Interference-destructive spread-spectrum receiver for multi-channel spread-spectrum ranging

Abstract

The invention discloses an interference cancellation spread spectrum receiver for multi-channel spread spectrum ranging. Based on the existing direct spread spectrum baseband, combined with the periodical characteristics of pseudo-code, by delaying the input signal of the pseudo-code loop by TPN without delaying the input signal of the carrier loop, the interference cancellation can be completed on the input signal of the pseudo-code loop without increasing the information symbol demodulation delay, thus the ranging accuracy of this kind of system can be improved. In addition, the invention does not need to calculate the inverse matrix or the cascade receiver, so the complexity and the resource consumption of the system can be effectively reduced, and the invention can be realized on the platform such as FPGA or DSP, and is particularly suitable for the application scenarios such as spacecraft measurement and control where the resource is limited.

Description

technical field [0001] The invention belongs to the technical field of wireless communication and ranging, in particular to an interference cancellation spread spectrum receiver for multi-channel spread spectrum ranging. Background technique [0002] The spread spectrum measurement and control system of the spacecraft not only has a point-to-point ranging mode, but also a point-to-multipoint ranging mode, which supports multiple ground measurement and control stations to measure the distance of the same spacecraft at the same time. On the one hand, the point-to-multipoint mode can improve the orbit determination accuracy of the spacecraft; on the other hand, since the spreading codes of each channel are not completely orthogonal; therefore, multiple access interference will be formed between each channel, resulting in Ranging accuracy is reduced. Aiming at the problem of multiple access interference in spread spectrum systems, the industry has proposed a multi-user detectio...

AI Technical Summary

Problems solved by technology

Although the efficiency of the parallel interference cancellation detector is higher, the problem of the misjudgment of the previous stage and the influence of the subsequent stage will be more serious

[0005] The above two types of methods have their own defects. First, the amount of calculation of the linear detector is too large. Secondly, it only pays attention to the correctness of the symbol judgment, and does not consider the tracking accuracy of the pseudo-code phase. Therefore, the linear detector cannot improve the spread spectrum ranging. Ranging performance of transponders

Both serial and parallel interference cancellation detectors require multiple receivers to be cascaded, which not only wastes on-chip logic resources, but also increases the demodulation delay of information symbols, and this demodulation delay will affect the real-time performance of the ranging system. sex

In addition, parallel interference cancellation detectors are susceptible to false positives from previous stages, and serial interference cancellation detectors have delays in each channel that vary with signal power, so they cannot be applied to multi-channel spread spectrum ranging responses machine

Images