Rapid-fluctuating Radar Signal Detection with Unknown Arrival Time

Abstract

We study the rapid-fluctuating radar signal detection, where the arrival time of the received signal, i.e., the range cell index of the target, as well as the complex amplitude of the signal and the noise are unknown. We show that even in Additive White Gaussian Noise (AWGN) environment, Uniformly Most Powerful Invariant (UMPI) test does not exist. Instead, the UMPI detector in known SNR is used as an upper performance bound for performance evaluation of any invariant detector performance. In addition, we derive Generalized Likelihood Ratio (GLR) detectors for this signal in AWGN with unknown noise variance and also in clutter with unknown covariance matrix. The GLR test statistic for AWGN represents the ratio of the maximum power over all cells to the total power. The GLRT for a clutter environment is also a power ratio which is the maximum over all range cells of the Euclidean norms of the spatially whitened observed sequence. Simulation results demonstrate that the performance of the proposed GLR test in AWGN is very close to the upper bound performance, i.e., to the UMPI test in known SNR.

Optimal invariant detection of a monochromatic plane wave with five unknown parameters

“…Suboptimal tests such as GLRT and locallymost-powerful-invariant (LMPI) test and other fast algorithms are implemented as practical methods to approach the bound. Invariance principle is applied to detect a rapid-fluctuating radar signal with arrival time, complex amplitude of signal and the noise variance unknown [1].…”

“…Signal detection is a critical problem for radar, sonar and wireless communication application [1][2][3][4][5][6][7]. In radar and sonar application, if a target appears, due to environmental uncertainty and Doppler effect, the received data are composed of signal with uncertain amplitude, frequency, phase and direction of angle arrival (DOA) and noise with unknown variance.…”

Optimal invariant detection of a monochromatic plane wave with unknown amplitude, frequency, phase, direction of arrival and noise variance

“…Signal detection is a critical problem for radar, sonar and wireless communication applications [1–7]. In radar and sonar applications, if a target appears, because of environmental uncertainty and the Doppler effect, the received data are composed of signals with uncertain amplitude, frequency, phase, direction of angle arrival (DOA) and noise with unknown variance.…”

“…Suboptimal tests such as the GLRT and locally most‐powerful‐invariant (LMPI) tests, and other fast algorithms are implemented as practical methods to approach the bound. In [2], the invariance principle is applied to a detection problem of a rapidly‐fluctuating radar signal with unknown arrival time, complex amplitude embedded in AWGN with unknown variance.…”