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GPS接收机的核心器件即为GPS OEM板(即GPS芯片),对其直接进行开发,在使用上具有灵活方便、经济实用、便于融合等优点。本文以Motorola M12MT+TIMING ONCORE型GPS OEM板为例,论述了GPS OEM板的具体开发使用过程和相关注意事项,并对其授时性能、1pps(秒脉冲)输出的特点等进行了研究,提供了用其实现精确授时的方法,并对授时精度进行了分析,对于测量中精确数字授时的实现具有一定的实际意义。 相似文献
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利用GPS OEM板对计算机进行高精度授时的研究 总被引:1,自引:0,他引:1
本文介绍了GPS OEM板的授时原理及计算机内部守时原理;分析了计数器频率的稳定性,提出了修正方案;阐述TN用GPS OEM板对计算机授时的实现过程,并做了时间比对实验。结果表明,计数器频率的漂移对授时精度有较大的影响。经频漂修正后,授时精度和守时精度都得到了很大的改善,最终授时精度优于6μs。 相似文献
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介绍GPS OEM板的授时原理及计算机的计时原理;分析计算机串、并行接口的特性;研究用计算机串行接口、并行接口接收GPS秒脉冲实现精确计时的原理及具体实现过程,并通过实验分别给出了其计时精度。 相似文献
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GPS除了能进行定位、测速和授时外,还可以进行方位的测量。对基于两片GPS OEM板同步载波相位观测量来测定载体的精确方位进行了算法研究。应用GPS的相位双差观测方程和两个天线间已知的准确距离,对方位角和俯仰角进行两维的搜索,搜索中采用了模糊度函数作为初始判断依据,然后再依据一定历元数据的残差进行分析得到比较准确的方位角。从而再反求出相位的模糊度,最后采用最小二乘原理计算出基线矢量,从而最终得到精确的方位和俯仰角。经过试验表明,该算法是切实可行,在5m基线下,方位精度能达到0.08度,而且定向时间一般只需40秒钟左右。 相似文献
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提出了利用GPS的精确授时功能,采用现场可编程门阵列(FPGA)技术,构建高精度短时标的设计方法.为了确保短时标的同步精度,从晶体的准确度以及守时精度等方面进行了理论和数据分析,采取了一系列措施保证了短时标设计μs级的精度. 相似文献
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主要介绍了GNSS接收机动态精度检定系统的设计。提出了利用光电传感器的快速响应特性构建GNSS接收机动态精度检定系统的基本方法;设计了基于FPGA和授时模块的高精度触发时间记录电路;给出了利用精确触发时间和触发位置确定动态条件下接收机测量数据"真值"的计算方法;最后分析讨论了该系统检定时的主要误差因素与精度评估方法。该系统可实现GNSS接收机动态测量精度的检定。 相似文献
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简要介绍了手持电脑和Windows CE操作系统的特点。以CMC SuperStar GPS OEM板为例,讨论了在二进制和NMEA-0183两种格式下对GPS OEM板设置时的指令格式,详细介绍了利用Windows API函数对手持电脑的串口进行操作的方法,实现了在Windows CE环境下对GPS OEM板进行设置和导航定位数据及时间信息的提取与处理等功能。 相似文献
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简要介绍了手持电脑和Windows CE操作系统的特点.以CMC SuperStar GPS OEM板为例,讨论了在二进制和NMEA-0183两种格式下对GPS OEM板设置时的指令格式,详细介绍了利用Windows API函数对手持电脑的串口进行操作的方法,实现了在Windows CE环境下对GPS OEM板进行设置和导航定位数据及时间信息的提取与处理等功能. 相似文献
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A combination of GPS and GLONASS observations can offer improved reliability, availability and accuracy for precise point positioning (PPP). We present and analyze a combined GPS/GLONASS PPP model, including both functional and stochastic components. Numerical comparison and analysis are conducted with respect to PPP based on only GPS or GLONASS observations to demonstrate the benefits of the combined GPS/GLONASS PPP. The observation residuals are analyzed for more appropriate stochastic modeling for observations from different navigation systems. An analysis is also made using different precise orbit and clock products. The performance of the combined GPS/GLONASS PPP is assessed using both static and kinematic data. The results indicate that the convergence time can be significantly reduced with the addition of GLONASS data. The positioning accuracy, however, is not significantly improved by adding GLONASS data if there is a sufficient number of GPS satellites with good geometry. 相似文献
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For precise real time or near real time differential GPS positioning in a wide or global area, precise GPS orbits or, alternatively,
precise orbital corrections with respect to a reference orbit, such as GPS broadcast ephemerides, must be used. This work
tests orbit interpolation methods, in order to represent the GPS orbits and orbital corrections accurately and efficiently
for these and other GPS applications. For precise GPS orbits given in the SP3 format at the 15 min interval, numerical tests
were conducted using Lagrange and Chebyshev as well as trigonometric polynomial functions. The results have demonstrated that
the 19- or 20-term trigonometric function is apparently the most efficient interpolator for a 12 h GPS orbital arc, achieving
1 cm level 3D interpolation accuracy that can meet the requirements of most precise applications. The test results also demonstrated
that the 9-term trigonometric function always yields optimal interpolation for a 2 h GPS orbit arc, in terms of interpolation
errors, compared to the results when using a different number of terms for the same function or one of the other tested polynomial
functions. This is evident from the minimal performance degradation when using the 9-term trigonometric function to interpolate
near or at the end of a data interval. By limiting interpolation to the center 15 min to 1.5 h of a 2 h orbit arc, thereby
eliminating the need to interpolate near the ends of that interval, users can opt for more terms (11 and 13) or different
interpolators to further improve interpolation accuracy. When interpolating the orbital corrections with respect to the GPS
broadcast ephemeris, all the tested interpolation functions of 3- to 9-term yield the same suitably accurate results. Therefore,
a 3- to 5-term trigonometric function is arguably sufficiently accurate and more efficient for GPS orbital correction messaging
in wide area and real time positioning. 相似文献
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针对单频精密单点定位(PPP)两种常用的定位模型:非组合模型和附加电离层约束模型,同时综合考虑电离层约束模型三种不同约束策略(常数约束,时空约束,逐步松弛),对比分析了其使用GPS单系统及GPS+BDS双系统观测值的定位收敛时间,定位精度及其优缺点. 实验结果表明:使用GPS单系统,附加不同电离层约束对单频PPP收敛时间缩短效果显著,其中逐步松弛约束平均收敛时间最短,其平均收敛时间为32.36 min,四种定位模型收敛后的定位精度基本相当. 加入北斗卫星导航系统(BDS)后,四种定位模型的收敛时间均有不同程度的缩短,其中时空约束模型缩短最为显著,收敛时间缩短为单系统的59.22%. 在定位精度方面,加入BDS观测值后水平方向定位精度可提升0.5~1.3 cm,垂直方向定位精度略有下降. 相似文献
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GPS非差相位精密单点定位技术探讨 总被引:77,自引:12,他引:77
探讨了精密单点定位的基本原理,处理方法,所涉及的误差改正及数据处理中的一些关键技术;采用直接内插IGS卫星精密星历的方法代替利用IGS跟踪站进行轨道精化方法计算卫星轨道参数,对现有精密单点定位计算方法进行了简化,使之更具有实用性。最后利用自主研发的精密非差单点定位软件计算和分析了实测数据。计算结果表明,经过大约15min的初始化后,非差相位单历元的定位结果精确度在X,Y,Z方向上均优于20cm。 相似文献
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探讨了精密单点定位的基本原理、处理方法、所涉及的误差改正及数据处理中的一些关键技术;采用直接内插IGS卫星精密星历的方法代替利用IGS跟踪站进行轨道精化方法计算卫星轨道参数,对现有精密单点定位计算方法进行了简化,使之更具有实用性。最后利用自主研发的精密非差单点定位软件计算和分析了实测数据。计算结果表明,经过大约15 min的初始化后,非差相位单历元的定位结果精确度在X,Y,Z方向上均优于20 cm。 相似文献
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The Global Positioning System (GPS), in addition to providing precise navigation and positioning information, produces precise
time and frequency measurements. These measurements result from the atomic clocks in the GPS satellites, which are closely
coupled to Universal Coordinated Time as maintained by the U. S. Naval Observatory [UTC(USNO)]. The application of these measurements
to timekeeping and other systems requiring precise time and frequency is distinct from the navigation/positioning mission.
This article will describe the differences in application of GPS to time and frequency uses. These uses will be described
in the major areas of timekeeping; stationary uses, such as communications networking; and mobile use for aircraft and shipboard
applications. The major considerations in application and operation with precise and less-capable oscilators will be described.
Examples and data will be presented to illustrate the applications. ? 1999 John Wiley & Sons, Inc. 相似文献
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Precise GPS Positioning by Applying Ionospheric Corrections from an Active Control Network 总被引:2,自引:1,他引:1
In this article, initial results are presented of a method to improve fast carrier phase ambiguity resolution over longer
baselines (with lengths up to about 200 km). The ionospheric delays in the global positioning system (GPS) data of these long
baselines mainly hamper successful integer ambiguity resolution, a prerequisite to obtain precise positions within very short
observation time spans.
A way to correct the data for significant ionospheric effects is to have a GPS user operate within an active or permanently
operating network use ionospheric estimates from this network. A simple way to do so is to interpolate these ionospheric estimates
based on the expected spatial behaviour of the ionospheric delays. In this article such a technique is demonstrated for the
Dutch Active Control Network (AGRS.NL). One hour of data is used from 4 of the 5 reference stations to obtain very precise
ionospheric corrections after fixing of the integer ambiguities within this network. This is no problem because of the relatively
long observation time span and known positions of the stations of the AGRS.NL. Next these interpolated corrections are used
to correct the GPS data from the fifth station for its ionospheric effects. Initial conclusions about the performance of this
technique are drawn in terms of improvement of integer ambiguity resolution for this baseline. ? 1999 John Wiley & Sons, Inc. 相似文献
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Online GPS processing services: an initial study 总被引:1,自引:2,他引:1
There are a number of online Global Positioning System (GPS) processing services that provide GPS processing results to the
user free of charge and with unlimited access. These services provide solutions for a user-submitted Receiver Independent
Exchange Format (RINEX) file based on differential methods using reference stations or precise point positioning using precise
GPS orbit and clock data. Different data sets varying in time and location were submitted to the online services and their
results compared. Although the quality of results depends on many factors, in most cases the users can expect reliable online
processing results for a 10-h data set made by a geodetic dual frequency receiver anywhere in the world. 相似文献