Dechirping processing method based on synchronization of multiple DDSs

Abstract

The invention discloses a dechirping processing method based on synchronization of multiple DDSs. The method comprises the following steps: step 1, providing completely consistent reference clocks forall DDSs; 2, providing completely consistent IO _ UPDATE signals for all the DDSs through an FPGA (Field Programmable Gate Array); 3, performing synchronous configuration on the DDS through the FPGA;judging whether the synchronous clock signals of all DDSs are completely aligned or not; if not, carrying out reconfiguring; 4, after synchronization is completed, transmitting one or more paths of DDS signals to the transmitting front end to be transmitted according to actual requirements, and transmitting one path of DDS signal as a reference signal to the receiving end; and step 5, performingtime delay fine control on the transmitting signal and the reference signal to complete dechirping processing. According to the invention, the problem of time delay deviation caused by poor device synchronism in the traditional radar altimeter dechirping processing is solved, the time delay between output signals is accurately controlled by combining a plurality of DDS chips with the FPGA, the difference frequency point and the signal bandwidth are reduced, the system hardware pressure is reduced, and the effect of more accurate distance measurement result is realized.

Description

technical field [0001] The invention relates to the technical field of radar altimeters, in particular to a deslant processing method based on multi-block DDS synchronization. Background technique [0002] As a high-resolution radar, the two-dimensional imaging of SAR requires high range resolution, which means that the transmitted signal must have a large bandwidth. The increase in signal bandwidth puts forward higher requirements on the acquisition capability of the radar system receiver. In order to reduce the pressure on the system hardware, the echo signal bandwidth can be reduced by deskewing processing, thereby reducing the difficulty of data acquisition. At the same time, the time delay between the transmitted signal and the reference signal can be preset according to the target distance, reducing the frequency point of the difference after de-skewing processing, and further reducing the pressure on the system hardware. [0003] The above processing method requires ...

AI Technical Summary

Problems solved by technology

This method aims to solve the problem of delay deviation caused by poor synchronization of devices in the traditional radar altimeter de-skewing process. Through multiple DDS chips synchronously combined with FPGA to accurately control the delay between output signals, reduce the difference frequency point and signal bandwidth, and reduce the system Hardware pressure to achieve more accurate ranging results

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