KL-divergence kernel regression for non-Gaussian fingerprint based localization

Piotr Mirowski*, Harald Steck, Philip Whiting, Ravishankar Palaniappan, Michael MacDonald, Tin Kam Ho

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contributionpeer-review

50 Citations (Scopus)


Various methods have been developed for indoor localization using WLAN signals. Algorithms that fingerprint the Received Signal Strength Indication (RSSI) of WiFi for different locations can achieve tracking accuracies of the order of a few meters. RSSI fingerprinting suffers though from two main limitations: first, as the signal environment changes, so does the fingerprint database, which requires regular updates; second, it has been reported that, in practice, certain devices record more complex (e.g bimodal) distributions of WiFi signals, precluding algorithms based on the mean RSSI. In this article, we propose a simple methodology that takes into account the full distribution for computing similarities among fingerprints using Kullback-Leibler divergence, and that performs localization through kernel regression. Our method provides a natural way of smoothing over time and trajectories. Moreover, we propose unsupervised KL-divergence-based recalibration of the training fingerprints. Finally, we apply our method to work with histograms of WiFi connections to access points, ignoring RSSI distributions, and thus removing the need for recalibration. We demonstrate that our results outperform nearest neighbors or Kalman and Particle Filters, achieving up to 1m accuracy in office environments. We also show that our method generalizes to non-Gaussian RSSI distributions.

Original languageEnglish
Title of host publication2011 international conference on indoor positioning and indoor navigation, IPIN 2011
Place of PublicationPiscataway, NJ
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Number of pages10
ISBN (Electronic)9781457718045, 9781457718038
ISBN (Print)9781457718052
Publication statusPublished - 2011
Externally publishedYes
Event2011 International Conference on Indoor Positioning and Indoor Navigation, IPIN 2011 - Guimaraes, Portugal
Duration: 21 Sep 201123 Sep 2011


Other2011 International Conference on Indoor Positioning and Indoor Navigation, IPIN 2011


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