Sensing technique of dynamic marine mammal's attitude by use of low-cost inertial and magnetic sensors

This paper presents the design and performance evaluation of a theoretical sensing technique of dynamic marine mammal's attitude. A single sensor pack composed by an Inertial Measurement Unit (IMU), provides all the data required to feed the nonlinear estimator. The proposed algorithm uses complementary data from a 3-axis accelerometer, a 3axis magnetometer and a 3-axis gyroscope. These sensors are mounted in a single tag and appropriately located on the animal. The approach developed here is applied in Bio-logging, an interdisciplinary research area at the intersection of animal behavior and bioengineering. By considering the rigid-body dynamics expressed in quaternion representation, a Complementary Sliding Mode Observer (CSMO) is derived taking advantages from strapdown inertial measurement from gyroscope and vector observations from accelerometer and magnetometer to provide accurate attitude estimates in quaternion representations. The proposed algorithm is based on a multiplicative quaternion correction technique and allows the estimation of large attitude maneuvers of the marine animal. The efficiency of the algorithm herein designed is illustrated through simulations using a theoretical example of animal motion.