摘要：基于2010—2020年青藏高原及邻区163个gps连续观测站的观测数据,解算gps垂向坐标时间序列。利用GFZ提供的全球负载格网数据,采用双三次线性插值方法计算环境负载位移,并对gps垂向时间序列进行修正。结果表明,水文负载对研究区gps观测站位移的影响最大,且对研究区南部测站的影响较大,RMS达9.45 mm(MUET站)。通过对比环境负载修正前后加权均方根值(WRMS)、周年项振幅、速度不确定度等指标发现,环境负荷修正可以减少青藏高原及其周边地区大部分gps站点垂向时间序列中的非线性变化,同时能显著提升绝大多数gps测站的速度精度。

摘要：With research on the carrier phase synchronization and symbol synchronization algorithm of demodulation module, a synchronization circuit system is designed for gps software receiver based on field programmable gate array （FPGA）, and a series of experiment is done on the hardware platform. The result shows the all-digital synchronization and demodulation of gps intermediate frequency （IF） signal can be realized and applied in embedded real-time gps software receiver system. It is verified that the decision-directed joint tracking algorithm of carrier phase and symbol timing for received signals from gps is reasonable. In addition, the loop works steadily and can be used for receiving gps signals using synchronous demodulation. The synchronization circuit for gps software receiver designed based on FPGA has the features of low cost, miniaturization, low power and real-time. Surely, it will become one of the development directions for gps and even GNSS embedded real-time software receiver.

摘要：This article presents an L1 band low noise integrated global positioning system （gps） receiver chip using 0.18 μm CMOS technology. Dual-conversion with a low-IF architecture was used for this gps receiver. The receiver is composed of low noise amplifier （LNA）, down-conversion mixers, band pass filter, received signal strength indicator, variable gain amplifier, programmable gain amplifier, ADC, PLL frequency synthesizer and other key blocks. The receiver achieves a maximum gain of 105 dB and noise figure less than 6 dB. The variable gain amplifier （VGA） and programmable gain amplifier （PGA） provide gain control dynamic range over 50 dB. The receiver consumes less than 160 mW from a 1.8 V supply while occupying a 2.9 mm2 chip area including the ESD I/O pads.

摘要：多通道全球定位系统(gps)卫星信号模拟器用来为gps接收机和导航系统提供逼真的测试信号。该文从模拟器设计的角度对到达gps接收机天线的卫星信号进行了分析,着重讨论了因众多误差因素影响而不易直接利用经验模型确定的几个波形参量的估计问题。基于人工神经网络(ANN)理论,提出一种利用ANN来模拟信号传播延迟、载波相位、信号功率等参量的方法。给出了基于ANN的模拟器闭环测试系统的结构。并对所设计的ANN进行了训练和验证,仿真实验结果表明,所设计的ANN能够在统计意义上逼真地模拟样本数据,从而使基于ANN的模拟器信号状态参量计算能够满足设计要求,可以直接应用于多通道gps信号模拟器的研制。

摘要：为发展小卫星 ,需要研制成本低、小而轻又能满足精度的姿态测量系统。论述了利用全球定位系统 ( gps)载波相位观测值进行姿态测量的原理 ,介绍了航天器姿态测量软件 THADS的算法和软件设计。在软件设计时 ,采用了周跳和粗差判定的改进方法 ,编制了相应的模块 ,结合地面实验数据进行仿真计算 ,在 1m左右的基线上姿态均方差小于0 .4°。结果表明利用

摘要：This paper develops a WebGIS\|based gps vehicle monitoring system with typical three\|tier application architecture of B/S pattern. It provides ordinary registered users with a valid and convenient means to get access to real\|time gps location information of certain moving vehicles at any place, and further offers a powerful tool for super users to manage user information and remotely monitor those vehicles and provide corresponding services timely if necessary. The system architecture, function modules, key technologies and application interfaces are given. Finally, the validity of our system is demonstrated in practical cases.

摘要：针对gps实时动态定位技术在铁路勘测中的应用,提出连续三角网重复设站测量既有线的方法。该方法以铁路控制测量的首级控制网点作为gpsRTK作业基准点,无需设置外移桩。数据处理时采用带约束条件的最小二乘法进行解算,可准确恢复既有线的各项参数,进而根据设计线形参数求得设计坐标,精确计算每一点的拨距量。

摘要：在对gps、GIS与GSM的最新发展进行深入介绍的基础上 ,论述基于gps/GIS/GSM开发车辆动态监控调度系统的关键技术 ,包括系统设计、基于VB6 0和GIS控件MapX的系统功能开发、gps定位数据的处理、用于车辆监控调度的交通电子地图的制作、双向通信功能的实现等 ,最后给出实现系统主要功能的VB6 0编程方法。

摘要：通过所建立的gps接收信号模型,从消除互相关干扰的角度出发,设计了gps弱信号捕获系统。并通过仿真测试出相关的系统参数及系统对捕获灵敏度的改善程度。

摘要：编队卫星的控制和应用需要确定编队卫星的运动状态,包括卫星绝对的和相对的位置、姿态以及钟差。本文设计联合利用gps和一种类似gps的载波相位和伪码交联测距技术的方案,快速实现星间gps载波相位差分的整周模糊度的确定,进一步提高相对状态确定的精度,使相对位置精度达到厘米级、相对姿态角精度达到角分级。