共查询到20条相似文献,搜索用时 15 毫秒
1.
In this article, the architecture of a software Global Positioning System (GPS) receiver is described and an analysis is included
of the performance of a software GPS receiver when tracking the GPS signals in challenging environments. Results are included
that demonstrate the advantage of the software GPS receiver in tracking the GPS signals in low signal-to-noise or jamming
scenarios. Various current and previous applications of the software GPS receiver are also described. ? 2000 John Wiley &
Sons, Inc. 相似文献
2.
Architectures of Software GPS Receivers 总被引:6,自引:0,他引:6
There are various applications in which a Global Positioning System (GPS) sensor only down-converts and digitizes the received
GPS signal and sends the digitized data to a processor, where the processor software performs all the correlation, search/track
operations, navigation solution, and so on. Among the applications are military and commercial ones (e. g., GPS(Communication
handheld sets, people tracking systems).
A major problem with the Software GPS Receiver is the large computing resources required for correlation or acquisition of
the GPS signal. In this article, several possible approaches for reducing computing resources will be introduced and analyzed.
It will be shown that the performance of the GPS software design strongly depends on the features of the computer hardware.
Implementations will be described on the TMS320C6201 processor and the Pentium II.
Experimental results will be demonstrated by processing of real GPS signals. A complete 16-channel GPS receiver was implemented
on the single TMS320C6201 processor in real-time mode and on the Pentium II processor with a duty cycle of about 50%. ? 2000
John Wiley & Sons, Inc. 相似文献
3.
Absolute Positioning with Single-Frequency GPS Receivers 总被引:11,自引:3,他引:11
Ola Øvstedal 《GPS Solutions》2002,5(4):33-44
The use of precise post-processed satellite orbits and satellite clock corrections in absolute positioning, using one GPS
receiver only, has proven to be an accurate alternative to the more commonly used differential techniques for many applications
in georeferencing.
The absolute approach is capable of centimeter accuracy when using state-of-the-art, dual-frequency GPS receivers. When using
observations from single-frequency receivers, however, the accuracy, especially in height, decreases. The obvious reason for
this degradation in accuracy is the effect of unmodeled ionospheric delay.
This paper discusses the availability of some empirical ionospheric models that are publicly available and quantifies their
usefulness for absolute positioning using single-frequency GPS receivers. The Global Ionospheric Model supplied by International
GPS Service (IGS) is the most accurate one and is recommended for absolute positioning using single-frequency GPS receivers.
Using high-quality single-frequency observations, a horizontal epoch-to-epoch accuracy of better than 1 m and a vertical accuracy
of approximately 1 m is demonstrated. ? 2002 Wiley Periodicals, Inc. 相似文献
4.
5.
The NMEA GGA standard for global positioning system (GPS) and GLONASS receiver interfaces provides smooth data transfer from
receiver to computer for postprocessing. Specifically, the NMEA GGA specifies that the orthometric height and the undulation
be listed in addition to other quantities. The Ashtech manual (Ashtech, 1997; p. 104), however, specifies that the respective
field in the NMEA GGA message contains the ellipsoidal height when outputting from Ashtech's GG24 receiver. Because such an
inconsistency between the official NMEA GGA specifications and the implementation by a manufacturer can potentially confuse
the user, we carried out a numerical test to confirm Ashtech's implentation. The result indicates that Ashtech indeed gives
the ellipsoidal height in the fielt that should actually contain the orthometric height according to the NMEA GGA specifications.
Firmware version after and including GF02 have corrected this situation. ? 2000 John Wiley & Sons, Inc. 相似文献
6.
7.
8.
GPS接收机动态检定场中的时间同步问题 总被引:1,自引:0,他引:1
首先,阐述了时间同步问题在GPS接收机动态检测中的重要性.其次,就相机快门延迟检测原理、检测方法进行了详细的讨论,检测出所使用的相机快门时间延迟约为90 ms,但有时会出现突变,得出了仅仅依靠机械快门无法实现相机在动态条件下的同步拍摄的结论.然后,结合液晶快门的控制对相机时间同步等问题进行了讨论.最后,给出了数码相机配合液晶快门以实现相机高精度同步的方法. 相似文献
9.
描述一种基于非专用接收机的GPS实时定姿算法,主要工作可以分为两个部分:第一,采用最小二乘方法和乔里斯基分解,基于基线长度约束压缩整周模糊度搜索空间,以达到实时计算的目的;第二,结合姿态角约束,使用金字塔算法提高了整周模糊度求解效率.经过实验,算法在基线长度为3 m的条件下,航向角精度优于0.1°. 相似文献
10.
11.
单频GPS短基线快速定位中的少数历元算法 总被引:2,自引:0,他引:2
研究了短基线时利用少数历元的单频GPS载波相位观测值进行快速定位的一种算法。基于TIK-HONOV正则化原理,选择了一种具有物理意义的正则化矩阵,以减弱法矩阵的病态性。新算法只需解算几个历元的单频GPS相位数据,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,用均方误差矩阵代替协方差阵,结合LAMBDA方法,可准确、快速地确定模糊度,最后得到基线向量的解。结合短基线算例,将少数历元算法与最小二乘估计的结果作了比较分析,得出了新解法的有效性。 相似文献
12.
目的 交通拥挤在高度城市化地区正在成为一个日益严重的问题,而造成拥堵的原因之一就是由于一些不安全驾驶行为所带来的交通事故。因此,准确评价驾驶员的驾驶行为是否安全成为研究的热点。提出了一种利用车载GPS模块采集的车辆轨迹数据实现车辆驾驶行为安全性分析的方法,试图自轨迹数据中提取超速、急加速、急减速、急转弯这些潜在的不安全驾驶行为,进而评估驾驶行为的安全性,为交通管理部门评价和管理驾驶员的驾驶行为提供科学的依据。由于实验数据来自于公交车辆,因此,以公交车驾驶行为为潜在的研究对象。 相似文献
13.
北斗产品产业化步伐不断加快,针对用户高精度的应用需求,有必要研究有效的接收机性能检测方法检定北斗产品内部噪声。研究了检定高精度GPS/BDS兼容接收机内部噪声水平的方法,引入站间单差残差法检定接收机内部噪声水平,并用实测零基线数据验证了该方法的有效性。结果表明,零基线单差残差法可以直观地反映接收机内部噪声水平,更适用于混合星座的北斗系统。 相似文献
15.
16.
An effective method of decreasing multipath errors in GPS or GPS/GLONASS receivers by changing delay lock loop correlator
reference signal is discussed. Unlike other approaches, this method does not lead to apparatus complication, power comsumption
increase, or augmentation of digital processor load. This method eliminates the multipath error completely if the difference
in delays of direct and reflected signal is more than 30 m, and decreases this error for smaller delays. The cost of such
decrease is that the noise error is decreased. However, the noise error is much less dangerous than the multipath one because
of its smaller value and much shorter correlation interval. Calculated and experimental data for the method are given for
multipath and noise errors. ? 1998 John Wiley & Sons, Inc. 相似文献
17.
18.
探讨了几种新的电离层延迟改正算法,通过算例检验了新方案的效率和可行性,对不同精度用户选取电离层延迟改正方案给出了建议。 相似文献
19.
单频GPS快速定位中病态问题的解法研究 总被引:17,自引:3,他引:17
研究只利用少数历元GPS载波相位观测值进行快速定位时的新解法.在分析病态法矩阵结构特性的基础上,基于TIKHONOV正则化原理,提出一种选择正则化矩阵R的新方法,减弱法方程的病态性.与其他方法相比,新方法得到与模糊度准确值更接近的浮动解及其相应的均方误差矩阵.结合LAMBDA方法,用均方误差矩阵代替协方差阵确定模糊度的搜索范围,可准确快速地确定模糊度,最后得到基线向量的解.结合算例,将新解法与最小二乘估计、岭估计和截断奇异值法分别结合LAMBDA方法解算模糊度的结果进行比较分析,展示新解法的效果. 相似文献