Doppler frequency cancellation based full digital main carrier tracking method

Abstract

The invention relates to an all-digital main carrier tracking method based on a Doppler frequency cancellation which belongs to a measurement and control communications field. The invention is characterized in that: by using a characteristic of a frequency spectrum which is dual-modulated by the main carrier and a vice-carrier of a USB measurement and control signal, in the signal of carrying outthe main carrier capture and removing most of Doppler frequency difference, a FIR lowpass filter is used for extracting the main carrier signal carrying a negative Doppler rest frequency difference information, a positive-negative cancellation of the Doppler rest frequency difference is completed, and a purpose of tracking the main carrier is reached. The invention overcomes problems of trouble ina ring road structure and parameter design, a Doppler residual error not able to be removed completely in a traditional way of using a phase-locked loop, and thus the invention is suitable for tracking the main carrier in the USB measurement and control system.

Description

technical field [0001] The invention relates to an all-digital main carrier tracking method based on Doppler frequency cancellation, which is suitable for main carrier tracking of unified S-band (Unified S-band, USB) measurement and control signals. This method does not need a feedback control loop, and can better achieve the purpose of eliminating Doppler frequency offset. This scheme is especially suitable for the tracking control of the main carrier under the condition of Doppler frequency change rate. The method belongs to the field of measurement and control communication. Background technique [0002] During the communication process, due to the radial movement speed (the speed along the straight line direction of the communication object) between the communication objects, the Doppler effect appears between the received signal and the transmitted signal, so that there is a Doppler frequency difference; In addition, in most cases, the movement of the communication ob...

AI Technical Summary

Problems solved by technology

Using a phase-locked loop to track the remaining Doppler frequency difference has a simple structure and does not occupy much resources, but there is always a certain frequency residual, and the Doppler frequency difference cannot be completely eliminated; when the Doppler change rate is large , in order to track the change of the upper Doppler frequency, a high-order phase-locked loop is required, and the design of a high-order phase-locked loop involves the stability of the loop, which is very difficult to implement

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