共查询到20条相似文献,搜索用时 140 毫秒
1.
针对CORS系统建设成本高和选址困难的问题,该文提出GPS长距离网络RTK定位算法。该算法首先利用MW组合观测方程解算基准站双差宽巷整周模糊度,采用Saastamoinen模型和GMF映射函数模型相结合解算双差对流层干分量延迟残差,并将双差对流层湿分量延迟残差作为未知参数进行估计,同时结合无电离层组合观测值解算基准站双差载波整周模糊度;然后,采用综合误差内插法解算基准站和流动站的误差改正数;最后,采用最小二乘法逐历元进行法方程叠加解算流动站双差模糊度浮点解,并利用LAMBDA算法和通过TIKHONOV正则化改进的LAMBDA算法搜索固定流动站双差宽巷整周模糊度和双差载波整周模糊度。实验表明,该算法能够将基准站间距离提高到100~150km,使流动站用户可以获得厘米级定位结果。 相似文献
2.
网络RTK参考站间模糊度固定新方法 总被引:1,自引:0,他引:1
针对当前网络RTK参考站间模糊度解算时模糊度检验的Ratio值较小、固定时间较长的局限性,提出了一种新的模糊度解算方法用于网络RTK参考站间模糊度的固定.首先在模糊度区域内对原始的模糊度通过整数变换,形成宽巷与L2模糊度及其对应的方差协方差阵,然后采用LAMBDA方法对转换后的模糊度分块序贯固定.实验结果表明,与现有的模糊度解算方法相比,本文方法不但可以快速可靠地固定宽巷整周模糊度,而且提高了L2模糊度正确固定时的Ratio值,便于模糊度的正确检验,减少了模糊度的初始化时间,提高了模糊度解算的成功率. 相似文献
3.
BDS网络RTK中距离参考站整周模糊度单历元解算方法 总被引:1,自引:1,他引:0
提出了一种BDS网络RTK中距离(50~100 km)参考站间的双频载波相位整周模糊度单历元解算方法。该方法首先利用B1、B2载波相位整周模糊度间的线性关系选取B1、B2载波相位整周模糊度备选值。利用双频载波相位整周模糊度备选值计算双差电离层延迟误差,根据参考站各卫星电离层延迟误差间的空间关系,使用双差电离层延迟误差构建双差电离层延迟误差的线性计算模型。通过双差电离层延迟误差线性计算模型的建立搜索和确定B1、B2载波相位的整周模糊度。经CORS网实测数据试验算例的验证,该方法只需一个历元的观测数据即可确定参考站间双差B1、B2载波相位整周模糊度,且不受周跳影响。 相似文献
4.
5.
由于电离层延迟、对流层延迟等系统误差具有随测站间距离增加而相关性降低的特性,长距离情况下准确快速得到载波相位整周模糊度十分困难.因此文章提出了一种长距离网络RTK基准站间双差整周模糊度的快速解算方法,该方法利用M-W组合观测值进行双差宽巷整周模糊度的计算,结合无电离层组合观测值进行基准站间双差载波相位整周模糊度的确定,且不需线性化、不需解求方程组,各双差整周模糊度之间相互独立.最后通过实测数据进行算法验证,证明了该方法能够快速、可靠地解算长距离基准站间的双差整周模糊度. 相似文献
6.
7.
8.
针对北斗卫星导航系统中高轨卫星角速度较慢引起的基线网络实时动态差分法模型病态性减弱较慢而造成的模糊度收敛较慢的问题,提出一种适用于网络实时动态差分法参考站间双差整周模糊度快速解算的新方法。首先,在分析北斗系统快速定位模型中法矩阵结构病态性的基础上,基于岭估计的原理提出一种减弱法矩阵病态性的新方法。该方法只需几个历元的北斗系统载波相位观测值,就可得到比较准确的模糊度浮动解及其相应的均方误差矩阵。利用最小二乘相关分解法方法,用与模糊度浮点解相应的均方误差矩阵代替协方差阵,可准确、快速地搜索固定整周模糊度。结合算例,将新方法和最小二乘法分别结合最小二乘相关分解法方法解算的整周模糊度结果进行比较,结果证明新方法能实现北斗系统双差整周模糊度的固定。 相似文献
9.
10.
大范围网络RTK基准站间整周模糊度实时快速解算 总被引:1,自引:0,他引:1
网络RTK是目前实现高精度实时动态定位的重要手段之一,而网络RTK高精度定位的关键问题是基准站间整周模糊度的实时快速准确固定。对于大范围网络RTK,由于基准站间距离的增加,电离层延迟误差、对流层延迟误差和卫星轨道误差相关性降低,导致基准站间整周模糊度不能快速准确地固定,因此本文提出了一种大范围网络RTK基准站间整周模糊度固定算法。该算法首先利用L1、L2载波相位观测值和P1、P2伪距观测值解算基准站间的双差宽巷模糊度;然后采用Saastamoinen模型和Chao映射函数模型相结合解算双差对流层延迟误差,并将双差宽巷模糊度作为L1、L2双差载波相位整周模糊度的约束关系来确定L1、L2双差载波相位整周模糊度;最后采用CORS站的实测数据进行试验,并将本文的试验结果同GAMIT软件的解算结果进行比对,结果表明该算法可以快速准确地实现单历元双差载波相位整周模糊度的固定。 相似文献
11.
12.
13.
三步法确定网络RTK基准站双差模糊度 总被引:4,自引:2,他引:4
提出了一种新的由宽巷模糊度、窄巷模糊度到原始载波模糊度逐步固定地确定基准站间的双差模糊度的三步法,该方法不需线性化,不需解求方程组,双差观测值之间相互独立,且与基线长度无关,并用实例证明了该方法确定基准站模糊度速度快、可靠性高的特点。 相似文献
14.
基于北斗三频的短基线单历元模糊度固定 总被引:2,自引:0,他引:2
采用三频观测值能组成更多波长更长、噪声较小的观测值;通过依次固定超宽巷、宽巷、窄巷模糊度,可以实现模糊度的快速固定。目前以TCAR、CIR为代表的方法均是基于无几何模型的方法,通过伪距直接求解相位模糊度;由于不同卫星模糊度各自单独求解,没有综合利用所有卫星的观测值信息。基于有几何模型,使用LAMBDA方法进行逐级模糊度固定,依次固定超宽巷、两个宽巷、两个无电离层组合窄巷模糊度,最后使用模糊度固定的两个无电离层组合进行最终基线解算。北斗实测数据验证表明,针对10km的短基线数据,采用本文方法可以实现100%的单历元模糊度固定的成功率。 相似文献
15.
16.
针对常规GNSS解算模糊度存在的问题,该文提出了一种新的GNSS宽巷模糊度单历元求解算法。利用单历元双频码伪距观测值和载波相位观测值得到双差宽巷模糊度浮点解,将所有浮点宽巷模糊度分别向上、向下取整建立模糊度搜索空间;将模糊度空间中的所有备选组合代入双差宽巷观测方程中进行最小二乘解算,其中单位权中误差最小的组合就是最优的宽巷模糊度组合;然后对最优组合进行正确性检验以确定宽巷模糊度。确定宽巷模糊度后,可以利用宽巷观测值和载波观测值求出基础模糊度整周解。实验表明,该文提出的模糊度固定方法具有较高的成功率和可靠性,静态数据中模糊度固定成功率达到98.84%,动态数据中模糊度固定成功率达到了99.60%。 相似文献
17.
网络RTK参考站间模糊度动态解算的卡尔曼滤波算法研究 总被引:10,自引:1,他引:9
提出一种适用于参考站网络的站间模糊度解算方法,该方法使用CA码与相位的电离层无关组合解算宽巷模糊度,利用多路径效应的周期性削弱CA码多路径效应。在宽巷模糊度得到固定后,利用卡尔曼滤波对L1模糊度进行估计,并使用模糊度失相关搜索算法,动态地确定模糊度。这种方法已经应用在自主开发的网络RTK软件上,并以四川GPS综合服务网络SIGN(Sichuan Integrated GPS Network)作为试验网络,进行了试验和分析。 相似文献
18.
At present, reliable ambiguity resolution in real-time GPS precise point positioning (PPP) can only be achieved after an initial observation period of a few tens of minutes. In this study, we propose a method where the incoming triple-frequency GPS signals are exploited to enable rapid convergences to ambiguity-fixed solutions in real-time PPP. Specifically, extra-wide-lane ambiguity resolution can be first achieved almost instantaneously with the Melbourne-Wübbena combination observable on L2 and L5. Then the resultant unambiguous extra-wide-lane carrier-phase is combined with the wide-lane carrier-phase on L1 and L2 to form an ionosphere-free observable with a wavelength of about 3.4 m. Although the noise of this observable is around 100 times the raw carrier-phase noise, its wide-lane ambiguity can still be resolved very efficiently, and the resultant ambiguity-fixed observable can assist much better than pseudorange in speeding up succeeding narrow-lane ambiguity resolution. To validate this method, we use an advanced hardware simulator to generate triple-frequency signals and a high-grade receiver to collect 1-Hz data. When the carrier-phase precisions on L1, L2 and L5 are as poor as 1.5, 6.3 and 1.5 mm, respectively, wide-lane ambiguity resolution can still reach a correctness rate of over 99 % within 20 s. As a result, the correctness rate of narrow-lane ambiguity resolution achieves 99 % within 65 s, in contrast to only 64 % within 150 s in dual-frequency PPP. In addition, we also simulate a multipath-contaminated data set and introduce new ambiguities for all satellites every 120 s. We find that when multipath effects are strong, ambiguity-fixed solutions are achieved at 78 % of all epochs in triple-frequency PPP whilst almost no ambiguities are resolved in dual-frequency PPP. Therefore, we demonstrate that triple-frequency PPP has the potential to achieve ambiguity-fixed solutions within a few minutes, or even shorter if raw carrier-phase precisions are around 1 mm. In either case, we conclude that the efficiency of ambiguity resolution in triple-frequency PPP is much higher than that in dual-frequency PPP. 相似文献
19.
URTK: undifferenced network RTK positioning 总被引:3,自引:1,他引:2
Standard network RTK has been widely used since it was proposed in the mid-1990s. Rovers can obtain high-precision estimates of position by resolving double-differenced (DD) ambiguities. The focus of this study is a new undifferenced network RTK method, abbreviated as URTK hereafter, based on undifferenced (UD) observation corrections whose single-differenced (SD) ambiguities between satellites can be resolved in several seconds. The tools for studying the real-time realization of the new method are our developments of logical schemes that have the capability for the real-time modeling of a reference network and the instantaneous resolution of SD ionosphere-free (IF) ambiguities at a single station. This research demonstrates the validity of modeling regional UD-unmodeled errors on the ground and examines the maximum differences when compared to modeling the errors using ionospheric pierce points (IPP). With data collected at 48 stations from a CORS network in Shanxi Province (SXCORS) in China through May 21, 2010, the efficiency of the presented real-time strategies is validated using IGS final products in a postprocessing mode. The results verify that more than 83 % of SD wide-lane (WL) ambiguity can be fixed with 5 s of observation data, and the average resolution time of all the WL tests is 4.96 s. More than 80 % of SD L1 ambiguity can be fixed within 5 s, and the average resolution time is only 6.66 s. Rovers could gain rapidly centimeter-level absolute positioning service, comparable to standard network RTK. In addition, the URTK method transforms the fixed DD-ambiguities of the reference network into UD-ambiguities, and it does not need to set the base station and base satellite. Since the UD-corrections are modeled for each common visible satellite, it breaks down the connections between stations and satellites of the DD-corrections in the current network RTK. The UD-corrections can be broadcast by the base station and automatically selected and optimized by a rover during the real-time kinematic processing, thus avoiding ambiguity in reinitialization due to the change of reference, so it should be very flexible and useful for a wide range of applications. 相似文献
20.
Jianghui Geng Xiaolin Meng Alan H. Dodson Maorong Ge Felix N. Teferle 《Journal of Geodesy》2010,84(12):705-714
Integer ambiguity resolution at a single receiver can be achieved if the fractional-cycle biases are separated from the ambiguity
estimates in precise point positioning (PPP). Despite the improved positioning accuracy by such integer resolution, the convergence
to an ambiguity-fixed solution normally requires a few tens of minutes. Even worse, these convergences can repeatedly occur
on the occasion of loss of tracking locks for many satellites if an open sky-view is not constantly available, consequently
totally destroying the practicability of real-time PPP. In this study, in case of such re-convergences, we develop a method
in which ionospheric delays are precisely predicted to significantly accelerate the integer ambiguity resolution. The effectiveness
of this method consists in two aspects: first, wide-lane ambiguities can be rapidly resolved using the ionosphere-corrected
wide-lane measurements, instead of the noisy Melbourne–Wübbena combination measurements; second, narrow-lane ambiguity resolution
can be accelerated under the tight constraints derived from the ionosphere-corrected unambiguous wide-lane measurements. In
the test at 90 static stations suffering from simulated total loss of tracking locks, 93.3 and 95.0% of re-convergences to
wide-lane and narrow-lane ambiguity resolutions can be achieved within five epochs of 1-Hz measurements, respectively, even
though the time latency for the predicted ionospheric delays is up to 180 s. In the test at a mobile van moving in a GPS-adverse
environment where satellite number significantly decreases and cycle slips frequently occur, only when the predicted ionospheric
delays are applied can the rate of ambiguity-fixed epochs be dramatically improved from 7.7 to 93.6% of all epochs. Therefore,
this method can potentially relieve the unrealistic requirement of a continuous open sky-view by most PPP applications and
improve the practicability of real-time PPP. 相似文献