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Copyright of Journal of Signal Processing is the property of Journal of Signal Processing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Signal Processing is the property of Journal of Signal Processing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Passive bistatic radar detects targets by exploiting available local broadcasters and communication transmissions as illuminators, which are not designed for radar. The signal usually contains a time-varying structure, which may result in high-level range ambiguity sidelobes. Because the mismatched filter is effective in suppressing sidelobes, it can be used in a passive bistatic radar. However, due to the low signal-to-noise ratio in the reference signal, the sidelobe suppression performance seriously degrades in a passive bistatic radar system. To solve this problem, a novel mismatched filtering algorithm is developed using worst-case performance optimization. In this algorithm, the influence of the low energy level in the reference signal is taken into consideration, and a new cost function is built based on worst-case performance optimization. With this optimization, the mismatched filter weights can be obtained by minimizing the total energy of the ambiguity range sidelobes. Quantitative evaluations and simulation results demonstrate that the proposed algorithm can realize sidelobe suppression when there is a low-energy reference signal. Its effectiveness is proved using real data. [ABSTRACT FROM AUTHOR]

In random frequency-hopping pulse–Doppler radar, the transmitted frequencies are randomly distributed in the given frequency bandwidth. As a result, this kind of radar has the advantage of anti-jamming. However, because of the sidelobe level fluctuating randomly, the sidelobe of a large scatterer can mask the presence of nearby smaller scatterers. The adaptive pulse compression (APC) algorithm has been shown capable of effectively suppressing the range sidelobes, but the performance gain is diminished whenever the return signals have a low signal-to-noise ratio (SNR). Furthermore, moving targets with high speed bring about the range migration problem. To solve these problems, the coherent integration APC (CIAPC) algorithm is proposed. The simulation results indicate that in a low SNR scenario, the CIAPC algorithm can suppress the range sidelobes of large scatterers and can improve detection performance.

In random frequency-hopping pulse–Doppler radar, the transmitted frequencies are randomly distributed in the given frequency bandwidth. As a result, this kind of radar has the advantage of anti-jamming. However, because of the sidelobe level fluctuating randomly, the sidelobe of a large scatterer can mask the presence of nearby smaller scatterers. The adaptive pulse compression (APC) algorithm has been shown capable of effectively suppressing the range sidelobes, but the performance gain is diminished whenever the return signals have a low signal-to-noise ratio (SNR). Furthermore, moving targets with high speed bring about the range migration problem. To solve these problems, the coherent integration APC (CIAPC) algorithm is proposed. The simulation results indicate that in a low SNR scenario, the CIAPC algorithm can suppress the range sidelobes of large scatterers and can improve detection performance. [ABSTRACT FROM AUTHOR]

Pulse compression, usually achieved using a matched filter, is extensively applied in radar/sonar systems. This process improves the signal-to-noise ratio (SNR) of the received signal without increasing the peak transmitted power. However, it is often desirable to accept a slight penalty in the target SNR in order to suppress the range sidelobes. In this paper, a novel weighted mismatched filter (WMMF) that can reduce range sidelobes to the designed level over specified regions is proposed. Two algorithms are provided to calculate the WMMF in different situations. A novel performance metric, the mean sidelobe level over a specified region, is also proposed to demonstrate the performance of the proposed method. Then, the SNR loss is deduced and analyzed based on several experiments. Finally, simulations and experiments based on real measured data are conducted to illustrate the effectiveness of this method. The theoretical evaluation and experiments show that the proposed WMMF can be used for all types of waveforms based on pulse compression processing and can flexibly and effectively suppress range sidelobes. Moreover, the mainlobe and the SNR loss can also be controlled by the proposed algorithms. In addition, this method can be easily applied to existing radar systems without modifying the radar transmitter or receiver. [ABSTRACT FROM AUTHOR]

We propose a double-modulated frequency modulation waveform for multiple-input multiple-output radars. The transmitted waveforms are divided into two segments with the same bandwidth and different durations. The durations of all the segments among different waveforms are used to optimize the performance. Theoretical analyses are provided to study the relationships between the autocorrelation/cross-correlation functions and parameters such as bandwidth, pulse duration, and segment durations. Numerical results show that the proposed waveform has low cross correlation even with Doppler shifts. The autocorrelation sidelobes, cross-correlation levels, and range sidelobes of the proposed waveform reduce with the increase in the time-bandwidth product. [ABSTRACT FROM PUBLISHER]