X-ray pulsar navigation TOA estimation method based on Bayes estimation

Abstract

The invention belongs to the technical field of X-ray pulsar autonomous navigation and discloses an X-ray pulsar navigation TOA estimation method based on Bayes estimation. Under the condition that the overall trend of a photon counting rate accords with the Poisson distribution, an X-ray photon arrival time sequence can be modeled into a non-homogeneous Poisson process; the flow characteristics of PSR B0531 + 21 pulsars accord with the Poisson distribution, and a Poisson distribution signal model is established and divided into a time-frequency model and a frequency-stabilizing model; the frequency-stabilizing model of the photon sequence is selected to perform Fourier transform and then the frequency-stabilizing model is converted into a frequency domain to obtain a photon flow probability function expression with time delay estimation parameters; the photon flow probability function expression is converted into a likelihood function capable of calculating a time delay parameter by using a Bayes theorem for solving; and a Tool multi-mode nested sampling algorithm is calculated by Bayes estimation, iteration is carried out, and the parameter estimation value of the likelihood function is further calculated. The invention effectively improves the TOA estimation precision within the observation time and meets the future engineering development requirement of pulsar navigation.

Description

technical field [0001] The invention belongs to the technical field of X-ray pulsar autonomous navigation, in particular to a TOA estimation method for X-ray pulsar navigation based on Bayesian estimation. Background technique [0002] At present, in astronomical navigation, X-ray pulsar navigation is a new navigation technology that relies on pulsar signal sources. Among many celestial bodies, X-ray pulsars have the characteristics of good period stability, strong flow, and predictable rotation frequency. It is precisely because of the above-mentioned advantages that pulsars have been incorporated into the current navigation system as a "lighthouse" for deep space exploration missions. TOA estimation is the basic observation of the navigation system, so as to obtain important information such as the position and attitude of the spacecraft. [0003] Universities and research institutes at home and abroad have done a lot of research work on the arrival time of pulsars. The...

AI Technical Summary

Problems solved by technology

[0004]The current algorithm still has defects in meeting the requirements of the navigation system, and the efficiency and accuracy cannot meet the requirements of the pulsar navigation system

The algorithm for solving TOA by using the cumulative contour model is limited by the contour sampling frequency and cannot obtain high precision

There are few algorithms for solving the photon flow model, and they are easily limited by the observation time. Higher accuracy can be obtained in a shorter time, otherwise the system delay accuracy cannot be guaranteed.

[0005] To sum up, the problems existing in the existing technology are: the current algorithm still has defects in meeting the requirements of the navigation system, and the efficiency and accuracy cannot meet the requirements of pulsar navigation. system requirements

[0007] The time-domain method is limited by the contour sampling frequency and cannot obtain high precision

Directly use the photon sequence to solve the problem, which requires a large amount of calculation and takes a long time

Therefore, it is very difficult to obtain a high-precision TOA within the effective observation time

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