Target Detection Algorithm for Hypersonic Vehicle Based on Wideband Radar Echo Model

Abstract

High speed of the hypersonic vehicle can cause the noticeable scale effect and intra-pulse Doppler on radar echoes, especially under the large time-bandwidth product transmitting signal. Under this condition, the conventional narrowband matched filter can introduce an obvious output signal-to-noise ratio loss to the radar target detection and big errors to motion parameter estimation. In addition, the long-time integration and high speed can lead to the across range unit, which further deteriorates the detection performance and motion parameter estimation. In order to address these problems, we first mathematically analyze the wideband radar echo model (because the narrowband condition is not met for hypersonic vehicle detection) and obtain the mathematic relationship among the scale effect, speed, and time-bandwidth product. Thereafter, based on this mathematic relationship, we define a generalized matched filter and propose a coherent long-time integration algorithm for the hypersonic vehicle detection. Compared with the full parameter space searching algorithm, this proposed algorithm obtains nearly the same anti-noise performance with a much lower computational complexity. Through mathematical analyses and numerical simulations, we verify the effectiveness of the proposed algorithm. It is worthwhile noting that the aforementioned mathematic relationship provides a theoretical basis for the transformation from the wideband radar echo model to the conventional narrowband radar echo model. On this basis, the hypersonic vehicle detection algorithm can be studied widely.