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严格论证了在对空间或地面目标的定位中,利用伪距测量观测模型的几何因子大于用台站间一次差分观测模型的几何因子.此外,台站间完全差分测量观测的定位精度优于不完全测量情形的定位精度.这些结果给人们在实际工作中采取何种定位方式提供了可靠的理论依据. 相似文献
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DAVID SWANLUND RAMONA MARAJ NADINE SCHUURMAN ROXANNE HOPE KATE DONKERS MATT AQUIN GWEN RICKERBY 《Geografiska Annaler: Series A, Physical Geography》2016,98(4):361-368
This study analyses GPS performance in Yukon's Arctic coast to inform future research that uses this technology in the region. To test this, Telonics GPS collars were placed on stakes during the summers of 2009 and 2010 throughout the region for varying lengths of time. The fix records produced by these collars were then collected and cleaned, leaving 30 samples. Using these records combined with a digital elevation model, eight variables were extracted and analysed in an attempt to find relationships, such that a fix rate could be predicted throughout the landscape. The results indicated that very few strong relationships existed. Densiometer values proved to be the only relationship between an environmental variable and fix rate. Available sky and aspect data produced results that were contrary to those expected. Overall, Telonics Generation 3 collars had extremely high fix rates, high accuracy, and low positional dilution of precision. Moreover, there was little variation in these results. This means that future GPS studies in the region would likely require minimal correction for fix rate bias. However, if corrections were to be made, more data would have to be gathered to ensure the results were statistically sound. The analysis suffered from the limitations of small sample size and low sample variance, among several others. Therefore, future studies should increase the number and diversity of sites tested. 相似文献
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针对低轨卫星星座有待合理化设计的问题,深入研究了低轨卫星星座增强北斗三号系统定位性能。分析轨道高度、轨道倾角、星座构型对星座覆盖性能的影响,仿真北斗三号、GPS和3种不同类型的低轨星座,研究各低轨星座与北斗三号、GPS的组合系统在所选7个测站以及全球范围内的可见卫星数和PDOP值分布。结果表明低轨卫星对北斗三号的增强效果主要与低轨卫星数目有关,且不同轨道倾角的组合低轨星座有利于均衡系统在全球范围内的可见卫星数与PDOP值分布。低轨卫星有望通过改善卫星观测几何构型提高北斗三号系统的定位性能,且增强效果与低轨星座构型密切相关。 相似文献
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针对GEO卫星几何法定轨中系统误差对PDOP值的影响进行研究,首先回顾了经典几何法定轨的基本原理,然后根据顾及系统误差的几何法定轨原理推导出PDOP值计算公式,并利用5个跟踪站的模拟数据,计算了多种系统误差情况下PDOP值。结果表明:系统误差对GEO卫星几何法定轨的PDOP值影响很大;采用顾及系统误差的几何法定轨方法可以较好地削弱系统误差对PDOP值的影响;国外布设跟踪站比仅在中国布设跟踪站能更好地削弱系统误差对PDOP值的影响。 相似文献
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在实现BDS/GPS/GLONASS组合精密单点定位的基础上,模拟多种遮挡环境;利用3个MGEX测站的数据进行三系统组合PPP试验;并在可见卫星数、PDOP值、定位精度、收敛时间和定位可用性等方面与GPS单系统PPP进行了比较分析。结果表明:在亚太地区,相比于GPS单系统PPP,三系统组合PPP可见卫星数增加了2~3倍,PDOP值显著减小。动态试验中,在无遮挡环境下,三系统组合PPP相较于GPS PPP收敛时间更短,且收敛后定位精度更高;在遮挡环境下,GPS PPP性能急剧下降,三系统组合PPP较好的保证了定位精度,提高了系统定位可用性。 相似文献
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顾及卫星故障修复的导航星座PDOP可用性分析方法研究 总被引:1,自引:0,他引:1
利用马尔科夫链等方法建立了评价单星可用性的数学模型,利用组合数学和全概率公式建立了评价导航星座PDOP可用性的数学模型,仿真实现了在一定故障率、修复率下,PDOP在中国服务区的可用性。仿真结果表明,星座构型、故障类型及数量、故障率和故障修复率对星座PDOP可用性有显著影响。 相似文献
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???GNSS/Pseudolites???????α????????????????????????????????μ?GNSS????α????????????,??????????λ??????????????????????????????????????????????????????????????????α??????????????????????????????????????仯????Ч????????????????????????λ????????????μ?PDOP????????????????????仯?????????????PDOP?????????????????????????????????ЧЭ?????????????????????????????????????????Ч????α???????GNSS?????Ч?????? 相似文献