Doppler-Tags with Self-Interference Cancellation for High-Accuracy Chirp Sequence Radars (DoSIS)

用于高精度线性调频脉冲序列雷达 (DoSIS) 的具有自干扰消除功能的多普勒标签

• 批准号: 533282729
• 负责人: Dr.-Ing. Benjamin Nuß
• 金额: --
• 依托单位: Institut für Hochfrequenztechnik und Elektronik (IHE)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/533282729?language=en
• 关键词: Doppler; Tags; Self; Interference; Cancellation

An energy efficient Doppler tag is proposed as radar tag together with a chirp sequence radar system exploiting the signal phase to reach high accuracy above the bandwidth related value. The Doppler tag introduces an artificial Doppler shift characteristic for the tagged object of interest to the radar signal reflected off this object. The radar signal is received at the tag, mixed with a frequency acting as artificial Doppler, and sent back in direction towards the radar sensor. In the processing of the raw radar data, the velocity and range of the tagged object are estimated with high accuracy. Here, the velocity estimation is required to correct phase errors that would affect the range estimation. The artificial Doppler shift is corrected in the signal after identification. After the removal of the Doppler shift, a chirp Z-transform along the samples of the chirp can give a first, coarse range estimate. This is used as starting point for the phase-based range estimation within the range bin determined by the frequency analysis. The high-accuracy range within this bin is determined using the phase offset, where the main challenge is the sufficient suppression of quadratic phase terms. Another critical aspect to consider is self-interference. Even if the receive and transmit channels of the tag are separated, there will be a finite leakage of the transmit signal into the receiver, which will generate a tone at twice the intended Doppler shift. This will potentially have a significant impact on the overall radar performance, as the leakage signal may not only saturate the receiver, but could also create wrong target signatures after being remixed with the Doppler frequency again, that could potentially swamp out the actual signal of interest. To overcome this limitation, we will investigate enhancing the proposed tag architecture by a self-interference cancellation stage. The delay in this cancellation path has to be equal to the one from the coupling path from the Tx to the Rx antenna. This way, combined with additional measures, such as optimized placement and design of the receive and transmit antennas, the impact of interference on the tag performance can be minimized. By subtracting the internal leakage signal with the correct delay, phase and amplitude from the receive signal, the unwanted external leakage signal will be cancelled. The quality of this cancellation strongly depends on the ability to accurately adjust the internal cancellation path to the external coupling path. Here, variable delay lines are required. And finally, if not only a single tag but multiple tags per object are used in conjunction with a multi-sensor setup, the determination of the object orientation in 3D can be enabled with high accuracy. For the envisioned application, it is important that the tags have a low energy budget and they are highly miniaturized. Therefore, we will investigate an IC-based solution at 60 GHz.

提出了节能多普勒标签作为雷达标签，并与chirp序列雷达系统一起利用信号相，以达到带宽相关值以上的高精度。多普勒标签引入了一个人工多普勒移位特征，该特征是对此对象反射的雷达信号感兴趣的对象。在标签处接收雷达信号，与充当人造多普勒的频率混合，并向雷达传感器朝向雷达传感器。在处理原始雷达数据时，标记对象的速度和范围具有很高的精度。在这里，需要估算速度估计以纠正会影响范围估计的相误差。鉴定后，在信号中校正了人工多普勒偏移。去除多普勒偏移后，沿着chirp的样品的chirp z变换可以给出第一个粗糙的范围估计值。这用作由频率分析确定的范围内基于阶段范围估计的起点。使用相位偏移确定该垃圾箱内的高准确范围，其中主要挑战是对二次相项的充分抑制。要考虑的另一个关键方面是自我干扰。即使将标签的接收通道和传输通道分开，也会在接收器中传输信号有限泄漏，这将在预期的多普勒移位时产生两倍的音调。这可能会对整体雷达的性能产生重大影响，因为泄漏信号不仅可能使接收器饱和，而且在再次与多普勒频率进行混合后，可能会造成错误的目标签名，这可能会淹没实际感兴趣的信号。为了克服这一限制，我们将通过自我干扰取消阶段来调查增强所提出的标签架构。该取消路径的延迟必须等于从TX到Rx天线的耦合路径的延迟。这样，结合了其他措施，例如接收和传输天线的优化放置和设计，可以最大程度地减少干扰对标签性能的影响。通过以正确的延迟，相位和接收信号的幅度减去内部泄漏信号，将取消不需要的外部泄漏信号。该取消的质量在很大程度上取决于能够准确调整内部取消路径到外部耦合路径的能力。在这里，需要可变的延迟线。最后，如果不仅与多传感器设置一起使用每个对象的多个标签，而且每个对象的多个标签，则可以以高精度启用3D中对象方向的确定。对于设想的应用程序，重要的是标签的能源预算低，并且高度微型。因此，我们将在60 GHz下研究基于IC的解决方案。