Research On Signal Analytical Method For Asymmetric Spatial Heterodyne Spectral Velocimetry In Deep Space Exploration

With the increasing demand for space exploration and the accelerated development of aerospace technology,the deep space universe exploration is a necessary path for humanity in the future.Among them,the precise spatial positioning technique of artificial detectors is the basis for all their exploration work.Due to the increasing distance between spacecraft with Earth,traditional space exploration methods are increasingly constrained by signal delay,stellar occlusion,and radiation interference,making it much more difficult for ground-based stations to locate and control detectors,which will seriously affect the working performance and even survival ability of the spacecraft.Under this trend,the development of autonomous navigation and detection technology for detectors in deep space environments is increasingly receiving attention from people.At the same time,from the perspective of the first mover advantage in technological competition among countries,mastering high-precision exploration technology for deep space in the universe will also have a decisive role in China’s comprehensive national strength layout in the future.This paper focuses on the space velocity sensor carried by spacecraft in the deep space background,fully utilizing the advantages of small volume,light weight,high spectral resolution,and no moving components of Doppler Asymmetric Spatial Heterodyne interferometers.The research work on space heterodyne spectral velocimetry technology is carried out,mainly including the construction of signal models for spatial heterodyne spectral velocimetry,analysis of measurement accuracy constraints,demonstration of signal process methods,and engineering implementation of technical solutions.In the 6-degree-of-freedom positioning system of three-dimensional space,a Star Sensor that uses the observation angle of celestial bodies as measurement information have solved the problem of autonomous measurement of 3-axis rotation,while there is still a blank window for autonomous measurement of 3-axis translation.Taking cars as an example,the speedometer on the driver’s console is converted from axle speed and wheel size,it is not a true speed vector.The commonly used electronic eyes or navigation software(based on GPS and electronic maps)also belong to the non-autonomous measurement of third-party devices.Even the most cutting-edge autonomous driving technology(based on Li DAR and big data)has only just reached the threshold of autonomous speed measurement.Compared to aircraft in deep space environments,it is very difficult to accurately measure velocity solely by carrying instruments when far away from Earth base stations and other supported by various sources.Therefore,in order to meet the high-precision & real-time detection of extremely long range target sources,developing a space spectral velocimeter with miniaturization,device ization,and quasi real-time characteristics that can be carried on deep space detectors is an urgent technical challenge in the field of deep space detection.The main research work and innovative achievements in this dissertation include:1.A theoretical analysis model for asymmetric spatial heterodyne spectral velocimetry was constructed,and system mathematical modeling was achieved through the series superposition of optical amplification,measurement amplification,and analytical amplification.2.Through the analysis of the constraint conditions that affect the measurement accuracy,it is found that the root cause of the contradiction between absorption spectra,measurement accuracy,and instrument miniaturization is that the spectral characteristics of stars are reflected by the absorption peaks in their photosphere,while the resolution of absorption spectra does not meet the measurement amplification and analytical amplification effects in theoretical models.3.A technical scheme of background light synchronous elimination speed measurement have been proposed,which is based on the synchronization effect between the target light signal and the background light signal in a short period of time,the absorption spectrum signal could be transformed into an equivalent emission spectrum signal for analyze and process.This method can bypass the constraints of absorption spectrum resolution,and creates conditions for achieving high-precision spectral velocimetry.4.A compound optical path difference calculation and an adaptive frequency tracking method have been proposed.By optimizing the phase difference velocity measurement formula and configuring improved algorithms for single frequency transmission signals,the analytical amplification ability of the asymmetric spatial heterodyne spectral velocimetry system for micro variable signals has been greatly improved.At the end,the proposed signal analysis theory and spectral velocity measurement scheme were technically demonstrated through data simulation and multiple indoor and outdoor experiments.The experimental results show that under limited experimental environments and conditions,the outfield test results could comply with the theoretical model of spatial heterodyne spectral velocimetry technology proposed in the dissertation.The obtained laboratory velocity measurement accuracy was consistent with the research results of foreign teams,and the obtained field velocity measurement accuracy can also match the instability of the solar photosphere spectrum itself.Therefore,it can be considered that the research in this dissertation is helpful in promoting the application and development of autonomous navigation technology for deep space exploration in China.