C/N0 estimators for high-sensitivity snapshot GNSS receivers

GPS Solutions - Tập 22 - Trang 1-11 - 2018
David Gómez-Casco1, José A. López-Salcedo1, Gonzalo Seco-Granados1
1IEEC-CERES, Universitat Autonoma de Barcelona (UAB), Barcelona, Spain

Tóm tắt

We address the problem of estimating the carrier-to-noise ratio (C/N0) in weak signal conditions. There are several environments, such as forested areas, indoor buildings and urban canyons, where high-sensitivity global navigation satellite system (HS-GNSS) receivers are expected to work under these reception conditions. The acquisition of weak signals from the satellites requires the use of post-detection integration (PDI) techniques to accumulate enough energy to detect them. However, due to the attenuation suffered by these signals, estimating their C/N0 becomes a challenge. Measurements of C/N0 are important in many applications of HS-GNSS receivers such as the determination of a detection threshold or the mitigation of near-far problems. For this reason, different techniques have been proposed in the literature to estimate the C/N0, but they only work properly in the high C/N0 region where the coherent integration is enough to acquire the satellites. We derive four C/N0 estimators that are specially designed for HS-GNSS snapshot receivers and only use the output of a PDI technique to perform the estimation. We consider four PDI techniques, namely non-coherent PDI, non-quadratic non-coherent PDI, differential PDI and truncated generalized PDI and we obtain the corresponding C/N0 estimator for each of them. Our performance analysis shows a significant advantage of the proposed estimators with respect to other C/N0 estimators available in the literature in terms of estimation accuracy and computational resources.

Tài liệu tham khảo

Bhuiyan M, Söderholm S, Thombre S, Ruotsalainen L, Kirkko M, Kuusniemi H (2014) Performance evaluation of carrier-to-noise density ratio estimation techniques for BeiDou Bl signal. In: Proceeding of Ubiquitous Positioning Indoor Navigation and Location Based Service (UPINLBS), pp 19–25. https://doi.org/10.1109/UPINLBS.2014.7033706 Brown R, Hwang P (1997) Introduction to random signals and applied Kalman filtering: with MATLAB exercises and solutions. Wiley, New York Bruggemann S, Greer D, Walker R (2006) Chip scale atomic clocks: Benefits to airborne GNSS navigation performance. In: Proceedings of international global navigation satellite systems society symposium, Holiday Inn, Surfers Paradise, Australia, 17–21 July 2006, pp 1–16 Corazza G, Pedone R (2007) Generalized and average likelihood ratio testing for post detection integration. IEEE Trans Commun 55(11):2159–2171. https://doi.org/10.1109/TCOMM.2007.908531 Elders H, Dettmar U (2004) Efficient differentially coherent code/Doppler acquisition of weak GPS signals. In: IEEE Proceedings of International Symposium on Spread Spectrum Techniques and Applications, pp 731–735. https://doi.org/10.1109/ISSSTA.2004.1371796 Falletti E, Pini M, Presti L (2011) Low complexity carrier-to-noise ratio estimators for GNSS digital receivers. IEEE Trans Aerosp Electron Syst 47(1):420–437. https://doi.org/10.1109/TAES.2011.5705684 Gaggero P, Borio D (2008) Ultra-stable oscillators: limits of GNSS coherent integration. In: Proceedings of ION GNSS 2008, Institute of Navigation, Savannah International Convention Center, Savannah, 16–19 September 2009 pp 565–575 Gómez D, López J, Seco G (2016) Generalized integration techniques for high-sensitivity GNSS receivers affected by oscillator phase noise. In: Proceedings of IEEE Statistical Signal Processing Workshop (SSP). Palma de Mallorca, pp 1–5. https://doi.org/10.1109/SSP.2016.7551809 Gómez D, López J, Seco G (2017) Optimal fractional non-coherent detector for high-sensitivity GNSS receivers robust against residual frequency offset and unknown bits. In: Proceedings of IEEE Workshop on Positioning, Navigation and Communications (WPNC). Bremen, pp 1–5. https://doi.org/10.1109/WPNC.2017.8250055 Groves P (2005) GPS Signal-to-noise measurement in weak signal and high-interference environments. Navigation 52(2):83–94 Kaplan E, Hegarty C (2005) Understanding GPS: principles and applications. Artech House, Norwood Klobuchar J (1996) Global positioning system: theory and applications. American Institute of Aeronautics and Astronautics. Inc., Washington DC Lopez J, Vicario J, Seco G (2008) Optimal noncoherent detector for HS-GNSS receivers. In: Proceedings of IEEE Signal Processing for Space Communications. Rhodes Island, pp 1–6. https://doi.org/10.1109/SPSC.2008.4686722 López G, Seco G (2005) CN0 estimation and near-far mitigation for GNSS indoor receivers. In: Proceedings of IEEE Vehicular Technology Conference. Stockholm, pp 2624–2628. https://doi.org/10.1109/VETECS.2005.1543810 Musumeci L, Dovis F, Silva P, Lopes H, Silva J (2014) Design of a very high sensitivity acquisition system for a space GNSS receiver. In: Proceedings of IEEE/ION PLANS. Hyatt Regency Hotel, Monterey, 5–8 May 2014, pp 556–568. https://doi.org/10.1109/PLANS.2014.6851417 Schmid A, Neubauer A (2005a) Carrier to noise power estimation for enhanced sensitivity Galileo/GPS receivers. In: Proceedings of IEEE Vehicular Technology Conference, vol 4. Stockholm, pp 2629–2633. https://doi.org/10.1109/VETECS.2005.1543811 Schmid A, Neubauer A (2005b) Differential correlation for Galileo/GPS receivers. In: Proceedings of IEEE International Conference on Acoustics, Speech, and Signal Processing. Philadelphia, pp 953–956. https://doi.org/10.1109/ICASSP.2005.1415869 Seco G, Lopez J, Jimenez D, Lopez G (2012) Challenges in indoor global navigation satellite systems: unveiling its core features in signal processing. IEEE Signal Process Mag 29(2):108–131. https://doi.org/10.1109/MSP.2011.943410 Strässle C, Megnet D, Mathis H, Bürgi C (2007) The squaring-loss paradox. In: Proceedings of ION GNSS 2007, Institute of Navigation, Fort Worth Convention Center, Fort Worth, 25–28 September 2007, pp 2715–2722