Kavita Guddad; K. L. Sudha

PLL based IRNSS Signal Tracking using Real Time Data

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Author(s)

Kavita Guddad ^1,* K. L. Sudha ¹

1. Department of Electronics and Communication Engineering, Dayananda Sagar College of Engineering, Bengaluru, India

* Corresponding author.

DOI: https://doi.org/10.5815/ijigsp.2026.05.06

Received: 9 Feb. 2026 / Revised: 5 Mar. 2026 / Accepted: 9 Jul. 2026 / Published: 8 Oct. 2026

Index Terms

GNSS, IRNSS, Signal Tracking, Satellite Navigation, Phase-Locked Loop.

Abstract

The need for flexible software receivers for research and experimentation has naturally grown due to the rapid development of Global/Regional Navigation Satellite System (GNSS/RNSS) constellations, created to cater to the navigation requirements of various countries. The two primary functions of all such receivers are signal acquisition and signal tracking. One must have a firm understanding of these functions to design or improve an existing navigation receiver. Signal acquisition is the first operation at the receiver, after filtering the received signal to remove noise. It provides the preliminary estimates of the carrier frequency and code phase and assists in identifying the satellites that are in view of the receiver. The accuracy of these estimates is then progressively improved by tracking. To accomplish this refinement using a correlation operation to compare the received signal and locally generated code and carrier replicas, the tracking process uses a tracking loop whose main part is a Phase-Locked Loop (PLL). This step is especially crucial because it eliminates the modulation that was added at the transmitter, enabling the receiver to retrieve the navigational information required for position calculation. The PLL continuously modifies the locally generated code and carrier replicas based on the discriminator output to maintain alignment with the incoming signal. The correlation peaks, when the local replicas and the received signal are well synchronized, showing the effective cancellation of the code and carrier modulation. This makes it possible to reliably extract the navigation message. Using GPS as the reference model, we present in this work a thorough explanation of the tracking mechanism, the structure of the PLL, and the mathematical principles governing its operation. The Indian Regional Navigation Satellite System (IRNSS) signal structure is then subjected to the same methodology. To validate the method we have used the actual intermediate-frequency data from an IRNSS-User Receiver (IRNSS-UR) installed by ISRO at the IRNSS lab of Jain University, Bengaluru. The obtained values of frequency and phase jitter to measure the performance of the tracking loop show that the tracking loop is stable.

Cite This Paper

Kavita Guddad, K. L. Sudha, "PLL based IRNSS Signal Tracking using Real Time Data", International Journal of Image, Graphics and Signal Processing(IJIGSP), Vol.18, No.5, pp. 93-109, 2026. DOI:10.5815/ijigsp.2026.05.06

Reference

[1]J. B.-Y. Tsui, Fundamentals of Global Positioning System Receivers. Hoboken, NJ, USA: John Wiley & Sons, 2000.
[2]J. J. Spilker Jr., P. Axelrad, B. W. Parkinson and P. Enge, Global Positioning System: Theory and Applications, vol. 1. Washington, DC, USA: AIAA, 1996.
[3]T. Pany et al., “GNSS Software-Defined Radio: History, Current Developments, and Standardization Efforts,” Navigation, vol. 71, no. 1, article navi.628, Mar. 2024, doi: 10.33012/navi.628.
[4]S. Stevanović and B. Pervan, “A GPS Phase-Locked Loop Performance Metric Based on the Phase Discriminator Output,” Sensors, vol. 18, no. 1, article 296, Jan. 2018, doi: 10.3390/s18010296.
[5]D. V. Fernandes, P. K. Jain, V. N. Srinivas, V. Chavan, K. M. Gayathri, and N. Thangadurai, “Acquisition and Tracking of S-Band Signals of Navigation with Indian Constellation (NavIC),” International Journal of Recent Technology and Engineering, vol. 8, no. 2, pp. 503–508, Jul. 2019. doi: 10.35940/ijrte.B1567.078219.
[6]M. T. R. Manjula and G. Raju, “Acquisition and Tracking of NavIC L5 Band Signals,” Int. J. Appl. Eng. Res., vol. 12, no. 19, pp. 8115–8119, 2017.
[7]C. Srinu and L. Parayitam, “Performance Analysis of NavIC Software Receiver for Single Frequency Ionospheric Delay Corrections,” in Proc. ION GNSS+ 2021, St. Louis, MO, USA, Sept. 2021, pp. 3886–3896, doi: 10.33012/2021.18059.
[8]R. Capua and A. Bottaro, “A GNSS Software Receiver for Governmental Applications,” in Proc. ION GNSS 2011, Portland, OR, USA, Sept. 2011, pp. 813–823.
[9]J. Nurmi, E. S. Lohan, S. Sand, and H. Hurskainen, Eds., “GALILEO Positioning Technology,” Signals and Communication Technology. Dordrecht, The Netherlands: Springer, 2015. doi: 10.1007/978-94-007-1830-2.
[10]S. N. Pitchumani, S. A. Sundar, T. Srinivasan and S. Savitri, “Mathematical Modelling of Indian Regional Navigation Satellite System Receiver,” Defence Sci. J., vol. 67, no. 4, pp. 443–448, Jul. 2017, doi: 10.14429/dsj.67.11547.
[11]Chittimalla Srinu, Laxminarayana Parayitam, “ Performance of GNSS-SDR for IRNSS L5 Signals Using a Low-Cost RF Front-End”, NAVIGATION: Journal of the Institute of Navigation , June 2023, 70 (2) , navi.573, DOI: https://doi.org/10.33012/navi.573
[12]D. L. Mute and S. Bhattacharyya, “A Robust Signal Tracking Algorithm for GPS and NavIC Constellations,” GPS Solutions, vol. 27, no. 3, Apr. 2023, doi: 10.1007/s10291-023-01444-2.
[13]Hiep Van Hoang , Ty Dinh Viet , Hung Pham Ngoc , Tung Hai Ta , Nguyen Dinh Thuan , “Performance Evaluation of a Deep Learning-Enhanced Software-Defined Receiver for IRNSS SPS Signals in Vietnam”, 2025, Artificial Satellites, vol. 60, no. 4, pp. 137-160, DOI: 10.2478/arsa-2025-0008.
[14]Mohanty, A., & Gao, G. (2024). A survey of machine learning techniques for improving globalnavigation satellite systems. EURASIP Journal on Advances in Signal Processing, 2024(1), 73.https://doi.org/10.1186/s13634-024-01167-7.
[15]Bhardwajan, A.A., Dharmappa, D., Ganesh, T.S., Vashisth, S., Gupta, A.S. (2026). “Design Aspects of an SDR for the New NavIC L1 SPS Signals”, Proceedings of Smart and AI Enabled Technology for Sustainable Development . SAIT 2023. Lecture Notes in Electrical Engineering, vol 1452. Springer, Singapore. https://doi.org/10.1007/978-981-96-9370-2_6.
[16]K. Guddad and K. L. Sudha, “Analysis of Acquisition Algorithms Using IRNSS Data,” in Proc. CE2CT 2025, Bhimtal, Nainital, India, 2025, pp. 62–66, doi: 10.1109/CE2CT64011.2025.10939882.
[17]K. Borre, D. Akos, N. Bertelsen, P. Rinder and S. Jensen, A Software-Defined GPS and Galileo Receiver: A Single-Frequency Approach.New York, NY, USA: Springer, 2007, doi: 10.1007/978-0-8176-4540-3.
[18]P. Misra and P. Enge, Global Positioning System: Signals, Measurements, and Performance. Lincoln, MA, USA: Ganga-Jamuna Press, 2001.
[19]C. Macabiau, L. Ries, F. Bastide and J.-L. Issler, “GPS L5 Receiver Implementation Issues,” in Proc. ION GPS/GNSS 2003, Portland, OR, USA, Sept. 2003, pp. 153–164. Available: http://www.ion.org/publications/abstract.cfm?articleID=5191
[20]Indian Space Research Organisation (ISRO), “Indian Regional Navigation Satellite System Signal-in-Space ICD for Standard Positioning Service,” Version 1.1, ISRO-IRNSS-ICD-SPS-1.1, Aug. 2017.
[21]K. Krumvieda et al., “A Complete IF Software GPS Receiver: A Tutorial about the Details,” in Proc. ION GPS 2001, Salt Lake City, UT, USA, Sept. 2001.
[22]J. H. Lee, D. W. Lim, J. H. Noh, G. H. Jo, C. Park, J. M. Ahn and S. J. Lee, “A GPS Multipath Mitigation Technique Using Correlators with Variable Chip Spacing,” E3S Web Conf., vol. 94, 2019, Art. no. 03006, doi: 10.1051/e3sconf/20199403006.
[23]W. K. Khaing et al., “Analysis of Acquisition and Tracking Algorithms for Software GNSS Receivers,” Int. J. Adv. Electron. Comput. Sci., vol. 2, no. 6, Jun. 2015.

International Journal of Image, Graphics and Signal Processing (IJIGSP)