GPS／GLONASS双星定位差分解算失效分析及解决措施

分析了GPS（全球定位系统）／GLONASS（全球卫星导航系统）双星接收机双星定位的原理,目的是解决多站雷达高精度定位中接收数据差分解算的失效,提出在GLONASS变化时把导航数据文件．jps转换成Rinex后再用Pinnacle处理或将双星接收机设置为单一的GPS模式下导航数据用Pinnacle处理的方法,用这两种方法处理的导航数据可进行差分解算,计算的定位精度满足设计要求。     

卫星导航兼容机的需求

以GPS／GLONASS卫星导航兼容接收机为代表开拓了一片小小的市场空间，由于其价格比普通的GPS接收机昂贵许多．所以它的用户面较窄。国际上，真正有政策规定的只有俄罗斯，明令凡进口卫星导航接收机者必须是GPS／GLONASS兼容机，不允许进单一的GPS接收机，这当然是出于为了让自己的GLONASS卫星能用起来     

GPS卫星导航接收机RF电路的设计

GPS卫星导航接收机主要由天线、RF电路、相关器和控制电路构成,其中,RF电路是GPS卫星导航接收机的关键组成部分.针对GPS卫星导航接收机的要求,介绍了其RF部分的电路设计和版图设计.采用TSMC 0.35 μm 3P3M SiGe BiCMOS工艺进行了流片.测试结果表明,电路工作频率1 575.42 MHz,接收灵敏度达到-130 dBm,满足GPS/GLONASS卫星导航兼容接收机的要求.     

新产品：东方联星公司多模兼容芯片抱眼年会

受大会邀请,东方联星公司张峻林总经理对“多模兼容芯片技术”作了特别报告。报告充分向大家展示了该公司已经批量生产和应用的北斗多模卫星导航芯片,以该款芯片为核心的卫星导航接收机,可以同时接收北斗二号、GPS、GLONASS卫星信号,具有北斗、GPS或GLONASS单星座定位、北斗／GPS双星座联合定位、北斗／GLONASS双星座联合定位、北斗／GPS／GLONASS三星座联合定位的能力。     

GPS／GLONASS卫星导航兼用接收机的优势与现状

随着GPS，GLONASS及Galileo等卫星导航系统的研制和发展，这些系统相继投入运行，为了发挥这些系统的综合效能，应该努力发展多系统用户设备，本文力求通俗地说明多系统用户带来的好处，包括提高信息安全与抗干扰能力，提高导航精度，以及提高完好性，并对GPS／GLONASS兼用接收机的现状作了介绍。     

华力创通中国卫星应用技术交流暨设备展

北京华力创通科技股份有限公司作为大会赞助之一参加了本次大会,并展出了包括北斗/GPS多频精密导航基带芯片、三系统（北斗/GPS/GLONASS）专业型卫星导航接收机、北斗/GPS抗干扰型接收机、北斗/GPS户外手持终端、多模多频高精度天线,以及卫星广播接收机与VPX等系列产品。来自航天、卫星、通信、广播、电视及国防军工行业一线的专家与学者参观了公司展台。     

我国卫星导航产业未来几年发展的思考

中国的卫星导航定位技术,经历了"引进应用期"、"消化创业期"、"系统创建期"和"系统发展期",迎来了国家大投入、全民竞参与的大发展时期。笔者认为,在未来几年,我国的卫星导航产业.应该抓住Compass系统发展机遇,开创国产卫星导航新局面;充分利用GPS/GLONASS现代化新成果,创造多系统集成应用的更多大众化新产品;研制GPS/GLONASS/Compass三频集成接收机.谱写卫星导航高动态应用的新篇章。     

BD-2/GLONASS集成接收机关键技术研究

为解决北斗卫星导航系统星座不足,避免不利条件下的定位盲区,提高定位精度,实现北斗2代系统与GLONASS系统的多星座空时统一,开展了BD-2/GLONASS集成接收机课题的研究。论文对多星座卫星导航系统的优点和定位算法进行了研究,对BD-2与GLONASS系统的时间系统、公共频率、坐标系统进行了分析。实验结果表明,该研究在可见卫星数,PDOP方面可以解决星座不足有效提高了导航定位的精度,增加了系统的定位性能和可靠性。     

基于北斗RDSS的GPS区域差分技术

本文提出了一种基于北斗RDSS的GPS区域差分技术的实现方案,该方案克服了差分GPS技术受到参考站和用户站之间距离的限制。本系统中基准型GPS接收机伪距修正数的计算、用户接收机导航解算所需的卫星星历数据、时间数据、伪距信息和伪距修正数的提取以及差分算法实现和接收机定位算法全部在DSP＋FPGA中实现。通过试验数据分析比较可见,采用基于北斗RDSS的GPS区域差分技术,对GPS导航定位精度有明显提高,该技术为未来实现高精度GPS导航定位有一定的参考价值。     

GPS/GLONASS导航定位中卫星位置和速度的计算

介绍了GPS和GLONASS卫星导航系统的星历参数,详细讨论了在GPS/GLONASS组合导航定位解算中卫星位置和速度计算的方法和流程,利用c语言完成了该算法的实现并用于组合导航接收机PVT解算。实验结果证明：该组合PVT解算程序能顺利完成定位,且优于单独使用GPS进行定位。     

Study on the algorithms to correct and compensate for GLONASS signal deviation based on GNSS receiver

At present, because of the construction of the navigation and positioning systems such as the China BeiDou, the research on complex receivers has become very urgent and active. This paper reports on the compatibility of the combined GPS and GLONASS data processing system. Because of the Frequency Division Multiple Access (FDMA) access technique applied in GLONASS satellites, while different signals of GLONASS satellites pass through different parts of the Radio Frequency (RF), the group delay effect can appear. Especially, if the hardware design of the base station and rover station are different, the problem is more severe. Aimed at these issues, the reasons and conditions are studied and then the comprehensive correction methods of deviation are proposed such as: effective real‐time pseudorange and carrier phase deviation correction compensation; tracking GLONASS L2 signal; establishing a eceiver name database; base station providing the receiver name; rover station correcting deviation according to different base stations, and so on. Through the use of schemes and algorithms, the objective existence GLONASS deviation can be reduced, and the capacity of the GPS+GLONASS complex system can be improved. It is also demonstrated that if the base station receiver and rover are from different manufactures, the deviation from GLONASS pseudorange and carrier phase can lead to the failure of achieving centimeter level. With the algorithms, in all the applications and in any base station or networked system, the GPS+GLONASS complex system can exhibit the advantages over just GPS applied system both in positioning accuracy and positioning speed and other real‐time kinematic (RTK) positioning performance. Copyright © 2012 John Wiley & Sons, Ltd.     

Slot stripline circular-polarization antennas for a few-element antenna array for a high-accuracy receiver of signals from global navigation satellite systems

New radiators for slot stripline leaky-wave circular-polarization antennas for high-accuracy GLONASS/GPS receivers have been developed. The main technical characteristics of antennas with new radiators have been theoretically and experimentally studied. It is shown that application of the new radiators improves the axial ratio, increases suppression of the cross polarization, increases the stability of the antenna phase center, and thus can increase the GLONASS/GPS positioning accuracy. The results of the analysis of the GLONASS/GPS positioning accuracy with the use of these antennas in an angle-measuring receiver and as elements of a few-element antenna array are presented.     

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.     

Frequency and time stability of GPS and glonass clocks

The frequency stability and reliability of the clocks are critical to the success of the GPS and GLONASS programs. We will show some of the similarities and differences between the clocks involved in these two systems. Because both systems plan to be operational in the next few years, the data leading up to this operational stage is of significant interest. On-board clocks and the stability of the master control clocks for these systems are analysed. We will discuss the attributes of these two systems as time and frequency references. Their relationship to UTC will also be illustrated. More data over a longer period of time was available for the authors from GPS than from GLONASS. Even so it is obvious that both systems have matured. Though the GLONASS system was developed later, its overall clock performance has improved more rapidly. Some of the more recent GLONASS clock performance is at about the same level as that of the GPS clocks. The analysis has yielded some very interesting contrasts, comparisons and changes in these systems that should be of great interest for time and frequency users, as well as for clock vendors and receiver vendors.     

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.     

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。     

Low Computational Complexity in Low-Cost GNSS Receivers

One of the key issues in low-cost GNSS receivers is the computational complexity. One of the computational components of the GNSS receivers is the satellite positioning calculations. The main focus of this paper is to reduce the computational burden of this stage of processing. In this paper, four different models to fit the GPS and GLONASS satellites orbit are investigated. These models are compared with each other in terms of their computational load and accuracy, and the models have good accuracy and less computational load are selected. Among these four methods, the Hermite model and the Chebyshev model are superior to other methods for determining orbits of GPS and GLONASS satellites, respectively. In order to evaluate the performance of these models, two different data including ground stations data and measured data by GNSS receivers are used. The results show that these two models can improve the computational burden by about 90% compared to conventional methods like the Runge–Kutta and the Keplerian parameters that used in GNSS receivers.

     

Performance Analysis of GPS Receivers in Non-Gaussian Noise Incorporating Precorrelation Filter and Sampling Rate

Global positioning system (GPS) receivers find growing applications in indoor and outdoor communication environments, including urban and rural areas. Interference and noise sources for GPS receivers may assume Gaussian or non-Gaussian distributions. The GPS receiver performance under Gaussian additive noise has been studied. Non-Gaussian noise may equally contaminate the GPS satellite signals and disturb the receiver delay lock loops (DLL), producing significant tracking errors. These sources include impulsive noise, ultra-wideband (UWB) signals, and impulse and noise radar signals for target tracking and indoor imaging applications. This paper considers non-Gaussian noise of finite variance and examines its effect on the discriminator outputs for the commercial GPS receiver that uses the coarse acquisition (C/A) code. The correlator noise output components are produced from the correlation between the noise sequence and the early, late, and punctual reference C/A code. Due to the long time averaging, which is characteristic of the GPS correlation loops, these components assume Gaussian distributions. The discriminator tracking error variance is derived, incorporating the effect of noise, the front-end precorrelation filter, and the sampling rate.     

WAW Location-based Service Positioning

Coordinated positioning operations require the user to be aware, not only, of his own position but also of the positions of the other elements on his team. Its deployment can be supported in WAW (??Where Are We???) location-based services, where the position of each user is made available to the rest of the group. This paper presents a method for the estimation of a user??s position based on measurements from a group of Global Positioning System (GPS) receivers. None of the GPS receiver positions, used in the estimation process, is considered to be known. The proposed approach leads to an improvement on the accuracy of the position estimates, when compared with those computed on an autonomous way, and has a direct application in the development of enhanced services in WAW location-based services. The positioning estimator takes advantage from the fact that, in this type of location-based service, GPS measurements are available from several receivers. Instead of estimating the user??s position based only on the measurements of his own GPS receiver, the proposed approach uses the measurements from all the GPS receivers in the group. The paper presents details of the positioning model and estimator used to achieve the accuracy improvements. Simulation results are presented based on real GPS satellite ephemeris, collected at the University campus.