Pulsar frequency parameter quick search method

Abstract

The invention provides a pulsar frequency parameter quick search method, in particular to a frequency parameter quick search method applied to a spaceborne detector for receiving pulsar signals. The method comprises the following three steps of: determining an index function of frequency parameter search; applying a dynamic cross entropy reduction method to carry out pulse signal frequency parameter large-range coarse search to obtain an accurate search sample space; and utilizing a small-scale differential evolution method to complete rapid iterative refinement calculation of frequency parameters in an accurate sample space. According to the scheme, quick and accurate pulsar actual measurement signal frequency parameter estimation is realized so that a real-time on-orbit dynamic signal processing process is completed, and the accurate pulse signal frequency and the frequency first-order derivative estimation value can be obtained.

Description

technical field [0001] The invention relates to the field of aerospace technology, in particular to a fast search method for pulsar frequency parameters. Background technique [0002] X-ray pulsar navigation has entered the stage of space demonstration and verification. In order to meet the actual engineering application requirements of pulsar navigation, the signal processing technology suitable for on-orbit spacecraft is becoming the focus of research. [0003] The X-ray pulsar signal flow is extremely weak. In the actual navigation process using X-ray pulsars, the spacecraft needs to continuously observe the pulsars in orbit to accumulate enough photons, and the Doppler effect caused by the orbital motion of the spacecraft will make the detector The frequency of the received pulsar signal is shifted. For dynamic signal processing technology, that is, using the estimated orbit information, the position information of the spacecraft within the observation time is obtained ...

AI Technical Summary

Problems solved by technology

Since the photon TOA data is a non-equally spaced discrete sequence, the frequency domain search methods mostly use approximate processing methods such as resampling or equal space difference, and problems such as "spectrum leakage" will lead to poor frequency search accuracy, and the measured data processing shows that, The processing results of most frequency-domain search methods are significantly different from the actual situation; time-domain search methods generally have high precision and can meet high-precision frequency estimation, but the large search range will affect the calculation efficiency, and the search process index function Problems such as strong noise and multiple extreme values ​​will also affect the frequency search accuracy

[0005] The search methods in the prior art have the following problems: (1) Most of the existing frequency (period) search methods do not consider the actual orbital dynamics of the spacecraft or use the simulation data of the simulated orbital dynamics for inspection, but the actual data processing shows that most of the The processing results of the frequency domain search method are significantly different from the actual situation, the estimation accuracy is poor, and the amount of calculation is huge; (2) Most of the existing frequency (period) search methods only search for the frequency (period) of the received pulsar signal, without considering the The impact of the orbit dynamics on the first-order derivative of the frequency leads to poor error absorption effect, and the high precision of processing and calculation efficiency cannot be balanced; (3) The calculation efficiency of the traditional grid two-dimensional search algorithm is extremely poor, and the distribution of index function values ​​​​is messy , there are a large number of local value peaks at different positions, which is a complex multi-extreme value optimization problem, and it is easier to fall into a local optimum during the search process; (4) Some methods reduce the frequency of calculation by batch processing photon data (Periodic) search method, because less photon information is used each time, the result is easier to converge to a local optimum, and the robustness is poor

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