UWB radar imaging based multipath delay prediction for NLOS position estimation

Abstract

Conventional Time-of-Arrival (ToA) based UltraWideband (UWB) positioning suffers strongly from multipath. Harsh propagation environments or non-line-of-sight (NLOS) situations lead to biased position estimates with high estimation errors. To overcome this problem, we propose a radar imaging based method to predict delays of dominant propagation paths. This is done in a three-step approach: First, a radar image of the environment is created using measured training data. We generate a scattering coefficient map with the large synthetic aperture of distributed and moving antennas. The training data can easily be obtained from channel estimates of a UWB communication system with mobile nodes. Second, the radar image is used to reconstruct path gains and path delays. Thus, the channel response is predicted for arbitrary transmitter and receiver positions. Finally, dominant multipath delays are extracted using WRELAX. The proposed algorithm is validated by anechoic chamber measurements with controlled reflectors. Moreover, an extensive measurement campaign in a laboratory/office environment shows that strong paths can be predicted with nanosecond accuracy in a real world scenario.

Detection, localization, and tracking of unauthorized UAS and Jammers

“…In order to coherently combine the multiple signals coming from various paths and extract the range information, some prior information on the topology of the environment, such as exact locations of roads and buildings, should be utilized [76]. In this regard, the channel impulse response or equivalently the scattering map of the environment should be characterized a priori [77]. It can be argued that the detection of a breathing human by micro-Doppler techniques can be extended to NLOS environments when a perfect knowledge of the surrounding geometry is known and multipath signals are employed in ranging [73], [78].…”

Estimation of multiple target location in multi-path wireless systems

“…A multiple-hypothesis-based approach for multiple target localization is proposed in [4], without the consideration of the IPs. There have also been a number of papers on identifying and eliminating the detrimental effects of IPs [5], [6], [7], [8], [9] and [10]. However, existing IP identification methods suffer from a dependence on the statistical information of channel parameters, directional information, etc.…”