3. Hybridization architectures

There are three ways of coupling GPS and inertial navigation systems: loose, tight or very tight, depending on the type of GPS information used for integration.

All these processes are made up of three parts.

In the first, the IRS supplies inertial data to the integration process, i.e. calculated position, velocity, attitude and accelerometric measurements. It is used as the reference system.

GPS will provide different information depending on the type of integration in the second part:

• the position and velocity estimated by the receiver, for loose hybridization (figure 11 ). The disadvantage of this process is that when the number of satellites tracked drops below 4, integration is...