Multi-frame superimposed satellite signal capturing method and device

Abstract

The invention discloses a multi-frame superimposed satellite signal capturing method and device, and the method comprises the steps: carrying out the complex conjugate multiplication of a received digital baseband signal and a known symbol of a lead code, and achieving the demodulation; performing sliding window energy accumulation on the demodulated signal, and solving an energy value of an accumulation result to generate N energy value results, N being the symbol length of the physical frame; solving difference values between the N energy values of the current physical frame and N energy smooth values of a historical physical frame, multiplying the difference values by an influence factor a, performing accumulation operation on the difference values and a previous calculation result to obtain N smooth accumulation results, and taking the N smooth accumulation results as N energy smooth values of a new historical physical frame to obtain N energy smooth values of the historical physical frame; forming a first-order feedback loop structure; and reading an energy smooth value of a smooth accumulation result, searching a maximum value and a corresponding cache address, and judging the position of the needle head. Multi-frame superposition is carried out after demodulation, so that the anti-noise capability and the capture probability of capture are improved.

Description

technical field [0001] The invention relates to satellite communication technology, in particular to a multi-frame superimposed satellite signal acquisition method and device. Background technique [0002] The satellite link adopts a transparent forwarding method, and the satellite terminal can send and receive spontaneously. The capture capability of the satellite link is mainly determined by the length of the preamble of the physical frame. The longer the preamble, the higher the probability of satellite signal capture. The adaptive capture threshold The lower the value, the stronger the environmental adaptability of the satellite terminal; at the same time, the longer the length of the preamble, the greater the overhead of the physical frame, the less the payload transmitted per unit time, and the lower the bandwidth utilization of the satellite. [0003] In the existing satellite communication technology field, there have been many methods to improve the capture capabili...

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Problems solved by technology

[0004] For example, the patent publication number: CN 103543456 A discloses a large frequency offset GNSS signal acquisition method based on segmented correlation combined with FFT operation. Through segmented correlation combined with FFT operation, the parallel search of the carrier frequency can be completed while the code phase is serially searched. Search can effectively shorten the acquisition time of GNSS signals with large frequency offset and improve the anti-frequency offset ability of acquisition, but the anti-noise ability of the system acquisition has not been substantially improved

[0005] For example, the patent publication number: CN 106685879 A discloses a multi-frame synchronization method based on IEEE802.11 protocol OFDM technology, which uses coarse synchronization frame header estimation, fine synchronization frame header estimation, and frame tail estimation to ensure capture Under the condition of performance, the requirements for fine synchronization frame header estimation are simplified, but the coarse synchronization frame header estimation is realized by the special frame structure of the system silent period, and its application scenarios are greatly limited

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