Method and realization for a radar digital IF receiver processing

A method of processing is proposed for radar digital intermediate frequency(IF) receiver with sum-difference three channels. Digital down conversion(DDC) is used to transform the intermediate frequency signal to the orthogonal video frequency signals. Digital automatic gain control(DAGC) is designed for enhancing dynamic range of IF digital receiver. Coherent accumulation and digital frequency discrimination are adopted to extract Doppler frequency. The angle errors of azimuth and pitch are measured by comparing amplitude of sum-difference channels, and the correction of amplitude and phase imbalance of sum-difference channels is realized by changing initial phases of local oscillator of difference channels. The realization of preprocessing of IF digital receiver based on single field-programmable gate array (FPGA) is introduced concretely. Actual testing on the digital receiver demonstrates that the measurement accuracy of processing fits the need of system.