Abstract
Cognitive radar can overcome the shortcomings of traditional radars that are difficult to adapt to complex environments and adaptively adjust the transmitted waveform through closed-loop feedback. The optimization design of the transmitted waveform is a very important issue in the research of cognitive radar. Most of the previous studies on waveform design assume that the prior information of the target spectrum is completely known, but actually the target in the real scene is uncertain. In order to simulate this situation, this paper uses a robust waveform design scheme based on signal-to-interference-plus-noise ratio (SINR) and mutual information (MI). After setting up the signal model, the SINR and MI between target and echo are derived based on the information theory, and robust models for MI and SINR are established. Next, the MI and SINR are maximized by using the maximum marginal allocation (MMA) algorithm and the water-filling method which is improved by bisection algorithm. Simulation results show that, under the most unfavorable conditions, the robust transmitted waveform has better performance than other waveforms in the improvement degree of SINR and MI. By comparing the robust transmitted waveform based on SINR criterion and MI criterion, the influence on the variation trend of SINR and MI is explored, and the range of critical value of Ty is found. The longer the echo observation time is, the better the performance of the SINR-based transmitted waveform over the MI-based transmitted waveform is. For the mutual information between the target and the echo, the performance of the MMA algorithm is better than the improved water-filling algorithm.
Highlights
Radar uses radio method to find targets and determine their spatial position
In [2], based on information theory, the author proposes a water-filling algorithm to maximize the mutual information between the received radar waveform and the target. e author studies the use of information theory to design the waveform to measure the resonance phenomenon of the extended radar target
Erefore, the energy distribution of the transmitted waveform is mainly concentrated around − 0.2, 0.2, and 0.4, so that a larger mutual information or signal-to-interference-plus-noise ratio can be obtained, so as to obtain better target estimation performance
Summary
Radar uses radio method to find targets and determine their spatial position. with the wide application of electromagnetic spectrum, the working environment of radar is more and more complex. e traditional radar has a single transmitting waveform, which is difficult to adapt to the complex and changeable working environment. In [2], based on information theory, the author proposes a water-filling algorithm to maximize the mutual information between the received radar waveform and the target. In [4], considering the uncertainty of the prior information of the radar target in the actual scene, the authors propose a waveform design method based on mutual information to ensure the parameter estimation performance of complex target models. In [10], the authors propose an adaptive orthogonal frequency division multiplexing radar communication waveform design method to improve the efficiency of limited spectrum resources and study the optimization problem of the conditional mutual information between the random target impulse response and the received signal and data information rate for frequency-selective fading channels.
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