Improved Velocity Estimation with High-Sensitivity Receivers in Indoor Environments

Zhe He, Mark Petovello and Gerard Lachapelle

Abstract:	Doppler measurements play an important role in high sensitivity receivers for a few of reasons. They can provide some level of immunity over communication channels, convey user velocity, and attitude information, and can also be used to smooth pseudorange measurements. Regarding velocity, conventional estimation methods in high sensitivity receivers first get the Doppler by block processing the incoming samples and then compute the velocity using least squares (LSQ) or Kalman filtering (KF). However, in harsh indoor environments, Doppler measurements are often biased and very noisy due to multipath and fading, thus conventional velocity estimation methods are not very accurate and the quality is often very poor. This paper first reviews the implementation of a direct velocity estimation algorithm, which is basically the maximum likelihood estimate (MLE) of velocity, and then presents the Cramer-Rao lower bound (CRLB) of the Doppler estimated with high-sensitivity receivers in indoor multipath environments. The CRLB of the conventional method and the direct method are then presented and discussed. Data collected inside a concrete building is processed in order to evaluate performance. In addition, the effect of adding signals from another GNSS (GLONASS in this case) is also assessed. Results show that jointly and directly processing GPS and GLONASS signals outperforms the conventional method, and the benefits of GLONASS are also apparent in some cases.
Published in:	Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012) September 17 - 21, 2012 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	1004 - 1016
Cite this article:	He, Zhe, Petovello, Mark, Lachapelle, Gerard, "Improved Velocity Estimation with High-Sensitivity Receivers in Indoor Environments," Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012), Nashville, TN, September 2012, pp. 1004-1016.
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