Analysis of Frequency Agile Radar via Compressed Sensing

Abstract

Frequency agile radar (FAR) is known to have excellent electronic counter-countermeasures (ECCM) performance and the potential to realize spectrum sharing in dense electromagnetic environments. Many compressed sensing (CS) based algorithms have been developed for joint range and Doppler estimation in FAR. This paper considers theoretical analysis of FAR via CS algorithms. In particular, we analyze the properties of the sensing matrix, which is a highly structured random matrix. We then derive bounds on the number of recoverable targets. Numerical simulations and field experiments validate the theoretical findings and demonstrate the effectiveness of CS approaches to FAR.

Theoretical Analysis of Multi-Carrier Agile Phased Array Radar

“…This section presents a theoretical analysis of range-Doppler recovery of Algorithm 1. Since both WMAR and CAESAR are generalizations of FAR, the following analysis is inspired by the study of CS-based FAR recovery in [7]. In particular, we extend the results of [7] to multi-carrier waveforms, as well as to extremely complex electromagnetic environments, where some transmitted pulses are interfered by intentional or unintentional interference.…”

“…Since both WMAR and CAESAR are generalizations of FAR, the following analysis is inspired by the study of CS-based FAR recovery in [7]. In particular, we extend the results of [7] to multi-carrier waveforms, as well as to extremely complex electromagnetic environments, where some transmitted pulses are interfered by intentional or unintentional interference. In the presence of such interference, only partial observations in the beamformed matrix Z remain effective for range-Doppler reconstruction.…”

“…Following [7], we focus on the MIP. A sensing matrix Φ is said to satisfy the MIP when its coherence, defined as…”

“…This reduced performance is a byproduct of the relatively small number of radar measurements processed by FAR, which stems from its usage of a single narrwoband waveform for each pulse. The performance reduction can be relieved by using compressed sensing (CS) algorithms that exploit sparsity of the target scheme [7]. However, the degradation becomes notable in extremely congested or contested electromagnetic environments [8], where there may be no vacant bands in some pulses or some radar returns of the transmitted pulses may be discarded due to strong interference [9], [10].…”

“…Frequency agility is induced by randomly selecting the carriers utilized, resulting in a wideband multicarrier agile radar (WMAR) scheme. While the increased number of carriers is shown to achieve improved reconstruction performance compared to conventional FAR [8], WMAR utilizes multiband signals, thus its implementation is more costly than that uses conventional narrowband monotones, and may suffer from envelope fluctuation [16].…”