Automatic Censoring CFAR Detector Based on Ordered Data Difference for Low-Flying Helicopter Safety.

Wen Jiang,Yulin Huang,Jianyu Yang

doi:10.3390/s16071055

Abstract

Being equipped with a millimeter-wave radar allows a low-flying helicopter to sense the surroundings in real time, which significantly increases its safety. However, nonhomogeneous clutter environments, such as a multiple target situation and a clutter edge environment, can dramatically affect the radar signal detection performance. In order to improve the radar signal detection performance in nonhomogeneous clutter environments, this paper proposes a new automatic censored cell averaging CFAR detector. The proposed CFAR detector does not require any prior information about the background environment and uses the hypothesis test of the first-order difference (FOD) result of ordered data to reject the unwanted samples in the reference window. After censoring the unwanted ranked cells, the remaining samples are combined to form an estimate of the background power level, thus getting better radar signal detection performance. The simulation results show that the FOD-CFAR detector provides low loss CFAR performance in a homogeneous environment and also performs robustly in nonhomogeneous environments. Furthermore, the measured results of a low-flying helicopter validate the basic performance of the proposed method.

Highlights

Helicopters, used in law enforcement, fire fighting, medical evacuation, civil emergencies, search and rescue and new/traffic reporting, are often required to fly at low altitudes of limited visibility [1,2]
We study the performance of first-order difference (FOD)-constant false alarm rate (CFAR) detector for a variety of homogeneous, multiple target and clutter edge environments
We first give the censoring probability of interference targets and compare the detection performance of FOD-CFAR to those of the CA-CFAR, OS-CFAR, censored mean level detector (CMLD) and variability index (VI)-CFAR

Summary

Introduction

Helicopters, used in law enforcement, fire fighting, medical evacuation, civil emergencies, search and rescue and new/traffic reporting, are often required to fly at low altitudes of limited visibility [1,2]. Obstacles in the flight path or close to it often pose a significant threat to low-flying helicopters [3]. Such obstacles may be power lines, aerial cableways, pylons and towers [3,4]. Many researchers developed optical sensors to improve the safety of low-flying helicopters [1,3,4]. Radar provides robustness to atmospheric conditions, and it is widely used in a low-flying helicopters to sense the surrounding environment [2,10,11,12,13,14,15,16].

Methods

Results

Conclusion