Method for weakening near-far effect of pseudo-satellite based on subspace projection

Abstract

The invention aims to provide a processing method for a pseudo-satellite signal receiving process, and the method comprises the following steps of: detecting a weak signal of a pseudo-satellite signalby a kurtosis detection method, and performing subspace projection processing on the condition that the weak signal exists until a characteristic value K is smaller than a threshold. Due to the adoption of a subspace projection method, a strong signal is projected to an orthogonal space by a received signal through an orthogonal projection operator of a strong signal vector to capture a weak signal, so that the interference of the strong signal to the weak signal can be basically eliminated. Meanwhile, the method does not need a signal amplitude parameter for the construction of a strong signal space, only needs two parameters of signal delay tau and Doppler frequency shift fd, and improves the efficiency and accuracy. According to the subspace projection method provided by the invention,the captured pseudo satellite signal is suitable for a code division multiple access modulation mode, and has very good application advantages in indoor and outdoor fusion positioning application.

Description

Technical field: [0001] The invention belongs to the field of satellite signal propagation and reception, and in particular relates to a pseudo-satellite signal receiving and processing algorithm for weakening the near-far effect. [0002] technical background: [0003] Global Navigation Satellite System (GNSS) is an infrastructure that can provide users with continuous, real-time, precise position, velocity and time information. At present, there are mainly four global satellite navigation systems, namely GPS in the United States, GLONASS in Russia, Galileo in the European Union and BDS in China. After decades of development, these systems have penetrated into all aspects of people's lives, providing great convenience for production and life. However, under the existing technical conditions, the GNSS system can only provide accurate information services in a relatively open outdoor environment. In narrow valley areas, especially in closed indoor spaces, due to terrain and ...

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Problems solved by technology

[0004] However, the pseudolite system deployed in the indoor space is very close to the user receiver, the relative distance difference is obvious and the range of change is large. According to the theory of radio transmission, this will lead to a large dynamic range of received signal power, and the receiver Nearby pseudolite signals will interfere with distant pseudolite signals, affecting the capture of distant signals and causing large errors in the positioning calculation results of the receiver

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