We have observed weather clutter containing targets (ships) using an S-band radar with a frequency 3.05 GHz, a beam width 1.8°, and a pulsewidth 0.5 μs. To investigate the weather clutter amplitude statistics, w...We have observed weather clutter containing targets (ships) using an S-band radar with a frequency 3.05 GHz, a beam width 1.8°, and a pulsewidth 0.5 μs. To investigate the weather clutter amplitude statistics, we introduce the Akaike Information Criterion (AIC). We have found that the weather clutter amplitudes obey the log-normal, Weibull, and log-Weibull distributions with the shape parameters of 0.308 to 0.470, 4.42 to 4.51, and 15.91 to 16.44, respectively, for small data within the beam width of an antenna. We have proposed the log-normal/CFAR circuit modified a Cell-Averaging (CA) LOG/CFAR circuit. It is found that weather clutter is suppressed with improvement of 51.58 dB by log-normal/CFAR. As a result, we have showed that weather clutter observed by S-band radar does not obey the Rayleigh distribution and our log-normal/CFAR circuit has an effect on suppression of clutter and detection of target, while conventional LOG/CFAR circuit does not. In addition, if our circuit can be realized, we will have an advantage economically.展开更多
在S波段测波雷达系统中,系统的相干性直接影响了系统对海浪参数的测量。对于采用数字信号处理器(digital signal processor,DSP)为核心处理器的微波雷达系统,由于DSP的SYSBIOS系统对硬件中断的响应和任务调度存在时间不定性,破坏了系统...在S波段测波雷达系统中,系统的相干性直接影响了系统对海浪参数的测量。对于采用数字信号处理器(digital signal processor,DSP)为核心处理器的微波雷达系统,由于DSP的SYSBIOS系统对硬件中断的响应和任务调度存在时间不定性,破坏了系统的相干性,导致回波信噪比下降。针对这一问题,提出利用DSP的可编程实时单元子系统(programmable real-time unit subsystem,PRUSS)对中断采集信号进行实时查询与响应,可以实现中断的无延迟响应,严格保证了雷达对信号回波采集的相干性。展开更多
文摘We have observed weather clutter containing targets (ships) using an S-band radar with a frequency 3.05 GHz, a beam width 1.8°, and a pulsewidth 0.5 μs. To investigate the weather clutter amplitude statistics, we introduce the Akaike Information Criterion (AIC). We have found that the weather clutter amplitudes obey the log-normal, Weibull, and log-Weibull distributions with the shape parameters of 0.308 to 0.470, 4.42 to 4.51, and 15.91 to 16.44, respectively, for small data within the beam width of an antenna. We have proposed the log-normal/CFAR circuit modified a Cell-Averaging (CA) LOG/CFAR circuit. It is found that weather clutter is suppressed with improvement of 51.58 dB by log-normal/CFAR. As a result, we have showed that weather clutter observed by S-band radar does not obey the Rayleigh distribution and our log-normal/CFAR circuit has an effect on suppression of clutter and detection of target, while conventional LOG/CFAR circuit does not. In addition, if our circuit can be realized, we will have an advantage economically.
文摘在S波段测波雷达系统中,系统的相干性直接影响了系统对海浪参数的测量。对于采用数字信号处理器(digital signal processor,DSP)为核心处理器的微波雷达系统,由于DSP的SYSBIOS系统对硬件中断的响应和任务调度存在时间不定性,破坏了系统的相干性,导致回波信噪比下降。针对这一问题,提出利用DSP的可编程实时单元子系统(programmable real-time unit subsystem,PRUSS)对中断采集信号进行实时查询与响应,可以实现中断的无延迟响应,严格保证了雷达对信号回波采集的相干性。