investigation of reliable, secure, and scalable cns

Investigation of Reliable, Secure, and Scalable CNS Options for Urban Air Mobility for the UAM Coordination and Assessment Team

Deliverable 4 - Final BriefingJuly 23, 2020

Virginia Stouffer, Technical LeadRonald Lehmer, Task Order Manager

© SAIC. All rights reserved.

Agenda

• Task Approach• CONOPS Review• Requirements• Technologies • Recommendations

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Task Approach


Goal of this study

• “The Contractor shall conduct and document a study that informs NASA about various

technical approaches to providing reliable and secure CNS services to support UAM

operations at UML-4, with special considerations for early test and deployment at UML-2 and

3, as well as extensibility considerations to UML-6. The UAM community will use the results

and recommendations of this study to improve understanding of the current state-of-the-art,

aid in efforts to prioritize UAM challenges, identify technology gaps, and better inform decision-

makers.”

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Schedule (updated)

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Communication1.1 Data service requirements1.2 Wireless links1.3 Ground based architecture

Navigation2.1 Navigation requirements2.2 Navigation technologies2.3 Denied navigation2.4 Augmented navigation for T/O/L

Surveillance3.1 UAM A/C Detection & tracking3.2 Non-UAM Detection3.3 Non-A/C Detection

Integration4.1 Avionics Guidelines & Stds4.2 Avionics architecture4.3 Exploit CNS Commonality4.4 Efficient spectrum use

Interoperability5.1 Shared airspace concepts5.2 CNS Interoperability UAM-UAS


Review of Process

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Area Ele Fn

Pilot or Remote

Definition Availability Reliability Capacity Demand Precision Update Rate

Comm AOC AOC: Vehicle HeatlhP, R

Like for-hire aircraft today, aircraft owners are required to maintain an independent communication with aircraft that monitors aircraft condition and issues

10^-5, Ref ACARSassume msg size similar to flt plan

N/AOn status change - after take off, start cruise, every 15 minutes (ref1) during flight, begin ascent, on ground; may be continuous (recommended)

Comm AOC AOC: Flight Plan

P, R

Like for-hire aircraft today, an aircraft owner/operator maintains an operational center (AOC) where flight plans are created, sent to the aircraft (& pilot) and filed with the FAA. When the aircraft needs to change its flight plan due to weather or other hazards, the AOC negotiates and plans the new flight plan and transmits it to the flight deck

Depends on CONOPS: may not need A-G uplink if the flight plan and alternates are loaded at the vertiport; If A-G upload needed, 10^-5, like AOC health

UML1-2: LTE 100KB at a time. UML 3-4, LT 2 MB/hr. UML 6, LTE 10 MB/hr. Assume flight plan is 1-2KB each, each flight includes primary and secondary plans. Number per city UML1-2, a dozen aircraft at

N/AAssume flight plans are 1-2 KB, communicated once or twice per flight

Comm AOC

Vehicle Situational Awareness, OTW Video, Downlink (Wx, etc.)

R

–OTW video, downlink. A great deal of weather expertise and judgment is incorporated in a human pilot. A vast suite of sensors would be required to fully replace the pilot’s situational awareness of hazards, including weather, both before takeoff and en route. For instance, many airports do not have lightning sensors.

100% when airborne, downlink assurance 99.9%

0.5GB/aircraft while on 480p 60Hz

Comm ATCFAA: Voice (UML 1-3) and datalink (UML 4-6)

P, R Required communications with ATC in Class A/B/C/D airspace. Per current specs4KHz digital voice bounced via C2. Future: controller may have VOIP or may

N/AEvery aircraft has a minimum of 4 comms per sector. Sector time is 20-60 minutes

Comm ATC

Position and intent to ANSP and other coop vehicles, pos. vertiports

P, R

Includes UAM-to-UAM and UAM to nonUAM cooperative aircraft Detection & Tracking. Supporting technologies include ADS-B, TCAS and DAA solutions. Specifications for this function are closely linked with related FAA requirements for "well clear", collision avoidance, and surveillance (transponder, Mode C, S, ADS-B out, etc., as applicable. Surveillance sensor specifications should be addressed within this line item including DAA This item could have been classified as "Surveillance"

100% 116 bits per msg See Navigation. Own-aircraft positional awareness requirement of 10 Hz and 100m

Comm C2 AOC: monitor position

P, R(Draft) R vehicles need to be monitored by owner/operators to ensure compliance with flight plans

100% when airborne, downlink assurance 99.9%

100 bits per msg, 1 Hz per aircraft (continuous)

Tenths of degree-minutes / NACp = 11

Once per second

Comm Pax

Communications, Passenger Welfare, Passenger Emergency

RPassenger emergency communications: video and voice (PTT) to AOC, potentially to ANSP/USSs/police

5 second reliability 4 KHx voice N/A infrequent use: emergencies only

Comm Wx AOC: Wx

P–FAR 135.175 & 121.357 require approved wx radar equipment for a/c over 12,500 lbs. max gross takeoff weight. FAR 135.173 requires approved tstm detection equipment for aircraft over 9 pax

--- --- ---

Nav Appr Vertical

P, R–The aircraft must selflocate with greater precision than in en route when on approach to a vertiport with uneven obstacles potentially in its flight path; unlike an airport, the flight path may not be obstaclefree

For autonomy, will need 99% and possibly higher availability, due to operating constraints, namely low range on battery. Based on ILS, 95-98% availability

N/A

Altitudinal position certainty under precision within 5 feet for rotorcraft gentle landings. 5 meters [GBAS]; 2 ft radar altimeter

At 10 Hz and 100kts, minimum lateral position uncertainty = 5.1 m (before considering precision inertial navigation)

Nav Appr Lateral

P, R–The aircraft must selflocate with greater precision in the x,y coordinate plane for approach


N/A 4.5 meters 10Hz. Assumption. Current D-GPS capable of 5 Hz. Speed and closer approach of autonomous vehicles requires higher certainties. 10Hz achievable with current electronics.

Nav EnRt Vertical

P, R

The aircraft must be able to conform to an assigned or suitable altitude for its speed, phase of flight, vehicle size and potentially other considerations. Altitudinal separation is assumed to be used to prevent collisions and thus the aircraft must know its altitude.


N/A

14 CFR Part 43 Appendix E alt calibration requirement is 125 ft (barometric altitude). RVSM requirement is 3-sigma, equates

10Hz. Assumption. Current D-GPS capable of 5 Hz. Speed and closer approach of autonomous vehicles requires higher certainties. 10Hz achievable with current electronics.

Nav EnRt Lateral

P, RThe aircraft must know where it is and be able to self-locate on the basis of sensors in order to complete a flight to a destination and to avoid known obstacles and hazards.


N/A

Precision/Lateral Position Certainty: LTE 100m. Ex:Lateral position certainty must be better than 100 m at UML-4 due to

At 10 Hz and 100kts, minimum lateral position uncertainty = 5.1 m (before considering precision inertial navigation). UAM-UAM collision avoidance buffer: 4 seconds

Nav Land Lateral

P, RThe aircraft must be able to sense location in low visibility conditions and with sufficient update rates to land safely on a vertiport at a high degree of availability.


N/A

Precision/Lateral Position Certainty: better than 1.5 meters in precision situations (landing) - 5 ft based on team analysis of


Nav Land Vertical

P, RThe aircraft must be able to sense location in low visibility conditions and with sufficient update rates to land safely – and without a “hard landing” on a vertiport at a high degree of availability.


N/APrecision/Position Certainty: 0.3 meters in precision situations (landing) - for soft landing


Surv Ground Monitor

P, RAASP and/or USSs need to monitor the airspace to 1) verify that authorized aircraft are where they say they are and are not in trouble and 2) monitor dynamic density

For UAM health, should be operational 99% of time during prevailing flight hours.

Area to be covered may start with core urban area (10 mi x 10mi) and eventually extend to

must be able to detect a small UAM (2-3 sq m cross section)among clutter

Cooperative comm is at least 1/sec. Verification sensing must more frequent than every 4 sec to confirm. 1,2 seconds preferred.

Surv Ground Non cooperative surveil

P, RAASP and/or USSs need to monitor the airspace to detect noncooperative and unauthorized aircraft

For detecting unauthorized aircraft, availability based on urban requirements but targeted at 90% of time; unplanned outages limited to 1 hr continuous during operational

Area to be covered may start with core urban area (10 mi x 10mi) and eventually extend to

To detect aircraft, must be able to detect a small UAM (2-3 sq m cross section)among clutter. UAS detection may impose higher

1 or 2 seconds

Surv UAM airborne

P, RThe UAM needs to be able to detect and avoid non-cooperative aircraft, whether they are cloaked police/security vehicles, UAS, or potentially unauthorized aircraft, that present a hazard.

Must be operative to fly the aircraft N/A

Must be able to detect a 5 lb UAS or bird (enough to cause damage) at a distance sufficient to avoid collision. At low altitude, speed is

10 Hz based on Own-aircraft positional awareness requirement of 10 Hz and 100m

Surv UAM ground

P, R UAM vehicle must avoid obstacles including cranes, flagpoles, wires, buildings, etc.Must be operative to fly the aircraft. Can potentially be same sensor for landing system.

N/A

Must be able to detect large obstacles that could cause substantial damage to UAM in a collision with sufficient time to

10 Hz based on own-aircraft positional awareness requirement of 10 Hz and 100m


Interviews

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Subject Interviewee orgNumber

interviewedUAM and UTM researchers NASA 11FAA Spectrum and UAS FAA 10AI and autonomous navigation developers Industry & Academia 3Communications experts: Satcom,V2X, wireless Industry 7Nationwide wireless law enforcement network, FirstNet Govt, DoD, Industry, Academia >12UAM start-ups Industry 6AI and autonomous navigation developers Industry & Academia 4UAS researchers and developers Industry & Academia 8Spectrum multipath experts Industry 2Avionics manufacturers Industry 5Standards representatives Industry 7Chief Pilots and Maint Chiefs Industry 0DARPA waveform specialists DoD 1

Informed both requirements and alternatives; provided sanity checking of findings; provided feedback on our logic

CONOPS Assumptions


Why Use CONOPS Assumptions?

• To evaluate CNS alternatives, one needs to have requirements to evaluate against– Range, update rate, channel capacity and signal strength are critical to grading CNS alternatives– Determinations needed about speed of closure, altitude (range), density (capacity), types of messages

(capacity)

• We relied on the NASA and FAA UTM CONOPS to provide foundational requirements for the study• UTM CONOPS principally describe a network of UAM commercial transport services in an urban

environment, served by USSs providing connection, navigation, and data services– FAA does not provide traditional ATC services in this ecosystem– FAA does not provide navigation and separation services– Service-provider based nontraditional communication and surveillance – Given the signal problems in the environment, surveillance is non-NAS

• The FAA UTM CONOPS is clearly intended for small unmanned cargo copters (less than 50 lbs) in low altitudes (below 400 ft)

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Nontraditional Comm Requirements out of FAA UTM CONOPS

• COM: Communication through a distributed network of highly automated systems … and not between pilots and air traffic controllers via voice (p5)

• COM+NAV: Operators via FIMS are responsible for managing their own operations safely… without receiving services from the FAA. (p 5)

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FAA UAM CONOPS v 1.0 (June 2020)

• Many similarities to UTM

• FAA provides “tailored oversight”

• The FAA may, might, or may not provide services

• Nominal use case does not describe FAA services to UAM

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FAA UAM CONOPS v 1.0• UAM fly in corridors

between established endpoints

• Corridor is above 400 ft AGL

• Corridor does not follow roofline

• UAM encounter non-UAM aircraft

• UAM must have ADS-B when outside corridor in B/C airspace

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Urban Air Environment Assumptions• We assume there will be an “Air Authority Service Provider” who will:

– Monitor airspace congestion– Provide instructions in emergency situations (earthquake, fires, etc.)– Monitor the airspace for aircraft operated with ill intent; residents will require it– Will NOT provide radar position surveillance and deconfliction of aircraft flying in a dense urban

environment at low altitudes• Close to major airports and in the near term, airspace under Class B and C will continue to

require Mode C transponders• For collision avoidance and winds, UAM will cruise above 400 ft AGL, determined by specific

city rooflines– Urban wind canyons make aircraft maneuvering difficult, hazardous– VTOL downwash is hazardous to citizenry*– Average distance between US urban buildings (street + sidewalk width) is 72 ft– Better GNSS reception above roofline

• UAM will land at lower altitudes, such as 400 ft AGL and below

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*https://www.youtube.com/watch?v=09bvuYRKwwc

https://www.youtube.com/watch?v=09bvuYRKwwc


Urban Air Environment Assumptions

• UAM vehicles are expected to land vertically or in extremely short spaces, such as on top of a parking garage

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• UAM aircraft will cruise at >50 kts

• UAM vehicles in UML-4 may have a pilot on board, may be autonomous, or may be semi-autonomous

• From a sensor standpoint, autonomy is the same as zero visibility operations

• UAM will have to operate in IMC by UML-4


General CNS Findings Reinforce Choice of Distributed Architectures• Remote control turn-by-turn instructions to aircraft over networked comms or below the roofline

will be impossible– Networked communications have latency issues that constrain their uses– Design around this operationally (in other words, don’t rely on remote pilot commands to fly an urban aircraft)– Reliance on pre-deconfliction and cooperative separation is the functional solution to avoid most air-ground

signal problems– Urban signal problems drive a distributed CONOPS solution

• FAA systems would be overwhelmed or unable to handle UAM traffic due to density and signal obstructions

• Given that the FAA is not controlling the UAM environment, it is unlikely that the FAA and federal tax dollars will be funding implementation of ground infrastructure– A service fee model of ground comms and/or vehicle-centric operations are probable

• Spectrum is scarce, and demand for large allocations of uncommitted spectrum is increasing– Future aviation spectrum uses will be hard-pressed to find new allocations– Reduce demand for spectrum in design, use existing aviation spectrum and lock in choices

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Requirements


Derivation of Requirements

• For each Area (Communications, Navigation, Surveillance), we defined the functions that must be fulfilled for flight, sketching these in overviews

• We then defined the “specifications” of each function, in terms of– Availability & Reliability– Capacity/Demand– Precision– Update rate

• The specifications were sometimes borrowed from existing flight regulations or existing flight equipment, e.g., reliability and availability– The specifications were meant to be approximately right rather than a hard requirement for writing a MOPS

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UAM Communication Link Needs

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Legacy ATC: Voice or data link in classes B, C, D

Transponder w/in 30 mi of class B, above class C floor

Urban Air Authority Service Provider (AASP)

UAM Operator/AOC

V2V SA: Position and intent required; important in dense UMLs.

Vehicle Monitoring: Vehicle Health, Fuel, Vehicle Position

Emergency Comm: Change Flight Path

Weather and Hazard Updating Downlinks Subject to Available Comm

Vehicle Emergencies, ObstructionsDynamic and Emergent Constraints

Flight Performance (“flight plan”) Request and Authorization


ATC Comms

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Function Definition

FAA: Voice or datalink (P,N)

Required communications with ATC in Class B/C/D airspace.

Position and intent to AASP and other cooperative vehicles, possibly including vertiports (P,N)

Includes UAM-to-UAM and UAM to non-UAM cooperative aircraft detection & tracking. Specifications for this function are closely linked with related FAA requirements for "well clear", collision avoidance, and surveillance (transponder, Mode C, S, ADS-B out, etc., as applicable. Surveillance sensor specifications should also be addressed within this line item.

P = human pilot on boardN = no human pilot on board


Aircraft-AOC Comms for Piloted and Non-piloted

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Function Definition

AOC: Flight Plan

Like for-hire aircraft today, an aircraft owner/operator maintains an operational center (AOC) where flight plans are created, sent to the aircraft (& pilot) and filed with the FAA. When the aircraft needs to change its flight plan due to weather or other hazards, the AOC negotiates and plans the new flight plan and transmits it to the flight deck

AOC: Vehicle Health Like for-hire aircraft today, aircraft owners are required to maintain an independent communication with aircraft that monitors aircraft condition and issues

AOC: WxPilot acquires weather briefing prior to take-off and receives updates in the air. Pilot may advise AOC of weather hazards encountered in the air.


Additional Aircraft-AOC Comms for Nonpiloted UAM

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Function Definition

Vehicle Situational Awareness, OTW Video, Downlink (Wx, etc.)

OTW video, downlink. A great deal of weather expertise and judgment is incorporated in a human pilot. A vast suite of sensors would be required to fully replace the pilot’s situational awareness of hazards, including weather, both before takeoff and en route. For instance, many airports do not have lightning sensors. Incorporating an OTW video to remote surveillance is an additional needed safety net.

FAA-required communications such as ATC-voice and ADS-B

Required communications with ATC in Class B/C/D airspace.

AOC: monitor position Vehicles need to be monitored by owner/operators or their designated service provider to ensure compliance with flight plans

Communications, Passenger Welfare, Passenger Emergency Communications

Passenger emergency communications: video and voice (PTT) to AOC, potentially to AASP/USSs/police


UAM Navigation Needs

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Navigation Functions for Piloted and Nonpiloted

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Function Definition

En Route Vertical

The aircraft must be able to conform to an assigned or suitable altitude for its speed, phase of flight, vehicle size and potentially other considerations. Altitudinal separation is assumed to be used to prevent collisions and thus the aircraft must know its altitude.

En Route Lateral

The aircraft must know where it is and be able to self-locate on the basis of sensors in order to complete a flight to a destination and to avoid known obstacles and hazards.

Approach Vertical

The aircraft must self-locate with greater precision than in en route when on approach to a vertiport with uneven obstacles potentially in its flight path; unlike an airport, the flight path may not be obstacle-free

Approach Lateral

The aircraft must self-locate with greater precision in the x,y coordinate plane for approach

Landing Lateral

The aircraft must be able to sense location in low visibility conditions and with sufficient update rates to land safely on a vertiport at a high degree of availability.

Landing Vertical

The aircraft must be able to sense location in low visibility conditions and with sufficient update rates to land safely – and without a “hard landing” on a vertiport at a high degree of availability.


UAM Surveillance Needs

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AASP

Obstruction

Cooperative and Non-cooperative Surveillance

SSR

FAR 91.225Allows law enforcement

to turn off ADS-B

Non-cooperative Aircraft

Cooperative Aircraft

Class B Airspace

UAMOperator


Surveillance Functions, Piloted and Nonpiloted

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Function Definition

Ground-based MonitorAASP and/or USSs need to monitor the airspace to 1) verify that authorized aircraft are where they say they are and are not in trouble and 2) monitor dynamic density

Ground-based non cooperative aircraft surveillance

AASP and/or USSs need to monitor the airspace to detect noncooperative and unauthorized aircraft

Air-based airborne detectionThe UAM needs to be able to detect and avoid non-cooperative aircraft, whether they are cloaked police/security vehicles, UAS, or potentially unauthorized aircraft, that present a hazard.

Air-based obstacle and terrain detection

UAM vehicle must avoid obstacles including cranes, flagpoles, wires, buildings, etc.

Technologies


Technological Alternatives Considered

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Comm Navigation Surveillance - Air Surveillance - Ground

5G Cellular Barometric Pressure Altitude ACAS-X, TCAS Advanced Doppler Range Gating Radar

5G Satellite Integration Radar Altimetry ADS-B (current) Bistatic Radar

Bluetooth 5 Altimetry with broadcast references UAT ADS-B Army Ground Based Sense and Avoid

C Band GNSS only Dedicated Short Range Comm. IR Sensing

DME Whitespace GNSS + INS/IRS (FOG/MEMs) FLARM (Europe) Lasergate monitoring

Laser Communications GNSS +PNT Nav LIDAR Machine Vision

LEO (Commercial) GNSS +eLoran FMCW RADAR in GHz range Holographic RADAR

VDL Mode 2 GNSS + GBAS (LAAS) K band RADAR K band FMCW RADAR

VDL Model 3 GNSS + WAAS Acoustic Detection UWB MIMO

UWB MIMO GNSS + RF mapping RF Detection Mode C/S Multi-lateration

GNSS + SAR/ISAR Acoustic Detection

LIDAR RF Detection

Machine Vision

IR

RF Beacon

Sensor Fusion


Attributes of the Technologies

• Description • Size• Weight• Power• Bandwidth

– Handling of obstructions, BVLOS, and urban clutter

– Range– Licensed? Aero-reserved?

• Cost

• Advantages• Disadvantages• Precision• FAA acceptance• Cyber security and privacy• Maturity in time: UML

readiness

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• Use Case evaluations– Fog, rain, snow– High traffic, low traffic– Night– City emergency– Vehicle emergency– Birds


Technology Alternatives Recommended for Research and Development Ordered for Readability, Not by Rank

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Function Alternative Recommended TechnologiesCom: UAM-AOC: Health, flight plan, position, Wx 5G 5G Sat C-band LEO VDL-3Com: ATC relay to AOC 5G 5G Sat C-band LEO VDL-3Com: Video to AOC 5G 5G Sat LEOCom: Pax emergency 5G 5G Sat C-band LEOSurv: Cooperative Surveillance UAT2/ADS-B Multi-lateration ACAS 5G

Nav: En Rt LatAugmented GNSS

(WAAS, LAAS, PNT) GNSS+RF mapping GNSS+ISAR LEO

Nav: En Rt Vert Augmented GNSS Radar Altimeter LEONav: App Lat Augmented GNSS GNSS + RF mapping RF Beacon LEONav: App Vert Augmented GNSS Radar Altimeter RF Beacon LEO LIDARNav: Land Lat** Augmented GNSS Radar K-band, FMCW RF Beacon Machine Vision LIDARNav: Land Vert** Augmented GNSS Radar K-band, FMCW Radar Altimeter RF Beacon LIDARSurv: Ground Non-cooperative* Advanced Radar IR Bistatic AcousticSurv: Air Non-Coop & Obstacles RADAR Kband IR LIDAR RF

• In the category of Ground Non-Cooperative Surveillance, none of the alternatives scored as feasible• **With a pilot onboard, 1m precision; total automation requires 0.3 m precision

Recommendations


Agenda


– 8 CNS Recommendations– 11 Integration Recommendations– 12 Certification Recommendations– 3 Interoperability Recommendation Areas

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CNS Recommendation #1

• Cooperative surveillance for vehicle-to-vehicle separation is a must-have function for UAM• UAT2 (on proposed 1104 MHz) is a highly superior alternative to satisfy that function

– New message set design can incorporate detailed intent and contingency planning– It is ATC compliant but filterable; the return from UAM aircraft over the urban environment can be filtered out

from a controllers’ display, and will automatically appear when the UAM approaches the airport– Aero-reserved frequency– Both ground surveillance and air vehicle to vehicle operations will use the same frequency– Can be re-broadcast or sent to LAANC for sUAS interoperability

• NASA should – Lead by developing a cooperative surveillance concept for UAM airspace– Research the design of that concept– Integrate: Support FAA allocation of the frequency, Support the creation of the message set

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CNS Recommendation #2

• Develop and implement performance-based standards to enable sensor fusion navigation in UAM– Sensor fusion technologies are strong candidates for non-cooperative functions such as navigation and

noncooperative DAA– Dual redundant and independent nav systems will be required on board under Pt 135– Non-cooperative functions are more appropriate for performance-based MOPS standards– Cooperative functions tend to require more exacting standards, e.g. MASPS– Sensor fusion solutions often incorporate complex algorithms or AI to encompass a wide range of potential

sensor data, environmental conditions, locations, etc.– AI and complex algorithms are more difficult to describe in exacting standards and to certify– Augmented GNSS is going to be workable above the roofline and a sensor solution will be needed for

approach and landing• NASA should

– Test fusion technologies with industry, in support of certification

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CNS Recommendation #3• Using 5G for airspace requires infrastructure changes at the carrier and cell tower levels; without these required

changes 5G is not a suitable alternative • 5G’s strengths:

– Commercial provisioning– Very high capacity– Planned network slices and sidelink could provide message security and vehicle to vehicle connectivity

• 5G’s weaknesses:– Hype dramatically precedes fielding. The capabilities that make 5G a good alternative are not yet available in US (features from

3GPP’s Release 17)– FAA requires prioritization of cell service for aviation use. If UAM operates under an AFR construct, clarification needs to be

sought with the FAA whether the prioritization is needed.– Testing of signal elevation die-off needed; fielding of antennas pointing at aviation elevations may be required– Testing to define the suitable range for a signal and voluntary use of sidelink will define the ground network requirements

(geography of cell towers to ensure coverage)– Need to implement a secured aviation network slices instead of relying on geographical cells for security

• NASA should– Test 5G and other communications technologies to provide factual findings – Industry commitment to testing and changes in network protocols required (or testing will be a waste of time)

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CNS Recommendations (4-5 of 8)

4. Define and Research Non-cooperative Ground-Based Surveillance– Need is not well-defined, but security will be a concern– Alternatives include: perimeter security vs defined route monitoring vs pervasive monitoring – Recommend a distributed, low-cost, privacy-respecting network, e.g., upward pointing cameras in a node and

link structure on publicly owned posts, towers, and vehicles– NASA should: research alternatives under the identified use cases

5. Widespread Augmented GNSS– Need: Vulnerable to jamming, solar flare, obstructions. Augmentation needed for IMC & automated ops.– Alternatives

– Real Time Kinematic fixed ground broadcast from towers– Ground-based timing network – Corrections broadcast at vertiports– Additional satellite channels (GPS-3) or additional satellites (LEO)– Recommend identifying an alternative that addresses solar flare and EMI issues

– NASA should:– Research alternatives to identify best market solution– Integrate providers and start-ups around the best alternative to promote use

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CNS Recommendations (6-7 of 8)

6. Spectrum-Free Future Comms with Point-to-Point Laser for UML-6– NASA should: research air-air and air-ground secure laser communications

7. Evolve the Separation Paradigm, with Cooperative Surveillance– 3 nm terminal separation will not yield any appreciable density in the urban environment– Below the roofline, separation will be not detectable except linearly (chiefly head-on or following)– If UAM cruise at >1000 ft AGL and descend for approach, then closest separation is in approach and

departure traffic flows, which need definition– However, for UML-6, a better system based on dynamic separation will be required– Recommend starting with an AFR paradigm, and working to promote & expand it– NASA should:

• Research urban airspace rules under reduced separation • Conduct research to define vertiport approach and departure• Conduct research simulating vertiport arrivals and departures, en route flight, under alternative rules• Research a plan to reduce RNP to needed levels• Integrate: work with the FAA to establish urban flight rules under reduced self-separation• Research dynamic separation not based on standard distance for UML-6

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CNS Recommendations (8 of 8)

8. UAM Flight Levels Need to be Defined– Requirement definition needed to develop appropriate vertical guidance sensors– Radar altimeter good for absolute altitude above roofline, but is subject to WiFi blinding – Barometric good for pressure altitude, but subject to urban canyon pressure differentials, particularly close to

buildings (such as when landing)– Augmented GNSS is going to be workable above the roofline and a sensor solution will be needed for

approach and landing, but range and environment needs to be known• No single solution for precision landing will work across all vertiports

– NASA should research UAM flights levels, and integrate with airspace research (CNS-7)

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Agenda



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Integration Recommendations (1 & 2 of 11)

1. Develop an Integrated System Architecture to Optimize Avionics Development– Launching the UAM industry under existing NAS rules locks in the use of legacy aircraft for >10 years– Legacy avionics will not support UML-4– Allowing UAM fleet accumulation to significantly outpace airspace development delays realization of UML-4

because of the need to maintain dual capabilities– Worse, disparate operating models in different cities fracturing the manufacturing base and threatening

the US ability to participate in UAM– NASA should research to mature and publish the UAM baseline mission, system architecture, operating

environment, validating operating requirements (reduced spacing, flight levels, cooperative distributed separation)

2. NASA Needs to Lead Convergence on a Collaborative Common Architecture– To avoid disparate operating models in different US cities– Industry and FAA are not suited to lead this effort– Development of a common architecture and common industry standards lowers development costs for

manufacturers and accelerates implementation– NASA should lead the founding of a new US industry area through definition of common architectures– NASA should integrate the common architecture concept with FAA and industry

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Integration Recommendations (3 & 4 of 11)3. Over The Air Software Updates

– History shows the woes of locking datasets and algorithms into firmware– Need to roll the box to upgrade the dataset or incorporate reduced separation– SDR pushes the ability to recode avionics to a software level that can be transmitted wirelessly when the aircraft is parked,

out of service– Shortens out of service periods for upgrading avionics, reduces costs, reduces legacy fleet woes– NASA should

• Research the protocols and constraints needed for FAA-certifiable OTA software updates• Integrate the research product with FAA and industry to bring to fruition

4. Modular, Upgradeable Avionics Architectures– UAM industry will need to adapt, possibly repeatedly, to get to UML-4, particularly as aircraft built for the legacy NAS enter and

remain in service– Avionics should design for these foreseeable evolutions:

• Increasing SVO and smaller HMI• Better and better sensors, which will mean moving them to different positions on the aircraft skin and re-wiring• Communications channel agnosticism• Decreasing aircraft-to-aircraft separation and upgraded position information rates and precision (10 Hz, see #8)

– NASA should conduct research with industry to develop modular means to incorporate rapid upgrades such as complete change out of communications systems on the aircraft

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5. Plan a Decadal Architecture– Planning for long term integrated vehicle architectures is needed– The time line from ideation to certification is often 7 years– Industry needs incentives to equip, so retrofits can also drag out– A decadal roadmap provides better coordination across ground, air, training– NASA should research a roadmap to achieve NASA-defined UAM airspace architectures (INT-1 )

6. Synchronize Air, Ground, Equipment and Training– Implementation of evolutionary change, such as reduced separation in urban airspace, cannot be enacted

until enough vehicles are equipped for that change to make it worthwhile– Inclusion of legacy vehicles in the urban airspace reduces benefits for as long as those vehicles continue to

be operated– Hands-on management is used to ease the problems of different generations of avionics mixing in the air,

for instance, human controllers granting clearances at vertiports based on aircraft ability, instead of using an automated landing coordinator, which is cheaper

– NASA should • Continue the decadal roadmap research in subsequent years to encompass processes to integrate mixed fleets and the

tools and automation needed• Integrate such findings with the FAA

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Integration Recommendations (7 - 9 of 11)7. Designate Trusted Agents to manage multi-generational fleet avionics problems

– A service supplier provides this hands-on management for generational avionics problems, at a cost– NASA should research the attributes and roles of trusted agents that manage UAM airspace

8. High Density Requires Higher Navigation Precision and Updating– Own-aircraft position needs to be known with greater precision (GNSS-augmented and 10Hz)– Paves the way for automated flight control– Legacy aircraft will fall short of this standard and require greater separation, possibly different handling rules for landing– Avionics manufacturers will need new rules of thumb to manage the integrated engineering – 5G electronics manufacturing &

suppliers leading the way on faster components– NASA should conduct research with industry to develop more precise and higher update rate integrated avionics, to support

safely decreased separation under cooperative surveillance for the urban environment9. Develop Electromagnetic Interference Engineering for Avionics, Signals

– Large electric motors and wires to them are generating EMF– GNSS receivers today incorporate magnetic compasses in orientation, are confused by EMF – Small-wavelength signals (GNSS, GHz) bounce off metal (in wires, windings, magnets)– Orientation may impact interference; vertiport design may be affected as well– GHz sensor-to-FMS signals onboard may be a part of the future aircraft– NASA should research and test operation of low-power sensors and comms, especially GNSS nav and low power UAT2, on

board an operating electric air vehicle to determine EMF pitfalls and engineering needs

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10. Establish an Industry-Government Body to Establish Standards and Rate Complex SVO/Automation Software as a Step in Software Certification

– Complexity and AI are difficult to get through certification. FAA certification of vehicles and avionics will continue

– SVO and sensor fusion will incorporate complexity and AI– Need an industry consensus body that creates accepted software modules/library with established

functionality and reliability. The standards are submitted to FAA for certification– Developing common software standards lowers the cost of development, reduces time in certification,

and reduces the number of unique code libraries that need to be run through the FAA for certification– NASA should lead/integrate: work with industry and FAA to identify/establish an independent complex

aviation software standards organization11. Develop a Common Flight Test/Simulation Environment for CNS Avionics in UAM Operations

– Many new challenges: urban wind canyons and ducted props, landing on rooftops, high EMI/EMF environment, limited signal availability

– NASA should develop a flight test environment for numerous safety of flight, signal strength, EMF, cooperative separation and other testing

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Agenda



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Certification Process, Simplified

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Certification Recommendations (1-3 of 12)1. Support UAT2 for Cooperative Surveillance

– NASA should integrate: • Work with FAA to reserve frequency within the new architecture• Encourage industry work group to design a message set for the future, 2030

– NASA should research cooperative surveillance CONOPS, to ensure mutual separation, coordinate flight paths (eg landing) and in mixed fleets (re-broadcast to sUAS)

2. Develop MOPS for Recommended Communications Technologies– NASA should integrate:

• Work with industry standards groups for MOPS within the new architecture• Roll back or limit C band TSO 213

– NASA should test solutions to support industry standards-making3. Re-Allocate VDL-3 for UAM

– Particularly for human pilots and the legacy NAS interactions– NASA should integrate: work with FAA to reserve frequency, within the

new architecture– NASA should research integrating UAM in traditional NAS using data

communications over VDL-346

5G

5G Sat

C-band

LEO

VDL-3

Augmented GNSS

GNSS+RF mapping

LEO

RF Beacon

GNSS+ISAR

LIDAR

Machine Vision

K-band Radar, FMCW

Radio Altimeter

5G

ACAS/TCAS

UAT2

Multilateration

Infrared (IR)

LIDAR

Acoustic

RF Detection

K band Radar

Advanced Radar

Bistatic Radar

Com

mun

icatio

nsN

avig

atio

nCo

oper

ativ

eSu

rvei

llanc

e

KeyFAA Use/MPSInstallation ACOperations AC


Certification Recommendations (4 & 5 of 12)

4. Develop MOPS for Navigation Technologies– Multiple sensor fusion MOPS need to be developed for navigation, landing, and for non-cooperative collision

avoidance– CNS 2: NASA should test fusion sensors with industry in support of standards– Int 7: NASA should research with industry in modular software practices that will assist in certifying

advanced coding techniques used with fusion sensors– NASA should integrate, working with RTCA to support MOPS for fusion navigation

5. Develop Requirements for Ground-Based Noncooperative Surveillance– Develop a solution before a security mandate arises– CNS 4: NASA should research alternatives under the identified use cases– NASA should research who is the consumer of ground-based surveillance– NASA should lead development of the system architecture, and include the role of the consumer of ground-

based surveillance– NASA should integrate the solution with FAA, DHS, other government organizations

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Certification Recommendations (6-8 of 12)

6. Develop Simulations and Requirements for Conflict Avoidance Between UAM and sUAS– Are developing different comms and SAA– May have different avionics with different update rates– Will have different maneuverability characteristics– May use same vertiports– Need to develop DAA algorithms for each– NASA should research solutions, test them, and integrate solutions with industry and FAA

7. Emphasize Performance Based Standards for Development of Novel Technologies– Particularly for noncooperative solutions such as navigation– NASA research should work with several technologies in CNS areas to promote standards based on

performance rather than point designs8. Establish a Design Assurance Level (DAL) for UAM Designs

– Reliability and availability levels needed for detailed designs, to bring CNS products to market, to mature the industry

– NASA should support/integrate industry and FAA as they work toward a solution

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9. Ensure Appropriate Aviation Type Testing As Novel Solutions to UAM CNS Capabilities Mature – E.g., shake and bake, environmental, reliability testing needed to either trust or re-work COTS products– Dispel myths about the suitability of consumer-grade electronics when safety is on the line– NASA should conduct testing of CNS solutions to support industry standards (CNS 3, Int 9, Int 11)

10. Define Minimum Performance Standards for Autonomy and Assistive Automation and Evaluate Impact on Existing Regulatory Frameworks

– Regulatory allowance for sensor-based perception to conduct flight operations is extremely limited; emergency landing and Cat IIIc landing only

– Must encompass use of sensor-based perception in Parts 91 and 135; MOPS and ACs can follow– NASA should conduct research to assist in the extension of FARs permitting operational use of sensors in

place of physical human eyes, working with industry standards bodies to integrate findings

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11. Research and Mature Digital Data Communications Architectures– Voice comms, not CPDLC, is required in Parts 91, 121, 135– Digital/data comms needed to free up frequency and lower workload by automating routine reporting– Necessary for greater automation – NASA should

– conduct research to identify how CPDLC can be standardized for required UAM communications, especially when operating in traditional NAS

– conduct research to identify processes to reduce controller workload in mixed traffic, using CPDLC in the NAS– conduct research to identify whether VDL-3 CPDLC could coordinate vertiport operations

12. Research and Define Appropriate Spacing Standards in Urban Airspace Procedures– Multi-year timelines needed to reduce spacing through RNP mechanism– Concepts like spacing drive performance specifications to MOPS and to TSOs; compliant avionics follow– NASA should research and define reduced spacing requirements and the roadmap to accomplish increasing

density (CNS 7)– NASA should lead the effort to define reduced spacing for UAM operations

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Agenda



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Interoperability Recommendations (1 of 3)

1. Research Collaborative Detect and Avoid• No convergent CONOPS for UAM and sUAS• No convergent comms for UAM and sUAS• Standards are needed for USS Data Exchange

– ASTM F34 working this for UTM, between USSs• NASA should research ways for these vehicles to work collaboratively or they will be restricted by

airspace• NASA should integrate, to build consensus on equitable access to low altitude airspace

– Establish or task a working group• NASA should lead/integrate to define the authority that provides the communication gateway

between sUAS and UAM, in collaboration with industry, for the system architecture• NASA should test and support development of the means by which cooperative shared

surveillance assures safety between sUAS and UAM– Or alternatively, test to determine dual stack safe separation feasibility

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Interoperability Recommendations (2-3 of 3)

2. Determine Vertiports Compatibility– Develop standards for vertiports

• In terms of required functions, layout, user classes, size, equipment– Investigate sUAS and UAM Vertiport Compatibility

• Are Autoland capabilities compatible?• What’s the sUAS use case for Vetriports? A new Fedex-Office facility?• Do sUAS and UAM have compatible requirements for vertiports, such as EMF resilience?

– NASA should • Research vertiport standards, procedures• Research through simulation and test whether sUAS and UAM can both operate out of a vertiport

3. Determine shared data sets on urban terrain and navigational features– Community data sets for RF mapping, terrain mapping, obstacle reporting– NASA should integrate data set and CNS sharing between the UAM and sUAS communities

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Summary

• Traditional NAS CNS technologies are not expected to be able to support the densities of UML-4– Separation through voice commands not expected– Surveillance from airport and en route radar– GPS denied environments– 1090 ADS-B restrictions– Standard separation will not support densities

• Alternatives must replace these technologies, rules and processes– Must be cooperative, vehicle-based– Signal-denied environment and a cooperative set of rules are the basis for these recommended CNS

technologies• UML-4 cannot be achieved until a selection of the recommended CNS technologies are described

in aviation standards and available as avionics• A more detailed architecture needs to be defined to ease the uncertainty and establish a path

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Recommendations for NASA Role by Area

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NASA should pursue this kind of action

Recommendation area

Research Test Integrate Lead

CNS 1, 4, 5, 7, 8 2, 3 1, 5, 7 1

Integration 1, 3, 4, 5, 6, 7, 8, 9 9, 11 2, 3, 6, 10 2, 10

Certification 1, 3, 5, 6, 7, 10, 11 2, 6 2, 3, 4, 5, 6, 8, 10

5, 12

Interoperability 1, 2 1, 2 1, 3 1

UML-6 recommendations are found in CNS-6 & 7 and Integration-4

The numbers in the table refer to the numbered recommendations in each area of the briefing

Thank you

investigation of reliable, secure, and scalable cns

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