ADS-B mixed SUAS and NAS system capacity analysis and DAA performance

Abstract

Automatic Dependent Surveillance-Broadcast (ADS-B) technology was introduced more than twenty years ago to improve surveillance within the US National Airspace Space (NAS) as well as in many other countries.Via the NextGen initiative, implementation of ADS-B technology across the US is planned in stages between 2012 and 2025. ADS-B's automatic one second epoch packet transmission exploits on-board GPS-derived navigational information to provide position information, as well as other information including vehicle identification, ground speed, vertical rate and track angle. The purpose of this technology is to improve surveillance data accuracy and provide access to better situational awareness to enable operational benefits such as shorter routes, reduced flight time and fuel burn, and reduced traffic delays, and to allow air traffic controllers to manage aircraft with greater safety margins. Other than the limited amount of information bits per packet that can be sent, ADS-B's other hardlimit limitation is capacity. Small unmanned aircraft systems (sUAS) can utilize limited ADS-B transmission power, in general, thus allowing this technology to be considered for use within a combined NAS and sUAS environment, but the potential number and density of sUAS predicted for future deployment calls into question the ability of ADS-B systems to meet the resulting capacity requirement. Hence, studies to understand potential limitations of ADS-B to fulfill capacity requirements in various sUAS scenarios are of great interest. In this paper we, validate/improve on, previous work performed by the MITRE Corporation concerning sUAS power and capacity in a sUAS and General Aviation (GA) mixed environment. In addition, we implement its inherent media access control layer capacity limitations which was not shown in the MITRE paper. Finally, a simple detect and avoid (DAA) algorithm is implemented to display that ADS-B technology is a viable technology for a mixed NAS/sUAS environment even in proposed larger mixed density environments.

Enabling UAS BVLOS flights in CTR

“…These are mainly connected with the future intended operation in VLL, without transported persons on board. According to the statement of ICAO [17,18], the widespread provision of UA ADS-B (Out) in mode S on the frequency band 1090 MHz (1090 ES) is inappropriate due to the already considerable congestion of this band, which is at the limit of its capacity. Another obstacle can be the height of the UAS operation, and therefore the risk of signal reflection from physical obstacles (buildings) and the resulting interference.…”

Modelling and Simulation of Collaborative Surveillance for Unmanned Traffic Management

“…In [21], a similar scenario was studied, also considering the current regulatory practices of the U.S. National Airspace System, and the authors finally reported that ADS-B should be used along with some other system, especially optical sensors for collision avoidance. Other works were focused on the simulation of the ADS-B mounted on UAS to evaluate performance at low altitudes [22] or to propose collision-avoidance algorithms based on the ADS-B information [23].…”

Evaluating the Interoperability of Urban Air Mobility Systems and Airports

“…Previous studies by MITRE and NASA determined that 1,400 or more ADS-B-equipped small, unmanned aircraft can be supported below 400 ft in a metropolitan area without frequency saturation if they use a low power setting (17,18). Although passenger carrying UAM operations will operate above 400 ft, the tradeoff between flight speed, aircraft density, and power setting provides flexibility to manage ADS-B frequency saturation and is not anticipated to restrict UAM operations.…”