Digital intermediate frequency receiver and method for single pulse radar

Abstract

The invention relates to the technical field of radars, in particular to a digital intermediate frequency receiver and method for a single pulse radar. The digital intermediate frequency receiver comprises a data acquisition module, a data preprocessing module, a signal processing module and a communication module, wherein the data acquisition module, the data preprocessing module, the signal processing module and the communication module are integrated in a hardware circuit board, so that the hardware size is reduced, the hardware complexity is reduced, and AGC, AFC and angle measurement of aweak signal at a negative signal to noise ratio are achieved by adopting digital detection algorithms such as FFT accumulation; the performance of poor channel amplitude and phase consistency after multiple frequency conversion and processing of an analog circuit is improved through a multi-channel amplitude and phase error correction function, and high channel amplitude-phase consistency is achieved; a data frame queuing selection rule is adopted in the angle error information, AGC code and AFC code transmission, the communication conflict caused by multi-serial-port communication is avoided, and the stability and reliability of the system are improved.

Description

technical field [0001] The present invention relates to the technical field of radar, to digital signal processing and Field Programmable Gate Array (Field Programable Gate Array, FPGA for short), in particular to a digital intermediate frequency receiver of monopulse radar, which can be used in a monopulse radar receiving subsystem. Background technique [0002] With the development of software radio, digital radar has become the trend of radar development. Due to the high requirements for the consistency of the amplitude and phase responses of the three channels of sum, pitch difference and azimuth difference in traditional monopulse radar, it is difficult to achieve the amplitude and phase of each channel after multiple frequency conversion and processing by analog circuits. Consistency of response, for this purpose, dual-channel, single-channel or conical scanning technology is often used, but these combined simplifications, collectively referred to as "channel combining...

AI Technical Summary

Problems solved by technology

Since the traditional three-channel monopulse radar receiver is difficult to guarantee the consistency of the amplitude and phase responses of the three channels, the accuracy is poor. Since the birth of software radio, digital intermediate frequency receivers have solved this problem very well and have been widely used. Applications

However, the existing digital IF receivers do not involve automatic gain control (AGC) and automatic frequency control (AFC), but only improve the accuracy of amplitude-phase error consistency, thereby improving the accuracy of angle measurement. In AGC and AFC, analog circuits are still used to achieve frequency And gain control, the analog AGC is through the gain control of each channel, so it is difficult to achieve the same gain response of each channel, so that the angle measurement accuracy cannot be further improved, and the requirements of modern precision tracking radar for angle measurement accuracy higher

The angle measurement function is only completed through the digital intermediate frequency receiver, and the AFC function is completed through the analog circuit, which will also cause the frequency control and the angle measurement to be out of sync, which affects the improvement of the angle measurement accuracy

Moreover, the analog AGC and AFC have relatively large defects in terms of accuracy and sensitivity. For example, in the case of weak signals and negative signal-to-noise ratios, it is difficult for analog circuits to extract signals for gain and frequency control.

Existing digital intermediate frequency receivers use digital circuits to implement angle measurement, and analog circuits to implement AGC and AFC. Communication conflicts will occur during multi-serial communication, making the system less reliable.

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