Department of Electronics Engineering, Centers of Excellence in Science and Applied Technologies (CESAT), Islamabad, Pakistan
Email: ushaq71@yahoo.com (M.U.); rasheeq1@gmail.com (M.R.U.B.M.); abbasimerium@gmail.com (M.F.A.)
*Corresponding author
Manuscript received May 27, 2025; revised June 23, 2025; accepted July 29, 2025.
Abstract—Navigation is a method of determining or planning a vehicle’s position and path/trajectory; employing sensors, geometry, astronomy and radio signals etc. Navigation is a combination of science, engineering and art. The determination of the position, velocity and attitude of a moving body with respect to a known reference-frame is the science or engineering of navigation. The planning and maintaining the intended path from one point to another, evading hindrances and crashes, is the art of navigation and has the forms as guidance, pilotage, or routing depending on the type of applications. Inertial Navigation System (INS) is a completely self-contained form of navigation and regarded as the most robust and complete navigation-system, as it renders navigation information including position, velocity, acceleration, attitude and attitude rates of the host body. INS always requires information of initial position, velocity and attitude-angles. The azimuth (angle of forward axis of vehicle with respect to the True North) is the most important and critical initial information required for the INS. Initial azimuth angle can be provided to INS by optical means or gyro-compassing. Conventional Gyrocompasses (using suspended gyroscopes) have been in use for high precision azimuth determination for last several decades. Conventional gyrocompass gives azimuth information by sensing the combined effect of Earth spin-rate and local-gravity. But gyrocompasses are highly delicate and expensive equipment requiring careful handling/transportation, periodic calibration and challenging storage conditions. To overcome these issues, extensive research has been going-on for development of rugged north finding systems based on Strapdown inertial sensors for last few decades. Herein one or more strapdown gyroscopes are used to measure the component of Earth Spin Vector in the local horizontal plane. Azimuth is mathematically computed from the output of gyroscopes. This research paper is focused on the comparative analysis of different schemes used in strapdown Azimuth Determining Systems (ADS), including, single-position, 2-position, 4-position and multi-position azimuth finding schemes. We have elaborated the methodology and analyzed the pros & cons of all schemes vis-à-vis accuracy/precision, sampling-time, effect of different types of errors of gyroscopes and total process time. We have concluded that 4-position azimuth finding scheme renders the optimal performance in terms of accuracy and time for azimuth finding.
Keywords—MEMS gyroscope, fiber optic gyroscope, accelerometers, inertial sensors, azimuth determining, Global Navigation Satellite System (GNSS), inertial navigation, strapdown navigation systems
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Cite: Muhammad Ushaq, M. Rasheeq Ullah Baig Mirza, and Merium Fazal Abbasi, "Comparative Analysis of Multiposition Strapdown Azimuth Determining Schemes," International Journal of Modeling and Optimization, vol. 15, no. 2, pp. 32-38, 2025.
Copyright © 2025 by the authors. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
(CC BY 4.0).
