共查询到17条相似文献,搜索用时 175 毫秒
1.
针对GPS/INS紧耦合导航中GPS伪距观测值精度较低的问题,提出了一种多普勒平滑伪距在GPS/INS紧耦合导航的应用算法。首先给出了GPS/INS紧耦合导航详细的动力学模型和观测模型,在载波相位平滑伪距的基础上推导了多普勒平滑伪距的具体算法和方差-协方差计算公式,并引入遗传算法对平滑因子进行最优估计;然后利用实测数据验证了新算法的有效性。结果表明,平滑算法能够有效提高伪距观测值的精度,从而提高组合导航的定位精度,相对于载波相位平滑伪距,多普勒平滑伪距的精度略有提高,而且多普勒平滑伪距不受周跳的影响,算法的效率更高。与此同时,伪距观测值精度的提高使其与伪距率观测值精度相当,增强了滤波系统的稳定性。 相似文献
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GPS/INS直接定向精度分析 总被引:1,自引:0,他引:1
近年来,GPS/INS融合技术在国内逐渐被应用于航空摄影测量中,利用其直接获得外方位元素,从而减少外业控制点。通过试验,在DMC数码相机同高精度的GPS/INS系统联结下,直接获取了试验区的外方位元素,并对GPS/INS数据直接定向的精度进行分析和总结,得出了一些有益的结论。 相似文献
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目前GPS/INS制导控制技术已成为精确制导武器的核心技术。根据GPS导航的特点及GPS/INS制导机理,对压制式干扰对GPS接收机的影响进行了分析,并分析了采用自适应调零天线技术来提高GPS/INS组合式导航抗干扰能力的有效性。 相似文献
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针对在导航实践中低成本MEMS使用传统紧耦合方法计算精度受到限制的问题,提出了一种采用载波相位平滑伪距GNSS PPP/INS紧耦合的算法。实验表明,使用相位平滑伪距的GNSS PPP/INS紧耦合方法后低精度的MEMS和GPS组合位置精度为dm级,速度精度为cm/s甚至mm/s,比传统C/A码紧耦合定位精度高,有较好的收敛性;其次当增加相位平滑的历元数后精度也相应提高。当出现GPS信号中断时,该方法能够加速中断以后滤波收敛的速度,将导航精度控制在中高精度惯导作业要求范围内。该方法节约了导航作业的设备成本,具有一定实际意义。 相似文献
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GPS/INS组合制导技术在现代战争中的应用及发展趋势 总被引:2,自引:2,他引:0
现代战争大量使用精确制导武器,广泛应用先进的GPS/INS组合制导技术。分析了GPS/INS组合制导技术的优势,结合其在军事领域的应用,展望了GPS/INS关键技术的发展趋势。 相似文献
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在GPS/INS辅助航空摄影测量作业过程中,如果GPS失锁时间过长将会影响到整个机载POS数据后处理精度,从而影响制图效果。文章旨在研究解决传统基于位置、速度组合的松耦合导航系统在GPS失锁情况下后处理精度不高的问题,提出基于伪距、伪距率的紧耦合导航系统:在保证外符合精度前提下,后处理后的位置内符合精度达到0.05m、航向角内符合精度约为0.005deg,各项指标均满足国外GPS/INS辅助航空摄影测量系统解算精度要求。研究结果可以为解决相关问题提供参考。 相似文献
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GPS/INS组合系统应用于航空摄影测量时可以直接给出相机曝光瞬间的外方位元素,从而部分乃至全部地摆脱传统摄影测量对地面控制点的依赖。本文主要介绍GPS/INS组合系统的工作原理及特点,以及GPS/INS组合系统辅助航空摄影测量与遥感的国内外应用现状。 相似文献
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This paper (the first part of two to be published in this journal) presents the process and results of a critical review of
the integrated GPS and inertial navigation system (INS) architectures, the corresponding failure modes and the existing integrity
monitoring methods. The paper concludes that tightly coupled GPS/INS systems have the highest potential for detecting slowly
growing errors (SGEs). This is due to access to pseudorange measurements and a relatively simpler configuration compared to
the other architectures. The second paper (Part II) takes this further and carries out a detailed characterisation of the
performance of the current integrity algorithms for tightly coupled systems and develops a new algorithm that detects SGEs
faster than the current methods. 相似文献
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建立了GPS/INS紧组合定位模型,改正惯性器件误差及电离层折射误差,对不同组合观测量的误差影响进行了分析,构造不同观测值组合,提出了基于惯性信息辅助的GPS周跳自适应探测方法,分析了INS定位误差对周跳探测的影响,给出了周跳探测误报率及修复成功率评价指标,提出了一种周跳检测阈值自适应确定方法。利用实测组合导航试验数据验证本文的算法,文中模拟了不同的单历元多周跳及信号失锁条件,结果表明,在GPS信号完全失锁20 s内,该方法能准确检测和修复所有周跳,中断时间的延长降低了周跳修复的成功率;GPS信号部分失锁时,在模拟的90 s中断时段内仍能修复所有周跳;模拟了170历元的5 s间隔密集周跳,周跳探测成功率为100%,正确修复率为99.41%。 相似文献
14.
Differential carrier phase observations from GPS (Global Positioning System) integrated with high-rate sensor measurements,
such as those from an inertial navigation system (INS) or an inertial measurement unit (IMU), in a tightly coupled approach
can guarantee continuous and precise geo-location information by bridging short outages in GPS and providing a solution even
when less than four satellites are visible. However, to be efficient, the integration requires precise knowledge of the lever
arm, i.e. the position vector of the GPS antenna relative to the IMU. A previously determined lever arm by direct measurement
is not always available in real applications; therefore, an efficient automatic estimation method can be very useful. We propose
a new hybrid derivative-free extended Kalman filter for the estimation of the unknown lever arm in tightly coupled GPS/INS
integration. The new approach takes advantage of both the linear time propagation of the Kalman filter and the nonlinear measurement
propagation of the derivative-free extended Kalman filter. Compared to the unscented Kalman filter, which in recent years
is typically used as a superior alternative to the extended Kalman filter for nonlinear estimation, the virtue of the new
Kalman filter is equal estimation accuracy at a significantly reduced computational burden. The performance of the new lever
arm estimation method is assessed with simulated and real data. Simulations show that the proposed technique can estimate
the unknown lever arm correctly provided that maneuvers with attitude changes are performed during initialization. Field test
results confirm the effectiveness of the new method. 相似文献
15.
Hung Lee Jinling Wang Chris Rizos Dorota Grejner-Brzezinska Charles Toth 《GPS Solutions》2002,6(1-2):34-46
This paper discusses the introduction of pseudolites (ground-based GPS-like signal transmitters) into existing integrated
GPS/INS systems in order to provide higher availability, integrity, and accuracy in a local area. Even though integrated GPS/INS
systems can overcome inherent drawbacks of each component system (line-of-sight requirement for GPS, and INS errors that grow
with time), performance is nevertheless degraded under adverse operational circumstances. Some typical examples are when the
duration of satellite signal blockage exceeds an INS bridging level, resulting in large accumulated INS errors that cannot
be calibrated by GPS. Such a scenario, unfortunately, is a common occurrence for certain kinematic applications. To address
such shortcomings, both pseudolite/INS and GPS/pseudolite/INS integration schemes are proposed here. Typically, the former
is applicable for indoor positioning where the GPS signal is unavailable for use. The latter would be appropriate for system
augmentation when the number and geometry of visible satellites is not sufficient for accurate positioning or attitude determination.
In this paper, some technical issues concerned with implementing these two integration schemes are described, including the
measurement model, and the appropriate integration filter for INS error estimation and correction through GPS and pseudolite
(PL) carrier phase measurements. In addition, the results from the processing of simulated measurements, as well as field
experiments, are presented in order to characterize the system performance. As a result, it has been established that the
GPS/PL/INS and PL/INS integration schemes would make it possible to ensure centimeter-level positioning accuracy even if the
number of GPS signals is insufficient, or completely unavailable.
Electronic Publication 相似文献
16.
GPS/MEMS INS integrated system for navigation in urban areas 总被引:1,自引:2,他引:1
This paper evaluates the performance of a tightly coupled GPS/INS integrated system based on low cost MEMS IMUs in dense urban
areas, and investigates two different methods to improve its performance. The first method used is to derive observations
from two different constraint equations reflecting the behavior of a typical land vehicle. The first constraint equation is
derived assuming that the vehicle does not slip and always remains in contact with the ground. If these assumptions are true
the velocity of the vehicle in the plane perpendicular to the forward direction should be zero. The second constraint equation
is derived from the fact that the height does not change much in a short time interval in a land vehicular environment. Thus,
when a GPS outage occurs (partial/complete), the integrated system combines the INS and constraints-derived virtual measurements
to keep the position and velocity errors bounded. This method is suitable for use in real-time applications. The second method
is specifically suitable for a post-mission application and involves the use of Rauch-Tung-Striebel (RTS) smoother. The designed
system performance is evaluated using two data sets collected in dense urban areas. The obtained results demonstrate the effectiveness
of different algorithms considered, in controlling the INS error growth, and indicates the potential of MEMS IMUs for use
in land vehicle navigation applications. 相似文献
17.
基于抗差EKF的GNSS/INS紧组合算法研究 总被引:2,自引:0,他引:2
提出了GNSS/INS紧组合导航的抗差EKF算法,采用21状态GNSS/INS紧组合状态方程,根据多余观测分量及预测残差统计构造抗差等价增益矩阵,建立抗差EKF算法,通过迭代给出GNSS/INS组合导航的抗差解,并开发GNSS/INS紧组合导航模拟平台,通过对观测值加入单粗差、多粗差及缓慢增长三类误差,测试本文算法对不同粗差的抑制能力。分析表明,抗差EKF可以将三类粗差抑制在相应观测值的残差中,达到削弱其对状态参数估计的影响。本文算例证明,抗差EKF算法可将导航解的误差精度从dm级提高为cm级甚至mm级,导航精度及可靠性得到明显提高。 相似文献