Pseudo-satellite near-far effect inhibition method based on multi-constrained beam forming

Abstract

The invention provides a pseudo-satellite near-far effect inhibition method based on multi-constrained beam forming. Signals received by an antenna array are subjected to A / D (analog / digital) sampling, bandpass filtering, amplitude-phase error correction, covariance matrix and inverse matrix calculation, MUSIC (multiple signal classification) direction finding, pseudo-satellite and navigation satellite signal power estimation, calculation of constraint response vectors corresponding to the direction of pseudo-satellite signals, calculation of multi-constrained beam forming weight, digital beam forming, and navigation solution, so that local position is obtained finally. The method is more universal capable of operating in interference environment, convenient and flexible, modification of a transmitting terminal (pseudo-satellite) is avoided, and modification of radio frequency of a receiving terminal is also avoided. Verification shows that the method is effective and easy to implement.

Description

technical field [0001] The invention belongs to the field of GNSS pseudolite positioning and relates to a method for suppressing near-far effect of pseudolite. Background technique [0002] At present, the global navigation and positioning system (GPS) has been widely used in the field of sea, land and air. Generally speaking, at least 4 navigation satellites are required for accurate positioning of the receiver. However, in some unfavorable conditions, such as urban centers, canyons, mines, indoors and other areas, the number and geometric distribution of navigation satellites that can be received are limited, resulting in the inability of the receiver to locate accurately. Therefore, people have proposed a method for pseudolites to enhance satellite navigation and positioning systems. [0003] The so-called pseudolite refers to a signal generator on the ground that can emit signals similar to navigation satellites. Pseudolites can improve the availability, stability, rel...

AI Technical Summary

Problems solved by technology

The first four methods are difficult to implement and require a lot of changes to the radio frequency part or correlator of the receiver, so they are not widely used at present

The last method of pulse transmission has achieved better results in some cases, but there are still some problems: 1. The pulse signal has high requirements on the AGC (Automatic Gain Control) performance of the receiver, and also has a high impact on the dynamic range of the receiver. High requirements, for some receivers, due to the instantaneous interference effect of the pulse signal, the reception quality of the pulse signal is obviously not as good as that of the continuous signal

2. The pulse signal leads to an overall decrease in the signal power received by all receivers, which affects the use effect

And the above methods are all based on the transmitter (pseudolites), the versatility of the receiver is very poor

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