基于微纳卫星编队的到达时差(TDOA)/到达频差(FDOA)无源定位系统中, 定位精度的提高需大幅度增加链路传输数据量, 在星间链路带宽受限情况下将严重制约系统的工作效率。该文提出了一种欠采样传输时频差估计方法, 在不增加传输数据量条件下, 保持TDOA估计精度不变, 且FDOA估计精度随欠采样所形成的时间扩展显著提升。分析了欠采样传输的时差估计精度, 以及最大欠采倍数约束条件。仿真表明: 对于宽带信号, 该方法在传输数据量相同条件下, 定位性能相对于压缩感知(CS)方法可提升6倍以上。
In time difference of arrival (TDOA)/frequency difference of arrival (FDOA) passive location systems used in micro/ nano-satellite formations, improving the location accuracy usually requires a large increase in data transmissions, which severely reduces the system efficiency due to the narrow data link bandwidth of the satellites. A TDOA/FDOA estimation method is developed based on sub-sampling transmissions without increasing the data transmissions, which significantly improves the FDOA accuracy by a time expansion while maintaining the TDOA estimation accuracy. The TDOA accuracy is analyzed and the maximum sub-sampling rate is derived. Simulations show that for wideband signals, the location accuracy of this method is improved more than 6 fold over that of the compressed sensing method for the same data transmission.
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