Multistatic coherent MIMO radar networks

雷达网络代表了现有雷达系统的持续进一步发展，其中通过将多个雷达节点联网可以提高整个系统的性能。由于与单个传感器相比目标和雷达节点之间的附加路径，例如由于若干雷达的附加双基地视角以及由于若干雷达节点的附加相位信息，可以更好地分辨目标，所述雷达节点在相干操作中跨越大孔径。雷达网络的一种新方法，这是前一个项目的重点，结果是，除了雷达传感器之外，还实现了额外的网络节点作为中继器元件，这些中继器元件不是为信号处理而设计的，而是仅放大入射信号，通过混频器对其进行调制并对其进行解调。在所开展的项目中，相干雷达中继器网络比单一传感器具有显著优势。为此，开发了中继器网络功能的系统概念以及包括近场效应校准和补偿的信号处理链。结果表明，采用三角形路径时，中继器网络具有较高的角分离能力和良好的信噪比。对于中继器网络，主要的缺点已经被证明是，由于中继器信号的调制和中继器的非理想特性引起的所需基带宽度的大幅增加，网络是不可任意扩展的。为了克服中继器方法的这些弱点，在现在申请的后续项目中，将使用多通道数字接收器装置，而不是中继器。在此，数字接收机单元被理解为雷达接收机-如在数字雷达的情况下-其中整个高频带通过模拟混频被移位到基带并且在那里被数字化。因此，网络由至少一个模拟线性调频序列MIMO雷达和一个或多个数字接收器单元组成。与中继器网络一样，这些混合模拟-数字雷达网络承诺能够在没有网络节点的电缆连接的情况下构建相干网络。然而，与中继器网络相比，存在以下优点：模拟-数字网络也可扩展到大量节点，并且由于多信道操作，使得虚拟MIMO孔径能够比使用中继器时显著更完全地被占用。

Radar networks represent a consistent further development of existing radar systems in which the performance of the overall system can be increased by networking several radar nodes. Due to the additional paths between the target and the radar nodes compared to the single sensor, targets can be resolved better, e.g. due to the additional bistatic viewing angle of several radars and due to the additional phase information of several radar nodes, which span a large aperture in coherent operation. A novel approach of a radar network, which was the focus of the predecessor project, results when additional network nodes are implemented as repeater elements in addition to the radar sensors, which are not designed for signal processing but only amplify incident signals, modulate them via a mixer and retransmit them. In the project carried out, significant advantages of coherent radar repeater networks over single sensors were demonstrated. For this purpose, a system concept for the function of the repeater networks was developed as well as a signal processing chain that includes calibration and compensation of near-field effects. The high angular separation capability of the repeater networks and the good SNR when using the triangular paths were demonstrated. For the repeater networks, the main drawback has been shown to be that the networks are not arbitrarily scalable due to the large increase in the required baseband widths caused by the modulation of the repeater signals and the non-ideal characteristics of the repeaters. In order to circumvent these weaknesses of the repeater approaches, multi-channel digital receiver units are to be used instead of repeaters in the follow-up project now applied for. In this context, a digital receiver unit is understood to be a radar receiver - as in the case of a digital radar - in which the entire high-frequency band is shifted to the baseband by analog mixing and digitized there. Consequently, the network then consists of at least one analog chirp sequence MIMO radar and one or more digital receiver units. Like the repeater networks, these mixed analog-digital radar networks promise to enable the construction of coherent networks without cable connections of the network nodes. Compared to the repeater networks, however, there is the advantage that the analog-digital networks are also scalable to a large number of nodes and, due to multi-channel operation, enable virtual MIMO apertures that are significantly more fully occupied than when using a repeater.