Abstract
In this paper, the data wipe-off (DWO) algorithm is incorporated into the vector tracking loop of the Global Positioning System (GPS) receiver for improving signal tracking performance. The navigation data, which contains information that is necessary to perform navigation computations, are binary phase-shift keying (BPSK) modulated onto the GPS carrier phase with the bit duration of 20 ms (i.e., 50 bits per second). To continuously track the satellite’s signal in weak signal environment, the DWO algorithm on the basis of pre-detection method is adopted to detect data bit sign reversal every 20 ms. Tracking accuracy of a weak GPS signal is decreased by possible data bit sign reversal every 20 ms to the predetection integration time (PIT) or integration interval. To achieve better tracking performance in weak signal environment, the coherent integration interval can be extended. However, increase of the integration interval lead to decrease of the tracking accuracy by possible data bit sign reversal every 20 ms to the integration interval. When the integration interval of the correlator is extended over 20 ms in low C/No levels, the navigation DWO algorithm can be employed to avoid energy loss due to bit transitions. The method presented in this paper has an advantage to continuously estimate the navigation data bit and achieve improved tracking performance. Evaluation of the tracking performance based on the various integration intervals for the vector tracking loop of a GPS receiver will be presented.
Highlights
The Global Positioning System (GPS) [1,2,3,4] is a satellite-based navigation system [5,6] that provides a user with the proper equipment access to useful and accurate positioning information anywhere on the globe
The GPS vector tracking loop (VTL) differs from the traditional scalar tracking loop (STL) in that the task of navigation solutions, code tracking and carrier tracking loops for all satellites are combined into one loop
The computer codes were developed by the authors using the Matlab® software
Summary
The Global Positioning System (GPS) [1,2,3,4] is a satellite-based navigation system [5,6] that provides a user with the proper equipment access to useful and accurate positioning information anywhere on the globe. The discriminator measures code phase error and carrier frequency error These are passed to navigation filter and through loop filter to control NCO. The vector tracking loop (VTL) [7,8] provides a deep level of integration between signal tracking and navigation solutions in a GPS receiver. Correlation integration intervals generally do not exceed the duration of a navigation data bit for those cases where the receiver operates in open sky conditions. Employed to avoid energy loss that occurs due to bit transitions during the correlation integration These techniques are most effective for GPS receivers that already have high anti-jam immunity and are not expected to significantly improve the tracking thresholds of most unaided GPS receivers. This paper presents the vector tracking loop performance improvement of a GPS receiver using the data wipe-off techniques.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
