Flight Testing an ADS-B Equipped sUAS in GPS-Denied Environments

摘要

This paper details integration and flight testing of an automatic dependent surveillance-broadcast (ADS-B) transponder onto a small unmanned aerial system (sUAS). The sUAS broadcasts ADS-B packets on 1090 MHz and is visible to any aviation stakeholder with an ADS-B in receiver. In general, this provides a means for other observers such as air traffic control (ATC) or manned traffic to track the sUAS position. However, ADS-B relies heavily on availability of the global positioning system (GPS) and cannot function properly without reliable GPS. The work includes development of a secondary position estimation system that utilizes a local area multilateration system (LAMS) to interrogate the ADS-B transponder as a standard Mode S transponder and localize the sUAS in GPS-denied environments. The system consumes position information from both ADS-B and LAMS sources and fuses these reports into consistent estimates of the sUAS position. These fused estimates are then made available to aviation stakeholders so the situational awareness of the sUAS operator is not compromised. This allows the system to operate even if the sUAS enters into a GPS-denied environment. This paper describes the development of the fusion system as well as the flight testing and results of the integrated system.