A Novel Sampling Approach in GNSS-RO Receivers with Open Loop Tracking Method

Document Type : Research Article


PHD student in IROST, faculty member in ITRC


Propagation of radio occultation (RO) signals through the lower troposphere results in high phase acceleration and low signal to noise ratio signal. The excess Doppler estimation accuracy in lower troposphere is very important in receiving RO signals which can be estimated by sliding window spectral analysis. To do this, various frequency estimation methods such as MUSIC and ESPRIT can be adopted. Due to the cost and bandwidth constraints, reducing the sampling rate at GNSS receivers of LEO satellite is necessary which causes aliasing. A method of resolving frequency ambiguities is the simultaneous sampling of signal by multiple sample frequencies (MSF). Accordingly, we study the capacity of MSF method to improve the spectral efficiency and use accurate frequency estimation schemes to enhance the excess Doppler estimation accuracy of RO signal in post-processing. Via simulation results, the accuracy of excess Doppler estimation in post-processing based on both single sample frequency (SSF) and MSF methods for different frequency estimation methods are compared. Simulation results reveal that the MSF method has better performance than that of the SSF method. Besides, it is shown that Jacobsen and Jacobsen with Bias methods almost have the same performance and their estimation error is less than that of other methods. By exploiting the proposed scheme, the frequency estimation error is significantly decreased and it is negligible compared to the traditional methods. Moreover, by using this scheme, we have 41.6%


Main Subjects

[1] P. Bauer, G. Radn´oti, S. Healy, C. Cardinali, GNSS radio occultation constellation observing system experiments, Monthly Weather Review 142 (2) (2014) 555–572.
[2] A. Finger, Satellite positioning and navigation: Fundamentals, operation and application of global navigation satellite systems, AEUE-International Journal of Electronics and Communications 7 (64) (2010) 694–695.
[3] C. Ao, G. Hajj, T. Meehan, D. Dong, B. Iijima, A. Mannucci, E. Kursinski, Rising and setting GPS occultations by use of open-loop tracking, Journal of Geophysical Research: Atmospheres 114 (D4).
[4] G. Beyerle, F. Zus, Open-loop GPS signal tracking at low elevation angles from a ground-based observation site, Atmospheric Measurement Techniques 10 (1) (2017) 15.
[5] K.-N. Wang, J. L. Garrison, U. Acikoz, J. S. Haase, B. J. Murphy, P. Muradyan, T. Lulich, Open-Loop Tracking of Rising and Setting GPS Radio-Occultation Signals From an Airborne Platform: Signal Model and Error Analysis, IEEE Transactions on Geoscience and Remote Sensing 54 (7) (2016) 3967–3984.
[6] S. V. Sokolovskiy, Tracking tropospheric radio occultation signals from low Earth orbit, Radio Science 36 (3) (2001) 483–498.
[7] A. Helm, O. Montenbruck, J. Ashjaee, S. Yudanov, G. Beyerle, R. Stosius, M. Rothacher, GORS-a GNSS occultation, reflectometry and scatterometry space receiver .
[8] S. Sokolovskiy, Nonlinear resonant circuit devices, U.S. Patent 6,731,906 B2.
[9] S. V. Sokolovskiy, Modeling and inverting radio occultation signals in the moist troposphere, Radio Science 36 (3) (2001) 441–458.
[10] S. Sokolovskiy, C. Rocken, W. Schreiner, D. Hunt, J. Johnson, Postprocessing of L1 GPS radio occultation signals recorded in open-loop mode, Radio Science 44 (2).
[11] S. Sokolovskiy, C. Rocken, D. Hunt, W. Schreiner, J. Johnson, D. Masters, S. Esterhuizen, GPS profiling of the lower troposphere from space: Inversion and demodulation of the open-loop radio occultation signals, Geophysical research letters 33 (14).
[12] K.-N.Wang, Signal analysis and radio holographic methods for airborne radio occultations, Ph.D. thesis, Purdue University, 2015.
[13] M. Gorbunov, Radio-holographic analysis of Microlab-1 radio occultation data in the lower troposphere, Journal of Geophysical Research: Atmospheres 107 (D12).
[14] E. R. Kursinski, G. A. Hajj, S. S. Leroy, B. Herman, The GPS radio occultation technique, Terrestrial, atmospheric, and oceanic sciences 11 (1) (2000) 53–114.
[15] M. Gorbunov, Canonical transform method for processing radio occultation data in the lower troposphere, Radio Science 37 (5).
[16] M. E. Gorbunov, L. Kornblueh, Analysis and validation of GPS/MET radio occultation data, Journal of Geophysical Research: Atmospheres 106 (D15) (2001) 17161–17169.
[17] A. S. Jensen, M. S. Lohmann, H.-H. Benzon, A. S. Nielsen, Full spectrum inversion of radio occultation signals, Radio Science 38 (3) (2003) 6–1.
[18] L. Adhikari, F. Xie, J. S. Haase, Application of the full spectrum inversion algorithm to simulated airborne GPS radio occultation signals, Atmospheric Measurement Techniques 9 (10) (2016) 5077.
[19] M. Gorbunov, K. Lauritsen, Analysis of wave fields by Fourier integral operators and their application for radio occultations, Radio Science 39 (4).
[20] A. S. Jensen, M. S. Lohmann, A. S. Nielsen, H.-H. Benzon, Geometrical optics phase matching of radio occultation signals, Radio science 39 (3).
[21] K. Hocke, A. Pavelyev, O. Yakovlev, L. Barthes, N. Jakowski, Radio occultation data analysis by the radioholographic method, Journal of Atmospheric and Solar-Terrestrial Physics 61 (15) (1999) 1169–1177.
[22] S. Sokolovskiy, C. Rocken, W. Schreiner, D. Hunt, On the uncertainty of radio occultation inversions in the lower troposphere, Journal of Geophysical Research: Atmospheres 115 (D22).
[23] Sørensen, Mikael, and Lieven De Lathauwer. "Multidimensional harmonic retrieval via coupled canonical polyadic decomposition—Part II: Algorithm and multirate sampling." IEEE Transactions on Signal Processing 65.2 (2016): 528-539.
[24] P. Stoica, R. L. Moses, Introduction to spectral analysis, vol. 1, Prentice hall Upper Saddle River, 1997.
[25] S. Marple, Digital signal analysis with applications, Prentir. c-Hall, Englcwood Cliffs, NJ.
[26] K. Cui, W. Wu, J. Huang, X. Chen, N. Yuan, DOA estimation of LFM signals based on STFT and multiple invariance ESPRIT, AEU-International Journal of Electronics and Communications 77 (2017) 10–17.
[27] Y. Tian, X. Sun, Passive localization of mixed sources jointly using MUSIC and sparse signal reconstruction, AEU-International Journal of Electronics and Communications 68 (6) (2014) 534–539.
[28] B. G. Quinn, Estimating frequency by interpolation using Fourier coefficients, IEEE Transactions on Signal Processing 42 (5) (1994) 1264–1268.
[29] M. D. Macleod, Fast nearly ML estimation of the parameters of real or complex single tones or resolved multiple tones, IEEE Transactions on Signal processing 46 (1) (1998) 141–148.
[30] Y. Zakharov, V. Baronkin, T. Tozer, DFT-based frequency estimators with narrow acquisition range, IEE Proceedings-Communications 148 (1) (2001) 1–7.
[31] E. Aboutanios, S. Reisenfeld, Frequency estimation and tracking for low earth orbit satellites, in: Vehicular Technology Conference, 2001. VTC 2001 Spring, vol. 4, 3003–3004, 2001.
[32] B. G. Quinn, Estimation of frequency, amplitude, and phase from the DFT of a time series, IEEE transactions on Signal Processing 45 (3) (1997) 814–817.
[33] L. Mohammadi, S. Amiri, Performance Analysis of Different Frequency Estimation Methods in GNSSRO Receivers with Open Loop Tracking, The Modares Journal of Electrical Engineering 13 (2) (2013) 29–42.
[34] E. Jacobsen and P. Kootsookos, "Fast, accurate frequency estimators," IEEE Signal Processing Magazine, March 2007.
[35] V. Vetterling, W. Press, S. Teukolsky and B. Flannery, Numerical Recipes in C, Cambridge, United Kingdom: Cambridge Univ. Press, ch. 10., 1992.
[36] P. Voglewede, "Parabola approximation for peak determination," Global DSP Magazine, vol. 3, no. 5, p. 13–17, May 2004.
[37] A. Candan, "A method for fine resolution frequency estimation from three DFT samples," IEEE SIGNAL PROCESSING LETTERS, vol. 18, no. 6, p. 351–354, June 2011.
[38] Roy, R. and T. Kailath, “Espritestimation of signal parameters via rotational invariance techniques. IEEE Transactions on acoustics, speech, and signal processing, July 1989. 37: p. 984–995.
[39] Roy, R., A. Paulraj, and T. Kailath, ESPRIT--A subspace rotation approach to estimation of parameters of cisoids in noise. IEEE Transactions on Acoustics, Speech and Signal Processing, Oct 1986. 34(5): p. 1340-1342.
[40] M. E. Gorbunov, A. S. Gurvich, L. Kornblueh, Comparative analysis of radio holographic methods of processing radio occultation data, Radio science 35 (4) (2000) 1025–1034.
[41] L. Priebe, M. P. Swenholt, R. Persson, Use of multiple sample frequencies to resolve ambiguities in band-folded digital receivers, February 2000, US Patent 6,031,869.
[42] H. Lee, H.-G. Ryu, Compensation of RF impairment in multi-band receiver based on RF sub-sampling, AEU-International Journal of Electronics and Communications 66 (8) (2012) 613–618.
[43] M. R. Yuce, A. Tekin, W. Liu, Design and performance of a wideband sub-sampling front-end for multi-standard radios, AEU-International Journal of Electronics and Communications 62 (1) (2008) 41–48.