Generalised likelihood ratio test-based multiple-target detection for fluctuating targets with unknown parameters

In this paper, we address the radar adaptive detection problem in the case of multiple fluctuating targets with unknown parameters. The unknown parameters are: the number and location of targets, the amplitude and phase of received signals, the Doppler frequency of targets in slowly fluctuating case the target signal vectors in rapid-fluctuating case and the statistical characteristics of noise and clutter. We extract the generalised likelihood ratio test (GLRT) in Gaussian interference with unknown covariance matrix. Owing to high computational complexity of these detectors when the number of probable targets is large, we design a simple detector relying on the GLRT procedure, namely simplified GLR detector for implementation. This detector achieves satisfactory performance under several situations of practical interest and is simpler to implement than the designed GLR detector. Also in slowly fluctuation case, based on adaptive-matched filter (AMF), Kelly´s detector (KD) and adaptive coherence estimator (ACE) that are used for single-target detection, some detectors are presented for multiple-target detection called generalised AMF, generalised KD and generalised ACE. Furthermore, in rapid fluctuation case in Gaussian interference with unknown covariance matrix, we propose an intuitive inexpensive detector with low computational complexity, which we will refer to as the generalised energy detector. Simulation results illustrate and compare the performance and the efficiency of the proposed detectors.