2. Why GPS/IRS coupling

Most often, the aim of this integration is to estimate IRS errors, which are errors in position, velocity and attitude angles, sensor errors from several sources (accelerometer bias and gyro drift), as well as GPS error terms (GPS receiver clock bias and clock bias drift, for example), using GPS as the reference for measurements.

The diagram in figure 7 shows the principle of classic GPS/IRS hybridization, in which the information provided by the GPS represents the exact trajectory. This integration therefore assumes that the information provided by the GPS is error-free.

Figure 7 illustrates closed-loop integration in particular, since the...