Analysis of Radar and ADS-B Influences on Aircraft Detect and Avoid (DAA) Systems

Abstract

Detect and Avoid (DAA) systems are complex communication and locational technologies comprising multiple independent components. DAA technologies support communications between ground-based and space-based operations with aircraft. Both manned and unmanned aircraft systems (UAS) rely on DAA communication and location technologies for safe flight operations. We examined the occurrence and duration of communication losses between radar and automatic dependent surveillance-broadcast (ADS-B) systems with aircraft operating in proximate airspace using data collected during actual flight operations. Our objectives were to identify the number and duration of communication losses for both radar and ADS-B systems that occurred within a discrete time period. We also investigated whether other unique communication behavior and anomalies were occurring, such as reported elevation deviations. We found that loss of communication with both radar and ADS-B systems does occur, with variation in the length of communication losses. We also discovered that other unexpected behaviors were occurring with communications. Although our data were gathered from manned aircraft, there are also implications for UAS that are operating within active airspaces. We are unaware of any previously published work on occurrence and duration of communication losses between radar and ADS-B systems.

Probabilistic Safety Assessment for UAS Separation Assurance and Collision Avoidance Systems

“…Although adequate performance standards were established for various surveillance equipment, to date the impacts of surveillance system failures in terms of separation degradation, specifically in the UAS platform, have not been defined. Moreover, traditional radar and Mode-A/C transponder technologies show inherent deficiencies in different airspace and equipage scenarios especially in the presence of high air traffic densities [25][26][27][28][29][30][31][32][33]. The failure modes for different cooperative sensors such as Mode S, TCAS, ADS-B are well defined and safety assessments have been carried out on the individual surveillance sensor considering functions in the manned aircraft.…”

Assessing the Effect of ADS-B Message Drop-Out in Detect and Avoid of Unmanned Aircraft System Using Monte Carlo Simulation

“…As the onboard computer will make use of surveillance sensor data to trigger alert in the absence of the 'human eye', it is crucial to have robust and efficient surveillance sensors. However, studies have shown that, both the 1090ES and UAT ADS-B are prone to significant message degradations [8][9][10][11][12][13][14][15][16]. One of the drawbacks of ADS-B is message loss or dropout.…”

“…One of the drawbacks of ADS-B is message loss or dropout. In our previous studies, ADS-B has shown significant message loss along with different message anomalies [13][14][15][16]. In this work, the severity and risk associated with ADS-B drop-out in DAA function are investigated utilizing Monte Carlo simulation.…”

Severity and Effect of ADS-B Message Drop Out in Detect and Avoid of Unmanned Aircraft System

“…Initial assessment of UAT ADS-B [5], [6], [7] showed significant message degradations. One of the anomalies of ADS-B is message discontinuation or drop out.…”

“…This work emphasizes the severity and risk associated with drop out in UAS DAA. The investigation is based on the extended ADS-B data analysis carried out at be Semke et el [6]. The analysis predicts how ADS-B message drop out could affect UAS DAA system if used as a single means of surveillance.…”