X-ray pulsar signal time delay estimation method based on maximum posteriori estimation

A technique of maximum a posteriori estimation and time delay estimation, which is applied in the field of signal processing and can solve problems such as low estimation accuracy

Active Publication Date: 2021-09-10
XIDIAN UNIV
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Problems solved by technology

[0005] The purpose of the present invention is to address the deficiencies in the prior art above, and propose a method for estimating time delay of X-ray pulsar signals based on maximum a posteriori estimation, which is used to solve the technical problem of low estimation accuracy existing in the prior art

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  • X-ray pulsar signal time delay estimation method based on maximum posteriori estimation

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[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] refer to figure 1 , the present invention comprises the following steps:

[0036] (1) Initialization parameters:

[0037] Initialize the normal distribution of the spacecraft in the barycentric coordinate system BCRS of the solar system The position prediction error of The unit direction vector of an X-ray pulsar is n=(n x ,n y ,n z ), X-ray pulsar signal processing reference time t 0 , t 0 The rotation frequency of the X-ray pulsar is f(t 0 ), f(t 0 ) of the first and second derivatives are The spacecraft is at the observation time [t a ,t b ], the time sequence of the detected X-ray pulsar photons reaching itself is in represents the estimated value of δr of the spacecraft, and w represents the normal distribution (0,σ 2 ) noise, σ 2 Indicates the variance of w, n x , n y , n z respectively represent t...

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Abstract

The invention provides an X-ray pulsar signal time delay estimation method based on maximum posteriori estimation. The method comprises the following implementation steps: (1) initializing parameters; (2) correcting the time sequence of the X-ray pulsar photons reaching the spacecraft; (3) obtaining a mean value and a variance of prediction phase delay corresponding to a spacecraft position prediction error delta r; (4) solving a maximum value of a maximum posteriori estimation MAP cost function; and (5) obtaining the time delay estimation value of the X-ray pulsar signal. The maximum value of the maximum posteriori estimation MAP cost function is solved through the corrected time sequence and the mean value and variance of the prediction phase delay corresponding to the spacecraft position prediction error, and the time delay estimation value of the X-ray pulsar signal is obtained through the maximum value of the maximum posteriori estimation MAP cost function and the rotation frequency of the X-ray pulsar, so that the influence on the estimation precision due to the fact that only the photon arrival time sequence is considered and the spacecraft position prediction error is not considered in the prior art is avoided, and the time delay estimation precision is improved under the same observation time.

Description

technical field [0001] The invention belongs to the technical field of signal processing, and relates to a method for estimating time delay of X-ray pulsar signals, in particular to a method for estimating time delay of X-ray pulsar signals based on maximum a posteriori estimation, which can be used for X-ray pulsar navigation. Background technique [0002] X-ray pulsars are neutron stars that rotate at high speed and have super-strong magnetic fields. They are located far away from the solar system, about 0.1-30kpc away from the earth. X-ray pulsar navigation XPNAV is a new type of navigation method, which can provide rich navigation information such as position and time for spacecraft, and realize high-precision autonomous navigation and precise control of spacecraft. In the XPNAV system, the distance from the spacecraft to the SSB along the direction of the X-ray pulsar is obtained by comparing the time delay between the cumulative profile at the spacecraft and the standa...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01C25/00G01C21/24
CPCG01C25/00G01C21/24
Inventor 方海燕苏剑宇张泽葳高敬敬张力张魁
Owner XIDIAN UNIV
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