GLONASS与GPS：竞争与合作

对目前国际上应用最广泛的两个卫星导航系统，即前苏联的“全球导航卫星系统”和美国的“全球定位系统”，作了详细的分析对比，特别比较了它们应用于时间传递、频率比对方面的性能差异。文章还总结分析了合成使用ＧＰＳ／ＧＬＯＮＡＳＳ的意义，关键问题和应用现状。     

GLONASS全球导航卫星系统现状及其未来发展趋势

简要介绍世界主要航天大国和国家集团为了在未来的导航战和信息战中夺取制天权和制信息权，相继研发导航卫星系统。并围绕俄罗斯GLONASS全球导航卫星系统的现状和未来发展做简要论述。     

GLONASS卫星导航系统的发展和现状

简要分析GLONASS（Global Navigation Satellite System)卫星导航系统的发展和现状,对该卫星导航系统的特点与GPS做出扼要比较。     

EGNOS——-GPS和GLONASS的欧洲区域增强

欧洲正在开发的ＥＧＮＯＳ系统可为欧洲物陆、海、空用户提供ＧＰＳ和ＧＬＯＮＡＳＳ的区域增强服务。ＥＧＮＯＳ计划是欧洲卫星导航计划一个主要组成部分，它是由欧洲联盟委员会（ＣＥＵ）、欧空局（ＥＳＡ）和欧洲航空安全组织（ＥＵＲＯ ＣＯＮＴＲＯＬ）联合制定的。ＥＧＮＯＳ将提供如下的业务：基于ＧＥＯ的类ＧＰＳ测距信号（Ｒ－ＧＥＯ），用以改善ＧＰＳ定位在静地广播区域（ＧＢＡ）上接收机自主完善性监测（ＲＡＩＭ）的     

GPS和GLONASS系统的坐标转换

ＧＰＳ和ＧＬＯＮＡＳＳ系统的联合应用，可以有效地改善可视卫星的数量的几何分布，因而出现了ＧＮＳＳ（ＧＰＳ＋ＧＬＯＮＡＳＳ）双系统卫星导航定位。要有效地联用ＧＰＳ和ＧＬＯＮＡＳＳ两个系统，必须了解两个系统间的差异并寻找解决的方法，两个系统各自使用没的地心参考坐标系统就是差异之一。介绍了ＧＰＳ和ＧＬＯＮＡＳＳ系统间的差异及国外对ＷＧＳ－８４和ＰＺ－９０坐标转换参数的研究成果，不仅可用于国内双系统卫星系     

GLONASS的发展历程和应用展望

ＧＬＯＮＡＳＳ已于１９９６年初建成满星运行，这是俄罗斯连续１３年努力的结果，这是卫星导航新的里程碑，对国际民航组织的ＧＮＳＳ体制进程起到推进作用，本文叙述卫星发射和组网过程，改频计划和系统的改进，差分和增强应用，预测它对ＧＰＳ民用政策将发生影响，并预示卫星导航进展上新的前景。     

Integrated GPS/GLONASS navigation: Algorithms and results

The presence of selective availability (SA) on GPS has led to a variety of proposals for mitigation of its effects, for example combining GPS with other sensors or by identifying and removing the SA using redundant information in the position solution. A further method for reducing the impact of SA is the combination of GPS and GLONASS measurements. GLONASS does not have any deliberate degradation. This paper describes several algorithms for combining GPS and GLONASS measurements in real time on a single receiver. There are two least squares solutions using the code phase measurements alone: one with the measurements from both systems weighted equally, and one with the measurements weighted by the covariance of the measurements. Kalman filters with no SA model, and first- and second-order models, using both the code and carrier phase to estimate user position and velocity, are also implemented. Two different adaptive schemes are compared which attempt to identify SA model parameters in real time. The algorithms are compared in terms of their positioning accuracy, computational overhead and robustness. A ten-channel GPS/GLONASS receiver developed at The University of Leeds is used to provide satellite data for the evaluation of the different methods.     

GLONASS卫星L1信号接收机的设计

基于高频电路设计的原理,设计了GLONASS接收机的方案。电路分为信号放大、中频分离和相干载波产生这三个部分。主要使用了微波集成电路放大器BGA2001,高频滤波器TA0676A,宽带正交解调器AD8347和集成压控振荡射频合成器Si4123。设计出的接收机能够接收GLONASS L1信号。     

GLONASS卫星信号仿真器设计与实现

基于DSP+FPGA的设计方案,实现了多通道GLONASS卫星信号的硬件仿真器。简单给出了硬件系统的基本架构,重点叙述了基于此上的软件结构和程序流程,并通过实验验证了该方案的可行性。实验结果表明,本方案设计的GLONASS仿真器信号逼真度高、可编程性强、使用灵活,并具有一定的动态性能,为GLONASS接收机的性能检测提供了有益的支持。     

Combined GPS/GLONASS LAAS flight trials

The use of GPS in aviation is now accepted, with extensive work being undertaken on the technological, precision and infrastructure requirements. Work has focused on providing a service that is able to operate continuously in all areas. GPS alone, however, is seen as being unable to satisfy the stringent requirements for some phases of flight. Of the many solutions proposed, the Russian GLONASS system has been regularly overlooked. The research described in this paper aims to present GLONASS as a realistic and proven augmentation to GPS for aircraft positioning. During October 1996 the Civil Aviation Authority (CAA) Institute of Satellite Navigation (ISN) at the University of Leeds, in conjunction with the National Air Traffic Services Ltd (NATS UK) and the Defence Evaluation and Research Agency (DERA), performed a series of landmark differential GPS/GLONASS flight tests using the DERA BAC 1–11 flying laboratory. A real-time differential system was constructed using two GPS/GLONASS receivers developed by the ISN and a C-band data link for the RTCA corrections. Integration onboard the aircraft with avionic sensors and flight management systems was achieved using the ARINC 429 protocol. Routes were designed and flown to evaluate the complete system over a variety of airborne dynamics for both en-route and approach situations. In total, over 16 h of flying time was recorded, including 30 runway approaches over nine flights. A thorough evaluation of the accuracy and integrity of the positioning system was performed. Emphasis was made in comparing the flight statistics with recognized Required Navigation Performance (RNP) figures. The paper describes in detail the project development and the results achieved. An analysis of the results, showing that aircraft positioning with GPS/GLONASS augmentation in a local area augmentation system (LAAS) scenario can achieve accuracies that are both comparable with GPS-alone solutions and can satisfy up to CAT II precision approach criteria, is presented. Results are also given for position propagation using velocities derived from GPS and GLONASS carrier phase measurements. © 1997 John Wiley & Sons, Ltd.     

GPS/GLONASS/BDS三系统组合定位的定权方法

为了提高 GPS/GLONASS/BDS三系统组合定位的稳定性和精确度,研究加权最小二乘定位中的定权方法。提出一种结合高度角先验定权和验后方差估计的定权方法,利用多系统兼容接收机实测数据进行仿真验证。结果表明,相较于传统的最小二乘法,该定权方法可以明显改善多系统组合定位的精确度,且具有很好的抗差性能,提高了定位结果的稳定性,可应用于多系统兼容接收机组合定位解算中。     

载波频率号提取算法对箭载GLONASS速度计算的影响

在GLONASS测速原理的基础上,研究了载波频率号解算方法对箭载GLONASS测速的影响,发现载波频率号解算方法错误将导致测速精度变差,并从理论上分析了载波频率号错误引起的测速精度误差为目标飞行速度的1/2850~1/220倍。设计了4种不同的载波频率号解算算法,采用火箭飞行试验数据对算法进行了测试,结果表明,通过卫星数判断载波频率号以及通过保留位判断载波频率号能获得正确结果,直接计算载波频率号以及丢弃保留串无法获取到全部正确结果;通过保留位判断载波频率号的算法具有最小的首次测速时间,比通过卫星数判断载波频率号的算法至少缩短30 s以上,载波频率号解算错误引起的测速精度误差与理论值分析基本一致。     

Performance of the GLONASS P-code at L1 and L2 frequencies

The transmission of satellite signals at two widely spaced frequencies allows correction of the ionospheric delay. Both GPS and GLONASS transmit such signals, and to date there have been no published dual frequency GLONASS studies. This paper shows the fundamental accuracy of the Leeds University multichannel GPS/GLONASS receiver. Details are then given of the processing methods that have been used to obtain the ionospheric group delay using GLONASS L1 and L2 P-code measurements. Examples of the measured delay are provided and compared with the GPS model. Navigation results are shown using the P-code phase at L1 only and with a combination of the L1 and L2 measurements. An analysis of the accuracy of the P-code pseudorange and navigation capability is presented.     

一种高精度GPS/GLONASS同步时钟锁相环

本文给出了一种可用于移动通信设备的高精度的时钟同步解决方案，外同步源来自GPS或GLONASS接收信号，CPU系统读入数字鉴相器输出相差，通过时间步长由小增大的方式调整恒温晶振的调谐电压，结果获得很高的同步精度。     

基于FFT的GLONASS中频信号快速捕获算法

为了提高GLONASS中频信号的捕获速度,根据GLONASS信号捕获的特点,引入离散傅里叶变换进行相关运算,实现并行捕获。实验利用实际采集的GLONASS中频数据,将传统的串行捕获算法与基于FFT的快速捕获算法在Matlab上进行了对比。实验结果表明,基于FFT的快速捕获算法大大提高了运算速度,减少了捕获时间,捕获方法也得到改进。     

基于Adams积分的GLONASS卫星位置解算

GLONASS卫星位置解算是多系统兼容卫星导航接收机组合定位解算中一项重要的内容,对算法的稳定性、精度和计算量有较高的要求。引入了一种求解GLONASS导航卫星位置的新方法———基于Adams预测校正公式的GLONASS卫星轨道积分方法。应用实际数据对此算法和四阶龙格—库塔算法进行了对比验证,结果表明此方法是一种求解GLONASS卫星位置的有效方法,其稳定度优于四阶龙格—库塔方法,且计算量小。