微小型IMU/GPS组合定位定向系统研究

介绍了一种低成本微小型惯性测量组件(inertialmeasurementunit,IMU)和双天线GPS构成的组合定位定向系统。为确保组合系统的实时性和滤波稳定性,提出了一种基于UD分解的快速卡尔曼滤波算法,给出了IMU/GPS组合系统的软硬件设计和实验结果。该组合系统应用于炮兵测地车,具有成本低、精度高等优点,能够提高炮兵测地保障的精度和速度。     

基于GPS的汽车稳定性控制系统研究

介绍GPS测姿原理,利用双天线GPS接收机直接测量车身侧偏角等汽车状态参数,采用卡尔曼滤波器融合GPS与INS测量数据。运用滑模控制理论,设计汽车稳定性控制器。运用Matlab/simulink软件仿真在变换车道等各种工况下控制器的控制效果。     

An integrated land vehicle navigation system based on context awareness

In the complex urban environments, land vehicle navigation purely relying on GNSS cannot satisfy user needs due to the loss of satellite signals caused by obstructions such as buildings, tunnels, and trees. To solve this problem, we introduce a GPS-/MSINS-/magnetometer-integrated urban navigation system based on context awareness. In this system, the data from the Micro Strapdown Inertial Navigation System (MSINS) are used to analyze and detect the context knowledge of vehicles, whose sensor errors can be compensated by the heuristic drift reduction algorithm for different motion situations. When GPS is available, the vehicle position can be estimated by unscented Kalman Filter, whereas in the case of GPS outages, the vehicle attitude is provided by an attitude and heading reference system and the motion constraints-aided algorithm is used to complete the positioning. In the experiment validation, the integrated navigation system is set up by low-cost inertial sensors. The result shows that the proposed system can achieve high accuracy when GPS is available. For most of the time without GPS, the system can guarantee the positioning precision of 10 m and compensate the errors of MSINS effectively, which fully satisfies positioning needs in complex urban environments.     

Integrated Navigation System and Experiment of a Low-Cost and Low-Accuracy SINS/GPS

When SINS (strap-down inertial navigation system) is combined with GPS, the observability of the course angle is weak. Although the course angle error is improved to some extent through Kalman filtering, the course angle still assumes a divergent trend. This trend is aggravated further when using low-cost and low-accuracy SINS. In order to restrain this trend, a method that uses AHRS to substitute for SINS course angle information is put forward aimed at the hardware component characteristic of the low-cost and low-accuracy SINS including AHRS (attitude and heading reference system) and IMU (inertial measurement unit). Real static and dynamic experiments show that the method can restrain the divergent trend of the navigation system angle effectively, and the positioning accuracy is high.     

Integrated navigation system and experiment of a low-cost and low-accuracy SINS/GPS

When SINS (strap-down inertial navigation system) is combined with GPS, the observability of the course angle is weak. Although the course angle error is improved to some extent through Kalman filtering, the course angle still assumes a divergent trend. This trend is aggravated further when using low-cost and low-accuracy SINS. In order to restrain this trend, a method that uses AHRS to substitute for SINS course angle information is put forward aimed at the hardware component characteristic of the low-cost and low-accuracy SINS including AHRS (attitude and heading reference system) and IMU (inertial measurement unit). Real static and dynamic experiments show that the method can restrain the divergent trend of the navigation system angle effectively, and the positioning accuracy is high.     

Design of a low-cost attitude determination GPS/INS integrated navigation system

Due to their complementary features of GPS and INS, the GPS/INS integrated navigation system is increasingly being used for a variety of commercial and military applications. An attitude determination GPS (ADGPS) receiver, with multiple antennas, can be more effectively integrated with a low-cost IMU since the receiver gives not only position and velocity data but also attitude data. This paper proposes a low-cost attitude determination GPS/INS integrated navigation system. The proposed navigation system comprises an ADGPS receiver, a navigation computer unit (NCU), and a low-cost commercial MEMS IMU. The navigation software includes a fault detection and isolation (FDI) algorithm for integrity. In order to evaluate the performance of the proposed navigation system, two flight tests have been performed using a small aircraft. The first flight test confirmed the fundamental operation of the proposed navigation system and the effectiveness of the FDI algorithm. The second flight test evaluated the performance of the proposed navigation system and demonstrated the benefit of GPS attitude information in a high dynamic environment. The flight test results show that the proposed ADGPS/INS integrated navigation unit gives reliable navigation performance even when anomalous GPS data is provided and gives better navigation performance than a conventional GPS/INS unit.     

差分GPS水下立体定位系统浮标姿态的测量

三维数字罗盘可以实时输出载体的二维姿态和地理方位角。在差分GPS精密水下立体定位系统中,可以用于GPS浮标姿态测定,进行GPS天线坐标实时三维改正。本文对三维数字罗盘工作原理进行了简要介绍,并针对三维数字罗盘与GPS同步问题进行了详细分析,同时给出了GPS天线坐标改正公式。     

一种低成本GPS/INS紧耦合组合导航系统

描述了一种低成本的GPS/INS组合导航系统,经过理论推导得到了系统具体的实现方法,并通过市场上大量使用的低成本GPS模块和MEMS陀螺和加速度计实现了该系统。实际路测数据结果显示,该系统基本达到了理论预期。     

Attitude estimation based on fusion of gyroscopes and single antenna GPS for small UAVs under the influence of vibration

An attitude estimation method is presented for small unmanned aerial vehicles (UAVs) powered by a piston engine which is the major source of vibration. Vibration of the engine significantly degrades the accuracy of the inertial measurement unit, especially for low-cost sensors that are based on micro electro-mechanical system. Therefore, a vibration model for a small UAV is proposed in order to examine the influence of vibration on attitude estimation with different sensors. The model is derived based on spectrum analysis with short-time Fourier transform. The vibration is compared with the drift of the gyroscope in order to examine the impact on attitude estimation. An attitude estimation method that fuses the gyroscopes and single antenna global positioning system (GPS) is proposed to mitigate the influence of engine vibration and gyroscope drift. The quaternion-based extended Kalman filter is implemented to fuse the sensors. This filter fuses the angular rates measured by the gyroscopes and the pseudo-attitude derived from the GPS velocity to estimate the attitude of the UAV. Simulations and experiment results indicate that the proposed method performs well both in short-term and long-term accuracy even though the gyroscopes are affected by drift and vibration noise, while the pseudo-attitude contains severe noise.     

基于几何约束的GPS测姿系统的原理和实验

详细描述了GPS测姿系统的原理,并给出了一种基于基线长度约束和空间几何约束的最小二乘模糊度搜索算法,并经过静态和动态车载试验证明GPS测姿系统切实可行,在基线长度为3m的条件下,航向角精度优于0.1°。     

一种新的车载低成本MEMS陀螺仪快速初始对准算法

车载导航系统常用惯性测量元件（IMU）与全球卫星导航系统（GNSS）技术组合以提高系统的稳定性。由于车载导航系统的应用场景限制,对初始对准速度有着较高要求。为了提高传统车载组合导航系统中低成本微机电系统（MEMS）陀螺仪的初始对准速度,降低初始对准过程中的计算量,本文提出了一种适用于任意失准角下的基于网络RTK辅助与无损Kalman滤波（UKF）的MEMS陀螺仪初始对准算法。同时针对车载系统的特点,简化了IMU系统误差方程,分析了简化带来的误差。在诺瓦泰ProPak6和诺瓦泰IMU-IGM-S1组成的导航系统中验证了本文提出的算法。试验结果表明,在以诺瓦泰双天线GNSS输出航向角为"真值"的情况下,本文提出的算法基本可以在5 s内完成陀螺仪的初始对准,对准精度达0.3°。     

3Dsurs系统姿态精度分析

GPS是3Dsurs系统中关键传感器之一,用于测量车载平台的位置和姿态角。姿态角获取是3Dsurs系统关键技术之一,其精度决定系统所能达到的测量精度。本系统中使用NovAtel DL-4型双频、高精度、高采样率GPS,采用差分后处理方法,数据处理中利用三台GPS间固定位置关系进行约束平差,并采用滤波方法提高解算精度。多组实验结果表明:使用GPS测姿可获得较高精度,系统中三个姿态角的精度有差异,航向角的精度最高,横滚角和俯仰角的精度接近。     

Pitch and roll attitude estimation of a small-scaled helicopter using single antenna GPS with gyroscopes

A method is presented for estimating the roll and pitch attitude of a small-scaled unmanned helicopter based on the velocity measurements of the global positioning system (GPS). The small-scaled helicopter is a radio controlled (RC) model which is readily available and affordable for academic laboratories as a research platform. Only one single antenna GPS receiver is equipped on the RC helicopter to acquire the velocity measurements needed for the attitude estimation. The velocity information is recorded by the onboard computer for post-processing. An attitude and heading reference system (AHRS) is used to provide the reference attitudes. The required angular rates and heading for this study are also given by the gyroscopes and compass of the AHRS for the sake of system’s simplification. The Kalman filter is applied to estimate the helicopter’s accelerations by using the GPS velocity measurements. The estimated accelerations form the fundamental elements of synthesizing the pseudo-roll and the pseudo-pitch. With some legitimate simplifications and assumptions, the relation between the helicopter’s attitudes and the accelerations estimated from the GPS velocity measurements can be developed. Furthermore, to enhance the accuracy of the pseudo-attitudes, the angular rates acquired from the gyroscopes are incorporated into the estimation algorithm of pseudo-attitudes by using a complementary filter.

面向低成本车载IMU的安装姿态估计

车载IMU相对于车体的安装姿态信息是应用车辆非完整约束的必需条件,而车辆非完整约束可以有效解决GNSS信号长时间中断的情形下低成本INS+GNSS组合导航系统精度降低的问题。本文针对车载场景下的低成本消费级IMU,基于卡尔曼滤波和粒子滤波提出了一种估计IMU安装姿态的算法。该算法无需限制IMU相对于车体的姿态为小角度;随后,基于仿真平台对低成本消费级IMU进行建模,利用生成的若干组不同安装姿态的IMU数据对算法进行验证;最后进行车载测试。仿真结果和车载测试结果都表明,该算法可以准确地估计IMU相对于车体的安装姿态,对于低成本INS+GNSS组合导航系统精度的提高具有实际意义。     

New method for single epoch, single frequency land vehicle attitude determination using low-end GPS receiver

Stand-alone, unaided, single frequency, single epoch attitude determination is the most challenging case of GNSS compass processing. For land vehicle applications, the baseline approximately lies in the plane of the local geodetic horizon. This provides an important constraint that can be exploited to directly aid the ambiguity resolution process. We fully integrate the constraint into the observation equations, which are transformed orthogonally. Our method can acquire the high-quality float solution by means of a heading search strategy. The fixed solution is obtained by weighted constrained integer least squares for each possible heading. The correct solution is identified by three consecutive steps: Kolmogorov?CSmirnov test, heading verification, and global minimizer of the fixed ambiguity objective function. The analysis focuses on single frequency, single epoch land vehicle attitude determination using low-end GPS receivers with very low precision of carrier phase and code measurements. The error analysis is given for choosing a proper baseline length in practical application. Experimental results demonstrate that this scheme can improve the ambiguity success rate for very short baseline.     

Attitude determination by integration of MEMS inertial sensors and GPS for autonomous agriculture applications

Integration of Global Positioning System (GPS) and Inertial Navigation System (INS) technologies, which has widespread usage in industry, is also regarded as an ideal solution for automated agriculture because it fulfils the accuracy, reliability and availability requirements of industrial and agricultural applications. Agriculture applications use position, velocity and heading information for automated vehicle guidance and control to enhance the yield and quality of the crop, and in order to vary the application of fertilizer and herbicides according to soil heterogeneity at sub-field level. A loosely coupled GPS/INS integration algorithm known as “AhrsKf” is introduced for automated agriculture vehicle guidance and control utilizing MEMS inertial sensors and GPS. The AhrsKf can produce high-frequency attitude solutions for the vehicle’s guidance and control system, by using inputs from a single survey grade L1/L2 antenna, eliminating the need for the previous two antenna solutions. Given its agricultural application, the AhrsKf has been implemented with some specific design features to improve the accuracy of the attitude solution including, temperature compensation of the inertial sensors, and the aid of plough lines of farm lands. To evaluate the AhrsKf solution, two benchmarking tests have been conducted by using a three-antenna GPS system and NovAtel’s SPAN-CPT. The results have demonstrated that the AhrsKf solution is stable and can correctly track the movement of the farming vehicle.     

一种基于非专用接收机的GPS实时定姿算法

描述一种基于非专用接收机的GPS实时定姿算法,主要工作可以分为两个部分:第一,采用最小二乘方法和乔里斯基分解,基于基线长度约束压缩整周模糊度搜索空间,以达到实时计算的目的;第二,结合姿态角约束,使用金字塔算法提高了整周模糊度求解效率.经过实验,算法在基线长度为3 m的条件下,航向角精度优于0.1°.     

GPS/GALILEO偏航姿态异常对动态PPP的影响及其改正模型

当GPS、GALILEO卫星运行至与太阳、地球近似共线时,卫星很难维持名义姿态,将出现一段时间的偏航姿态异常。本文基于不同分析中心所提供的精密轨道和钟差产品,在卫星偏航姿态异常时期,设计不同姿态改正策略,选取全球分布的7个MGEX站10 d实测数据,分析了GPS、GALILEO卫星的天线相位中心改正、相位缠绕改正对观测值残差及动态PPP定位结果的影响。研究表明,在卫星偏航姿态异常时期,采用名义偏航姿态对GPS、GALILEO卫星观测值残差的影响可分别达到8和11 cm,在此期间,GPS/GALILEO卫星采用模型偏航姿态,与采用名义偏航姿态相比,动态PPP的E、N、U 3个方向的定位精度可分别提高13.30%、15.77%和12.98%,相较于剔除卫星策略,采用模型偏航姿态的动态PPP定位精度在E、N、U方向可分别提高5.399%、4.430%、5.992%。     

基于四元数法的航向修正算法分析

目前载体的姿态解算已成为捷联式惯性导航系统精确导航的研究热点。为了减少由于陀螺仪漂移带来的航向误差,提出了一种基于启发式漂移消除算法(HDE)的改进航向修正方法。该方法采用四元数法解算载体航向,利用行人在室内环境下,行走直线时航向角偏差直接对行人航向进行修正,然后推算行人航向轨迹。实验采用低成本的智能手机,对比分析了不同采样频率以及二阶龙格-库塔法与四阶龙格-库塔法更新四元数解算航向角的精度,试验结果表明,提高采样频率能减小航向解算误差,提高定位精度。该算法对导航定位研究有一定的参考价值。      

偏航姿态对GPS和GLONASS精密轨道和钟差的影响

利用全球约110个国际GNSS服务（International GNSS Service,IGS）测站2013年全年观测数据,分析和研究了GPS和全球卫星导航系统（global navigation satellite system,GLONASS）卫星偏航姿态对其精密轨道和钟差的影响。结果表明,偏航姿态对不同型号GPS卫星轨道和钟差的影响程度不同,当采用偏航姿态改正后地影期的BLOCK ⅡA型卫星轨道改善可达17 mm,BLOCK ⅡF为近5 mm,而BLOCK ⅡR几乎不受影响。由于偏航姿态对GLONASS-M卫星定轨精度影响较大,因此,当改正偏航姿态后所有GLONASS卫星相对于IGS最终轨道平均一维差异提高10 mm,相对于德国地学中心（German Research Center for Geosciences,GFZ）最终钟差平均标准差提升0.034 ns。