Analysis of Dynamic North Finding based on Multiple Low-Precision MIMUs

This paper reports the use of low-precision micro inertial measurement units (MIMUs) based on micro-electro-mechanical systems (MEMS) technology for high-precision dynamic north finding and deduces the relationship among the number and performance of gyros and north finding time. North finding with MEMS gyros has attracted wide attention. However, it is found that the performance of gyros used in north finding accuracy less than 1° is high at present. This work achieves high- precision north finding through multiple relatively inexpensive MIMUs (ADIS16475) with lower accuracy that the angle random walk (ARW) is about 0.12 to 0.15° /$\sqrt h $ and the bias instability (BI) is about 2 to 6° / h. The relationship among the accuracy of north finding and the number and accuracy of gyros and time length of measured data is given, which can provide theoretical guidance for north seeking research. The accuracy of north finding is 0.57° when four low-precision MIMUs and the 30-min data to solve the azimuth, verifying the effectiveness of theoretical analysis.