EE 495 Modern Navigation Systems INS-GPS Integration Architectures Wednesday, April 09 EE 495 Modern Navigation Systems Slide 1 of 9

INS-GPS Integration Architectures Wednesday, April 09 EE 495 Modern Navigation Systems Uncoupled GPS/INS Integration  The most straight forward integration approach  The GPS essentially repeatedly “initializes” the INS  NOT error-space estimation o Requires a dynamic model of the PVA of the host!! Slide 2 of 9 The GPS “resets” the INS

INS-GPS Integration Architectures Wednesday, April 09 EE 495 Modern Navigation Systems Loosely-Coupled GPS\INS Integration: Open-Loop  Transitions from a “full-state” to an “error-state” estimation configuration  Potentially “large” INS derived PVA errors can cause filter divergence o Local-linearization assumptions may be violated Slide 3 of 9 The INS mechanization errors are estimated

INS-GPS Integration Architectures Wednesday, April 09 EE 495 Modern Navigation Systems Loosely-Coupled GPS\INS Integration: Closed-Loop  Also an “error-state” estimation configuration  Potential open-loop divergence problem addressed o Estimates of the errors in the INS are fed back into the INS mechanization (e.g., accel & gyro bias estimates) o Need to be careful how often feedback occurs (correlation) Slide 4 of 9 The INS mechanization errors are estimated

INS-GPS Integration Architectures Wednesday, April 09 EE 495 Modern Navigation Systems Tightly-Coupled GPS\INS Integration  Also an “error-state” estimation configuration o Errors NOT in PVA-domain – Use pseudorange errors – Can function with less than 4 GPS satellites Slide 5 of 9 The GPS aids the INS & the INS potentially aids the GPS

INS-GPS Integration Architectures Wednesday, April 09 EE 495 Modern Navigation Systems Deeply-Coupled GPS\INS Integration  INS aids the GPS carrier tracking loops o Reduced bandwidth  less noise & better jamming immunity o Substantial increase in computational complexity Slide 6 of 9 The GPS aids the INS & the INS aids the GPS