Ping 2020 ADS-B in Small UAS for Sense and Avoid Operations

Ping 2020 ADS-B in Small UAS for Sense and Avoid Operations

Research Analysis

Miguel A. Linares

Embry-Riddle Aeronautical University

  

Introduction

         Obstacle and traffic avoidance has been a growing concern to the Federal Aviation Administration (FAA) since the introduction of unmanned systems operations in the National Airspace System. (NAS). Larger UAVs like the MQ-9 Predator B are equipped with transponders that enable Air Traffic Controllers (ATC) to detect and identify the aircraft up to a certain range. Using radar technology, a Radio Frequency (RF) signal is sent out interrogating the transponders for aircraft information (Rogers, 2016). Although this technology works well for large UAV operations in the NAS it is unfeasible to include such hardware in small scale drones that also pose a potential hazard to other aerial platforms manned and unmanned in the NAS. Sense and avoid is, as the name describes, the ability of a system to detect and maneuver to prevent collisions. It has also become a term that mirrors the FAA Visual Flight Rules (VFR) term “See and Avoid” stating the pilot’s responsibility to fly actively avoiding traffic as a requirement to operate in the NAS while 1,000’ above, 500’ below, and 2,000’ horizontal from clouds and the visibility is at least 3 statute miles (FAR, 2011). Nonetheless, it is nearly impossible for a manned aircraft pilot to avoid collisions with small UAS (SUAS) if he/she cannot see or detect them.

uAvionix Ping 2020 Description

         One solution to this problem that the FAA is looking to implement by the year 2020 is Automatic Dependent Surveillance – Broadcast (ADS-B). This technology involves equipping aircraft, to include SUAS, with a sensor much like a transponder that can communicate with ATC and other aircraft via Line of Sight (LOS) and ground stations, to share information on satellite based navigation, position, altitude, and identification (TRIG, 2016).

        uAvionix has developed a full range ADS-B transceiver that is small enough to install in SUAS. This sensor is capable of detecting aircraft in real time, who are transmitting on the 1090MHz and 978MHz bands within 100 statute miles. It then generates the reports of potential threats based on a programmable spherical radius. Although the international standard for high altitude flight (at or above 18,000 feet) is the 1090MHz band for transmissions, the Ping2020 transmits on the 978MHz band which is within minimums for flight below the 18,000’ mark. This is particularly ideal for SUAS as they generally operate at lower altitudes. The fact that it transmits on a smaller band also equates to lower power consumption, which enhances the compatibility with SUAS. Measuring a minute 25x39x12mm and weighing only 20 grams, the required input power of the sensor is 6-29V and 30W peak. This low power consumption makes it a great match for SUAS. The sensor uses a MavLink for its input and output data interface. The final factor that makes the Ping2020 an ideal sense-and-avoid option for SUAS is its ability to integrate directly with the Pixhawk Autopilot and with DJI SUAS via a DJI software development kit (uAvionix, 2016).

Conclusion

              While the Ping2020 ADS-B sensor provides the “sense” portion of sense-and-avoid, it still relies on operator input or autonomous system reaction to maneuver and avoid collisions with the detected traffic. Also this system does not enable autonomous navigation indoors to avoid colliding against objects in the SUAS’s surroundings. This requires the use of technologies like LIDAR and vision based obstacle detection, along with the algorithms for autonomous avoidance maneuvers. Nonetheless, in the realm of “Sense and Avoid” in terms of the FAA’s “See and Avoid” requirements for NAS operations, the Ping2020 ADS-B sensor is the ideal choice for SUAS due to its size, power requirements, transmission capabilities, and interface assimilation features.

References

FAR. (2011). Sec. 91.155 — Basic VFR weather minimums. Retrieved from Rising Up Aviation: http://www.risingup.com/fars/info/part91-155-FAR.shtml

Rogers, T. (2016). Transponders, How They Work . Retrieved from Avionics List; new and used avionics: http://www.avionicslist.com/articles/how_transponders_work.php

TRIG. (2016). Introduction to ADS-B. Retrieved from Trig Avionics: http://www.trig-avionics.com/knowledge-bank/ads-b/introduction-to-ads-b/

uAvionix. (2016). ping2020 Overview. Retrieved from uAvionix: http://www.uavionix.com/products/ping2020/