Digital multimedia broadcasting signal is promised to be a wireless positioning signal.\nThis paper mainly studies a multimedia broadcasting technology, named China mobile multimedia\nbroadcasting (CMMB), in the context of positioning. Theoretical and practical analysis on the CMMB\nsignal suggests that the existing CMMB signal does not have the meter positioning capability.\nSo, the CMMB system has been modified to achieve meter positioning capability by multiplexing the\nCMMB signal and pseudo codes in the same frequency band. The time difference of arrival (TDOA)\nestimation method is used in base station positioning receivers. Due to the influence of a complex\nfading channel and the limited bandwidth of receivers, the regular tracking method based on pseudo\ncode ranging is difficult to provide continuous and accurate TDOA estimations. A pseudorange\nmeasurement scheme based on snapshot is proposed to solve the problem. This algorithm extracts\nthe TDOA estimation from the stored signal fragments, and utilizes the Taylor expansion of the\nautocorrelation function to improve the TDOA estimation accuracy. Monte Carlo simulations and\nreal data tests show that the proposed algorithm can significantly reduce the TDOA estimation\nerror for base station positioning receivers, and then the modified CMMB system achieves meter\npositioning accuracy.
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