Abstract
Coarse time error (CTE) is an additional systematic absolute-timing-related bias that must be compensated in an assisted GPS (A-GPS)-based snapshot receiver where the complex baseband signal available for processing is finite and short. Resolving for CTE instead of waiting for the time of week string in the satellite’s navigation message allows A-GPS receivers to achieve faster time to first fix in cold start and warm start conditions. This paper highlights the problem of CTE that is conventionally resolved using coarse time positioning (CTP)—a least-squares-based algorithm. Following this, the same problem is shown to occur when collective detection (CD)—a direct position estimation algorithm—is applied in place of CTP. Previous literature on CD has not discussed nor presented any resolution to the CTE problem. Directly augmenting CTE to be resolved together with the user’s position and common clock bias in CD requires huge computational resources, which is impractical to be implemented using current generation consumer-grade computers. Therefore, the main contribution of this research is to propose and implement a dichotomous search jointly with CD to resolve for the CTE and position-common-clock-bias vector, respectively, at a relatively low computational burden. Empirical results using live satellite signals show that the proposed method is capable of effectively eliminating the positioning error biases caused by CTE. It is shown that the proposed compensation method can achieve equivalent performance to the conventional CTP method without losing the benefits of CD.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Aboutanios E, Mulgrew B (2005) Iterative frequency estimation by interpolation on Fourier coefficients. IEEE Trans Signal Process 53(4):1237–1242
Axelrad P, Donna J, Mitchell M (2009) Enhancing GNSS acquisition by combining signals from multiple channels and satellites. In: Proceedings of the ION GNSS 2009. Institute of Navigation, Savannah, GA, pp 2617–2628
Borre K (2007) A software-defined GPS and Galileo receiver: a single-frequency approach. Springer
Bradley BK, Axelrad P, Donna J (2010) Performance analysis of collective detection of weak GPS signals. In: Proceedings of the ION GNSS 2010. Institute of Navigation, Portland, OR, pp 3041–3053
Cheong JW (2011) Towards multi-constellation collective detection for weak signals: a comparative experimental analysis. In: Proceedings of the ION GNSS 2011. Institute of Navigation, Portland, OR, pp 3709–3719
Cheong JW, Wu J, Dempster AG, Rizos C (2011) Efficient implementation of collective detection. In: IGNSS symposium, 15–17 November. University of New South Wales, Australia
Closas P, Fernandez-Prades C, Fernandez-Rubio J (2007) ML estimation of position in a GNSS receiver using the SAGE algorithm. In: IEEE International conference on acoustics, speech and signal processing (ICASSP 2007), vol 3, pp III-1045–III-1048
DiEsposti R (2007) GPS PRN code signal processing and receiver design for simultaneous all-in-view coherent signal acquisition and navigation solution determination. In: Proceedings of the ION-NTM 2007. Institute of Navigation, San Diego, CA, pp 91–103
Fuchs DL, Abraham C, Van Diggelen F (2002) Method and apparatus for locating and providing services to mobile devices. US Patent 6,453,237, 17 Sept 2002
Jimenez-Baños D, Blanco-Delgado N, Lopez-Risueno G, Seco-Granados G, Garcia-Rodriguez A (2006) Innovative techniques for GPS indoor positioning using a snapshot receiver. In: Proceedings of the ION GNSS 2006. Institute of Navigation, Fort Worth, TX, pp 2944–2955
Kaplan E, Hegarty C (2006) Understanding GPS: principles and applications. Artech House, Boston
Lannelongue S, Pablos P (1998) Fast acquisition techniques for GPS receivers. In: Proceedings of the ION 1998. Institute of Navigation, Denver, CO, pp 261–269
Muthuraman K, Brown J, Chansarkar M (2012) Coarse time navigation: equivalence of algorithms and reliability of time estimates. In: Proceedings of the ION-ITM 2012. Institute of Navigation, Newport Beach, CA, pp 1115–1138
Progri I, Bromberg M, Michalson W (2005) Maximum-likelihood GPS parameter estimation. Navig J Inst Navig 52(4):229–238
Psiaki ML, O’Hanlon BW, Bhatti JA, Shepard DP, Humphreys TE (2011) Civilian GPS spoofing detection based on dual-receiver correlation of military signals, In: Proceedings of the ION GNSS 2011. Institute of Navigation, pp 20–23
Qian Y, Cui X, Lu M, Feng Z (2008) Snapshot positioning for unaided GPS software receivers. In: Proceedings of the ION GNSS 2008. Institute of Navigation, Savannah, GA, pp 2343–2350
Sirola N, Syrjärinne J (2002) GPS position can be computed without the navigation data. In: Proceedings of the ION-GPS 2002. Institute of Navigation, Portland, OR, pp 2741–2744
Van Diggelen FST (2009) A-GPS: assisted GPS, GNSS, and SBAS. Artech House
Yao Z, Lu M, Feng Z (2010) Spreading code phase measurement technique for snapshot GNSS receiver. IEEE Trans Consum Electron 56(3):1275–1282
Acknowledgments
This research project is supported by the Australian Research Council Linkage Project under the Grant LP0776483 with Andrew Corporation (Australia) Pty Ltd., as the industrial partner.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Cheong, J.W., Wu, J. & Dempster, A. Dichotomous search of coarse time error in collective detection for GPS signal acquisition. GPS Solut 19, 61–72 (2015). https://doi.org/10.1007/s10291-014-0365-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10291-014-0365-9