High-resolution range estimation using time delays in ultra-wideband M-sequence radar

摘要

Getting a high range resolution is an important issue in many research areas and applications especially for narrowband system. Although wideband systems have a better condition from this viewpoint, they have additional challenges in terms of cost and RF manufacturing. Thus, overcoming the bandwidth constraint on the resolution can be a game changer in the simplicity and feasibility aspects of a system. In this paper, an accurate and efficient approach for high resolution range measurement is proposed. An ultra-wideband (UWB) M-sequence system is established for its simplicity and cost effectiveness compared to other methods like frequency modulated continuous wave (FMCW) and impulse technique. However, the limited usable bandwidth in the power spectrum of an M-sequence signal degrades its resolution. We have alleviated this shortcoming by applying a Least squares (LS) estimator to improve the resolution and accuracy of the system. The acceptable performance of the presented method is verified experimentally and numerically by achieving 45% improvement in the resolution with the accuracy of more than 95%. By considering the effects of different parameters such as response of antenna, method of scan and systematic errors, the proposed method would be a good candidate for remote sensing applications.