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Position, Velocity and Time Estimation in GNSS using MATLAB

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Position, Velocity and Time Estimation in GNSS using MATLAB

Description

This project focuses on enhancing the accuracy of Position, Velocity, and Time (PVT) estimation in Global Navigation Satellite Systems (GNSS) using MATLAB. It leverages a theoretical foundation of Maximum Likelihood Estimation (MLE) integrated into an Extended Kalman Filter (EKF) to mitigate signal noise. By implementing complex moving window averages, the system achieved an 87% accuracy rate and reduced noise by 30%, making it suitable for high-precision navigation in LEO/GEO satellite orbits.

Problem Statement

  1. Signal Noise and Residuals: GNSS receivers often suffer from clock noise and carrier phase errors, leading to positional inaccuracies.
  2. Dynamic Environment: Satellites in orbit move at extreme velocities; standard filters cannot always track these high-dynamic shifts without lag.
  3. Confidentiality and Policy: This work was associated with the Space Application Center (SAC), ISRO, requiring strict adherence to security and data handling policies.

Solution

Phase 1: Extended Kalman Filter (EKF) Design

Designed a robust EKF in MATLAB to track the state vector (position and velocity) of a GNSS receiver. The filter uses a prediction-correction cycle to smooth out erratic signal inputs.

Phase 2: Maximum Likelihood Estimation (MLE)

Forged a theoretical framework for using MLE to refine positioning by maximizing the likelihood function of the GNSS residuals. This updates the Covariance of Clock Noise (CNN) and Code/Carrier Phase (CEE) matrices dynamically.

Phase 3: Moving Window Averages

Implemented a complex moving window average function in MATLAB. This serves as a critical pre-processing step, smoothing out short-term oscillations before the data enters the EKF, contributing to the 30% noise reduction.

Conclusion

The project successfully demonstrates that adaptive filtering techniques like MLE-enhanced EKF can significantly improve navigation precision for space-bound assets. By increasing accuracy to 87%, it provides a robust foundation for orbital determination and satellite constellation management.

Other Use Cases

  1. High-Speed Rail Navigation: Ensuring precise location tracking for multi-coach trains moving at speeds exceeding 300km/h.
  2. Financial Time-Stamping: Using precision time estimation for high-frequency trading (HFT) servers that require nanosecond sync across global data centers.
  3. Defense Missilery: Providing terminal guidance systems with noise-resistant PVT estimation during flight.
  4. Unmanned Aerial Vehicles (UAVs): Precise hovering and waypoint navigation for industrial inspection drones in high-altitude environments.
  5. Smart Grid Synchronization: synchronizing phase measurements across large-scale electrical grids to prevent power surges and blackouts.

Tech Stack

MATLABMLEPythonC++GNSSKalman Filter

Developed Over

2024 - Present

Category

Geospatial Technologies

About the Author

Durvesh Baharwal

Durvesh Baharwal

Full Stack AI Engineer & Data Scientist
  • Full Stack AI Engineer @ AI Alpha Tech
  • Research Associate · ISRO / SAC
  • NASA Space Apps Participant
  • B.E. AI & Data Science, MET BKC Engineering

Durvesh builds production-grade AI systems ranging from satellite navigation algorithms to computer vision pipelines. He bridges deep research with practical deployment across industries.