Satellite navigation systems, such as GPS (Global Positioning System), and inertial navigation systems have many complementary features, which justify their integration.
The signals emitted by the satellites in the GPS constellation enable users equipped with the right receiver to position themselves and keep track of the time anywhere on the planet, provided they can receive 4 signals with sufficient power. Advances in GPS signal processing – A-GPS (Assisted GPS) and HSGPS (High Sensitivity GPS) – solutions make it possible to use GPS in increasingly constrained environments, such as city centers. However, they do not guarantee continuity of navigation in all environments.
Inertial navigation systems enable autonomous positioning of the carrier, which is highly accurate in the short term. But this accuracy will become increasingly degraded over time: the speed of this drift depends on the quality of the sensors used.
Immediately, we can see two advantages to integrating these two systems: firstly, it improves positioning accuracy, and secondly, when GPS signals are no longer available, positioning continuity can be ensured by recalibrating inertia.