The Combined-GEO-IGSO constellation is the combination of Geostationary Earth Orbit(GEO) satellite and Inclining GeoSynchronous Orbit(IGSO) satellite.The Combined-GEO-IGSO constellation can integrate the advantages of...The Combined-GEO-IGSO constellation is the combination of Geostationary Earth Orbit(GEO) satellite and Inclining GeoSynchronous Orbit(IGSO) satellite.The Combined-GEO-IGSO constellation can integrate the advantages of GEO and IGSO to achieve regional coverage.In order to discuss the performances of the Combined-GEO-IGSO constellation,the performances of coverage,elevation,diversity,and transmission are simulated in China and surrounding regions by Satellite Tool Kit(STK).The simulation results show that:the combined constellation can reach higher multi-satellite coverage and higher communication elevation in China and surrounding areas;the Doppler shift,delay,and propagation loss of this constellation have little impact on the system.As regional coverage constellation,the Combined-GEO-IGSO is feasible.展开更多
Positioning accuracy of the Global Navigation Satellite System(GNSS) can be analyzed by Positioning Dilution Of Precision(PDOP).In order to enhance the navigating performance of Asia and the Pacific areas,this paper a...Positioning accuracy of the Global Navigation Satellite System(GNSS) can be analyzed by Positioning Dilution Of Precision(PDOP).In order to enhance the navigating performance of Asia and the Pacific areas,this paper analyzes the next generation BeidouTM navigation satellite system(CompassTM) enhanced by Geostationary Earth Orbit(GEO) and Inclining GeoSynchronized Orbit(IGSO).As global navigation satellite system,CompassTM must be robust enough to avoid system layoff,when some nodes are not available.So,the CompassTM enhanced by GEO and IGSO constellation is proposed and analyzed its PDOP proformance,this paper shows some exciting results of performance of CompassTM enhanced by GEO and IGSO.From the simulation results,we can found that:when more than fifteen satellites are invalid,the enhanced system could be operating normally.展开更多
A new satellite orbit prediction method based on artificial neural network(ANN)model is proposed to improve the precision of orbit prediction.In order to avoid the difficulty of amending the dynamical model,it is atte...A new satellite orbit prediction method based on artificial neural network(ANN)model is proposed to improve the precision of orbit prediction.In order to avoid the difficulty of amending the dynamical model,it is attempted to use ANN model to learn the variation of orbit prediction error,and then the prediction result of ANN model is used to compensate the predicted orbit based on dynamic model to form a final predicted orbit.The experiment results showed that the orbit prediction error based on ANN model was less than that based on dynamical model,and the improvement effects for different satellites and different time were different.The maximum rates of improvement of predicting 8,15,30 d were respectively 80%,77.77%,85%.The orbit prediction error control technique based on the method of back overlap arc compare was brought forward to avoid the risk that the precision of predicted orbit is even worse after it is compensated by ANN model.The phenomena of failure were basically eliminated based on this technique,and the rate of failure was reduced from 30%to 5%.This technique could ensure that the engineering application of ANN model could come true.展开更多
基金Supported by the National Natural Science Foundation of China (No. 60972061,No. 60972062,and No. 61032004)the National High Technology Research and Development Program of China ("863" Program) (No. 2008AA12A204)the Natural Science Foundation of Jiangsu Province(BK2009060)
文摘The Combined-GEO-IGSO constellation is the combination of Geostationary Earth Orbit(GEO) satellite and Inclining GeoSynchronous Orbit(IGSO) satellite.The Combined-GEO-IGSO constellation can integrate the advantages of GEO and IGSO to achieve regional coverage.In order to discuss the performances of the Combined-GEO-IGSO constellation,the performances of coverage,elevation,diversity,and transmission are simulated in China and surrounding regions by Satellite Tool Kit(STK).The simulation results show that:the combined constellation can reach higher multi-satellite coverage and higher communication elevation in China and surrounding areas;the Doppler shift,delay,and propagation loss of this constellation have little impact on the system.As regional coverage constellation,the Combined-GEO-IGSO is feasible.
文摘Positioning accuracy of the Global Navigation Satellite System(GNSS) can be analyzed by Positioning Dilution Of Precision(PDOP).In order to enhance the navigating performance of Asia and the Pacific areas,this paper analyzes the next generation BeidouTM navigation satellite system(CompassTM) enhanced by Geostationary Earth Orbit(GEO) and Inclining GeoSynchronized Orbit(IGSO).As global navigation satellite system,CompassTM must be robust enough to avoid system layoff,when some nodes are not available.So,the CompassTM enhanced by GEO and IGSO constellation is proposed and analyzed its PDOP proformance,this paper shows some exciting results of performance of CompassTM enhanced by GEO and IGSO.From the simulation results,we can found that:when more than fifteen satellites are invalid,the enhanced system could be operating normally.
基金supported by the National Natural Science Foundation of China (41204022)the Opening Project of Shanghai Key Laboratory of Space Navigation and Position Techniques (12DZ2273300)
文摘A new satellite orbit prediction method based on artificial neural network(ANN)model is proposed to improve the precision of orbit prediction.In order to avoid the difficulty of amending the dynamical model,it is attempted to use ANN model to learn the variation of orbit prediction error,and then the prediction result of ANN model is used to compensate the predicted orbit based on dynamic model to form a final predicted orbit.The experiment results showed that the orbit prediction error based on ANN model was less than that based on dynamical model,and the improvement effects for different satellites and different time were different.The maximum rates of improvement of predicting 8,15,30 d were respectively 80%,77.77%,85%.The orbit prediction error control technique based on the method of back overlap arc compare was brought forward to avoid the risk that the precision of predicted orbit is even worse after it is compensated by ANN model.The phenomena of failure were basically eliminated based on this technique,and the rate of failure was reduced from 30%to 5%.This technique could ensure that the engineering application of ANN model could come true.
