共查询到19条相似文献,搜索用时 140 毫秒
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为了满足高动态用户及强干扰条件下的应用需求,提出了一种基于卫星信号矢量跟踪的SINS/GPS深组合导航方法,设计了基于FPGA硬件平台的实施方案。利用组合卡尔曼滤波器反馈回路取代了传统接收机中独立、并行的跟踪环路,能够同时完成所有可视卫星信号的跟踪和导航信息处理;通过矢量跟踪算法对所有可视卫星信号进行集中处理,能够增强跟踪通道对信号载噪比变化的适应能力,从而提高接收机在强干扰或信号中断条件下的跟踪性能;根据SINS导航参数和星历信息推测GPS伪码相位和多普勒频移等参数,用以辅助卫星信号的捕获和跟踪,能够大大缩短接收机的搜索捕获时间,并增强接收机在高动态条件下的跟踪性能。基于矢量跟踪的深组合方法不仅在GPS信号短暂中断期间,能够保证系统的导航精度和可靠性,而且在强干扰环境中能够维持较好的伪码相位和载波频率跟踪性能。 相似文献
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针对高动态环境下普通CPS接收机跟踪环路容易失锁的问题,考虑到锁频环动态性能好、锁相环跟踪精度高的特点,实现了二阶锁频环辅助三阶锁相环的载波跟踪环(FPLL)。根据FPLI.结构原理和误差分析理论,提出了一种FPLI.环路的码相位和载波相位精度分析方法。借助CPS软件接收机平台,在Matlab环境下仿真实现了FPLI.载波跟踪环,并利用Spircnt USS7700仿真器采集高动态CPS模拟信号对FPLI.环路进行了测试。测试结果和精度分析表明,在导航信号的载噪比为40 dB-Hz,加速度为26 g,加加速度为9g/s的条件下,该高动态跟踪环路能够达到码相位1. 31 m(1?),载波相位为4.24 X 10-3m/s(1?)的跟踪精度。 相似文献
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针对高动态场景,单独的码环路很难实现跟踪,由于高动态载波跟踪的算法很成熟,通常应用载波跟踪结果对码环路进行辅助,针对窄体制信号,这种方法可以帮助消除码环的动态误差,但对宽体制信号来说,辅助力度减小。从高动态宽带信号码跟踪误差门限以及跟踪精度入手,分析了单独码跟踪算法的易失锁性,理论和仿真验证应用高动态载波跟踪结果辅助码跟踪算法的有效性,且具有高的跟踪精度。这为导航接收机的跟踪算法提供了理论依据。 相似文献
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在多星座组合导航应用于高动态场景时,由于受加速度变化范围大、动态噪声和观测噪声难以准确预测等因素影响,常规联邦滤波估计精度将会严重下降甚至发散。针对这一问题,提出将强跟踪滤波算法应用到容错型联邦滤波器中,构成容错型联邦强跟踪滤波器。对COMPASS/GPS/GLONASS组合导航系统进行的仿真结果表明:该算法设计灵活,容错性强,对高动态目标有较强的跟踪能力,能够显著提高导航定位的精度和可靠性。同时,由于组合应用了无重置联邦滤波结构和渐消矩阵一步次优算法、残差χ2检验算法等实用算法,使得该算法整体计算量适中,易于实现,具有一定的工程实用价值。 相似文献
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PPP/INS组合导航系统中,接收机载波相位观测值由于接收机高动态、卫星低仰角、信号被遮挡等原因,往往发生周跳。周跳不仅会影响PPP定位精度,而且可能会导致模糊度参数重新初始化以致数十分钟才能重新收敛。针对以上问题,本文提出利用惯性导航系统(INS)辅助PPP宽巷周跳探测的新策略,通过具有短时高精度的INS信息,消除宽巷组合中的站星几何位置,克服传统MW方法中码伪距噪声及多路径误差的影响。试验表明,INS辅助的宽巷周跳探测方法能够精确识别各种宽巷小周跳。将该方法与无几何距离(GF)组合方法相结合,可以实现对双频等周周跳和特殊周跳(5/4、9/7等)的探测,具有较高探测精度,并可应用于实时周跳探测。 相似文献
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为了系统验证SINS/GPS紧组合系统的性能,基于GPS软件接收机,进行了仿真系统构建。仿真系统由轨迹发生器、GPS中频信号模拟器、IMU信号模拟器、GPS软件接收机、SINS导航解算模块、组合滤波算法和导航性能分析模块等部分构成,其中详细设计了GPS软件接收机中的捕获和跟踪算法、SINS解算以及基于伪距和伪距率的组合滤波算法。仿真结果表明:紧组合导航系统收敛性较好,能够一定程度上抑制惯导系统误差的积累,有较好的导航性能。设计的该系统满足紧组合导航系统性能验证的需要,也为后续的超紧组合研究奠定了良好的基础。 相似文献
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A reduced inertial measurement unit (IMU) consisting of only one vertical gyro and two horizontal accelerometers or three orthogonal accelerometers can be used in land vehicle navigation systems to reduce volume and cost. In this paper, a reduced IMU is integrated with a Global Positioning System (GPS) receiver whose phase lock loops (PLLs) are aided with the Doppler shift from the integrated system. This approach is called tight integration with loop aiding (TLA). With Doppler aiding, the noise bandwidth of the PLL loop filters can be narrowed more than in the GPS-only case, which results in improved noise suppression within the receiver. In this paper, first the formulae to calculate the PLL noise bandwidth in a TLA GPS/reduced IMU are derived and used to design an adaptive PLL loop filter. Using a series of vehicle tests, results show that the noise bandwidth calculation formulae are valid and the adaptive loop filter can improve the performance of the TLA GPS/reduced IMU in both navigation performance and PLL tracking ability. 相似文献
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Extended Kalman filter (EKF) is a widely used estimator for integrated navigation systems, and it works well in general situations. However, in adverse conditions such as partially observable environments and highly dynamic maneuvers, the performance of the traditional EKF-based strap-down inertial navigation system (SINS)/GPS integrated navigation system is easily to be affected by the dynamic changes of the specific force, thus leading to the problem of error covariance inconsistency. Though the inconsistency problem can be overcome to some extent if the system matrix, the states and the error covariance matrix are propagated as fast as possible in the SINS calculation rate, the problem cannot be fully solved. State transformation extended Kalman filter (ST-EKF) mechanization, with a new converted velocity error model for the SINS, is proposed, which can also be used to solve the inconsistency problem. In the ST-EKF, the specific force vector in the system error model is replaced by the nearly constant gravity vector for local navigation. Since the propagation and the updating of the ST-EKF can be executed simultaneously in the updating interval, the computation cost is greatly reduced compared with the traditional EKF. Experiments for the GPS/SINS tightly coupled navigation, including linear vibration Monte Carlo test and an unmanned aerial vehicle flight test, are implemented to evaluate the performance of the proposed ST-EKF. The results show that the proposed ST-EKF has superior performance to the traditional EKF, especially in partially observable situations. 相似文献
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The timing error between global navigation satellite system (GNSS) and inertial navigation system (INS) processes limits the integration performance in GNSS/INS integrated systems. In a deeply coupled system, this timing error affects not only the integrated navigation solution, but also the GNSS signal tracking. We propose a time-domain model of INS-aided second-order phase-locked loops (PLLs) in consideration of the INS aiding delay, and analyze the effect of INS aiding delay on the tracking errors in details. In addition, an integrated hardware deeply coupled system platform was developed to verify the impact of time delay on INS-aided PLLs. Simulation and field vehicles testing results demonstrate that the tracking error of the INS-aided PLL caused by aiding delay increases with the lengthening of the delay time, the compression of the bandwidth, and the increase in the acceleration. Testing results verify the proposed model. 相似文献
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A CE-5T1 spacecraft completed a high-speed skip re-entry to the earth after a circumlunar flight on October 31, 2014. In addition to the strapdown inertial navigation system (SINS), a lightweight GPS receiver with rapid acquisition was developed as a navigation sensor in the re-entry capsule. The GPS receiver effectively solved the poor accuracy problem of long-term navigation using only the SINS. In contrast to ground users and low-earth-orbit spacecraft, numerous factors, including high altitude and kinetic characteristics in high-speed skip re-entry, are important for GPS positioning feasibility and were presented in accordance with the flight data. GPS solutions started at nearly 4900 km orbital altitude during the phases of re-entry process. These solutions were combined by an inertial measurement unit in a loosely coupled integrated navigation method and SINS navigation initialization. A simplified GPS/SINS navigation filter for limited resources was effectively developed and implemented on board for spacecraft application. Flight data estimation analyses, including trajectory, attitude, position distribution of GPS satellite, and navigation accuracy, were presented. The estimated accuracy of position was better than 42 m, and the accuracy of velocity was better than 0.1 m/s. 相似文献
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分析了全球定位系统(GPS)、捷联惯导系统(SINS)和无线定位技术(WLAN)在城市复杂环境下室内外定位时的优缺点,提出了在城市复杂环境下采用基于卡尔曼滤波松组合的SINS/GPS组合导航定位方式,在室内环境下时,单独使用WLAN无线定位技术时易受室内复杂环境的影响,比如天花板、墙壁造成的多径效应,在传播过程中易受相近频段电器的干扰等等;提出了采用基于卡尔曼滤波的SINS/WLAN的组合导航定位技术来实现,从而实现更加平滑的导航定位结果。同时兼顾全组合导航系统高精度、低功耗、小型化的要求,设计出基于TMS320C6713和FPGA架构的嵌入式导航计算机平台。通过该平台系统的搭建,能够有效解决人们对泛在位置服务的需求问题。 相似文献
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Receiver Architectures for Improved Carrier Phase Tracking in Atenuation, Blockage, and Interference
James W. Sennott 《GPS Solutions》1999,3(2):40-47
A significant impediment to real-time centimeter survey and vehicle guidance in difficult reception environments is the underlying
signal tracking performance of the receiver. A number of researchers have investigated receiver signal tracking enhancements
that take advantage of intersatellite path correlations, of particular benefit in environments with multiple satellite attenuations
and blockages. This article surveys work in the area, with a focus upon an optimal estimation scheme known as integrated demodulation/navigation
(IDN). By contrast with other techniques, IDN employs a high update rate extended Kalman filter to combine and process raw
correlator data across satellites. Nonlinear loop simulations of real time kinematic (RTK) tracking during high-g aircraft
maneuvers with vehicle-induced blockages are used to illustrate the filtering method and it s robustness. ? 1999 John Wiley
& Sons, Inc. 相似文献
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利用神经网络预测的GPS/SINS组合导航系统算法研究 总被引:2,自引:0,他引:2
提出了一种基于神经网络预测的GPS/SINS组合导航系统算法。GPS信号可用时,该算法分别将惯性传感器的输出以及卡尔曼滤波器的输出信息作为神经网络的输入及理想输出信息,并进行在线训练;当GPS信息失锁时,利用已经训练好的神经网络预测各导航参数误差,并校正SINS。地面静态实验与动态跑车实验结果证明了该方法的可行性与有效性。 相似文献