Showing 3 results for Glonass
M. Mousavi Moaiied, M. R. Mosavi,
Volume 12, Issue 1 (3-2016)
Abstract
In this paper, combined GPS and GLONASS positioning systems are discussed and some solutions have been proposed to improve the accuracy of navigation. Global Satellite Navigation System (GNSS) is able to provide position, velocity and time with respect to coordinated universal time. GNSS positioning is based on received satellite signals, so its performance is highly dependent on the quality of these received signals. The effect of noise and multi-path can often be large enough to produce significant errors in positioning. Satellite navigation is difficult in this situation. In such circumstances, GPS or GLONASS alone are often not able to ensure consistency and accuracy in positioning due to the absence (or low quality) of signals. The combination of these two systems is an appropriate solution to improve the situation. In positioning a receiver, one of the ways that is often used to reduce the error due to observation noise and calculation errors is Kalman Filter (KF) estimation. In this paper, some changes in the structure of the KF is applied to improve the accuracy of positioning. Process of updating KF's gain, is done in fuzzy form based on the parameters available in RINEX files, including the P code pseudo-range used as an input of the proposed fuzzy system. Simulation results show that applying a fuzzy KF based on P code pseudo-range on the available data sets, in terms of noise and blocking condition, reduces the positioning error respectively from 24 to 14 meters and 90 to 25 meters.
N. Dabaghi Daryan, Mohammad Reza Mosavi, Sattar Mirzakuchaki, S. Tohidi,
Volume 22, Issue 0 (3-2026)
Abstract
GNSS simulators are essential tools for testing and validating satellite navigation system receivers across various civil applications. This study introduces an improved GLONASS satellite simulator to optimize navigation precision by enhancing the satellite constellation's Dilution of Precision (DOP). The proposed simulator operates in two steps. In the first step, the system performs a full-day search to identify time intervals with minimal DOP using a local moving-average technique. In the second step, the impact of adding one virtual satellite—selected using fuzzy logic and evaluated through the Residual Geometric Dilution of Precision (RGDOP) metric—is examined to minimize Geometric Dilution of Precision (GDOP). The fuzzy system uses two inputs (RGDOP and elevation angle), where RGDOP is modeled with four Gaussian membership functions (very small, small, medium, large), and the elevation angle is modeled with three triangular membership functions (small, medium, large). These scenarios are tested on a Software-Defined Radio (SDR) and then a u‑blox M8 receiver to evaluate and compare improvements in positioning accuracy across the tuned configurations. The results show that both optimization stages lead to significant gains in navigation performance. The first scenario leads to a 24.4% improvement in accuracy, while the second scenario achieves an even greater enhancement of 54.9%, highlighting the effectiveness of these approaches in reducing positioning error.
K. Bahmani, A. Sadr, M. R. Mosavi,
Volume 22, Issue 2 (3-2026)
Abstract
Blocking interference poses significant challenges to the accuracy and reliability of navigation systems by obstructing the communication path. Single-frequency receivers are generally more susceptible to blocking interference due to their limited ability to compensate for obstructed signals or access alternative signal sources. The integration of Global Navigation Satellite Systems (GNSS) is among the most effective strategies for mitigating blocking interference. By combining signals from multiple sources, the likelihood of accessing stable and reliable signals significantly improves. The four Global GNSS include Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), BeiDou, and Galileo. This paper examines the challenges of system integration in addressing navigation equations and proposes suitable solutions. Two datasets were collected under conditions of blocking disturbances, and receiver performance was simulated across 14 different modes using a software platform. The results were analyzed considering factors such as the number of satellites in view, satellite positions, extracted positions, as well as Root Mean Square (RMS), Geometric Dilution of Precision (GDOP), and Position Dilution of Precision (PDOP) parameters. In these scenarios, the GPS system in single-frequency mode, the combination of GPS and GLONASS in dual mode, and the combination of GPS, GLONASS, and Galileo in triple mode demonstrated the best performance. However, the best performance, irrespective of computational load and hardware complexity, was achieved in the quadruple integration mode.
