共查询到20条相似文献，搜索用时 31 毫秒
1.
GIOVE-B is one of two test satellites for the future European Global Navigation Satellite System Galileo. The Cooperative Network for GIOVE Observation (CONGO) is a global tracking network of GIOVE-capable receivers established by Deutsches Zentrum für Luft- und Raumfahrt (DLR) and Bundesamt für Kartographie und Geodäsie (BKG). This network provides the basis for the precise orbit determination of the GIOVE-B satellite for the time period 29 June till 27 October 2009 with a modified version of the Bernese GPS Software. Different arc lengths and sets of orbit parameters were tested. These tests showed that the full set of nine radiation pressure parameters resulted in a better performance than the reduced set of five parameters. An internal precision of about one to two decimeters could be demonstrated for the central day of 5-day solutions. The orbit predictions have a precision of about 1 m for a prediction period of 24 h. External validations with Satellite Laser Ranging (SLR) show residuals on the level of 12 cm. The accuracy of the final orbits is expected to be on the few decimeter level. 相似文献
2.
Characterization of between-receiver GPS-Galileo inter-system biases and their effect on mixed ambiguity resolution 总被引：12，自引：6，他引：6
The Global Positioning System (GPS) and Galileo will transmit signals on similar frequencies, that is, the L1–E1 and L5–E5a frequencies. This will be beneficial for mixed GPS and Galileo applications in which the integer carrier phase ambiguities need to be resolved, in order to estimate the positioning unknowns with centimeter accuracy or better. In this contribution, we derive the mixed GPS + Galileo model that is based on “inter-system” double differencing, that is, differencing the Galileo phase and code observations relative to those corresponding to the reference or pivot satellite of GPS. As a consequence of this, additional between-receiver inter-system bias (ISB) parameters need to be solved as well for both phase and code data. We investigate the size and variability of these between-receiver ISBs, estimated from L1 and L5 observations of GPS, as well as E1 and E5a observations of the two experimental Galileo In-Orbit Validation Element (GIOVE) satellites. The data were collected using high-grade multi-GNSS receivers of different manufacturers for several zero- and short-baseline setups in Australia and the USA. From this analysis, it follows that differential ISBs are only significant for receivers of different types and manufacturers; for baselines formed by identical receiver types, no differential ISBs have shown up; thus, implying that the GPS and GIOVE data are then fully interoperable. Fortunately, in case of different receiver types, our analysis also indicates that the phase and code ISBs may be calibrated, since their estimates, based on several datasets separated in time, are shown to be very stable. When the single-frequency (E1) GIOVE phase and code data of different receiver types are a priori corrected for the differential ISBs, the short-baseline instantaneous ambiguity success rate increases significantly and becomes comparable to the success rate of mixed GPS + GIOVE ambiguity resolution based on identical receiver types. 相似文献
3.
Carrier-phase inter-frequency biases of GLONASS receivers 总被引：19，自引：7，他引：12
The frequency division multiplexing of the GLONASS signals causes inter-frequency biases in the receiving equipment. These
biases vary considerably for receivers from different manufacturers and thus complicate or prevent carrier-phase ambiguity
fixing. Complete and reliable ambiguity fixing requires a priori information of the carrier-phase inter-frequency bias differences
of the receivers involved. GLONASS carrier-phase inter-frequency biases were estimated for 133 individual receivers from 9
manufacturers. In general, receivers of the same type and even receivers from the same manufacturer show similar biases, whereas
the differences among manufacturers can reach up to 0.2 ns (more than 5 cm) for adjacent frequencies and thus up to 2.4 ns
(73 cm) for the complete L1 or L2 frequency bands. A few individual receivers were identified whose inter-frequency biases
behave differently as compared to other receivers of the same type or whose biases vary with time. 相似文献
4.
We provide a comprehensive overview of pseudorange biases and their dependency on receiver front-end bandwidth and correlator design. Differences in the chip shape distortions among GNSS satellites are the cause of individual pseudorange biases. The different biases must be corrected for in a number of applications, such as positioning with mixed signals or PPP with ambiguity resolution. Current state-of-the-art is to split the pseudorange bias into a receiver- and a satellite-dependent part. As soon as different receivers with different front-end bandwidths or correlator designs are involved, the satellite biases differ between the receivers and this separation is no longer practicable. A test with a special receiver firmware, which allows tracking a satellite with a range of different correlator spacings, has been conducted with live signals as well as a signal simulator. In addition, the variability of satellite biases is assessed through zero-baseline tests with different GNSS receivers using live satellite signals. The receivers are operated with different settings for multipath mitigation, and the changes in the satellite-dependent biases depending on the receivers’ configuration are observed. 相似文献
5.
伪距偏差是指卫星导航信号非理想特征导致的不同技术状态接收机产生的伪距测量常数偏差。本文将伪距偏差作为一种用户段误差,提出基于并置接收机的伪距偏差计算方法和基于DCB参数的伪距偏差计算方法,以实现伪距偏差与其他误差的分离。然后利用实测数据测量了北斗卫星伪距偏差,结果表明伪距偏差标定序列波动STD约为0.1 m,不随时间明显变化,不同地点接收机测量的伪距偏差具有较好的一致性。在1.5 G频段,北斗卫星B1I频点伪距偏差最大。北斗卫星新体制信号B1C伪距偏差最小,较北斗卫星B1I频点伪距偏差明显改善,也明显好于GPS卫星L1C/A频点伪距偏差。在其他频段,GPS卫星L2C伪距偏差略大于北斗卫星B3I伪距偏差,L5C频点伪距偏差次之,B2a频点伪距偏差最小。最后,利用实测数据分析了伪距偏差对定位精度的影响。结果表明伪距偏差与卫星群延迟参数高度相关。若用户接收机与群延迟参数计算采用的接收机技术状态差异较大,用户接收机定位精度将明显恶化。 相似文献
6.
Jeffrey T. Freymueller 《Journal of Geodesy》1992,66(3):272-280
Summary Many GPS networks which were initially surveyed with Texas Instruments TI-4100 receivers have now been resurveyed with mixtures of TI-4100 and Trimble 4000 receivers or exclusively with Trimble receivers. In order to make confident tectonic interpretation of displacements observed between such surveys, it is necessary to understand any biases which may be introduced by using different receiver types or by mixing receivers within a network. Therefore, one of the primary objectives of the Ecuador 1990 GPS campaign (February 1990) was to provide a direct long baseline comparison between the TI-4100 and Trimble 4000SDT GPS receivers. p ]During this campaign, TI and Trimble receivers were co-located at each end of a 1323 kilometer baseline (Jerusalen to Baltra). Solutions for this baseline show no variation with receiver type. Zero-length baseline solutions showed no evidence for any intrinsic bias caused by mixing the two receiver types. Short baseline solutions indicate a bias of -34±10 mm in the baseline vertical component; the sign of the bias indicates that either the assumed phase center location for the TI is too low or the assumed location for the Trimble is too high. The bias is explainable if the phase centers of the Trimble SDT and SST antennas are similarly located. p ]Solutions for baselines measured with codeless receivers (such as the Trimble) should be as precise as those for baselines measured with P-code receivers (such as the TI) as long as it is possible to resolve ambiguities. Resolution of the widelane ambiguity is the limiting factor in ambiguity resolution with any codeless receiver, and in the February 1990 campaigns it was not successful fore baselines longer than 100 km. Without explicit modeling of the ionospheric effect on the widelane, ambiguity resolution with codeless receivers will not be successful for baselines longer than about 100 km, depending on the local ionospheric conditions. 相似文献
7.
M_DCB: Matlab code for estimating GNSS satellite and receiver differential code biases 总被引：6，自引：4，他引：2
Global navigation satellite systems (GNSS) have been widely used to monitor variations in the earth’s ionosphere by estimating total electron content (TEC) using dual-frequency observations. Differential code biases (DCBs) are one of the important error sources in estimating precise TEC from GNSS data. The International GNSS Service (IGS) Analysis Centers have routinely provided DCB estimates for GNSS satellites and IGS ground receivers, but the DCBs for regional and local network receivers are not provided. Furthermore, the DCB values of GNSS satellites or receivers are assumed to be constant over 1?day or 1?month, which is not always the case. We describe Matlab code to estimate GNSS satellite and receiver DCBs for time intervals from hours to days; the software is called M_DCB. The DCBs of GNSS satellites and ground receivers are tested and evaluated using data from the IGS GNSS network. The estimates from M_DCB show good agreement with the IGS Analysis Centers with a mean difference of less than 0.7?ns and an RMS of less than 0.4?ns, even for a single station DCB estimate. 相似文献
8.
提出了一种精确估计区域北斗接收机硬件延迟(DCB)的方法。该方法不需要传统复杂的电离层模型,在已知一个参考站接收机硬件延迟的条件下,利用正常情况下电离层延迟量和卫星-接收机几何距离强相关这一特点,采用站间单差法来精确估计区域内BDS接收机的硬件延迟。试验结果表明,该方法单站估计的单站北斗接收机连续30d的硬件延迟RMS在0.3ns左右。通过GEO卫星双频观测值扣除已知卫星DCB和本文方法估计的接收机DCB,计算对应穿刺点一天的VTEC并和GIM格网内插结果并进行比对分析,二者大小和变化趋势均符合较好,进一步验证了本文提出的方法具有可靠性。 相似文献
9.
Characterization of Compass M-1 signals 总被引：7，自引：4，他引：3
André Hauschild Oliver Montenbruck Jean-Marie Sleewaegen Lennard Huisman Peter J. G. Teunissen 《GPS Solutions》2012,16(1):117-126
An analysis of observations from China’s first medium earth orbit satellite Compass M-1 is presented, with main focus on the
first orbit and clock solution for this satellite. The orbit is computed from laser ranging measurements. Based on this orbit
solution, the apparent clock offset is estimated using measurements from two GNSS receivers, which allow Compass tracking.
The analysis of the clock solutions reveals unexpectedly high dynamics in the pseudorange and carrier-phase observations.
Furthermore, carrier-to-noise density ratio, pseudorange noise, and multipath are analyzed and compared to GPS and GIOVE.
The results of the clock analysis motivate further research on the signals of the geostationary satellites of the Compass
constellation. 相似文献
10.
11.
Kees De Jong 《GPS Solutions》2000,3(3):12-18
In this article, analytic expressions are given for the minimal detectable biases (MDBs) of dual-frequency cross-correlated
global positioning system (GPS) single difference code and carrier observations. They are given for three different short
baseline models. (Short here implies that orbital and atmospheric uncertainties are assumed absent.) A comparison is made
with the expressions for the MDBs of non-cross-correlating receivers. Finally, in order to get a better understanding of them,
MDBs are visualized as a function of the parameters on which they depend, such as the number ob tracked satellites and the
number of observation epochs. ? 2000 John Wiley & Sons, Inc. 相似文献
12.
13.
The main scope of this research is to assess the ultimate accuracy that can be achieved for the slant total electron content
(sTEC) estimated from dual-frequency global positioning system (GPS) observations which depends, primarily, on the calibration
of the inter-frequency biases (IFB). Two different calibration approaches are analyzed: the so-called satellite-by-satellite
one, which involves levelling the carrier-phase to the code-delay GPS observations and then the IFB estimation; and the so-called
arc-by-arc one, which avoids the use of code-delay observations but requires the estimation of arc-dependent biases. Two strategies
are used for the analysis: the first one compares calibrated sTEC from two co-located GPS receivers that serve to assess the
levelling errors; and the second one, assesses the model error using synthetic data free of calibration error, produced with
a specially developed technique. The results show that the arc-by-arc calibration technique performs better than the satellite-by-satellite
one for mid-latitudes, while the opposite happens for low-latitudes. 相似文献
14.
Richard A. Snay 《Journal of Geodesy》1986,60(1):37-50
Strategies applicable to the design ofGPS surveys involving deployment of either three or four compatible receivers are presented. During aGPS observing session, the receivers operate simultaneously, producing three-dimensional cartesian coordinate differences for
the lines interconnecting the receivers. Different strategies provide the network designer with several options for planning
the survey. The designer may opt for a survey in which each mark is occupied three times, that is, during three separate observing
sessions, or he may elect a more economical survey in which each mark is occupied only twice. The designer may also choose
between two fundamentally different network geometries (a loop geometry or an areal geometry) to design a survey compatible
with the spatial distribution of network marks. The strategies can be extended to other geometries. The strategies produce
efficient networks in that no two marks are jointly occupied for more than one observing session. This feature produces the
maximum number of distinct, directly observed lines for the given number of receivers and observing sessions. The strategies
also favor observations over those lines connecting marks near one another. This feature helps survey logistics by reducing
travel time between observing sessions. 相似文献
15.
The integer ambiguity resolution enabled precise point positioning (PPP-RTK) has been proven advantageous in a wide range of applications. The realization of PPP-RTK concerns the isolation of satellite phase biases (SPBs) and other corrections from a network of Global Positioning System (GPS) reference receivers. This is generally based on Kalman filter in order to achieve real-time capability, in which proper modeling of the dynamics of various types of unknowns remains crucial. This paper seeks to gain insight into how to reasonably deal with the dynamic behavior of the estimable receiver phase biases (RPBs). Using dual-frequency GPS data collected at six colocated receivers over days 50–120 of 2015, we analyze the 30-s epoch-by-epoch estimates of L1 and wide-lane (WL) RPBs for each receiver pair. The dynamics observed in these estimates are a combined effect of three factors, namely the random measurement noise, the multipath and the ambient temperature. The first factor can be overcome by turning to a real-time filter and the second by considering the use of a sidereal filtering. The third factor has an effect only on the WL, and this effect appears to be linear. After accounting for these three factors, the low-pass-filtered, sidereal-filtered, epoch-by-epoch estimates of L1 RPBs follow a random walk process, whereas those of WL RPBs are constant over time. Properly modeling the dynamics of RPBs is vital, as it ensures the best convergence of the Kalman-filtered, between-satellite single-differenced SPB estimates to their correct values and, in turn, shortens the time-to-first-fix at user side. 相似文献
16.
多系统的融合定位可有效提高用户导航定位的连续性、可靠性及定位精度。针对BDS、GPS观测量间存在系统间偏差的实际情况,建立了顾及系统误差的BDS/GPS融合定位模型,即在函数模型中增加附加参数来吸收系统间偏差,构造了新的顾及先验信息的融合定位模型,分析了这种新融合模型的特点及其对定位结果的影响。利用不同品牌接收机在中国不同地域对新的融合模型进行试验,试验结果表明:BDS、GPS观测量存在系统间偏差,且不同接收机的系统间偏差量值并不一样;增加系统参数的融合定位模型能较好地吸收BDS、GPS观测量的系统间偏差的影响,改善其融合导航定位性能;在观测卫星数不足、单系统不能定位的情况下,考虑先验信息的融合定位模型仍能获得较好的定位结果。 相似文献
17.
GNSS接收机端的UPD与接收到的信号频率有关,这导致GPS和BDS系统间的双差模糊度不具有整数特性,为了恢复其整数特性,两系统间的系统偏差需要进行估计或改正。在顾及GPS和BDS之间的时间系统、坐标系统和频率间偏差的基础上,推导出GPS/BDS系统偏差计算模型,并利用不同实验对系统偏差的稳定性进行验证。实验结果表明,不同品牌接收机在GPS/BDS系统偏差方面在一定条件下均具有稳定性;天线类型和天线连接线长度没有对GPS/BDS系统偏差产生显著影响。加入系统偏差改正的GPS/BDS紧组合定位在恶劣环境下表现良好,可将模糊度固定平均所需时间缩短33%,模糊度固定成功率提高31%。 相似文献
18.
GLONASS ambiguity resolution (AR) between inhomogeneous stations requires correction of inter-frequency phase biases (IFPBs) (a “station” here is an integral ensemble of a receiver, an antenna, firmware, etc.). It has been elucidated that IFPBs as a linear function of channel numbers are not physical in nature, but actually originate in differential code-phase biases (DCPBs). Although IFPBs have been prevalently recognized, an unanswered question is whether IFPBs and DCPBs are equivalent in enabling GLONASS AR. Besides, general strategies for the DCPB estimation across a large network of heterogeneous stations are still under investigation within the GNSS community, such as whether one DCPB per receiver type (rather than individual stations) suffices, as tentatively suggested by the IGS (International GNSS Service), and what accuracy we are able to and ought to achieve for DCPB products. In this study, we review the concept of DCPBs and point out that IFPBs are only approximate derivations from DCPBs, and are potentially problematic if carrier-phase hardware biases differ by up to several millimeters across frequency channels. We further stress the station and observable specific properties of DCPBs which cannot be thoughtlessly ignored as conducted conventionally. With 212 days of data from 200 European stations, we estimated DCPBs per stations by resolving ionosphere-free ambiguities of \(\sim \)5.3 cm wavelengths, and compared them to the presumed truth benchmarks computed directly with L1 and L2 data on ultra-short baselines. On average, the accuracy of our DCPB products is around 0.7 ns in RMS. According to this uncertainty estimates, we could unambiguously confirm that DCPBs can typically differ substantially by up to 30 ns among receivers of identical types and over 10 ns across different observables. In contrast, a DCPB error of more than 6 ns will decrease the fixing rate of ionosphere-free ambiguities by over 20 %, due to their smallest frequency spacing and highest sensitivity to DCPB errors. Therefore, we suggest that (1) the rigorous DCPB model should be implemented instead of the classic, but inaccurate IFPB model; (2) DCPBs of sub-ns accuracy can be achieved over a large network by efficiently resolving ionosphere-free ambiguities; (3) DCPBs should be estimated and applied on account of their station and observable specific properties, especially for ambiguities of short wavelengths. 相似文献
19.
This report provides a detailed performance analysis of three semicodeless dual-frequency GPS receivers for use in low Earth orbit (LEO). The test set comprises the IGOR receiver, which represents a follow-on of the flight-proven BlackJack receiver, as well as two geodetic receivers (NovAtel OEM4-G2 and Septentrio PolaRx2), which are entirely based on commercial-off-the-shelf technology (COTS). All three receivers are considered for upcoming flight projects or experiments and have undergone at least a preliminary environmental qualification program. Using extensive signal simulator tests, the cold start signal acquisition, tracking sensitivity, differential code biases, raw measurement accuracy, and navigation accuracy of each receiver have been assessed. All tests are based on a common scenario that is representative of an actual space mission and provides a realistic simulation of the signal dynamics and quality on a scientific LEO satellite. Compared to the other receivers, the IGOR instrument exhibits a superior tracking sensitivity and is thus best suited for occultation measurements with low tangent point altitudes. The OEM4-G2 and PolaRx2 receivers are likewise shown to properly track dual-frequency GPS signals and normal signal levels and to provide accurate code and carrier phase measurements. Given their limited resource requirements, these receivers appear well suited for precise orbit determination applications and ionospheric sounding onboard of microsatellites with tight mission budgets. 相似文献
20.
北斗三号卫星导航系统（BeiDou-3 navigation satellite system, BDS-3）已全面建成并向全球用户提供可靠的定位、导航和授时（positioning, navigation and timing, PNT）服务。为了实现与其他全球卫星导航系统（global navigation satellite system, GNSS）的兼容性和互操作性,BDS-3在BDS-2的基础上调制了B1C和B2a两个新信号,与伽利略系统（Galileo）的E1和E5a实现了频率的复用。系统间偏差（inter-system bias, ISB）对于实现不同GNSS之间的融合处理至关重要,为此提出了基于单差模型的ISB估计与应用算法,并对BDS-3与Galileo重叠频率之间的ISB进行了分析。基于可跟踪BDS-3新信号的几类接收机,揭示了BDS-3和Galileo之间的ISB的特性,在此基础上分析了BDS-3和Galileo组合的实时动态（real-time kinematic, RTK）定位性能。结果表明,基于相同类型的接收机B1C-E1和B2a-E5a之间是不存在ISB... 相似文献