It is a long dream to realize the communication and navigation functionality in a satellite system in the world. This paper introduces how to establish the system, a positioning system based on communication satellite...It is a long dream to realize the communication and navigation functionality in a satellite system in the world. This paper introduces how to establish the system, a positioning system based on communication satellites called Chinese Area Positioning System (CAPS). Instead of the typical navigation satellites, the communication satellites are configured firstly to transfer navigation signals from ground stations, and can be used to obtain service of the positioning, velocity and time, and to achieve the function of navigation and positioning. Some key technique issues should be first solved; they include the accuracy position determination and orbit prediction of the communication satellites, the measur- ing and calculation of transfer time of the signals, the carrier frequency drift in communication satellite signal transfer, how to improve the geometrical configuration of the constellation in the system, and the integration of navigation & communication. Several innovative methods are developed to make the new system have full functions of navigation and communication. Based on the development of crucial techniques and methods, the CAPS demonstration system has been designed and developed. Four communication satellites in the geosynchronous orbit (GEO) located at 87.5°E, 110.5°E, 134°E, 142°E and barometric altimetry are used in the CAPS system. The GEO satellites located at 134°E and 142°E are decommissioned GEO (DGEO) satellites. C-band is used as the navigation band. Dual frequency at C1=4143.15 MHz and C2=3826.02 MHz as well as dual codes with standard code (CA code and precision code (P code)) are adopted. The ground segment consists of five ground stations; the master station is in Lintong, Xi’an. The ground stations take a lot of responsibilities, including monitor and management of the operation of all system components, determination of the satellite position and prediction of the satellite orbit, accomplishment of the virtual atomic clock measurement, transmission and receiving navigation signals to and from each satellite. In the north, the south, the east, the west and the center of Chinese main land, the function of CAPS demonstration system is checked and measured. In cars and on board the system is also checked and measured. The results are as follow: CA-code, horizontal positioning accuracy, 15-25 m (1σ), vertical, 1-3 m; P-code, horizontal positioning accuracy, 8-10 m (1σ), vertical, 1-3 m; velocity accuracy, CA-code, 0.13-0.30 m/s, P-code, 0.15-0.17 m/s; time accuracy, CA-code, 160 ns, P-code, 13 ns; determination accuracy of orbit ≤2 m. About 20 million US $ and two years are spent for the development of demonstration. A complete CAPS system is now being established.展开更多
Subcarrier modulated signals are widely used in the new generation of Global Navigation Satellite Systems(GNSS)to improve spectral compatibility and ranging accuracy.The unique structure of subcarrier modulated signal...Subcarrier modulated signals are widely used in the new generation of Global Navigation Satellite Systems(GNSS)to improve spectral compatibility and ranging accuracy.The unique structure of subcarrier modulated signals poses an ambiguity threat to acquisition and tracking,rendering traditional GNSS signal processing algorithms unsuitable.Designing unambiguous acquisition and tracking as well as observation extraction techniques for subcarrier modulated signals that can realize the high ranging accuracy potential while avoiding the ambiguity threat is a topic of common interest in both academia and industry.Numerous studies have addressed the ambiguity elimination problem of subcarrier modulated signals.However,to the best of our knowledge,no updated reviews on this topic reflecting recent advances in the field have been presented in the past few years.On the one hand,the unique composite subcarrier modulated signal structure in the B1 and B2 bands of the BeiDou Navigation Satellite System(BDS)and the E5 band of the Galileo satellite navigation system(Galileo)has been gradually emphasized by academics.On the other hand,unambiguous processing methods for subcarrier modulated signals based on multidimensional tracking loops have flourished,which provides a new way to solve the ambiguity problem.An overview of the most representative subcarrier modulated signal processing techniques,focusing on the achievements made in the last decade,is presented in this article,which can be a starting point for the researchers who start their study in this area.Furthermore,we aim to present a complete review on the recent breakthroughs that have taken place within this research area,providing links to the most interesting and successful advances in this research field.Remaining challenges with prospects are also given.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 10453001)the National Basic Research Program of China (Grant No. 2007CB815500)+1 种基金the National High Technology Research and Development Program of China (Grant No. 2004AA105030)the Funds of the Chinese Academy of Sciences for Key Topics in Innovation Engineering (Grant No. KGCXI-21)
文摘It is a long dream to realize the communication and navigation functionality in a satellite system in the world. This paper introduces how to establish the system, a positioning system based on communication satellites called Chinese Area Positioning System (CAPS). Instead of the typical navigation satellites, the communication satellites are configured firstly to transfer navigation signals from ground stations, and can be used to obtain service of the positioning, velocity and time, and to achieve the function of navigation and positioning. Some key technique issues should be first solved; they include the accuracy position determination and orbit prediction of the communication satellites, the measur- ing and calculation of transfer time of the signals, the carrier frequency drift in communication satellite signal transfer, how to improve the geometrical configuration of the constellation in the system, and the integration of navigation & communication. Several innovative methods are developed to make the new system have full functions of navigation and communication. Based on the development of crucial techniques and methods, the CAPS demonstration system has been designed and developed. Four communication satellites in the geosynchronous orbit (GEO) located at 87.5°E, 110.5°E, 134°E, 142°E and barometric altimetry are used in the CAPS system. The GEO satellites located at 134°E and 142°E are decommissioned GEO (DGEO) satellites. C-band is used as the navigation band. Dual frequency at C1=4143.15 MHz and C2=3826.02 MHz as well as dual codes with standard code (CA code and precision code (P code)) are adopted. The ground segment consists of five ground stations; the master station is in Lintong, Xi’an. The ground stations take a lot of responsibilities, including monitor and management of the operation of all system components, determination of the satellite position and prediction of the satellite orbit, accomplishment of the virtual atomic clock measurement, transmission and receiving navigation signals to and from each satellite. In the north, the south, the east, the west and the center of Chinese main land, the function of CAPS demonstration system is checked and measured. In cars and on board the system is also checked and measured. The results are as follow: CA-code, horizontal positioning accuracy, 15-25 m (1σ), vertical, 1-3 m; P-code, horizontal positioning accuracy, 8-10 m (1σ), vertical, 1-3 m; velocity accuracy, CA-code, 0.13-0.30 m/s, P-code, 0.15-0.17 m/s; time accuracy, CA-code, 160 ns, P-code, 13 ns; determination accuracy of orbit ≤2 m. About 20 million US $ and two years are spent for the development of demonstration. A complete CAPS system is now being established.
基金supported by National Natural Science Foundation of China,under Grant No.42274018,and National Key Research and Development Program of China under Grant 2021YFA0716600。
文摘Subcarrier modulated signals are widely used in the new generation of Global Navigation Satellite Systems(GNSS)to improve spectral compatibility and ranging accuracy.The unique structure of subcarrier modulated signals poses an ambiguity threat to acquisition and tracking,rendering traditional GNSS signal processing algorithms unsuitable.Designing unambiguous acquisition and tracking as well as observation extraction techniques for subcarrier modulated signals that can realize the high ranging accuracy potential while avoiding the ambiguity threat is a topic of common interest in both academia and industry.Numerous studies have addressed the ambiguity elimination problem of subcarrier modulated signals.However,to the best of our knowledge,no updated reviews on this topic reflecting recent advances in the field have been presented in the past few years.On the one hand,the unique composite subcarrier modulated signal structure in the B1 and B2 bands of the BeiDou Navigation Satellite System(BDS)and the E5 band of the Galileo satellite navigation system(Galileo)has been gradually emphasized by academics.On the other hand,unambiguous processing methods for subcarrier modulated signals based on multidimensional tracking loops have flourished,which provides a new way to solve the ambiguity problem.An overview of the most representative subcarrier modulated signal processing techniques,focusing on the achievements made in the last decade,is presented in this article,which can be a starting point for the researchers who start their study in this area.Furthermore,we aim to present a complete review on the recent breakthroughs that have taken place within this research area,providing links to the most interesting and successful advances in this research field.Remaining challenges with prospects are also given.
