Adaptive Separation Thresholds for Self-Separation of Unmanned Aircraft System in Dynamic Airspace

Abstract

The key challenge to integrate the unmanned aircraft system (UAS) into airspace is to develop a means to sense and avoid (SAA) other aircrafts. The main function of the SAA is self-separation, i.e. remaining ''well clear'' of the other aircrafts. The separation thresholds must be quantitatively defined for the UAS to autonomously maintain self-separation. In this paper, the separation thresholds are defined quantitatively for the UAS in a dynamic airspace full of aircrafts that differ in motion state and performance. Then, a ''sector-like'' dynamic collision-free region (CFR) was set up around the UAS. The size of the CRF can be adjusted adaptively according to the relative motion states of the surrounding intruders, the performance of the UAS, and the altitude of the airspace. The simulation results show that the proposed adaptive separation thresholds adapted to the dynamic airspace environment better than the fixed separation thresholds recommended by Sense & Avoid Science and Research Panel (SARP), and controlled the missing and false alarm rates on low levels. This means our adaptive separation thresholds can effectively balance the safety and operation efficiency of the airspace. INDEX TERMS Unmanned aircraft system (UAS), airspace integration, well clear (WC), self-separation, collision avoidance, separation thresholds, sense and avoid (SAA).

A Real-Time Collision Avoidance Strategy in Dynamic Airspace Based on Dynamic Artificial Potential Field Algorithm

“…where, r connection safe can be derived from the geometric relationship in Figure 1. The specific computations can be seen in [31]. To sum up, the safety distance threshold of the UAV at time t can be expressed as:…”

“…If the obstacle is far away from the own UAV, the minimum safety distance is used. The detail of the ''sector-like'' dynamic CFR calculation can be found in [31].…”

An analytical view on Unmanned Aircraft Systems

“…If the above point is not satisfied, the pilot manually activates the termination system in which the command of a UAS pilot is required for safeguarding the public. e. On-board intelligence challenges On-board intelligence, teaming/swarming [35], health management, collision avoidance, affordability, sensing. f. Interoperability…”

Analyzing Sense and Avoid Requirements to Integrate Unmanned Aircraft Systems into Controlled Airspace

“…Analyitical frameworks have been devised to model the effectiveness of single and multiple fused sensor networks in timely detection of intruding aircraft (Ramasamy et al 2018). Significant study has been done to define performance standards for the algorithms required of integrated DAA systems, but little has been done to define the physical performance standards of proposed non-cooperative sensors (Du, Zhang, & Gu 2019;Fern 2017;Ghatas et al 2017). Non-cooperative sensor fusion requires that non-cooperative aircraft, those without a functioning transponder or ADS-B system, can be reliably detected such that the UAS has sufficient time to initiate a turn to maintain well-clear of the intruding aircraft.…”