摘要：The design of a global positioning system （GPS） software receiver is introduced. This design uses the concept of software radio, and it consists of the following parts： front-end, acquisition, tracking, synchronization, navigation solution and some assisting modules. In the acquisition module, the acquisition algorithm based on circular correlation is utilized. The input data and the local code are converted into the frequency domain by means of the fast Fourier transform （FFT）. After performing circular correlation, the initial phase of the C/A code can be obtained and the cartier frequency can be found in 1 kHz frequency resolution, which is too coarse to use for the tracking loop. In order to improve the frequency resolution, the fine frequency estimation through a phase relationship is then achieved, by which, the frequency resolution is improved dramatically. Experiments show that the inaccuracy of the carrier frequency can be estimated within a few hertz by the fine frequency estimation method, and the fine frequency attained can be directly used for the tracking loop.

摘要：In order to research on the design and implementation of a modernized GPS civil signals simulation system,a brief review of the modernized GPS signals is introduced,including the signal structure and characteristics of L2C,L5 and L1C *** design and implementation of the main modules of the simulation system is described in *** simulation system is mainly composed of parameter setting,system initialization,signal generator,noise generator,disturbance generator,signal synthesis,low-pass filter,A/D conversion and *** simulation results based on Matlab are then presented,and the power spectral density（PSD） of all navigation signals is *** simulation system completes the physical layer simulation of a modernized GPS new civil signal and can provide a controllable signal source for designing and testing of modernized GPS civil receivers,especially for the signal processing algorithm design of the GPS software receiver.

摘要：新伽利略系统计划提供E1、E5和E6导航信号服务于民用导航、商业服务和生命安全服务领域,预计导航性能将大幅提升。本文旨在设计一种基于软件的伽利略E1/E5/E6中频信号发生器以模拟未来的伽利略导航系统。首先简要概述了伽利略信号及其在无线电频段的分布,包括E1、E5和E6信号的信号结构和特点。然后对仿真系统的组成进行了详细描述并通过Matlab软件进行仿真,重点分析了所有导航信号的功率谱密度(PSD)。结果表明该仿真系统可为伽利略接收机的设计和测试提供可控信号源。

摘要：L2C信号是由现代化GPS IIR-M卫星播发的新一代民用信号。基于软件接收机的信号采集与数据处理的研究旨在提高信号在低信噪比环境下的捕获稳定性和跟踪精度。L2C信号结构描述了其民用中码和民用长码的时分复用特征。信号采集部分包括宽频天线和接收机前端的设计,工作频段为L1-L2频段,前端采用下变频和频谱搬移来避免频谱混叠。数据处理中采用降频处理的方法能有效增强信号捕获的稳定性,并利用圆周相关算法获得CM码的初始相位。码和载波跟踪数据处理包含计算原理的介绍和跟踪环结构设计。最后,通过低信噪比环境下的实验来验证L2C信号采集与数据处理方法的有效性。

摘要：文章中电控罗经采用数字伺服控制方案来取代传统的模拟伺服控制方案,将微处理机引入控制系统。设计了基于PID控制的静基座和摇摆基座下电控罗经的控制算法,运用Simulink进行建模和仿真,并通过实际转台测试实验得出,所设计的数字伺服控制电控罗经在摇摆实验环境下,稳定时间为1.8h,罗经的稳态误差为0.5°,满足设计预期指标和国际标准要求。该电控罗经可以克服系统调试困难的缺点,具有实现复杂计算和现代化控制算法的能力。

摘要：针对目前移动机器人同时定位与地图创建(SLAM)研究中多采用激光雷达或超声环作为测距传感器导致系统复杂、成本高的问题,提出了一种利用舵机带动单超声传感器扫描的低成本设计方案。在高斯超声模型基础上,利用贝叶斯公式对栅格地图进行概率更新,并结合Sobel边缘检测算法提取特征点,实现了由不确定的移动机器人坐标系向固定的以环境特征点为原点的全局环境坐标系的转换及全局定位,为在相同环境下通过重复实验进行多地图融合研究奠定了基础。该低成本移动机器人设计的有效性通过实验得以验证。

摘要：The received satellite signal amplitude is attenuated greatly due to the strong ionospheric scintillation for lowlatitude regions, which causes the GPS tracking loop＇s loss of lock, the positioning errors to increase, and navigation to be interrupted. To solve the above problems, a novel signal processing algorithm is proposed based on the GPS L1 software receiver during strong ionospheric scintillation using the multi-channel intermediate frequency（IF） data sampling system. Tens of thousands of fading events are obtained based on the signal intensity measurement. The amplitude fading characteristics in the lowlatitude region are analyzed,including fading duration, time separation between fades and the numbers of signal intensity fading events. The fading thresholds are set to be 15 and 10 dB, respectively. The main fading time is very short in- 15 dB fading threshold, which generally is less than 20 ms. The main time separation between fades is less than 2 s in a single one-hour period from the time 23： 00 to 24： 00. Therefore, it has the characteristic of a short reacquisition time for the receiver designed to reduce the probability of simultaneous loss of lock for some ***, the acquisition, tracking and PVT（position,velocity and time） calculations are completed by the customdesigned software receiver. The results show that the impact analysis of ionospheric scintillation on GPS amplitude attenuation in the lowlatitude region is helpful for designing the advanced tracking algorithm and to improve the robustness and accuracy of the GPS receiver.

摘要：分析程序设计课程应培养的卓越工程师思维模式和解决问题能力,包括快速实现需求、敏捷定位bug、自主学习、良好交流等,提出在C++课程教育中贯彻卓越工程师培养计划的几点认识,如规范编程习惯、建立代码安全与可信计算理念、强化调试技巧、培养自学能力等。

摘要：本文介绍我院在"程序设计与算法语言"课程双语教学实践中所进行的有益探索及取得的成效。主要从师资队伍建设、教学平台和优质资源整合建设、双语教学授课模式、课程考核及评价体系的改革完善等方面进行阐述,并针对双语教学普遍存在的问题提出一些思考和对策。