territory Unmanned military reconnaissance (and strike) missions are also flown both ways - Global Hawk is designed to loiter over friendly territory - Dark Star was stealthy and designed to fly over hostile territory (UCAV will also operate this way) - Predator is not a stealthy design but often loiters over hostile territory - It takes a calculated risk (and is sometimes lost) 5-12

Standoff vs. over flight
Design of UAV Systems Lesson Concepts of operation c LM Corporation Standoff vs. over flight Sensors - Sensors on penetrating platforms can look down and all around - Inherently, they can cover more target area than a standoff sensor Weapons - Weapons on penetrating platforms have the same advantages Border Penetrate Standoff Sensor Coverage Capability R R Standoff distance UAV Unusable sensor coverage Border 5-13

Plus many others and combinations thereof
Design of UAV Systems Lesson Concepts of operation c LM Corporation Loiter patterns Figure 8 Circle Search Racetrack Threat avoidance Elongated 8 Plus many others and combinations thereof 5-14

Search area coverage Design of UAV Systems Straight line coverage
Lesson Concepts of operation c LM Corporation Search area coverage Outside area Overlap Straight line coverage Area = SwathSpeedTime Equivalent range = Area/Swath Search pattern coverage KArea = SwathSpeedTime Typical factor (K) = 1.3? or 5-15

Combat Air Patrol (CAP)
Design of UAV Systems Lesson Concepts of operation c LM Corporation Combat Air Patrol (CAP) Target area coverage (and response time) from a CAP type mission is a bit complex and not well understood In this type mission, the air vehicle loiters over an area until it receives and order to observe or attack an area of interest Assumed to be at maximum fly-out distance Upon arrival over the target area, the air vehicle performs its mission and then returns to base The flight path, therefore, is triangular consisting of: - An outbound segment to the CAP location - Another segment to maximum distance - A third segment back to base Typically the CAP location is over friendly territory and we will call it a loiter/penetrate mission 5-16

Loiter/penetrate geometry - optional
Design of UAV Systems Concepts of operation c LM Corporation Loiter/penetrate geometry - optional Base Db Dso D1 D2min Loiter location D2max D3min Xmax Platform only Border D3max Note - Dso is negative here 2max Definitions D1+D2+D3 = 2*R - LED = 2R’ (10.7) where D3 = Distance back to base R = Mission radius LED = Loiter equivalent distance 2max = ArcCos(Dso/D2max) (10.8) From geometry D1+ D2min = D3max (10.9) (D1-Dso)^2+Xmax^2 = D3min^2 (10.10) Dso^2+Xmax^2 = D2max^2 therefore (D1+Dso)^2- D3min^2 = Dso^2-D2max^2 and D2max = [Dso^2-(D1-Dso)^2+(2R’-D1)^2] 2(2R’-D1) (10.11) Not optional 5-17

Solution approach Design of UAV Systems Platform only coverage
Concepts of operation c LM Corporation Solution approach Platform only coverage Define LED Solve for D2min (10.9) Solve for D2max (10.11) Solve for 2max (10.8) Solve for D3min (10.10) Numerically integrate sector area from 2 = 0 to 2max where 2 = 2max/n n = number of integration steps note D2' + = 2*R -LED - D1 - D3’ (10.12) and D3’ can be solved using the same approach used to solve for D2max Subtract triangular area defined by Dso, Xmax and D2max Optional topic D2max Base Db Dso D1 D2min D3' D2' Loiter location D3min x 2 Xmax 5-18

Platform coverage example
Design of UAV Systems Concepts of operation c LM Corporation Platform coverage example Solve for maximum area coverage (LED = 300nm) where R = 650nm Db = 250 nm Dso = -125nm Solution steps D2min = 375nm D2max = 410.7nm 2max = 72.3 deg D3min = nm Numerically integrate sector area from 2 = 0 to 72.3 deg (n=10) Sector area = sqnm Subtract triangular area defined by Dso, Xmax and D2max (48907sqnm) Total area = sqnm D2max Base Db Dso D1 D2min D3' D2' Loiter location D3min x 2 Xmax Optional topic 2max 5-19

Design of UAV Systems Approximate solution R = 650 nm LED = 300 nm
Concepts of operation c LM Corporation Approximate solution D2max Base Db Dso D1 D2min D3' D2' Loiter location D3min Xmax Circular segment approximation Radius = (D2Min+D2max)/2 Center at loiter location R = 650 nm LED = 300 nm Db = 250 nm Dso = -125nm therefore D2min = 375nm D2max = 410.7nm 2max = 72.3 deg D3min = nm Circular sector area (2 = 0 to 72.3 deg) Average radius = 393 nm Sector area = sqnm Subtract triangular area defined by Dso, Xmax and D2max (48907sqnm) Approximate area = sqnm (+4.5%) Optional topic 2max The approximation is valid for loiter penetrate only 5-20

But some ConOps require different metrics
Design of UAV Systems Concepts of operation c LM Corporation Figures of merit During pre-concept and conceptual design, simple figures of merit are typically used Examples: Operational time on station - Global Hawk goal = 24 hours at a distance of 1200 nm from base Target area coverage per unit time - Global Hawk wide area search goal = 40,000 sq.nm/day - With 10 km sensor swath width at 343 kts at 10% over lap (Area = SwathSpeed24 0.9) Number of targets per unit time - Global Hawk goal target coverage = Km x 2Km spot images/day But some ConOps require different metrics Increasingly the figure of merit of interest is area coverage within a given response time 5-21

- Put platform overhead, put sensor on target or put weapon on target
Design of UAV Systems Concepts of operation c LM Corporation Response time example Response time (Tr) - The time required to respond to a request or order such as: - Put platform overhead, put sensor on target or put weapon on target Platform response time On alert (pre-assigned) Tr = Tse+Ttto+Tcl+Tcr+Tpen where Tse = time to start engines (≈ 5 min) Ttto = time to taxi & takeoff (≈ 10 min) Tcl = time to climb = Dcl/Vcl Tcr = time to cruise = Db/Vcr-Tcl Tcr = time to penetrate = Dpe/Vpe On standby (not assigned) Tr = Tr+Tprep where Tprep = additional preparation times including Aircraft prep (1-2 hrs) Crew transit (2-4 hours) Mission planning (15-60 min) Flight plan coordination (45 min) ≈ Tr + 3 to 6 hrs minimum) 5-22

Sensors arrive on target before the platform (@ speed of light)
Design of UAV Systems Concepts of operation c LM Corporation Response time effects Sensors Sensors arrive on target before the platform speed of light) - Target coverage is increased by the range of the sensor at any given time Weapons If a weapon is faster than the platform - the weapon will arrive over target first and response time improves If the weapon is slower – coverage area may increase but at a slower response time 5-23

Figures of merit Design of UAV Systems
Concepts of operation c LM Corporation Figures of merit Platform only example For a specific missions with specific response time requirements, a calculation that includes all of the individual time increments and shows that the requirement can be met, will be the primary figure of merit. For more generalized missions, target coverage as a function of time, can be a good figure of merit - For example, Xsqnm target coverage within Y minutes Mission radius Border Base 5-24

Operating distance effects
Design of UAV Systems Lesson Concepts of operation c LM Corporation Operating distance effects The closer an air vehicle loiters to its target area, the more efficiently it can employ its sensors and the quicker it can respond to assignments or requests It does, however, reduce target area coverage - It is a simple matter of geometry for a vehicle with a fixed range or radius Example Base Loiter Border Radius = 500 nm 362 nm 438 nm 487 nm 463 nm 200 nm 50 nm Target coverage area 148K sqnm 130K sqnm Total mission radius = 650 nm LED = 300 nm 5-25

Concepts of operation Design of UAV Systems Next subject
Lesson Concepts of operation c LM Corporation Next subject Lesson objective – to discuss Concepts of operation including … Basic concepts Area coverage Combat air patrol Response time Example problem 5-26

Surveillance UAV - review
Design of UAV Systems Lesson Concepts of operation c LM Corporation Surveillance UAV - review Predator follow-on type Land based with 3000 foot paved runway - Mission : provide continuous day/night/all weather, near real time, monitoring of 200 x 200 nm area - Basing : within 100 nm of surveillance area Able to resolve range of 10m sqm moving targets to 10m and transmit ground moving target (GMT) data to base in 2 minutes - Able to provide positive identification of selected 0.5m x 0.5 m ground resolved distance (GRD or “resolution”) targets within 30 minutes of detection - Ignore survivability effects Minimum required trades Communication architecture Sensor(s) required Control architecture Operating altitude(s) Time on station Loiter pattern and location 5-27

Design of UAV Systems Surveillance UAV 200 nm Surveillance area
Lesson Concepts of operation c LM Corporation Surveillance UAV 200 nm Loiter location(s)? 100 nm Surveillance area 5-28

Our example – how to start?
Design of UAV Systems Lesson Concepts of operation c LM Corporation Our example – how to start? Analyze the problem What is the customer really asking for? What information is missing? Look at some potential solutions What are the overall system design drivers? ConOps Communications Payload Pick an initial approach (or starting “baseline”) Define requirements Analyze it Estimate cost and effectiveness Analyze the other approaches Compare results Select a baseline approach Reasonable balance of cost, risk and effectiveness Today 5-29

What is the customer asking for?
Design of UAV Systems Lesson Concepts of operation c LM Corporation What is the customer asking for? A system that can monitor a large area of interest Conduct wide area search (WAS) for 10 sqm ground moving targets (GMT), range resolution  10m. Send back data for analysis within 2 minutes A system that can provide more data on demand Based on analysis of wide area search information Based on other information A system that can provide positive identification of specific operator selected targets Within 30 minutes of request at a resolution of 0.5 m But what is positive identification? Does it require a picture or will a radar image suffice? …and what happens to search requirements while the UAV responds to a target identification request? …and how often does it respond? …and what is the definition of “all weather”? 5-30

But don’t always expect a definitive answer Some typical responses –
Design of UAV Systems Lesson Concepts of operation c LM Corporation Getting answers Ask the customer But don’t always expect a definitive answer Some typical responses – Positive identification : “Visual image required” Search while responding to target identification request: “interesting question, what are the options?” ID response frequency – Assume 1 per hour Weather definition : “Assume Clear day, unrestricted visibility (50% of the time) 10Kft ceiling, 10 nm visibility (30%) 5Kft ceiling, 5 nm visibility (15%) 1Kft ceiling, 1nm visibility (5%). Threshold target coverage = 80%; goal = 100%” Note: a measure of effectiveness just got defined! 5-31

WAS all weather sensors Assume minimum look down angle () = 5
Design of UAV Systems Lesson Concepts of operation c LM Corporation Some constraints WAS all weather sensors Assume minimum look down angle () = 5 Assume maximum look down angle () = 60 ID sensors Assume nominal maximum slant range = 30 nm For reasonable resolution against typical ground targets Max range Min range h = altitude Slant range - min Slant range - max    hmin = RmaxTan() GMTI coverage area  [Tan()/Tan()]^2 Strip coverage area  [Tan()/Tan()] Rmin = RmaxTan()/Tan() 5-32

1. It makes 2 minute turns (assuming a nominal 45
Design of UAV Systems Lesson Concepts of operation c LM Corporation WAS ConOps If a UAV loiters over a fixed point in the middle of a square surveillance area, it can meet the 80% coverage, 2 minute moving target detection wide area surveillance (WAS) requirement if 1. It makes 2 minute turns (assuming a nominal 45 degree WAS field of regard) And the image processing plus transmit time is held to 30 seconds or less 2. The WAS range is slightly larger than ½ the width of the surveillance area Area of circlesquare = /4 = 0.785 3. It has a 100% detection rate, 100 % of the time Target Target 101 nm Min range effects ignored 200 nm x 200 nm 5-33

To design our baseline for the threshold requirement
Design of UAV Systems Lesson Concepts of operation c LM Corporation Positive ID ConOps We have a threshold requirement for positive (visual image) target identification (ID) 80% of the time To design our baseline for the threshold requirement We have to be able to operate at or below 10 Kft for 30% of the target identifications 50% of the time we can stay at altitude and 20% of the time we won’t see a target (unless we image at <= 5 Kft) Cloud ceiling/visibility Clear day, unrestricted 10Kft ceiling, 10 nm 5Kft ceiling, 5 nm 1Kft ceiling, 1nm Percent occurrence 50% 30% 15% 05% Atmospheric conditions (customer defined) 5-34

The WAS and ID mission requirements are in conflict
Design of UAV Systems Lesson Concepts of operation c LM Corporation ConOps assessment The WAS and ID mission requirements are in conflict 80% WAS coverage is required (at a minimum) Assuming a uniform distribution of targets This implies that minimum sensor range  100 nm for a single UAV WAS ConOps which drives the WAS sensor to operate at high altitude Assume a minimum 5 degree look down angle and calculate the altitude required for 100 nm range Target ID, however, will be at 10Kft or less To meet the 80% visual ID requirement (weather) One option for reducing the mismatch is to go to a multi-UAV ConOps A four (4) UAV WAS ConOps would reduce the WAS range requirement to 50nm (at a minimum) A Sixteen (16) UAV WAS ConOps would reduce the range requirement to 25 nm 5-35

We can design one (1) air vehicle or two (2)
Design of UAV Systems Lesson Concepts of operation c LM Corporation Bottom line We can design one (1) air vehicle or two (2) A one air vehicle type solution will be a compromise Can’t optimize for both environments But only one development program, production line and support system will be required A two air vehicle type solution will require 2 development programs, 2 production lines and 2 support systems Cost will go through the roof We could do a trade study to determine which approach is most cost effective but historically a single, multi-capability design will be lower cost than 2 optimized single mission vehicles Therefore, we will try to find a single system design solution for both missions If that doesn’t work, we can always fall back to the other option 5-36

(1) Do a first order assessment of your selected system design project
Design of UAV Systems Lesson Concepts of operation c LM Corporation Homework (1) Do a first order assessment of your selected system design project Assume the answers in charts 30 and 31 apply (2) Define at least two (2) ConOps that might work (3) What are the range and altitude implications for the required WAS and ID sensors? (4) Do you think one air vehicle will be able to do both missions? If not, how many do you think will be required? Submit your homework via your to Egbert by COB next Thursday 5-37

Intermission Design of UAV Systems Lesson Concepts of operation
c LM Corporation Intermission 5-38

Concepts of operation Design of UAV Systems

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