Multiple Inertial Measurement Units–An Empirical Study

Ariel Larey,Itzik Klein,Eliel Aknin

doi:10.1109/access.2020.2988601

Ariel Larey, Itzik Klein + Show 1 more

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https://doi.org/10.1109/access.2020.2988601

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Abstract

An inertial navigation system is commonly used in various marine platforms above and below the sea surface to calculate the position, velocity and orientation of its carrier platform. Such systems contain an inertial measurement unit (IMU) to measure the specific force and angular velocity which in turn are integrated to obtain the navigation state. Due to sensor noises and other error terms, the navigation solution drifts in time. In situations of pure inertial navigation (no external aiding), multiple IMUs (MIMU) can be used to improve the performance of a single unit. In this paper, we explore the benefits of using a MIMU system for common navigation operations. To that end, a 32 MIMU architecture (192 inertial sensors) was designed and constructed for the experimental evaluations. Utilizing this system we examined the effect of the number of sensors in the architecture versus position accuracy, stationary calibration, coarse alignment and gyro free design. We derive closed form empirical expressions enabling insight to the connection between number of IMUs to the expected performance.

Highlights

INTRODUCTION IInertial Navigation System (INS) consist of an Inertial Measurements Unit (IMU) and algorithms to calculate the navigation solution: position, velocity, and orientation of a platform
EXPERIMENTAL RESULTS To evaluate and compare the performance as a function of the number of IMUs in the system, the root mean square (RMS) error is employed as the performance measure
The multiple IMUs (MIMU) architecture can be used to improve the performance of a single IMU in situations when pure inertial navigation is required

Summary

Introduction

Inertial Navigation System (INS) consist of an Inertial Measurements Unit (IMU) and algorithms to calculate the navigation solution: position, velocity, and orientation of a platform. The IMU has two types of sensors, accelerometers to measure the specific force and gyroscopes to measure the angular velocity. A typical low-cost IMU is based on Micro-ElectroMechanical-System (MEMS) technology and contains 3-axis orthogonal gyroscopes and accelerometers on the same silicon die [1]. The IMU measurements are not accurate and have significant measurement errors that cause the navigation solution to drift over time. INS are fused with external sensors [8]. In some situations the external sensor is not available (for example, GPS in an indoor environment) the navigation solution will rely only on the INS - a pure inertial navigation solution

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