Weak signal capturing method based on unequal-length double-block zero padding algorithm

Abstract

The invention discloses a weak signal capturing method based on an unequal-length double-block zero-filling algorithm, and mainly solves the defect that the existing double-block zero-filling method is poor in detection performance under small frequency offset. According to the implementation scheme, a local spreading code adopted by a sending end is subjected to shaping offset quadrature phase shift keying modulation, and an original local signal is obtained; sequentially carrying out filtering, down-conversion and digital sampling on the received radio frequency signal at a receiving end to obtain an original baseband complex signal; respectively carrying out block combination on the original baseband complex signal and the local signal, and increasing the length of a data sub-block on the premise of ensuring that the total length of the sub-block is not changed to obtain a new baseband complex signal data block and a new local signal data block; performing circumference correlation on the new baseband complex signal data block and the new local signal data block to obtain correlation value data; and judging whether capture succeeds or not according to whether a peak value appears in the correlation value data or not. The method can obtain better capture performance under small frequency offset, and can be used for data transmission and satellite positioning navigation.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and in particular relates to a method for capturing weak signals, which can be used for data transmission, satellite positioning and navigation and ranging. Background technique [0002] With the continuous development of satellite navigation technology, the application of global navigation satellite system GNSS is more and more extensive. The United States, Russia, China and the European Union all have satellite positioning and navigation systems covering the world. Positioning and navigation with no blind spots and high sensitivity has become the latest technological development direction, which requires the rapid acquisition of weak signals in a high dynamic environment. [0003] Traditional weak signal acquisition algorithms include serial acquisition algorithms and parallel acquisition algorithms. Among them, the serial acquisition algorithm realizes signal acquisition by cont...

AI Technical Summary

Problems solved by technology

However, in DBZP and its improved algorithm, the lengths of the two blocks are completely equal. When selecting the block length, choosing a shorter block length can ensure a larger Doppler frequency offset search range. However, when the frequency When the deviation is small, choosing a shorter block length will lead to a decrease in detection performance. Neither DBZP nor its improved algorithm can guarantee a larger Doppler frequency offset search range and better detection performance under small frequency offsets.

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