The Detect & Avoid Requirements and Technologies for small RPAS

Transcription

1 Royal Aeronautical Society Detect & Avoid Workshop March, 2015 The Detect & Avoid Requirements and Technologies for small RPAS Dr Joseph Barnard Barnard Microsystems Limited Unit 4, Coleridge Road London N8 8ED U.K.

2 AUVSI March 2015 RPAS VLOS Applications DAA for RPAS in BLOS apps Oil, gas and mineral geophysical survey work Oil pipeline and linear infrastructure monitoring Land & maritime border patrol Small cargo operations Military Remotely The Piloted D & Aircraft A requirements Systems (RPAS)... and technologies by Barnard for Microsystems small RPAS Limited 2

3 Remotely Piloted Aircraft System BLOS applications We will consider civilian RPA, as shown here, operating Beyond Line Of Sight in: Oil, gas and mineral geophysical survey ( GS ) work Oil pipeline and linear infrastructure monitoring Land and maritime border patrol

4 In a geomagnetic survey, the Users want a mapping of the Earth s magnetic field. The D & A requirements and technologies for small RPAS 4

5 In an airborne GS, the aircraft need to fly from 20m to 80m Above Ground Level... The D & A requirements and technologies for small RPAS 5

6 One would also like the survey to be performed at night when the electrical and magnetic noise levels are lowest. Quiet period from midnight to noon From a presentation by James Macnae at SEG 2006 The D & A requirements and technologies for small RPAS 6

7 A satellite data relay network is needed for RPA operating BLOS in GS activities so airborne object data could be sent to the RPA The D & A requirements and technologies for small RPAS 7 Results from the UASatCom Feasibility Study 7

8 Remotely Piloted Aircraft System BLOS applications We will consider civilian RPA, as shown here, operating Beyond Line Of Sight in: Oil, gas and mineral geophysical survey work Oil pipeline and linear infrastructure monitoring ( PM ) Land and maritime border patrol

9 In PM, the User needs to be notified of vehicles and people in the Right of Way Remotely The Piloted D Results & Aircraft A requirements from Systems the UASatCom (RPAS)... and technologies by Feasibility Barnard for Microsystems Study small RPAS Limited 9

10 The oil pipeline must be monitored at times in extreme climatic conditions Severe weather conditions in the Arctic: total darkness (in winter time) temperatures: drop to -40 C spray icing (wing icing) snow and ice Part of the Trans Alaska Pipeline In North Africa and in the Middle East, an unmanned aircraft could encounter: temperatures that reach +50 C fine dust abrasive sand storms. Pipeline in Saudi Arabia The D & A requirements and technologies for small RPAS 10

11 An RPA operating BLOS needs a single hop satellite based data relay link. airborne object data could be sent to the RPA Remotely The Piloted D & Aircraft A requirements Systems (RPAS)... and technologies by Barnard for Microsystems small RPAS Limited 11

12 If you plan to rely on a commercial satcoms link for your Detect & Avoid solution In our experience, the contested satellite data relay service link is limited to 50 to 200 kbit/sec: 640 x 480 pixel monochrome video at 10 fps ATC voice relay using VOIP and Voice Activity Detection (VAD) Even the contested service is relatively expensive: For commercial applications, relay of high definition video for Detect & Avoid usually does not make for a successful business case No satellite data relay company we are aware of will guarantee 100% link availability: The RPA must be able to fly predictably and safely without a communications link, and have an effective Detect and Avoid system The D & A requirements and technologies for small RPAS 12

13 Remotely Piloted Aircraft BLOS applications We will consider civilian RPA, as shown here, operating Beyond Line Of Sight in: Oil, gas and mineral geophysical survey work Oil pipeline and linear infrastructure monitoring Land and maritime border patrol

14 The D & A requirements and technologies for small RPAS 14

15 In land and maritime border patrol work: An RPA on border patrol will typically fly at 8,000 to 12,000 feet above Mean Sea Level A L band satcoms terminal, such as the Cobham SB 200 terminal shown on the left hand side, is used to relay lower data rate mission critical Command and Control data. A high data rate satcoms unit, such as the $350,000 Viasat terminal shown on the right hand side, is needed to relay the payload high definition video data. The D & A requirements and technologies for small RPAS 15

16 Now to the specific Detect & Avoid requirements From presentation on "Small sense and avoid system" by Dr John F. McCalmont, USAF Research Laboratory at UAV 2007 Conference in Paris. The D & A requirements and technologies for small RPAS 16

17 Current airborne object detection technology is based on the use of: Optical imaging and / or several cameras looking in different directions to get a wide field of view cameras in a stereovision configuration to also get distance information (+ FPGA) RADAR Rotating maritime type RADAR unit Phased Array electronic beam steering and imaging unit (this can be expensive) together with real time sensor data processing, implemented using a combination of: Multi-threaded software running on a high performance, multi-core, CPU Multiple Raspberry Pi 2 Single Board Computer (SBC) Multiple Arduino DUE SBC The D & A requirements and technologies for small RPAS 17

18 In parallel, the image processing software detects edges and straight lines In this case, the image processing software is detecting straight lines using the Hough lines algorithm, so removing the cloudy background. The D & A requirements and technologies for small RPAS 18

19 The image processing software appears to be better than unaided human vision... The D & A requirements and technologies for small RPAS 19

20 A Cessna Skycatcher light aircraft, at 17 km, detected using edge detection... The D & A requirements and technologies for small RPAS 20

21 Example of scanning RADAR sensor characteristics Rate of rotation (mechanical antenna rotation) Field of view when mounted in the nose of a RPA Operating frequency Tx signal modulation type 24 / 36 / 48 rpm -110 to +110 of direction of flight 9.3 to 9.4 GHz (X Band) FMCW Vertical FWHM antenna beam width 25 Horizontal FWHM antenna beam width Output CW microwave power level Electrical power requirement Range to detect 30 sq m cross section target Weight 2.6 or 5.2 (switchable) 165 mw 20 Watts (typically) at 13.8 Volts 66 km 7.4 kg without cables Work is currently underway to quantify the detection characteristics (detection range versus target cross section) of a low microwave output power scanning RADAR sensor. The D & A requirements and technologies for small RPAS 21

22 Scanning RADAR augmentation of optical detection technology There are several weak spots for airborne object detection using optical technology: Difficult to see aircraft approaching from out of the sun: this can be done with filtering, but at the expense of signal-to-noise ratio The effectiveness is reduced during night time operations: one can use thermal imaging, but the resolution and dynamic range is decreased The effectiveness is reduced when flying, possibly unintentionally, in clouds, or in fog: in light cloud and light fog, one can use an InGaAs short wavelength IR camera unfortunately, even low resolution SWIR cameras are relatively expensive Which suggests RADAR augmentation: however, RADAR detection itself has weaknesses: Low RADAR cross section targets are not readily detected (ropes, thin walled balloons) RADAR angular resolution is relatively low compared with optical imaging This leads us to select a combination of optical and RADAR detection. The D & A requirements and technologies for small RPAS 22

23 We use Thermal Imaging to detect distant aircraft at night and in clouds and fog. The D & A requirements and technologies for small RPAS 23

24 The D & A requirements and technologies for small RPAS 24

25 Making the small RPA more visible to other air space users 1. Use a miniature Mode S transponder 2. Automated, periodic (every 5 minutes, for example) computer generated, speech on VHF air band radio announcing RPA presence (TH suggestion) 3. Carry and activate a smoke canister to generate a short (up to 50m) smoke trail when necessary to alert an oncoming aircraft of the presence of the RPA (mentioned at AUVSI Europe Conference in Cologne) 4. Apply a thin metal film to the leading edges of the wings to increase the probability of Air Traffic Control and airborne RADAR detection 5. Use powerful lights to increase visibility of the RPA 6. Use a high visibility paint on the RPA, such as black on the underside, yellow on the top. The D & A requirements and technologies for small RPAS 25

26 Detection requirements for a small RPAS RPA cruise airspeed = 80 kph Maximum intruder airspeed = 330 kph (Diamond DA 42 twin engine aircraft) Maximum closing speed = 410 kph ABSOLUTE maximum D & A sensor processing time = 2 seconds Max avoidance manoeuvre calculation and flight planning time = 1 second Max time for RPA with 45 change to clear danger zone by 100m = 6.3 seconds Total manoeuvre time= 9.3 seconds Maximum closing distance travelled in 9.3 seconds = 1.06 km Hence, the sensor detection range has to be at least 1.5 km with a 40% safety margin Use the Cessna Skyhawk flying head on as an example of an intruder aircraft Cabin height = 1.22 m Cabin width = 1 m Wing span = 11m Colour = white (typically) Assume a non-cooperative intruder The D & A requirements and technologies for small RPAS 26

27 Detection range requirements for the Predator B RPA From presentation on "Small sense and avoid system" by Dr John F. McCalmont, USAF Research Laboratory at UAV 2007 Conference in Paris. The D & A requirements and technologies for small RPAS 27

28 Conclusions Current optical sensor hardware and software technology can readily meet the detection requirements for medium sized civilian RPA. In our opinion, one needs to implement both an optical and a RADAR based detection technology on medium sized RPA engaged in civilian operations to achieve the safety required for RPA used in BLOS missions to manage the detection of non-cooperative targets and to continue safe operation in the event of a communications link failure. This is ongoing work, the results of which will be discussed with staff at the UK CAA as a first step towards certification of this technology. Interestingly, once proven, this technology will have the potential to increase the safety of light manned aircraft. I can be contacted at joseph.barnard@barnardmicrosystems.com Acknowledgements Much of this work was supported by: the U.K. Technology Strategy Board in the form of the AeroVision II Proof of Concept Project, TSB Reference number , and the UASatCom Feasibility Study, contract number , and the SURMON Demo Project, contract number , both supported by the European Space Agency. The D & A requirements and technologies for small RPAS 28