To evaluate the performance of real time kinematic (RTK) network algorithms without applying actual measurements, a new method called geometric precision evaluation methodology (GPEM) based on covariance analysis was presented. Three types of multiple reference station interpolation algorithms, including partial derivation algorithm (PDA), linear interpolation algorithms (LIA) and least squares condition (LSC) were discussed and analyzed. The geometric dilution of precision (GDOP) was defined to describe the influence of the network geometry on the interpolation precision, and the different GDOP expressions of above-mentioned algorithms were deduced. In order to compare geometric precision characteristics among different multiple reference station network algorithms, a simulation was conducted, and the GDOP contours of these algorithms were enumerated. Finally, to confirm the validation of GPEM, an experiment was conducted using data from Unite State Continuously Operating Reference Stations (US-CORS), and the precision performances were calculated according to the real test data and GPEM, respectively. The results show that GPEM generates very accurate estimation of the performance compared to the real data test.
2015年3月,由国防科技大学独立研发的SGA-WZ02重力仪在湖南长沙进行了一次车载重力测量试验,目的是为了检验、评估该重力仪应用于车载重力测量的可行性和精度水平。该重力仪系统主要由捷联惯性导航系统(SINS)、差分GNSS系统以及数据记录系统组成。试验路线为长沙市区东部的一条长约35 km的高速公路,测量过程中平均车速为40 km/h,本次试验共得到3条重复测线数据以进行内符合精度评估。为了评估重力异常外符合精度,使用CG-5高精度地面重力仪对该测线区域进行了测量,建立了外部重力参考数据库。本次车载试验结果表明,重复测线的内符合精度为1.64 m Gal/1.1 km,1.12 m Gal/1.7 km,外符合精度为2.33 m Gal/1.1 km,1.77 m Gal/1.7 km。
