Speed-based Autonnomous Navigation Based On Astronomical Observation

Navigation,as one of the core technologies of spacecraft,is the key to ensuring the success of space missions.Astronomical navigation has become an effective means for spacecraft navigation with its advantages of good continuity,strong autonomy,and high navigation accuracy.The autonomous navigation based on the celestial spectral line information is a new navigation method proposed in recent years.The celestial radio or optical line information sensitive to the spacecraft detector is used as the navigation information source,and the space line information obtained from the real-time measurement is used to obtain aerospace.The radial velocity of the relative navigation source is combined with the ephemeris information of the navigation source and the inertial attitude information of the spacecraft to realize the autonomous navigation of the spacecraft.This navigation method is highly autonomous,does not require ground station support and obtains speed information in real time,without delays.It is a new type of effective means for autonomous navigation of spacecraft and has broad application prospects.As a new navigation method,celestial body line speed navigation is still relatively short in terms of research time,and there are still many key and difficult problems that need to be solved in real applications.For example,how to detect and extract useful spectral line information in the original observation spectrogram containing more background noise,that is,the high-precision perception and detection problem of navigation information source;how to lack the priori accurate model of the information of the navigation source line Next,the radial velocity of the spacecraft is extracted from the observation and measurement,and the system error and random error of the velocity measurement are analyzed.The speed error transmission flow is analyzed from the source error,the sensor error,and the speed measurement algorithm error of the navigation source,thereby improving velocity precision,the problem of the new measurement principle;how to design a reasonable navigation filter algorithm based on the physical properties of the navigation source and the movement law,the extractable measurement information accuracy,etc.,to achieve a higher positioning accuracy,that is,the new navigation algorithm problems.According to the current research status and main research directions of celestial body spectral line navigation,this paper discusses and studies the following aspects:Using wavelet method to denoise the original detection data and extract spectral line information.The wavelet transform method is introduced.Using its multi-resolution nature,the Mallat algorithm discrete wavelet transform is used to denoise the original data.In order to improve the spectral reconstruction accuracy,the dual-tree complex wavelet is used to process the data,which greatly improves the signal-to-noise ratio of the spectral line.Based on the principle of Doppler,radial velocity extraction is performed on radio lines and optical lines,respectively.A template was constructed using the measured spectral data and the red shift of the spectral line was measured using a cross correlation method based on PCA.In addition,the source of the speed estimation error is analyzed from the perspective of spectral line properties,measurement signal-to-noise ratio,and velocity measurement methods.The use of measured data for this speed measurement method verifies its feasibility.Radial velocity is used as the navigation algorithm to measure information,and the navigation filtering algorithm is designed according to the principle of celestial body line velocity navigation,and the systematic error introduced by the navigation source is considered.Combined with the bias separation estimation algorithm,the spacecraft navigation state quantity and measurement error quantity are simultaneously estimated.