Carrier tracking method and tracking device of extremely low signal-to-noise ratio based on fpga

Abstract

The invention discloses a carrier tracking method and a carrier tracking device with extremely low signal to noise ratios based on FPGA. The method comprises the steps of extracting a carrier signal by using a digital down conversion unit to serve as an input signal; performing frequency discrimination and phase discrimination on the input signal to acquire the frequency and phase of the input signal; performing loop filtering on the frequency and phase by using a loop filter of a frequency-locked loop and a loop filter of a phase-locked loop, and outputting a filter output value; adjusting the filter output value, adjusting output frequency, and performing frequency mixing with the input signal to form closed-loop tracking. The device comprises the digital down conversion unit, a frequency discriminator, a phase discriminator, the loop filters and a digital control oscillator. The carrier tracking method and tracking device with extremely low signal to noise ratios based on FPGA provided by the invention integrates advantages of the phase-locked loop and the frequency-locked loop, and can achieve low noise and high dynamic performance index, so that the tracking loop can achieve rapid and stable locking in the case of extremely low signal to noise ratio, high dynamic and large frequency deviation.

Description

Technical field [0001] The present invention relates to the field of carrier synchronization, in particular to a carrier tracking method and a tracking device based on FPGA with extremely low signal-to-noise ratio. Background technique [0002] The deep space measurement and control communication subsystem needs to complete a series of functions such as remote control, telemetry, data transmission, ranging, speed measurement, and angle measurement. The prerequisite is to achieve accurate carrier synchronization, which is divided into carrier acquisition and carrier tracking. The carrier acquisition unit performs FFT processing on the received signal to obtain a rough estimate of the Doppler frequency; the carrier tracking unit performs fine synchronization on the signal after successful acquisition, and tracks the phase offset, frequency offset, and frequency of the carrier in real time. Rate of change. [0003] The design of the carrier tracking phase-locked loop is very importan...

AI Technical Summary

Problems solved by technology

[0003] The design of the carrier tracking phase-locked loop is very important, and it is necessary to take into account the noise and dynamic performance indicators. The main carrier of the existing carrier tracking system is difficult to track and has low stability under extremely low signal-to-noise ratio.

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