共查询到20条相似文献，搜索用时 31 毫秒
1.
Due to the different signal frequencies for the GLONASS satellites, the commonly-used double-differencing procedure for carrier phase data processing can not be implemented in its straightforward form, as in the case of GPS. In this paper a novel data processing strategy, involving a three-step procedure, for integrated GPS/GLONASS positioning is proposed. The first is pseudo-range-based positioning, that uses double-differenced (DD) GPS pseudo-range and single-differenced (SD) GLONASS pseudo-range measurements to derive the initial position and receiver clock bias. The second is forming DD measurements (expressed in cycles) in order to estimate the ambiguities, by using the receiver clock bias estimated in the above step. The third is to form DD measurements (expressed in metric units) with the unknown SD integer ambiguity for the GLONASS reference satellite as the only parameter (which is constant before a cycle slip occurs for this satellite). A real-time stochastic model estimated by residual series over previous epochs is proposed for integrated GPS/GLONASS carrier phase and pseudo-range data processing. Other associated issues, such as cycle slip detection, validation criteria and adaptive procedure(s) for ambiguity resolution, is also discussed. The performance of this data processing strategy will be demonstrated through case study examples of rapid static positioning and kinematic positioning. From four experiments carried out to date, the results indicate that rapid static positioning requires 1 minute of single frequency GPS/GLONASS data for 100% positioning success rate. The single epoch positioning solution for kinematic positioning can achieve 94.6% success rate over short baselines (<6 km). 相似文献
2.
DAI LiwenHAN ShaoweiChris Rizos 《地球空间信息科学学报》2001,4(4):9-18
1 ＩｎｔｒｏｄｕｃｔｉｏｎＲｅａｌ＿ｔｉｍｅｋｉｎｅｍａｔｉｃＧＰＳｐｒｅｃｉｓｅｐｏｓｉｔｉｏｎｉｎｇｈａｓｂｅｅｎｐｌａｙｉｎｇａｎｉｎｃｒｅａｓｉｎｇｒｏｌｅｉｎｂｏｔｈｓｕｒｖｅｙｉｎｇａｎｄｎａｖｉｇａｔｉｏｎ ,ａｎｄｈａｓｂｅｃｏｍｅａｎｅｓｓｅｎｔｉａｌｔｏｏｌｆｏｒｐｒｅｃｉｓｅｒｅｌａｔｉｖｅｐｏｓｉｔｉｏｎｉｎｇ .Ｈｏｗｅｖｅｒ,ｒｅｌｉａｂｌｅａｎｄｃｏｒｒｅｃｔａｍｂｉｇｕｉｔｙｒｅｓｏｌｕｔｉｏｎｄｅｐｅｎｄｓｏｎｏｂｓｅｒｖａ ｔｉｏｎｓｕｐｏｎａｌａｒｇｅｎｕｍｂｅ… 相似文献
3.
Heading and Pitch Determination Using GPS/GLONASS 总被引：1，自引：0，他引：1
This article describes a single difference approach to estimate heading and pitch with a twin global positoning system (GPS)/GLONASS
(GG) receiver system. Augmentation of GPS with GLONASS is not straightforward, however, because the latter system employs
the frequency division multiple access technique to distinguish the signals form different satellites, rather than the code
division multiple access technique used by GPS. The fact that each GLONASS signal has its own slightly different frequency
makes the double difference (DD) of carrier phase observables no longer possible without modification. To get around this
problem, the use of the between-receiver single difference (SD) of the carrier phase observables is proposed. In this case,
however, receiver clock and other errors do not cancel out. The possibility of using a common external oscillator for the
two receivers is explored. Remaining time and other biases are estimated using a low-pass averaging filter. The single difference
integer ambiguities can then be resolved and the heading and pitch can be determined with a relatively good level of accuracy.
Static and kinematic tests conducted with a pair of GPS/GLONASS receivers are used to validate the approach. Under reduced
visibility, the combined GPS/GLONASS approach is shown to yield superior availability. ? 2000 John Wiley & Sons, Inc. 相似文献
4.
A user of heterogeneous GPS and GLONASS receiver pairs in differential positioning mode will experience ambiguity fixing challenges due to the presence of inter-channel biases. These biases cannot be canceled by differencing GLONASS observations, whether pseudorange or carrier phase. Fortunately, pre-calibration of GLONASS pseudorange and carrier phase observations can make ambiguity fixing for GPS/GLONASS positioning much easier. We propose an effective algorithm that transforms an RTK (real-time kinematic) solution in a mixed receiver baseline from a float to a fixed ambiguity solution. Carrier phase and code inter-channel biases are estimated from a zero baseline. Then, GLONASS both carrier phase and code observations are corrected accordingly. The results show that a mixed baseline can be transformed from a float (~100 %) to a fixed (more than 92 %) solution. 相似文献
5.
Single receiver phase ambiguity resolution with GPS data 总被引：26，自引：12，他引：14
Willy Bertiger Shailen D. Desai Bruce Haines Nate Harvey Angelyn W. Moore Susan Owen Jan P. Weiss 《Journal of Geodesy》2010,84(5):327-337
Global positioning system (GPS) data processing algorithms typically improve positioning solution accuracy by fixing double-differenced
phase bias ambiguities to integer values. These “double-difference ambiguity resolution” methods usually invoke linear combinations
of GPS carrier phase bias estimates from pairs of transmitters and pairs of receivers, and traditionally require simultaneous
measurements from at least two receivers. However, many GPS users point position a single local receiver, based on publicly
available solutions for GPS orbits and clocks. These users cannot form double differences. We present an ambiguity resolution
algorithm that improves solution accuracy for single receiver point-positioning users. The algorithm processes dual- frequency
GPS data from a single receiver together with wide-lane and phase bias estimates from the global network of GPS receivers
that were used to generate the orbit and clock solutions for the GPS satellites. We constrain (rather than fix) linear combinations
of local phase biases to improve compatibility with global phase bias estimates. For this precise point positioning, no other
receiver data are required. When tested, our algorithm significantly improved repeatability of daily estimates of ground receiver
positions, most notably in the east component by approximately 30% with respect to the nominal case wherein the carrier biases
are estimated as real values. In this “static” test for terrestrial receiver positions, we achieved daily repeatability of
1.9, 2.1 and 6.0 mm in the east, north and vertical (ENV) components, respectively. For kinematic solutions, ENV repeatability
is 7.7, 8.4, and 11.7 mm, respectively, representing improvements of 22, 8, and 14% with respect to the nominal. Results from
precise orbit determination of the twin GRACE satellites demonstrated that the inter-satellite baseline accuracy improved
by a factor of three, from 6 to 2 mm up to a long-term bias. Jason-2/Ocean Surface Topography Mission precise orbit determination
tests results implied radial orbit accuracy significantly below the 10 mm level. Stability of time transfer, in low-Earth
orbit, improved from 40 to 7 ps. We produced these results by applying this algorithm within the Jet Propulsion Laboratory’s
(JPL’s) GIPSY/OASIS software package and using JPL’s orbit and clock products for the GPS constellation. These products now
include a record of the wide-lane and phase bias estimates from the underlying global network of GPS stations. This implies
that all GIPSY–OASIS positioning users can now benefit from this capability to perform single-receiver ambiguity resolution. 相似文献
6.
GLONASS processing from mixed receiver types is typically subject to unmodeled inter-frequency phase biases which prevent carrier phase ambiguity parameters from converging to integers. Receiver-dependent values have been proposed to mitigate the contribution of these biases, but are still subject to a number of issues, such as firmware updates. Recent studies have demonstrated that the origin of inter-frequency biases is a misalignment between phase and code observations, and could be calibrated to first order by manufacturers. In this contribution, a calibration-free method for GLONASS ambiguity resolution is presented in which ambiguities naturally converge to integers. A mandatory condition is that two GLONASS satellites with adjacent frequency numbers are observed simultaneously, although this condition can be relaxed once a fixed solution has been obtained. This approach then permits the integration of different receiver types and firmware versions into seamless processing. 相似文献
7.
对于GPS短基线,载波相位双差观测量已基本消除了卫星轨道误差、钟差、大气折射误差等系统偏差的影响,主要包含距离观测量信息及随机测量误差,其中测量误差是高频的测量噪声,小波变换可将GPS载波相位双差观测量中的观测噪声(高频部分)分解出来。本文利用Coiflets小波基函数对GPS快速定位的原始载波相位双差观测量进行5层分解,通过重构第5层低频系数获得去除噪声的"干净"的载波相位双差观测量,然后利用"干净"的双差观测量进行最小二乘参数估计,以减小测量噪声对GPS快速定位病态方程解的扰动。计算结果表明该方法能够显著提高GPS快速定位中模糊度浮点解的精度,仅利用几个观测历元的数据就可以准确地固定模糊度。 相似文献
8.
GNSS algebraic structures 总被引：4，自引：3，他引：1
The first objective of this paper is to show that some basic concepts used in global navigation satellite systems (GNSS) are
similar to those introduced in Fourier synthesis for handling some phase calibration problems. In experimental astronomy,
the latter are at the heart of what is called ‘phase closure imaging.’ In both cases, the analysis of the related structures
appeals to the algebraic graph theory and the algebraic number theory. For example, the estimable functions of carrier-phase
ambiguities, which were introduced in GNSS to correct some rank defects of the undifferenced equations, prove to be ‘closure-phase
ambiguities:’ the so-called ‘closure-delay’ (CD) ambiguities. The notion of closure delay thus generalizes that of double
difference (DD). The other estimable functional variables involved in the phase and code undifferenced equations are the receiver
and satellite pseudo-clock biases. A related application, which corresponds to the second objective of this paper, concerns
the definition of the clock information to be broadcasted to the network users for their precise point positioning (PPP).
It is shown that this positioning can be achieved by simply having access to the satellite pseudo-clock biases. For simplicity,
the study is restricted to relatively small networks. Concerning the phase for example, these biases then include five components:
a frequency-dependent satellite-clock error, a tropospheric satellite delay, an ionospheric satellite delay, an initial satellite
phase, and an integer satellite ambiguity. The form of the PPP equations to be solved by the network user is then similar
to that of the traditional PPP equations. As soon as the CD ambiguities are fixed and validated, an operation which can be
performed in real time via appropriate decorrelation techniques, estimates of these float biases can be immediately obtained.
No other ambiguity is to be fixed. The satellite pseudo-clock biases can thus be obtained in real time. This is not the case
for the satellite-clock biases. The third objective of this paper is to make the link between the CD approach and the GNSS
methods based on the notion of double difference. In particular, it is shown that the information provided by a maximum set
of independent DDs may not reach that of a complete set of CDs. The corresponding defect is analyzed. One of the main results
of the corresponding analysis concerns the DD–CD relationship. In particular, it is shown that the DD ambiguities, once they
have been fixed and validated, can be used as input data in the ‘undifferenced CD equations.’ The corresponding algebraic
operations are described. The satellite pseudo-clock biases can therefore be also obtained via particular methods in which
the notion of double differencing is involved. 相似文献
9.
在进行GPS/GLONASS联合卫星钟差估计时,GLONASS码频间偏差（inter-frequency bias,IFB）因卫星频率间的差异而无法被测站接收机钟差参数吸收,其一部分将进入GLONASS卫星钟差估值中。通过引入多个"时频偏差"参数（inter-system and inter-frequency bias,ISFB）及附加基准约束对测站GLONASS码IFB进行函数模型补偿,实现其与待估卫星钟差参数的有效分离,并对所估计实时卫星钟差和实时精度单点定位（real-time precise point positioning,RT-PPP）进行精度评估。结果表明,在卫星钟差估计观测方程中忽略码IFB,会明显降低GLONASS卫星钟差估值精度;新方法能有效避免码IFB对卫星钟差估值的影响,所获得GPS、GLONASS卫星钟差与ESA（European Space Agency）事后精密钟差产品偏差平均均方根值分别小于0.2 ns、0.3 ns。利用实时估计卫星钟差进行静态RT-PPP,当观测时段长为2 h时,GPS单系统、GPS/GLONASS组合系统的3D定位精度优于10 cm,GLONASS单系统3D定位精度约为15 cm;三种模式24 h单天解的3D定位精度均优于5 cm。 相似文献
10.
针对卫星定位技术无法应用于室内环境的情况,提出了一种新颖的利用载波相位差值的伪卫星定位方法,该方法能够实现亚米级的定位精度,而且无需基准站的支持,无需伪卫星之间的时钟同步,也不需要求解整周模糊度。构建了伪卫星定位的系统模型,并阐述了利用载波相位差值进行定位的基本原理。首先将双天线接收机输出的两组载波相位测量值进行单次差分操作,消除共有误差带来的影响,然后通过非线性最小二乘方法迭代解算出双天线连线中点的空间位置。仿真结果和基于双通道软件接收机的实测数据均证明了该方法的可行性,能够作为现有室内定位技术的有效补充。 相似文献
11.
Although the computational burden of global navigation satellite systems (GNSS) data processing is nowadays already a big challenge, especially for huge networks, integrated processing of denser networks with data of multi-GNSS and multi-frequency is desired in the expectation of more accurate and reliable products. Based on the concept of carrier range, in this study, the precise point positioning with integer ambiguity resolution is engaged to obtain the integer ambiguities for converting carrier phases to carrier ranges. With such carrier ranges and pseudo-ranges, rigorous integrated processing is realized computational efficiently for the orbit and clock estimation using massive networks. The strategy is validated in terms of computational efficiency and product quality using data of the IGS network with about 460 stations. The experimental validation shows that the computation time of the new strategy increases gradually with the number of stations. It takes about 14 min for precise orbit and clock determination with 460 stations, while the current strategy needs about 82 min. The overlapping orbit RMS is reduced from 27.6 mm with 100 stations to 24.8 mm using the proposed strategy, and the RMS could be further reduced to 23.2 mm by including all 460 stations. Therefore, the new strategy could be applied to massive networks of multi-GNSS and multi-frequency receivers and possibly to achieve GNSS data products of higher quality. 相似文献
12.
受接收机类型、固件版本和天线的影响,GLONASS IFCB变化规律复杂且难以有效改正,导致GLONASS HMW组合包含系统性偏差,无法用于GLONASS宽巷模糊度固定。本文提出一种基于GLONASS HMW组合观测值残差的站间IFCB估计方法,并对站间IFCB变化特性进行分析。结果表明,站间IFCB长期稳定,少数相同类型硬件（包括接收机类型、固件版本和天线）站间IFCB可达0.5 m。为削弱伪距多路径效应对站间IFCB估值的影响,基于一个轨道重复周期的观测数据求得一组站间IFCB对实时观测值进行补偿,实现HMW组合平滑序列直接用于GLONASS宽巷模糊度实时固定。进行站间IFCB补偿后,基线宽巷模糊度固定正确率均在98%以上。 相似文献
13.
Weiwei Song Wenting Yi Yidong Lou Chuang Shi Yibin Yao Yanyan Liu Yong Mao Yu Xiang 《GPS Solutions》2014,18(3):323-333
GLONASS carrier phase and pseudorange observations suffer from inter-channel biases (ICBs) because of frequency division multiple access (FDMA). Therefore, we analyze the effect of GLONASS pseudorange inter-channel biases on the GLONASS clock corrections. Different Analysis Centers (AC) eliminate the impact of GLONASS pseudorange ICBs in different ways. This leads to significant differences in the satellite and AC-specific offsets in the GLONASS clock corrections. Satellite and AC-specific offset differences are strongly correlated with frequency. Furthermore, the GLONASS pseudorange ICBs also leads to day-boundary jumps in the GLONASS clock corrections for the same analysis center between adjacent days. This in turn will influence the accuracy of the combined GPS/GLONASS precise point positioning (PPP) at the day-boundary. To solve these problems, a GNSS clock correction combination method based on the Kalman filter is proposed. During the combination, the AC-specific offsets and the satellite and AC-specific offsets can be estimated. The test results show the feasibility and effectiveness of the proposed clock combination method. The combined clock corrections can effectively weaken the influence of clock day-boundary jumps on combined GPS/GLONASS kinematic PPP. Furthermore, these combined clock corrections can improve the accuracy of the combined GPS/GLONASS static PPP single-day solutions when compared to the accuracy of each analysis center alone. 相似文献
14.
Zhang Yongjun 《地球空间信息科学学报》2013,16(4):32-36
To obtain the GLONASS satellite position at an epoch other than reference time, the satellite's equation of motion has to be integrated with broadcasting ephemerides. The iterative detecting and repairing method of cycle slips based on triple difference residuals for combined GPS/GLONASS positioning and the iterative ambiguity resolution approach suitable for combined post processing positioning are discussed systematically. Experiments show that millimeter accuracy can be achieved in short baselines with a few hours' dual frequency or even single frequency GPS/GLONASS carrier phase observations, and the precision of dual frequency observations is distinctly higher than that of single frequency observations. 相似文献
15.
Oliver Montenbruck André Hauschild Peter Steigenberger Urs Hugentobler Peter Teunissen Shinichi Nakamura 《GPS Solutions》2013,17(2):211-222
An initial characterization and performance assessment of the COMPASS/BeiDou-2 regional navigation system is presented. Code and carrier phase measurements on up to three frequencies have been collected in March 2012 with a small regional network of monitoring stations. The signal and measurement quality are analyzed and compared with the Japanese Quasi Zenith Satellite System. A high level of stability is demonstrated for the inter-frequency carrier phase biases, which will facilitate the application of triple-frequency undifferenced ambiguity resolution techniques in future precise point positioning applications. The performance of the onboard Rubidium frequency standards is evaluated in comparison to ground-based hydrogen masers and shown to be well competitive with other GNSS satellite clocks. Precise orbit and clock solutions obtained in post-processing are used to study the presently achievable point positioning accuracy in COMPASS/BeiDou-2-only navigation. Finally, the benefit of triple-frequency measurements and extra-wide-lane ambiguity resolution is illustrated for relative positioning on a short baseline. 相似文献
16.
ZHANG Yongjun LIU Jingnan 《地球空间信息科学学报》2002,5(4):32-36
To obtain the GLONASS satellite position at an epoch other than reference time,the satellite‘s equation of motion has to be integrated with broadcasting ephemerides.The iterative detecting and repairing method of cycle slips based on triple difference residuals for combined GPS/GLONASS positioning and the iterative ambiguity resolution approach suitable for combined post processing positioning are discussed systematically.Experiments show that millimter accuracy can be achieved in short baselines with a few hours‘ dual frequency or even single frequency GPS/GLONASS carrier phase observation,and the precision of dual frequency observations is distinctly higher than that of single frequency observations. 相似文献
17.
GLONASS phase bias estimation and its PPP ambiguity resolution using homogeneous receivers 总被引：1，自引：0，他引：1
Integer ambiguity resolution (IAR) appreciably improves the position accuracy and shortens the convergence time of precise point positioning (PPP). However, while many studies are limited to GPS, there is a need to investigate the performance of GLONASS PPP ambiguity resolution. Unfortunately, because of the frequency-division multiple-access strategy of GLONASS, GLONASS PPP IAR faces two obstacles. First, simultaneously observed satellites operate at different wavelengths. Second and most importantly, distinct inter-frequency bias (IFB) exists between different satellites. For the former, we adopt an undifferenced method for uncalibrated phase delay (UPD) estimation and proposed an undifferenced PPP IAR strategy. We select a set of homogeneous receivers with identical receiver IFB to perform UPD estimation and PPP IAR. The code and carrier phase IFBs can be absorbed by satellite wide-lane and narrow-lane UPDs, respectively, which is in turn consistent with PPP IAR using the same type of receivers. In order to verify the method, we used 50 stations to generate satellite UPDs and another 12 stations selected as users to perform PPP IAR. We found that the GLONASS satellite UPDs are stable in time and space and can be estimated with high accuracy and reliability. After applying UPD correction, 91 % of wide-lane ambiguities and 99 % of narrow-lane ambiguities are within (?0.15, +0.15) cycles of the nearest integer. After ambiguity resolution, the 2-hour static PPP accuracy improves from (0.66, 1.42, 1.55) cm to (0.38, 0.39, 1.39) cm for the north, east, and up components, respectively. 相似文献
18.
GPS／GLONASS载波相位测量模糊度解算方法 总被引：3，自引：1，他引：3
GPS／GLONASS组合载波相位测量，在快速静态和动态定位等方面的应用具有一定的优势。由于GLONASS采用频分多址的方式识别卫星，每颗卫星的载波频率各不相同，所以在载波测量数据处理中不能采用与GPS载波相位测量数据处理相同的方法。文中就GLONASS、GPS／GLONASS组合载波相位测量整周模糊度解算的基本思路和方法进行了介绍。 相似文献
19.
GLONASS clock offset estimation is affected by the inter-channel biases (ICBs) caused by frequency division multiple access technique. The effect of ICBs on joint GPS/GLONASS clock offset estimation is analyzed. An efficient approach for joint estimation of GPS/GLONASS satellite clock offset is applied to the generation of 30-s clock offset products. During the estimation, the following three ICB handling strategies were tested: calculating ICBs for each GLONASS signal channel, calculating ICBs for each GLONASS satellite and neglecting ICBs. The behavior of ICBs under different strategies was statistically stable. Subsequently, the clock offset products using different ICB strategies were evaluated. The evaluation shows that consideration of the ICB is important when estimating the clock offset. Furthermore, estimating one ICB for each GLONASS satellite is better than estimating one for each GLONASS signal channel because, with the former strategy, the clock offset products behave more smoothly and have higher accuracy compared with products from the International GNSS Service Analysis Center. In addition, precise point positioning, using clock offsets based on one ICB for each GLONASS satellite, has the highest positioning accuracy. 相似文献
20.
Double-differenced (DD) ambiguities between overlapping frequencies from different GNSS constellations can be fixed to integers if the associated differential inter-system biases (DISBs) are well known. In this case, only one common pivot satellite is sufficient for inter-system ambiguity resolution. This will be beneficial to ambiguity resolution (AR) and real-time kinematic (RTK) positioning especially when only a few satellites are observed. However, for GPS and current operational BDS-2, there are no overlapping frequencies. Due to the influence of different frequencies, the inter-system DD ambiguities still cannot be fixed to integers even if the DISBs are precisely known. In this contribution, we present an inter-system differencing model for combined GPS and BDS single-frequency RTK positioning through real-time estimation of DISBs. The stability of GPS L1 and BDS B1 DISBs is analyzed with different receiver types. Along with parameterization and using the short-term stability of DISBs, the DD ambiguities between GPS and BDS pivot satellites and the between-receiver single-difference ambiguity of the GPS pivot satellite can be estimable jointly with the differential phase DISB term from epoch to epoch. Then the inter-system differencing model can benefit from the near time-constant DISB parameters and thus has better multi-epoch positioning performance than the classical intra-system differencing model. The combined GPS and BDS single-frequency RTK positioning performance is evaluated with various simulated satellite visibilities. It will be shown that compared with the classical intra-system differencing model, the proposed model can effectively improve the positioning accuracy and reliability, especially for severely obstructed situations with only a few satellites observed. 相似文献