GPS／伪卫星相对定位中伪卫星优化布设模型研究

分别阐述了GPS绝对定位精度因子（PDOP,HDOP,VDOP）与相对定位精度因子（PRDOP,HRDOP,VRDOP）的相关理论，并进行了相应的公式推导，系统比较了两种定位因子的异同点，说明了采用相对定位因子作为相对定位中伪卫星布设依据的必要性；在此基础上，建立了以高度角、方位角和观测时间为自变量，双差相对精度因子为因变量的四维模型，论述了运用该模型进行伪卫星优化布设的具体步骤。并分别以PPDOP和PRDOP为例，通过实测数据对模型进行测试和分析。结果表明：PDOP与PRDOP具有相似的变化趋势，但其局部不一致；建立的四维模型为PRDOP的变化趋势进行了全时空显示，为高效的伪卫星选址工作提供了可靠的依据，实现了伪卫星的最优化布设。

An optimal pseudolites location model of GPS/pseudolites integrated relative positioning

Comparing the differences between dilution of precision for absolute positioning(e.g.PDOP,HDOP,VDOP) and for relative positioning(e.g.PRDOP,HRDOP,VRDOP) of GPS,there fundamental theories and corresponding formulas were illustrated,and the necessity of the use of the dilution of precision of relative positioning was explained.On the basis of that,a four-dimensional model was proposed,taking the dilution of precision of relative positioning as the dependent variable and observation time,azimuth and elevation angle as the independent variables,and the concrete steps to the application of the model was given immediately.Then PDOP and PRDOP were taken as judgment indexes for result evaluation.The results indicate that PDOP and PRDOP generally vary in similar manners but their partial variation ranges are inconsistent,and the four-dimensional model realizes the optimal pseudolites location for the first time,and dramatically improves the reliability and efficiency of the pseudolites locations.