The HY-2 satellite carrying a satellite-borne GPS receiver is the first Chinese radar altimeter satellite, whose radial orbit determination precision must reach the centimeter level. Now HY-2 is in the test phase so t...The HY-2 satellite carrying a satellite-borne GPS receiver is the first Chinese radar altimeter satellite, whose radial orbit determination precision must reach the centimeter level. Now HY-2 is in the test phase so that the observations are not openly released. In order to study the precise orbit determination precision and procedure for HY-2 based on the satellite- borne GPS technique, the satellite-borne GPS data are simulated in this paper. The HY-2 satellite-borne GPS antenna can receive at least seven GPS satellites each epoch, which can validate the GPS receiver and antenna design. What＇s more, the precise orbit determination processing flow is given and precise orbit determination experiments are conducted using the HY-2-borne GPS data with both the reduced-dynamic method and the kinematic geometry method. With the 1 and 3 mm phase data random errors, the radial orbit determination precision can achieve the centimeter level using these two methods and the kinematic orbit accuracy is slightly lower than that of the reduced-dynamic orbit. The earth gravity field model is an important factor which seriously affects the precise orbit determination of altimeter satellites. The reduced-dynamic orbit determination experiments are made with different earth gravity field models, such as EIGEN2, EGM96, TEG4, and GEMT3. Using a large number of high precision satellite-bome GPS data, the HY-2 precise orbit determination can reach the centimeter level with commonly used earth gravity field models up to above 50 degrees and orders.展开更多
The GPS,DORIS,and SLR instruments are installed on Haiyang 2A(HY2A)altimetry satellite for Precise Orbit Determination(POD).Among these instruments,the codeless GPS receiver is the state-of-art Chinese indigenous onbo...The GPS,DORIS,and SLR instruments are installed on Haiyang 2A(HY2A)altimetry satellite for Precise Orbit Determination(POD).Among these instruments,the codeless GPS receiver is the state-of-art Chinese indigenous onboard receiver,and it is the first one successfully used for Low Earth Orbit(LEO)satellite.Firstly,the contribution assesses the performance of the receiver through an analysis of data integrity,numbers of all tracked and valid measurements as well as multipath errors.The receiver generally shows good performance and quality despite a few flaws.For example,L2 observations are often missing in low elevations,particularly during the ascent of GPS satellites,and the multipath errors of P1 show a slightly abnormal pattern.Secondly,the PCO(Phase Center Offset)and PCV(Phase Center Variation)of the antenna of the GPS receiver are determined in this contribution.A significant leap for Z-component of PCO up to-1.2 cm has been found on 10 October 2011.Thirdly,the obtained PCO and PCV maps are used for GPS only POD solutions.The post-fit residuals of ionosphere-free phase combinations reduce almost 50%,and the radial orbit differences with respect to CNES(Centre National d’Etudes Spatiales)Precise Orbit Ephemeris(POEs)improve about 13.9%.The orbits are validated using the SLR data,and the RMS of SLR Observed minus Computed(O-C)residuals reduces from 17.5 to 15.9 mm.These improvements are with respect to the orbits determined without PCO and PCV.Fourthly,six types of solutions are determined for HY2A satellite using different combinations of GPS,DORIS,and SLR data.Statistics of SLR O-C residuals and cross-comparison of orbits obtained in the contribution and the CNES POEs indicate that the radial accuracy of these orbits is at the 1.0 cm level for HY2A orbit solutions,which is much better than the scientific requirements of this mission.It is noticed that the GPS observations dominate the achievable accuracy of POD,and the combination of multiple types of observations can reduce orbit errors caused by data gaps and maintain more stable and continuous orbits.展开更多
针对GPS、卫星激光测距(satellite laser ranging,SLR)和天线电定位(doppler orbitography and radiopositioning integrated by satellite,DORIS)3种不同的观测手段,讨论姿态模型误差对定轨的影响,以SLR验证、轨道重叠和外部轨道对比3...针对GPS、卫星激光测距(satellite laser ranging,SLR)和天线电定位(doppler orbitography and radiopositioning integrated by satellite,DORIS)3种不同的观测手段,讨论姿态模型误差对定轨的影响,以SLR验证、轨道重叠和外部轨道对比3种方法评定无姿态数据条件下的定轨精度,并基于该结果讨论不同轨道叠加方法的效果。以Jason-2卫星为例,在详细讨论GPS、SLR和DORIS的定轨策略基础上并基于实测数据进行了试验,试验结果表明,Jason-2卫星姿态模型误差对DORIS、GPS和SLR轨道影响分别为0.040m、0.036m和0.033m;无姿态数据定轨时,DORIS定轨结果略优于GPS和SLR,SLR定轨精度略差;基于轨道重叠结果加权,对GPS、SLR和DORIS轨道进行轨道叠加可以达到比较好的效果,通过与JPL轨道比较,其轨道径向精度可优于2cm。展开更多
基金supported partially by the National Natural Science Foundation of China (Nos. 40974004 and 40974016)Key Laboratory of Dynamic Geodesy of CAS, China (No. L09-01) R&I Team Support Program and the Graduate Science and Technology Foundation of SDUST, China (No. YCA110403)
文摘The HY-2 satellite carrying a satellite-borne GPS receiver is the first Chinese radar altimeter satellite, whose radial orbit determination precision must reach the centimeter level. Now HY-2 is in the test phase so that the observations are not openly released. In order to study the precise orbit determination precision and procedure for HY-2 based on the satellite- borne GPS technique, the satellite-borne GPS data are simulated in this paper. The HY-2 satellite-borne GPS antenna can receive at least seven GPS satellites each epoch, which can validate the GPS receiver and antenna design. What＇s more, the precise orbit determination processing flow is given and precise orbit determination experiments are conducted using the HY-2-borne GPS data with both the reduced-dynamic method and the kinematic geometry method. With the 1 and 3 mm phase data random errors, the radial orbit determination precision can achieve the centimeter level using these two methods and the kinematic orbit accuracy is slightly lower than that of the reduced-dynamic orbit. The earth gravity field model is an important factor which seriously affects the precise orbit determination of altimeter satellites. The reduced-dynamic orbit determination experiments are made with different earth gravity field models, such as EIGEN2, EGM96, TEG4, and GEMT3. Using a large number of high precision satellite-bome GPS data, the HY-2 precise orbit determination can reach the centimeter level with commonly used earth gravity field models up to above 50 degrees and orders.
基金supported by the National Natural Science Foundation of China(Grant No.41231174)the Open Fund of Key Laboratory of Precision Navigation and Technology,National Time Service Center(Grant No.2012PNT06)the Fundamental Research Funds for the Central Universities of China(Grand No.2012618020201)
文摘The GPS,DORIS,and SLR instruments are installed on Haiyang 2A(HY2A)altimetry satellite for Precise Orbit Determination(POD).Among these instruments,the codeless GPS receiver is the state-of-art Chinese indigenous onboard receiver,and it is the first one successfully used for Low Earth Orbit(LEO)satellite.Firstly,the contribution assesses the performance of the receiver through an analysis of data integrity,numbers of all tracked and valid measurements as well as multipath errors.The receiver generally shows good performance and quality despite a few flaws.For example,L2 observations are often missing in low elevations,particularly during the ascent of GPS satellites,and the multipath errors of P1 show a slightly abnormal pattern.Secondly,the PCO(Phase Center Offset)and PCV(Phase Center Variation)of the antenna of the GPS receiver are determined in this contribution.A significant leap for Z-component of PCO up to-1.2 cm has been found on 10 October 2011.Thirdly,the obtained PCO and PCV maps are used for GPS only POD solutions.The post-fit residuals of ionosphere-free phase combinations reduce almost 50%,and the radial orbit differences with respect to CNES(Centre National d’Etudes Spatiales)Precise Orbit Ephemeris(POEs)improve about 13.9%.The orbits are validated using the SLR data,and the RMS of SLR Observed minus Computed(O-C)residuals reduces from 17.5 to 15.9 mm.These improvements are with respect to the orbits determined without PCO and PCV.Fourthly,six types of solutions are determined for HY2A satellite using different combinations of GPS,DORIS,and SLR data.Statistics of SLR O-C residuals and cross-comparison of orbits obtained in the contribution and the CNES POEs indicate that the radial accuracy of these orbits is at the 1.0 cm level for HY2A orbit solutions,which is much better than the scientific requirements of this mission.It is noticed that the GPS observations dominate the achievable accuracy of POD,and the combination of multiple types of observations can reduce orbit errors caused by data gaps and maintain more stable and continuous orbits.
文摘针对GPS、卫星激光测距(satellite laser ranging,SLR)和天线电定位(doppler orbitography and radiopositioning integrated by satellite,DORIS)3种不同的观测手段,讨论姿态模型误差对定轨的影响,以SLR验证、轨道重叠和外部轨道对比3种方法评定无姿态数据条件下的定轨精度,并基于该结果讨论不同轨道叠加方法的效果。以Jason-2卫星为例,在详细讨论GPS、SLR和DORIS的定轨策略基础上并基于实测数据进行了试验,试验结果表明,Jason-2卫星姿态模型误差对DORIS、GPS和SLR轨道影响分别为0.040m、0.036m和0.033m;无姿态数据定轨时,DORIS定轨结果略优于GPS和SLR,SLR定轨精度略差;基于轨道重叠结果加权,对GPS、SLR和DORIS轨道进行轨道叠加可以达到比较好的效果,通过与JPL轨道比较,其轨道径向精度可优于2cm。
