In this paper a novel approach for a high precision local positioning radar using an ultra wideband technique is presented. The concept is based on the standard FMCW (frequency modulated continuous wave) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. With this concept, a high accuracy in dense multipath indoor environments can be achieved, ideally suited for ID, 2D, and 3D localization. A prototype was built which operates around the center frequency of 7.5 GHz utilizing a bandwidth of I GHz. With the setup presented in this paper the distance between two wireless units can be measured achieving a low standard deviation.

In this paper an approach for high precision local positioning radar using an ultra wideband technique is presented. The concept is based on the standard FMCW (frequency modulated continuous wave) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. In this way, a high accuracy in dense multipath indoor environments can be achieved, ideally suited for 1D, 2D and 3D localization. A prototype was built which operates at a center frequency of 7.5 GHz utilizing a bandwidth of 1 GHz. With the setup presented in this paper the distance between two wireless units can be measured achieving a standard deviation down to 6 mm. Additionally, we studied the effects of short multipath propagation and present simulation results for an applicable mitigation technique.

In this paper a novel approach for mitigation of short multipath distortions is presented. The technique is applicable to FMCW-based distance measurement systems assuming distinctly separated targets. The effects of spectral distortion caused by short multipath propagation in conjunction with Fourier-based frequency analysis methods are mitigated. For this purpose the distorted spectrum is first analyzed and specific characteristics are calculated. A Feedforward Neural Network processes these characteristics and provides a correction frequency relative to the erroneously shifted maximum in order to estimate the true line-of-sight frequency. A comprehensive analysis was performed by means of a two tone test. Applicability to real world environments was investigated by means of a multi tone test using an IEEE 802.15.4a channel model.

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