Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-19T04:44:55.924Z Has data issue: false hasContentIssue false
  • English
  • Français

Locata Performance Evaluation in the Presence of Wide- and Narrow-Band Interference

Published online by Cambridge University Press:  28 May 2010

Faisal A. Khan ,
Chris Rizos  and
Andrew G. Dempster
Faisal A. Khan*
Affiliation:
(University of New South Wales, Australia)
Chris Rizos
Affiliation:
(University of New South Wales, Australia)
Andrew G. Dempster
Affiliation:
(University of New South Wales, Australia)
*
(Email: [email protected])
Get access Rights & Permissions [Opens in a new window]

Abstract

Classically difficult positioning environments often call for augmentation technology to assist the GPS, or more generally the Global Navigation Satellite System (GNSS) technology. The “Locata” ground-based ranging technology offers augmentation, and even replacement, to GPS in such environments. However, like any other system relying on wireless technology, a Locata positioning network also faces issues in the presence of RF interference (RFI). This problem is magnified due to the fact that Locata operates in the licence-free 2·4 GHz Industrial, Scientific and Medical (ISM) band. The licence-free nature of this band attracts a much larger number of devices using a wider range of signal types than for licensed bands, resulting in elevation of the noise floor. Also, harmonics from out-of-band signals can act as potential interferers. WiFi devices operating in this band have been identified as the most likely potential interferer, due partially to their use of the whole ISM band, but also because Locata applications often also may use a wireless network. This paper evaluates the performance of Locata in the presence of both narrow- and wide-band interfering signals. Effects of received interference on both raw measurements and final solutions are reported and analysed. Test results show that Locata performance degrades in the presence of received interference. It is also identified that high levels of received interference can affect Locata carriers even if the interference is not in co-frequency situation with the affected carrier. Finally, Locata characteristics have been identified which can be exploited to mitigate RFI issues.

Keywords

LocataRadio Frequency InterferenceWiFi
Type
Research Article
Information
The Journal of Navigation , Volume 63 , Issue 3 , July 2010 , pp. 527 - 543
Copyright
Copyright © The Royal Institute of Navigation 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Barnes, J., Rizos, C., Kanli, M., Pahwa, A., Small, D., Voigt, G., Gambale, N., & Lamance, J., (2005). High accuracy positioning using Locata's next generation technology. 18th Int. Tech. Meeting of the Satellite Division of the U.S. Institute of Navigation, Long Beach, California, 13–16 September, 2049–2056.Google Scholar
Gawthrop, P.E., Sanders, F.H., Nebbia, K.B., & Sell, J.J., (1994). Radio spectrum measurements of individual microwave ovens. NTIA Report 94-303-1.Google Scholar
Kaplan, E.D., & Hegarty, C.J., (2006). GPS: Principles and Applications. 2nd Edition, Artech House Publication.Google Scholar
Khan, F.A., Dempster, A.G., & Rizos, C., (2008a). Locata-based positioning in the presence of WiFi interference: Test results. 21st Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Savannah, Georgia, 16–19 September, 2645–2649.Google Scholar
Khan, F.A., Dempster, A.G., & Rizos, C., (2008b). Novel time-sharing scheme for virtual elimination of Locata-WiFi interference effects. Int. Symp. on GPS/GNSS, Tokyo, Japan, 25–28 November, 526–530.Google Scholar
Khan, F.A., Dempster, A.G., & Rizos, C., (2009a). Adaptive loop aiding for performance improvement in weak signal environment. European Navigation Conference, Naples, Italy, 3–6 May.Google Scholar
Khan, F.A., Choudhury, M.M., Dempster, A.G., & Rizos, C., (2009b). A hybrid carrier phase measurement weighting scheme for solution improvement of carrier point positioning. 22nd Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Savannah, Georgia, 22–25 September, to be presented.Google Scholar
Khan, F.A., Dempster, A.G., & Rizos, C., (2009c). Kalman filter based adaptive loop aiding for performance improvement in low C/(No+I) environments. IGNSS Symp. 2009, Gold Coast, Australia, 1–3 December, to be presented.CrossRefGoogle Scholar
Netgear WG102 Wireless Access Point Specifications (http://www.netgear.com/Products/ APsWirelessControllers/AccessPoints/WG102.aspx).Google Scholar
Sklar, B., (2001). Digital Communications: Fundamentals and Applications. 2nd edition, Prentice Hall.Google Scholar
Walke, B.H., Mangold, S., & Berlemann, L., (2006). IEEE 802 Wireless Systems: Protocols, Multi-hop Mesh/Relaying, Performance and Spectrum Coexistence. John Wiley & Sons Inc.CrossRefGoogle Scholar