Zhang Bingbing, Wang Zhengtao, Zhou Lv, Feng Jiandi, Qiu Yaodong, Li Fupeng
School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China.
Beijing Key Laboratory of Urban Spatial Information Engineering, Beijing Institute of Surveying and Mapping, Beijing 100038, China.
Sensors (Basel). 2017 Mar 20;17(3):635. doi: 10.3390/s17030635.
Swarm is a European Space Agency (ESA) project that was launched on 22 November 2013, which consists of three Swarm satellites. Swarm precise orbits are essential to the success of the above project. This study investigates how well Swarm zero-differenced (ZD) reduced-dynamic orbit solutions can be determined using space-borne GPS data and optimized pseudo-stochastic pulses under high ionospheric activity. We choose Swarm space-borne GPS data from 1-25 October 2014, and Swarm reduced-dynamic orbits are obtained. Orbit quality is assessed by GPS phase observation residuals and compared with Precise Science Orbits (PSOs) released by ESA. Results show that pseudo-stochastic pulses with a time interval of 6 min and a priori standard deviation (STD) of 10 mm/s in radial (R), along-track (T) and cross-track (N) directions are optimized to Swarm ZD reduced-dynamic precise orbit determination (POD). During high ionospheric activity, the mean Root Mean Square (RMS) of Swarm GPS phase residuals is at 9-11 mm, Swarm orbit solutions are also compared with Swarm PSOs released by ESA and the accuracy of Swarm orbits can reach 2-4 cm in R, T and N directions. Independent Satellite Laser Ranging (SLR) validation indicates that Swarm reduced-dynamic orbits have an accuracy of 2-4 cm. Swarm-B orbit quality is better than those of Swarm-A and Swarm-C. The Swarm orbits can be applied to the geomagnetic, geoelectric and gravity field recovery.
“蜂群”是欧洲航天局（ESA）的一个项目，于2013年11月22日发射，由三颗“蜂群”卫星组成。“蜂群”的精确轨道对上述项目的成功至关重要。本研究调查了在高电离层活动情况下，利用星载GPS数据和优化的伪随机脉冲能多好地确定“蜂群”零差分（ZD）简化动力学轨道解。我们选取了2014年10月1日至25日的“蜂群”星载GPS数据，并获得了“蜂群”简化动力学轨道。通过GPS相位观测残差评估轨道质量，并与ESA发布的精密科学轨道（PSO）进行比较。结果表明，对于“蜂群”ZD简化动力学精密轨道确定（POD），优化后的伪随机脉冲时间间隔为6分钟，径向（R）、沿迹（T）和交叉迹（N）方向的先验标准差（STD）为10mm/s。在高电离层活动期间，“蜂群”GPS相位残差的均方根（RMS）平均值为9 - 11mm，“蜂群”轨道解也与ESA发布的“蜂群”PSO进行了比较，“蜂群”轨道在R、T和N方向的精度可达2 - 4cm。独立卫星激光测距（SLR）验证表明，“蜂群”简化动力学轨道的精度为2 - 4cm。“蜂群 - B”轨道质量优于“蜂群 - A”和“蜂群 - C”。“蜂群”轨道可应用于地磁场、地电场和重力场恢复。
