A radio frequency cancellation method for passive radar dual-channel receiver

Abstract

The invention discloses a radio frequency cancellation system and method for a dual-channel receiver of a passive radar. The cancellation system comprises an analog phase shifter, an analog attenuator, a radio frequency switch, a combiner, a first digital analog converter, a second digital analog converter, an FPGA controller, an FLASH storage and an upper computer. The cancellation method comprises the calibration stage and the radar working stage, wherein in the calibration stage, the dual-channel receiver controls a target echo receiving antenna to rotate by a circle at the set step length, a system is calibrated in every direction, and an attenuator code word and a phase shifter code word in each direction are obtained; the radar works normally. The radio frequency cancellation system and method are simple, direct wave signals are restrained by more than 30 dB through radio frequency cancellation, the cancellation ratio is large, the dynamic receiving range of the whole radar is wider, and the requirement that a weak target reflection signal is extracted from an external radiation source signal is met.

Description

technical field [0001] The invention belongs to the field of radio frequency technology, and in particular relates to a radio frequency cancellation system and method for a passive radar dual-channel receiver. Background technique [0002] We know that passive radar uses external radiation sources (television, radio, and mobile communication network transmission signals) to detect targets, and it does not actively emit electromagnetic waves, so it is not easy to be discovered by enemy reconnaissance systems. Therefore, passive radar has the advantages of high concealment, strong anti-interference ability, and long operating distance, which is of great significance for improving the survivability of military electronic systems in the modern electronic warfare environment. [0003] Since the power of the external radiation source signal is relatively small, the power of the signal reflected by the target is also weaker; at the same time, there is also a strong direct wave sign...

AI Technical Summary

Problems solved by technology

At present, the circuit of general radio frequency cancellation system is complex, and the cancellation effect is not obvious, and can only achieve a cancellation ratio of about 20dB. The power difference after elimination makes it difficult for the radar's receiving dynamic range to meet the requirements of extracting weak target reflection signals from external radiation source signals

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