Determination method of pulse TOA of X-ray pulsar-based navigation

Abstract

The invention relates to a determination method of pulse TOA of X-ray pulsar-based navigation. The method comprises the steps of firstly, performing pulse contour folding in a selected folding cycle according to a photon sequence obtained within the observation time, performing normalization so as to obtain a normalized intensity vector, then performing feature subspace decomposition on a covariance matrix of the normalized intensity vector, so as to obtain a noise subspace matrix, constructing a searching vector according to a standard pulse contour, then obtaining a spectrum of the pulse TOA from the noise subspace matrix and the searching vector, and searching a spectrum peak value of the spectrum of the pulse TOA, so as to obtain a value of the pulse TOA. According to the method, the pulse TOA is determined on the basis of the feature subspace decomposition, so that the calculation accuracy of the pulse TOA can be effectively increased, and the pulse contour folding is adopted, so that the approximation degree of a pulse contour estimated value and the standard pulse contour is increased, thereby increasing the calculation accuracy of the pulse TOA within the observation time.

Description

technical field [0001] The invention relates to the technical field of spacecraft autonomous navigation, in particular to a method for determining the TOA of an X-ray pulsar navigation pulse. Background technique [0002] X-ray pulsar navigation (XPNAV) is a new concept of spacecraft autonomous navigation technology, which can provide rich navigation information such as position, velocity, time and attitude for spacecraft flying in low earth orbit, deep space and interstellar space. Its important engineering application value and strategic research significance have attracted the attention of international space agencies. Judging from public reports, the most well-known X-ray pulsar navigation program is the "X-ray Navigation and Autonomous Positioning" (XNAV) research program launched by the US Defense Advanced Technology Development Agency in 2004. Research and ground verification, space flight tests will be carried out on the International Space Station and high-orbit sa...

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Problems solved by technology

Xie Zhenhua et al. used bispectrum to suppress Gaussian noise in the document "Xie Zhenhua, Xu Luping, Ni Guangren. Time delay measurement of pulsar cumulative pulse profile based on bispectrum. Acta Physica Sinica, 2008,57(10):6683-6688". It also has a high estimation accuracy under the noise ratio, but this method is proposed for the pulse TOA determination of the cumulative profile of radio pulsars, and is not applicable to XPNAV; Su Zhe et al. A new measurement algorithm for pulsar cumulative pulse profile time delay. Acta Astronautica Sinica, 2011,32(6):1256-1261." A method for determining the TOA of XPNAV pulses combining rough estimation and precise measurement is proposed. Interpolation to improve precision

[0005] However, in order to obtain a better navigation effect, the accuracy of the existing pulse TOA determination method still needs to be further improved

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