The existing research results show that a fixed single station must conduct three consecutive frequency shift measurements and obtain the target’s moving speed by constructing two frequency difference equations. This...The existing research results show that a fixed single station must conduct three consecutive frequency shift measurements and obtain the target’s moving speed by constructing two frequency difference equations. This article proposes a new method that requires only two consecutive measurements. While using the azimuth measurement to obtain the angular difference between two radial distances, it also conducts two consecutive Doppler frequency shift measurements at the same target azimuth. On the basis of this measurement, a frequency difference equation is first constructed and solved jointly with the Doppler frequency shift equation. By eliminating the velocity variable and using the measured angular difference to obtain the target’s lead angle, the target’s velocity can be solved by using the Doppler frequency shift equation again. The new method avoids the condition that the target must move equidistantly, which not only provides an achievable method for engineering applications but also lays a good foundation for further exploring the use of steady-state signals to achieve passive positioning.展开更多
针对传统水下定位无法同时估算出移动目标的位置和速度问题,提出了一种基于多普勒频移(Doppler frequency shift, DFS)的水下移动目标测速定位算法,创新性地实现了移动目标任意时刻瞬时位置和瞬时速度矢量的同步获取,二者耦合度达到100...针对传统水下定位无法同时估算出移动目标的位置和速度问题,提出了一种基于多普勒频移(Doppler frequency shift, DFS)的水下移动目标测速定位算法,创新性地实现了移动目标任意时刻瞬时位置和瞬时速度矢量的同步获取,二者耦合度达到100%。该算法将移动目标的位置和速度联合构建成统一的高维矢量,利用梯度下降法收敛迭代出真实移动目标值。仿真结果表明:在无噪声影响且迭代次数到达10000次时,本算法的定位误差低于0.01 m,定速误差低于0.1 m/s。该算法具有复杂度低、运行速度快、定位精度高的优点。展开更多
文摘The existing research results show that a fixed single station must conduct three consecutive frequency shift measurements and obtain the target’s moving speed by constructing two frequency difference equations. This article proposes a new method that requires only two consecutive measurements. While using the azimuth measurement to obtain the angular difference between two radial distances, it also conducts two consecutive Doppler frequency shift measurements at the same target azimuth. On the basis of this measurement, a frequency difference equation is first constructed and solved jointly with the Doppler frequency shift equation. By eliminating the velocity variable and using the measured angular difference to obtain the target’s lead angle, the target’s velocity can be solved by using the Doppler frequency shift equation again. The new method avoids the condition that the target must move equidistantly, which not only provides an achievable method for engineering applications but also lays a good foundation for further exploring the use of steady-state signals to achieve passive positioning.
文摘5G超密集网络(ultra-dense network,UDN)的引入是为了提升吞吐量,特别是针对静态和低速场景,因此,无法同时满足高吞吐量和高移动速度的需求。对于未来需要同时支持高容量和高速移动的6G新场景,提出一种同心圆模型(homocentric sphere model,HSM)的网络架构,采用控制面/用户面数据分离、多发送接收节点(transmission and reception point, TRP)协同传输的方法来处理密集部署网络中多普勒效应影响大和TRP频繁切换的问题,使得该模型成为密集部署网络下提升网络容量、应对高速移动的有效方法。数据结果证明,所提的HSM有效减小了密集组网高速移动场景下多普勒频移效应,同时能够提供更高的网络遍历频谱效率。
