Abstract: This paper proposes a Call-Response Location System，where the UWB pulse train is utilized as the substitute for a single impulse. The energy detection can be exploited to reduce the complexity of the system. The call-response location algorithm and minimum mean-square error estimation are applied in the calculation of the time of arrival (TOA). And the mean delay spread is introduced to correct TOA for improved location accuracy in the multi-path and non-line-of-sight (NLOS) propagation environment. Results from the simulations conducted shows that in UWB channel proposed IEEE 802.15.4a the system succeeds in achieving a position location accuracy of ＜60cm when the SNR is set at the range of -20dB to 30dB.

Key words: UWB pulse train, energy detection, location in sensors network, mean delay spread