Strapdown inertial navigation system(SINS)/celestial navigation system(CNS)integrated navigation is widely used to achieve long-time and high-precision autonomous navigation for aircraft.In general,SINS/CNS integrated...Strapdown inertial navigation system(SINS)/celestial navigation system(CNS)integrated navigation is widely used to achieve long-time and high-precision autonomous navigation for aircraft.In general,SINS/CNS integrated navigation can be divided into two integrated modes:loosely coupled integrated navigation and tightly coupled integrated navigation.Because the loosely coupled SINS/CNS integrated system is only available in the condition of at least three stars,the latter one is becoming a research hotspot.One major challenge of SINS/CNS integrated navigation is obtaining a high-precision horizon reference.To solve this problem,an innovative tightly coupled rotational SINS/CNS integrated navigation method is proposed.In this method,the rotational SINS error equation in the navigation frame is used as the state model,and the starlight vector and star altitude are used as measurements.Semi-physical simulations are conducted to test the performance of this integrated method.Results show that this tightly coupled rotational SINS/CNS method has the best navigation accuracy compared with SINS,rotational SINS,and traditional tightly coupled SINS/CNS integrated navigation method.展开更多
With appropriate geometry configuration, helicopter- borne rotating synthetic aperture radar （ROSAR） can break through the limitations of monostatic synthetic aperture radar （SAR） on forward-looking imaging. With ...With appropriate geometry configuration, helicopter- borne rotating synthetic aperture radar （ROSAR） can break through the limitations of monostatic synthetic aperture radar （SAR） on forward-looking imaging. With this capability, ROSAR has extensive potential applications, such as self-navigation and self-landing. Moreover, it has many advantages if combined with the frequency modulated continuous wave （FMCW） technology. A novel geometric configuration and an imaging algorithm for helicopter-borne FMCW-ROSAR are proposed. Firstly, by per- forming the equivalent phase center principle, the separated trans- mitting and receiving antenna system is equalized to the case of system configuration with antenna for both transmitting and receiving signals. Based on this, the accurate two-dimensional spectrum is obtained and the Doppler frequency shift effect in- duced by the continuous motion of the platform during the long pulse duration is compensated. Next, the impacts of the velocity approximation error on the imaging algorithm are analyzed in de- tail, and the system parameters selection and resolution analysis are presented. The well-focused SAR image is then obtained by using the improved Omega-K algorithm incorporating the accurate compensation method for the velocity approximation error. FJnally, correctness of the analysis and effectiveness of the proposed al- gorithm are demonstrated through simulation results.展开更多
目前,大型水面和水下载体一般安装两套旋转惯导系统(RINS),两套系统按相同的旋转调制策略独立运行,系统信息仅互为备份,缺乏有效融合。针对两台旋转惯导系统配置,开展基于器件信息深度融合的联合旋转调制策略研究,进一步提高系统精度。...目前,大型水面和水下载体一般安装两套旋转惯导系统(RINS),两套系统按相同的旋转调制策略独立运行,系统信息仅互为备份,缺乏有效融合。针对两台旋转惯导系统配置,开展基于器件信息深度融合的联合旋转调制策略研究,进一步提高系统精度。不改变单套系统结构和编排的前提下,优化经典的单轴4位置旋转方案,联合设计两套系统惯性测量单元(IMU)的旋转策略和转停时序,确保任一时刻有一台惯导处于转停状态,在时序上对转停状态下的惯性测量单元输出(陀螺仪和加速度计)信息进行融合,减小因惯性测量单元转动与刻度系数误差和安装误差的耦合效应。误差特性的理论分析验证了联合调制策略的优势。仿真结果表明:在典型误差作用下,采用联合旋转调制策略的系统定位误差,由单套旋转惯导系统精度的2.3 n mile/72 h提高到0.7 n mile/72 h。展开更多
基金supported by the National Natural Science Foundation of China(61722301)
文摘Strapdown inertial navigation system(SINS)/celestial navigation system(CNS)integrated navigation is widely used to achieve long-time and high-precision autonomous navigation for aircraft.In general,SINS/CNS integrated navigation can be divided into two integrated modes:loosely coupled integrated navigation and tightly coupled integrated navigation.Because the loosely coupled SINS/CNS integrated system is only available in the condition of at least three stars,the latter one is becoming a research hotspot.One major challenge of SINS/CNS integrated navigation is obtaining a high-precision horizon reference.To solve this problem,an innovative tightly coupled rotational SINS/CNS integrated navigation method is proposed.In this method,the rotational SINS error equation in the navigation frame is used as the state model,and the starlight vector and star altitude are used as measurements.Semi-physical simulations are conducted to test the performance of this integrated method.Results show that this tightly coupled rotational SINS/CNS method has the best navigation accuracy compared with SINS,rotational SINS,and traditional tightly coupled SINS/CNS integrated navigation method.
基金supported by the National Basic Research Program of China(2011CB707001)the Fundamental Research Funds for the Central Universities(106112015CDJXY500001CDJZR165505)
文摘With appropriate geometry configuration, helicopter- borne rotating synthetic aperture radar （ROSAR） can break through the limitations of monostatic synthetic aperture radar （SAR） on forward-looking imaging. With this capability, ROSAR has extensive potential applications, such as self-navigation and self-landing. Moreover, it has many advantages if combined with the frequency modulated continuous wave （FMCW） technology. A novel geometric configuration and an imaging algorithm for helicopter-borne FMCW-ROSAR are proposed. Firstly, by per- forming the equivalent phase center principle, the separated trans- mitting and receiving antenna system is equalized to the case of system configuration with antenna for both transmitting and receiving signals. Based on this, the accurate two-dimensional spectrum is obtained and the Doppler frequency shift effect in- duced by the continuous motion of the platform during the long pulse duration is compensated. Next, the impacts of the velocity approximation error on the imaging algorithm are analyzed in de- tail, and the system parameters selection and resolution analysis are presented. The well-focused SAR image is then obtained by using the improved Omega-K algorithm incorporating the accurate compensation method for the velocity approximation error. FJnally, correctness of the analysis and effectiveness of the proposed al- gorithm are demonstrated through simulation results.
文摘目前,大型水面和水下载体一般安装两套旋转惯导系统(RINS),两套系统按相同的旋转调制策略独立运行,系统信息仅互为备份,缺乏有效融合。针对两台旋转惯导系统配置,开展基于器件信息深度融合的联合旋转调制策略研究,进一步提高系统精度。不改变单套系统结构和编排的前提下,优化经典的单轴4位置旋转方案,联合设计两套系统惯性测量单元(IMU)的旋转策略和转停时序,确保任一时刻有一台惯导处于转停状态,在时序上对转停状态下的惯性测量单元输出(陀螺仪和加速度计)信息进行融合,减小因惯性测量单元转动与刻度系数误差和安装误差的耦合效应。误差特性的理论分析验证了联合调制策略的优势。仿真结果表明:在典型误差作用下,采用联合旋转调制策略的系统定位误差,由单套旋转惯导系统精度的2.3 n mile/72 h提高到0.7 n mile/72 h。
