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Design of UAV Systems. c 2002 LM Corporation . Concepts of operation. Lesson objective – to discuss Concepts of operation including … Basic concepts Area coverage Combat air patrol Response time Example problem. 5-1. Design of UAV Systems. c 2002 LM Corporation .

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  1. Design of UAV Systems c 2002 LM Corporation Concepts of operation • Lesson objective – to discuss • Concepts of operation • including … • Basic concepts • Area coverage • Combat air patrol • Response time • Example problem 5-1

  2. Design of UAV Systems c 2002 LM Corporation Concepts of operation 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 anew 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. http://www.fas.org/spp/military/docops/afspc/i10_606.htm We will use the first definition – determining how something is used or operated vs. a ConOps document 5-2

  3. Design of UAV Systems • 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 • Continuous operations • High risk c 2002 LM Corporation Concepts of operation How UAVs are used 5-3

  4. Design of UAV Systems HeliWing Helios – Altitude record holder (air breathing aircraft) www.fas.org/irp/program/collect/vtuav.htm Predator A – Hellfire missiles MicroStar http://www.auvsi.org/members/us.cfm Global Hawk - 38 hour endurance Lockheed Martin Aeronautics Company c 2002 LM Corporation Concepts of operation Examples Tom Cat www.fas.org/irp/program/collect/docs/97-0230D.pdf DarkStar 5-4

  5. Design of UAV Systems c 2002 LM Corporation Concepts of operation 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

  6. Design of UAV Systems 12 13 14 17 16 15 4 9 5 6 7 8 10 11 18 1 0 19 3 2 Border - Penetrate/Loiter Border - Loiter/Penetrate Border - Standoff Terminology Notation 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) 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 c 2002 LM Corporation Concepts of operation Typical mission profile 5-6

  7. Design of UAV Systems Target coverage Area (Ap) Rp Xmax Target area Rp p Db Base c 2002 LM Corporation Concepts of operation Target area coverage from base 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

  8. Design of UAV Systems Rp = 500 nm Target coverage Area (Ap) Int’l waters Rp p Db Base c 2002 LM Corporation Concepts of operation Coverage area example 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 = 153549 nm^2 5-8

  9. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation 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

  10. Design of UAV Systems c 2002 LM Corporation Concepts of operation 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

  11. Design of UAV Systems c 2002 LM Corporation Concepts of operation 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

  12. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation 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

  13. Design of UAV Systems R R UAV c 2002 LM Corporation Lesson Concepts of operation 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 Standoff distance Unusable sensor coverage Border 5-13

  14. Design of UAV Systems Search Racetrack Circle Figure 8 Elongated 8 Threat avoidance c 2002 LM Corporation Lesson Concepts of operation Loiter patterns Plus many others and combinations thereof 5-14

  15. Design of UAV Systems Outside area Overlap c 2002 LM Corporation Lesson Concepts of operation Search area coverage 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

  16. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation 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

  17. Design of UAV Systems Platform only Xmax 2max D2min Border D2max Dso D3max Loiter location D3min D1 Db Note - Dso is negative here Base c 2001 LM Corporation Concepts of operation Loiter/penetrate geometry - optional • 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

  18. Design of UAV Systems x 2 Xmax D2min Dso D2' D2max Loiter location D3' D3min D1 Db Base c 2001 LM Corporation Concepts of operation 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 5-18

  19. Design of UAV Systems x 2 Xmax D2min Dso D2' D2max Loiter location D3' D3min D1 Db Base c 2001 LM Corporation Concepts of operation 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 = 464.3 nm • Numerically integrate sector area from 2 = 0 to 72.3 deg (n=10) • Sector area = 188767 sqnm • Subtract triangular area defined by Dso, Xmax and D2max (48907sqnm) • Total area = 139860 sqnm Optional topic 2max 5-19

  20. Design of UAV Systems • Circular segment approximation • Radius = (D2Min+D2max)/2 • Center at loiter location Xmax D2min Dso D2' D2max Loiter location D3' D3min D1 Db Base c 2001 LM Corporation Concepts of operation Approximate solution • R = 650 nm • LED = 300 nm • Db = 250 nm • Dso = -125nm • therefore • D2min = 375nm • D2max = 410.7nm • 2max = 72.3 deg • D3min = 464.3 nm • Circular sector area (2 = 0 to 72.3 deg) • Average radius = 393 nm • Sector area = 194895 sqnm • Subtract triangular area defined by Dso, Xmax and D2max (48907sqnm) • Approximate area = • 146078 sqnm (+4.5%) Optional topic 2max The approximation is valid for loiter penetrate only 5-20

  21. Design of UAV Systems c 2002 LM Corporation Concepts of operation 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 = 1900 2Km 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

  22. Design of UAV Systems c 2002 LM Corporation Concepts of operation 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

  23. Design of UAV Systems c 2002 LM Corporation Concepts of operation 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

  24. Design of UAV Systems Mission radius Base c 2002 LM Corporation Concepts of operation 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 Border 5-24

  25. Design of UAV Systems Radius = 500 nm Target coverage area 148K sqnm 130K sqnm Border Border 362 nm 463 nm Loiter 200 nm 438 nm 487 nm 50 nm Base c 2002 LM Corporation Lesson Concepts of operation 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 Total mission radius = 650 nm LED = 300 nm 5-25

  26. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation Next subject • Lesson objective – to discuss • Concepts of operation • including … • Basic concepts • Area coverage • Combat air patrol • Response time • Example problem 5-26

  27. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation 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

  28. Design of UAV Systems 200 nm Surveillance area 200 nm Loiter location(s)? 100 nm c 2002 LM Corporation Lesson Concepts of operation Surveillance UAV 5-28

  29. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation 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

  30. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation 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

  31. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation 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

  32. Design of UAV Systems Min range Max range h = altitude   Strip coverage area  [Tan()/Tan()] Slant range - min Slant range - max  GMTI coverage area  [Tan()/Tan()]^2 c 2002 LM Corporation Lesson Concepts of operation 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 • Assume minimum look down angle () = 5 hmin = RmaxTan() Rmin = RmaxTan()/Tan() 5-32

  33. Design of UAV Systems 101 nm 200 nm x 200 nm c 2002 LM Corporation Lesson Concepts of operation 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 Min range effects ignored 5-33

  34. Design of UAV Systems Atmospheric conditions (customer defined) Cloud ceiling/visibility Clear day, unrestricted 10Kft ceiling, 10 nm 5Kft ceiling, 5 nm 1Kft ceiling, 1nm • Percent occurrence • 50% • 30% • 15% • 05% c 2002 LM Corporation Lesson Concepts of operation 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) 5-34

  35. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation 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

  36. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation 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

  37. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation 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 Email your to Egbert by COB next Thursday 5-37

  38. Design of UAV Systems c 2002 LM Corporation Lesson Concepts of operation Intermission 5-38

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