Design And Realization Of Radio Frequency Interference Time - Frequency Detection System For Radiometer

With the worsening of electromagnetic environment, radio frequency interference (RFI) has become the biggest obstacle to improve microwave radiometer detection precision. So the study of the RFI detection is very significative. Aimed at the demand for the RFI detection of the radiometer, this paper studied the RFI detection algorithm based on the time-frequency domain, designed and implemented the RFI detection system of the radiometer in the time-frequency domain, and the system was verified.First of all, this paper studied the RFI detection method of the radiometer based on time-frequency domain. On the basis of the introduction of Kurtosis detection algorithm and energy detection algorithm, this paper analyzed the detection performance of Kurtosis detection under the constant false alarm to different SNR and duty ratio of RFI. The paper expounded the important role of the wavelet packet decomposition algorithm played in time-frequency analysis, put forward the kurtosis-wavelet packet and energy-wavelet packet RFI detection algorithm based on the time-frequency domain, and studied the performance of kurtosis-wavelet packet and energy-wavelet packet algorithm for the RFI detection through Matlab simulation.Second, the paper designed the hardware for the RFI detection system of the radiometer in the time-frequency domain, including the ADC acquisition circuit, the clock generator circuit, the FPGA core circuit, DSP core circuit, serial port and Ethernet communication circuit, power circuit, DDR2 and NAND FLASH storage circuit and communication module of FPGA and DSP. And it expounded the problems that needed pay attention in the design of hardware circuit PCB.Next, the paper designed the software for the RFI detection system of the radiometer in the time-frequency domain, including the clock generator control module, the ADC control module, FIR filter, uPP interface of FPGA and DSP, and ethernet and serial communication module. It also transplanted the RFI detection algorithm based on the time-frequency domain to DSP. And the transplant was verified successfully.Finally, the RFI detection system of the radiometer in the time-frequency domain was tested and experimentized, including function verification of the clock generator, ADC chip, UPP interface and DDR2 memory. Then, the RFI detection system of the radiometer in the time-frequency domain was experimentized. The result showed that the RFI detection algorithm of the radiometer based on the time-frequency domain can effectively realize RFI detection. It also verified the correctness of the RPI detection system of the radiometer in the time-frequency domain.