SPECTRUM SECURE COMMUNICATIONS FOR AUTONOMOUS

SPECTRUM‐SECURE COMMUNICATIONS FORAUTONOMOUS UAS/UAV PLATFORMSAndrew L. DrozdANDRO Computational Solutions, LLCAdvanced Applied Technology DivisionRome, NY26 October 2015Secure UAS Communications PanelUnclassified // Distribution A: Unlimited Distribution1

Topics ANDRO Technology Summary Background of key technical issues related to UAS/UAVspectrum, safety, security and airspace integration Potential spectrum contention and management issues Frequencies Used for Remote Control A Typical UAV Link UAS Integration to NAS Spectrum, Security and RTCA‐228 Relevant Issues Conclusion2

ANDRO Technology / Application SpacesRF ResourceManagement &Dynamic SpectrumAccess/SharingSpectrumDetect & Avoid(Spectral Contention)C2 (Cross‐layer RFCommunications /Cyber Security)Cyber‐SpectrumExploitation(Wireless Anti‐Hacking)EMI Avoidance(Coexistence)Pre‐test M&SCyber‐Spectrum Exploitation / Secure Wireless Comms / Cognitive Radio Networking /Trusted Routing Technologies for Autonomous Systems (RF sensor‐edge processing)3

BACKGROUND ANDRO has access to AFRL’s Stockbridge Controllable Contested EnvironmentFacility and Griffiss FAA UAS Test Site Rome, NY for communicationsup/down‐link experiments with large or small UAS/UAV platforms. Member of Northeast UAS Airspace Integration Research Alliance (NUAIR). Our overall focus is on assessing, pre‐certifying or assuring the following forC2/CDL, payload data link (VDL) and other future RF comms technologies:– RF spectrum collision/contention– Coexistence– Cyber Security (confidentiality/integrity/availability)– Safety.4

Daily Users of RF SpectrumCell phoneCordless phoneGarage door openerCar key remote controlStandard time broadcastMobile radioGPS navigationMicrowave ovenBluetoothWifiZigbeeBroadcast television and audioVehicle‐speed radar, air traffic radar, weather radarRFID devices such as active badges, passports, wireless gasoline token, no‐contact credit‐cards, andproduct tagsSatellite TV broadcast reception; also backend signal disseminationToll‐road payment vehicle transpondersCitizen's band radio and Family Radio ServiceRadio control, including Radio‐controlled model aircraft and vehicles5Wireless microphones and musical instrument links

Amateur Radio/Unlicensed Spectrum Bands:Frequencies Generally Used by Amateur UAVs6

Frequencies for Remote Control (RC) ActivitiesFCC has reserved frequency bands for RC uencies.aspx72 MHz: aircraft only (channels 21 through 35)OLDer75 MHz: surface vehicles53 MHz: all vehicles, older equipment on 100 kHz spacing50.8 to 51 MHz: for all vehicles at 20 kHz spacingVulnerable to amateurradio repeater stations27 MHz: general use, hobbyists.NEWer2.4 ‐ 2.485 GHz: Spread Spectrum band for general control900 MHz, 1.2 GHz, 2.4 GHz, 5.8 GHz: common for video transmission433 MHz or 869 MHz ‐ directional high‐gain antennas for video at increased range7

Frequencies for RC Activities (Continued) Older RC aircraft in the US utilized 72 MHz for comms: Tx broadcasts using AM or FM with PPM or PCM. A specific channel is used for each aircraft. Use of crystals to set the operating channel in the Rx and Tx. For an aircraft controlled on channel 35 (72.49 MHz), if someone turns their radioon the same channel, the aircraft's control may be compromised, so when flying atRC airfields, there is normally a board that flags used channels to avoid incidents. Latest Rx use synthesizer technology and are 'locked' to the Tx. For synthesized Rx crystalis not needed, full bandwidth can be used (i.e., 35 MHz). Newer Tx use spread spectrum technology in the 2.4 GHz frequency for communicationallowing pilots to transmit in the same band in proximity to each other with little fear ofconflicts, and receivers in this band are virtually immune to most sources of EMI.8

UAS / Airport Significant FrequenciesUAV control, telemetry, and video frequencies: 900 MHz, 1.2 GHz, 2.4 GHz, and 5.8 GHz900MHz and 2.4GHz are popular because they have more relaxed FCCregulations for transmit power and duty cycleOther UAV frequencies: Comms link metrics:a) Data rate is the amount of data transferred,measured in bits per second (Bps), alsocalled throughputb) Packet loss is packets received compared topackets sent, expressed as %ADS‐B for aircraft below 18,000 feet: 978 MHz and 1.090 GHzGPS: L1 and L2 at 1.2276 and 1.57542 GHzAirport System frequencies: Airport air‐to‐ground voice radio, ATM voice radio: 120 – 135 MHz (VHF radios)Airport ground radio: 460 MHzGriffiss Airport Radars ASR‐8 (airport ATM radar) is 2.7 – 2.9 GHz, 20 MHz wide SRC LSTAR is L‐band, 1.5 GHz Doppler weather are L‐band and S‐band: 1‐2 GHz and 2‐4 GHzThe 700 MHz Band – between 698 and 806 MHz ‐‐ is public safety groups: police, fire, emergency services9

A Typical UAV Link (for RC & Other Data)Uplink is used to control/change flight Periodic (1‐sec) to adjust flightparameters 900 MHz datalink Messages 1 kB, 56 kb/sec Often Spread Spectrum and/or encryptedUAVUplink: Control CommandsDownlink: Telemetry DataDownlink: Payload DataTelemetry is aircraft flight data Usually 900 MHz datalink Location, velocity, heading, altitude,battery lifePayload data is typically video (digital) up to 8 Mbit/sec for high quality video linkGround Control System Control Tx & telemetry Rx Video receiver Commercial digital video recorder RSSI indicatorSpectrum ManagementSecurity Control10

Radio Technical Commission for AeronauticsRTCA SC‐228 Phases / Timeline Minimum Performance Standards for UAS integration into non‐segregatedairspace – establish Detect & Avoid (DAA) and C2 Data Link capability: Provides the C2 function as the primary use of the spectrum. ITU has identified multiple spectrum band as candidates (L‐Band Terrestrial, C‐BandTerrestrial, SATCOM in multiple bands). Minimum Operational Performance Standards (MOPS) for C2 Data Link: Phase I MOPS: L‐ and C‐Band Terrestrial data links Phase II MOPS: SATCOM in multiple bandsSpecify equipment reqt’s for civil UAS; reqt’s inClass A are not part of this TOR; consider reqt’sbetween the UAS and ground subsystem.Consider extended UAS operation in Class D, G, and Eairspace; Ground taxiing is not part of this TOR.SC 228 Development Timeline:12/2013SC‐228 WhitepaperReqt’s for C2 Data Link forUAS integration into NAS.01/2014 – 06/2015C2 Data Link MOPS for V&VDevelop prelim MOPS forL‐Band & C‐Band solutions.07/2015 – 06/2016C2 Data Link MOPS V&VConduct V&V Test Program11

RTCA SC‐228 ScopeStandards development for civil UAS equipped to operateinto Class A airspace under IFR (instrument flight rules)Operational Environment: UAS transitioning to/from airspace Class A, traversingD/E/G Extended UAS operations in airspace Class D/E/GThe C2 Data Link: standards for Link using L‐band Terrestrial (960‐1164 MHz) data linksAirport environment, low altitude, wideband‐downlinks960‐977 MHz – assignments for UA at en routeNeed ‐ RF Spectrum for:cruising altitudes Pilot ATC Communications Link (voice, data)980‐1020 MHz – additional assignments to low‐ UAS control link (telecom [uplink], telemetryaltitude UA[downlink]) C‐band Terrestrial (5030‐5091 MHz) data links GPS – determine locationNarrowband uplinks; 300kHz channels and ADS‐B ‐ broadcast position locationRepetition rates for Modes of Operationsubmultiples (25,50,150)AeroMAX (broadband for airports) can be utilized for Automatic ‐ 10 Hz Manual ‐ 20 Hz (ITU‐R 643 Report M.2171 Tablesstreaming data from taxiing UA.23 and 24).12 SATCOM in multiple bands

Key Technical Issues in UAS Integration to NAS FAA identified relevant challenge areas: Communications Airspace UAS operations Unmanned Aircraft Human system integration13

Key Issues (Continued) Airspace UAS Operations Separation Concepts: Collision Avoidance (CA), Self‐Separation (SS), and SeparationAssurance (SA)Airspace Integration Safety: Risks and failure modes of SA/SS/CA integration, includingCockpit Display of Traffic InformationSense and Avoid Sensors and Fusion: Use on/off‐board sensors; radars; fusion of EO/IR,radar, SWIR, and ADS‐BSeparation Algorithms: Maneuvering algorithms for avoiding other aircraft, weather, wakevortices, terrain, etc.Availability of Surveillance Data: Impact of existing data on intent/trajectory predictionTerminal Airspace/Surface Operations: Complex and restrictive environment andresponsiveness to ATC. The Unmanned Aircraft State Awareness and Real Time Mission Management: Negotiate changes in UAS trajectoriesbased on aircraft operational state Airframe Certification: Emphasis on structural analysis and reduction in airframe testing Precise Location and Navigation: Alternative to GPS UAS Avionics and Control: Means to ensure safety and reliability.14

The Spectrum and Airspace Integration RF spectrum Protected safety RF spectrum for control communications Cyber secure RF infrastructure FAA‐UAS‐operator Control data link for given spectrum bands. SC‐228 relevant issues Evidence of old technology for link signal/spectrum and their management (narrowband, assigned bands, non‐adaptable, no feedback) Assumed “equal bandwidth for all” or “bands for thee modes” limits number ofusers of a frequency band and constraint flexibility of frequency access/usage Low power spread frequency waveforms not considered at all (will enable controlwithout contention for 100s of systems simultaneously in the same frequency) Evidence of limited consideration for link routing through relays, and multi‐hop highspeed networking.15

How to Improve Good intentions: SC 228 suggests to relegate signals from L band to C band whenpossible for surface, low‐altitude, downlink uses; allow C in both directions with software‐defined channel widths, support multi‐hop links, networking, etc. Can improve with: Interference analysisRange & Signal Strength prediction and test analysisReal‐time spectrum situational awarenessSpectrum management and interference mitigationSpectrum sharing technology to address signal collisions:‐ in L: Terminal Radar Approach Control (TRACON) signals, radar, etc.,‐ in C: Unlicensed National Information Infrastructure (U‐NII) signals, radar, etc. Technology preventing link loss‐ Lost Link Preparedness Spread spectrum and frequency hopping waveforms Different choice for carrier frequency‐ Laws of physics favors lower freq. ( 700 MHz), which better penetrate structures,propagate to longer ranges due to lower absorption Vulnerability analysis (cyber security)16

Frequency / Modulation SelectionSpread spectrum and frequencyhopping waveformsDifferent choice for carrier ��tips‐on‐picking‐frequencies17

Lost Link Preparedness 3 UAV links: uplink control, downlink telemetry, downlink payload ‐ any of these 3links can be interrupted by various forms of interference. When links are lost UAVs are programmed to fly in a circular pattern and work to re‐establish or restore the link.In worst‐case scenarios, they are supposed to return automatically to their launch base. UAV pilots have told investigators that they were so accustomed to lost links that they tendednot to get nervous unless the disruptions lasted for more than a few minutes. Losses: 200 mid‐size and large‐size UAVs lost in 2012‐2015, 25% associated to link loss. Loss of communication during operations may result from: Failure of system due to lack of reliability Loss of line‐of‐sight (LOS) due to geographic features blocking the signals Weakening of received power due to increasing distance to the UAV or UAV mobility(banking, antenna alignment) Unpredictable, transient fades due to interference or jamming (intentional or inadvertent). 18