Magneto-inertial navigation - Kalman filtering and artificial intelligence

The motion of a rigid body moving in its environment, whether on land, in the air or at sea, can be determined using navigation techniques. It is then necessary to estimate the dynamic states of this body in a two-dimensional (2D) or even three-dimensional (3D) space, such as position, velocity or attitude. The estimation of these states is fundamental to the mobile's ability to locate itself, calculate the distance it has travelled, and more generally to carry out its mission, such as following a trajectory.

There are four types of navigation:

• navigation by path ;

• systematic error navigation ;

• dead reckoning ;

• determination of heading, drift and ground speed.

Dead reckoning, one of the most common navigation techniques currently used in pedestrian and UAV navigation, enables these navigation-specific states to be determined by recursively measuring their evolution relative to their initial values. The need for dead reckoning arises from the limitations of typical satellite positioning techniques (e.g. GPS), which require a direct line of sight between the satellite receiver and at least four satellites to determine navigation states.

Inertial navigation is characterized by the use of inertial acceleration and rotation sensors, coupled with dead reckoning techniques, to determine the absolute motion of the moving body. In fact, if these sensors can measure the resultant force exerted on a moving body using Newton's second law, the rates of linear and/or rotational motion can be deduced. Inertial navigation dates back to the 17th century, with the development of these measuring devices. It has the advantage of being totally autonomous, but estimation performance is highly dependent on the quality of the sensors used.

As a result, inertial systems are prone to errors that can degrade performance over the long term. Compared with other navigation systems, it remains the most efficient, and can be hybridized with complementary systems such as GPS. Inertial navigation is commonly used today in pedestrian, aerial and underwater navigation, for example. A promising market is developing around this technique for health, personal safety and rescue, connected objects, etc.

Inertial sensors fall into two main categories: accelerometers and gyrometers. Accelerometers measure forces (the sum of the gravity vector and the linear acceleration vector), while gyrometers measure angular velocities.

When mounted in specific geometric shapes and rigidly attached to the body, the inertial sensor assembly is called an inertial...