A phased array radar seeker（PARS） must be able to effectively decouple body motion and accurately extract the line-of-sight（LOS） rate for target missile tracking.In this study,the realtime two-channel beam pointin...A phased array radar seeker（PARS） must be able to effectively decouple body motion and accurately extract the line-of-sight（LOS） rate for target missile tracking.In this study,the realtime two-channel beam pointing error（BPE） compensation method of PARS for LOS rate extraction is designed.The PARS discrete beam motion principium is analyzed,and the mathematical model of beam scanning control is finished.According to the principle of the antenna element shift phase,both the antenna element shift phase law and the causes of beam-pointing error under phantom-bit conditions are analyzed,and the effect of BPE caused by phantom-bit technology（PBT） on the extraction accuracy of the LOS rate is examined.A compensation method is given,which includes coordinate transforms,beam angle margin compensation,and detector dislocation angle calculation.When the method is used,the beam angle margin in the pitch and yaw directions is calculated to reduce the effect of the missile body disturbance and to improve LOS rate extraction precision by compensating for the detector dislocation angle.The simulation results validate the proposed method.展开更多
The blue-green light in the 450 nm to 550 nm band is usually used in underwater wireless optical communication (UWOC). The blue-green light transmission in seawater is scattered by the seawater effect and can achieve ...The blue-green light in the 450 nm to 550 nm band is usually used in underwater wireless optical communication (UWOC). The blue-green light transmission in seawater is scattered by the seawater effect and can achieve communication in non-line-of-sight (NLOS) transmission mode. Compared to line-of-sight (LOS) transmission, NLOS transmission does not require alignment and can be adapted to various underwater environments. The scattering coefficients of seawater at different depths are different, which makes the scattering of light in different depths of seawater different. In this paper, the received optical power and bit error rate (BER) of the photodetector (PD) were calculated when the scattering coefficients of blue-green light in seawater vary from large to small with increasing depth for NLOS transmission. The results show that blue-green light in different depths of seawater in the same way NLOS communication at the same distance, the received optical power and BER at the receiver are different, and the received optical power of green light is greater than that of blue light. Increasing the forward scattering coverage of the laser will suppress the received optical power of the PD, so when performing NLOS communication, appropriate trade-offs should be made between the forward scattering coverage of the laser and the received optical power.展开更多
针对无人农业机器人在复杂作业环境中因频繁非视距(non line of sight,NLOS)通信导致超宽带(ultrawide band,UWB)定位系统量测波动大、精度低的问题,提出一种改进误差状态卡尔曼滤波(error-state Kalman filter,ESKF)的UWB与惯性导航单...针对无人农业机器人在复杂作业环境中因频繁非视距(non line of sight,NLOS)通信导致超宽带(ultrawide band,UWB)定位系统量测波动大、精度低的问题,提出一种改进误差状态卡尔曼滤波(error-state Kalman filter,ESKF)的UWB与惯性导航单元(inertial measurement unit,IMU)紧耦合定位技术。首先,采用非对称双面双向测距法结合线性拟合校准优化UWB量测数据,设计基于改进的均值滤波算法剔除离群值;其次,基于改进ESKF框架实现UWB-IMU协同定位,利用IMU状态预测信息构建自适应因子,动态调整量测噪声协方差矩阵以削弱NLOS误差影响;最后,搭建四轮无人农业机器人平台,在典型NLOS农业场景下进行静态及动态目标定位试验验证。结果表明,在动态轨迹跟踪中,相较于纯UWB和传统EKF算法,总体定位精度分别提升53.38%和25.15%。该方法在复杂遮挡环境下具有良好的鲁棒性,可为无人农业机器人实现高精度自主导航定位提供技术支撑。展开更多
蓝牙+超宽带(Ultra Wide Band,UWB)混合定位系统结合低功耗广域覆盖特性和高精度时空解算能力,为智能物流提供高效精准的位置信息支撑。分析智能物流定位系统的现状和需求,研究蓝牙+UWB混合定位系统关键技术,提出基于粒子滤波和深度学...蓝牙+超宽带(Ultra Wide Band,UWB)混合定位系统结合低功耗广域覆盖特性和高精度时空解算能力,为智能物流提供高效精准的位置信息支撑。分析智能物流定位系统的现状和需求,研究蓝牙+UWB混合定位系统关键技术,提出基于粒子滤波和深度学习优化的混合定位算法,构建高精度终端节点布置方案,并设计非视距路径(None Line of Sight,NLOS)误差补偿策略,旨在提升智能仓储与物流调度的精确度、响应速度及系统稳定性,实现高效、安全、低能耗的智能物流管理。展开更多
文摘A phased array radar seeker（PARS） must be able to effectively decouple body motion and accurately extract the line-of-sight（LOS） rate for target missile tracking.In this study,the realtime two-channel beam pointing error（BPE） compensation method of PARS for LOS rate extraction is designed.The PARS discrete beam motion principium is analyzed,and the mathematical model of beam scanning control is finished.According to the principle of the antenna element shift phase,both the antenna element shift phase law and the causes of beam-pointing error under phantom-bit conditions are analyzed,and the effect of BPE caused by phantom-bit technology（PBT） on the extraction accuracy of the LOS rate is examined.A compensation method is given,which includes coordinate transforms,beam angle margin compensation,and detector dislocation angle calculation.When the method is used,the beam angle margin in the pitch and yaw directions is calculated to reduce the effect of the missile body disturbance and to improve LOS rate extraction precision by compensating for the detector dislocation angle.The simulation results validate the proposed method.
文摘The blue-green light in the 450 nm to 550 nm band is usually used in underwater wireless optical communication (UWOC). The blue-green light transmission in seawater is scattered by the seawater effect and can achieve communication in non-line-of-sight (NLOS) transmission mode. Compared to line-of-sight (LOS) transmission, NLOS transmission does not require alignment and can be adapted to various underwater environments. The scattering coefficients of seawater at different depths are different, which makes the scattering of light in different depths of seawater different. In this paper, the received optical power and bit error rate (BER) of the photodetector (PD) were calculated when the scattering coefficients of blue-green light in seawater vary from large to small with increasing depth for NLOS transmission. The results show that blue-green light in different depths of seawater in the same way NLOS communication at the same distance, the received optical power and BER at the receiver are different, and the received optical power of green light is greater than that of blue light. Increasing the forward scattering coverage of the laser will suppress the received optical power of the PD, so when performing NLOS communication, appropriate trade-offs should be made between the forward scattering coverage of the laser and the received optical power.
文摘针对无人农业机器人在复杂作业环境中因频繁非视距(non line of sight,NLOS)通信导致超宽带(ultrawide band,UWB)定位系统量测波动大、精度低的问题,提出一种改进误差状态卡尔曼滤波(error-state Kalman filter,ESKF)的UWB与惯性导航单元(inertial measurement unit,IMU)紧耦合定位技术。首先,采用非对称双面双向测距法结合线性拟合校准优化UWB量测数据,设计基于改进的均值滤波算法剔除离群值;其次,基于改进ESKF框架实现UWB-IMU协同定位,利用IMU状态预测信息构建自适应因子,动态调整量测噪声协方差矩阵以削弱NLOS误差影响;最后,搭建四轮无人农业机器人平台,在典型NLOS农业场景下进行静态及动态目标定位试验验证。结果表明,在动态轨迹跟踪中,相较于纯UWB和传统EKF算法,总体定位精度分别提升53.38%和25.15%。该方法在复杂遮挡环境下具有良好的鲁棒性,可为无人农业机器人实现高精度自主导航定位提供技术支撑。
文摘蓝牙+超宽带(Ultra Wide Band,UWB)混合定位系统结合低功耗广域覆盖特性和高精度时空解算能力,为智能物流提供高效精准的位置信息支撑。分析智能物流定位系统的现状和需求,研究蓝牙+UWB混合定位系统关键技术,提出基于粒子滤波和深度学习优化的混合定位算法,构建高精度终端节点布置方案,并设计非视距路径(None Line of Sight,NLOS)误差补偿策略,旨在提升智能仓储与物流调度的精确度、响应速度及系统稳定性,实现高效、安全、低能耗的智能物流管理。
