GNSS-based High-orbit Spacecraft Orbit Determination Algorithm And Performance Analysis

Because of the high orbit,the orbit of high-orbit satellites plas an irreplaceable role in meteorological and other aspects of communications.With the increasing usage of high-orbit satellites,the research on the orbit determination of high-orbit satellites has gradually increased.The traditional satellite orbit determination adopts the method of orbit measurement by ground stations.This method will impose extremely high requirements on the affordability of the ground stations and the complexity of resource allocation when the number of high-orbit satellites increases;With high and limited factors,it is difficult for China to achieve full coverage of ground stations in a short period of time.Therefore,the use of the Global Navigation Satellite System to locate high-orbit satellites has a very important significance.This topic will study the enhancement and evaluation of high orbit spacecraft positioning based on GNSS system.Firstly,this paper proposes the idea that taking advantage of back lobe signal together with the main lobe signal of a navigation satellite to positioning for high-orbit satellite and finished a simulation by STK.The constellation created for the simulation contains four major navigation constellations as well as GEO satellites and HEO satellites.Under the condition that the back lobe signal attenuate by 25 d B compared with the main lobe signal,the number of visible stars is located,the receiver signal power,and the geometry of the star can be seen.Analyze and compare the obtained data with the situation without considering the lobe signal of the navigation satellite,so as to obtain the performance evaluation of the main lobe and the back lobe when they participate in high-orbit satellite positioning at the same time.Then try to enhance the overall positioning effect from the perspective of enhancing the gain of the receiving antenna.A DOA estimation method based on orbit calculation is proposed.The real-time satellite position is obtained by orbit calculation.In the judgment of the visible star algorithm,the real-time visible star and visible satellite signal directions are finally obtained.After estimating the incoming wave direction of the signal,a certain number of star selection operations are performed among the visible stars,and the navigation satellites participating in the positioning are selected to respectively perform beamforming using different spatial filtering algorithms.Increasing the signal gain in the incoming wave direction so that the signal reaches the receiver's ability to capture the tracked power conditions.Finally,a simulation demonstration system is set up to demonstrate in real-time the system state obtained by system-level simulation,including visible satellite conditions,satellite selection conditions,and positioning accuracy(DOP)values.The demo system writes the program architecture using the state machine,controls STK from the bottom through Labview.Using STK's 3D and 2D animations to demonstrate real-time dynamic effects,and synchronously demonstrates visible stars and DOP values on the front panel of Labview.Dynamic trend.