Integrated Navigation Test 1 Practice

Timing alignment between INS and GNSS is crucial because the INS propagates the navigation solution by integrating IMU data in its own time frame, while GNSS provides position and velocity at its precise epoch. If the INS and GNSS clocks are not synchronized within sub-millisecond accuracy, the GNSS measurement effectively refers to a slightly different moment than the INS-predicted state. That small time mismatch translates into a mismatch in the measurement model that the fusion process must reconcile. The filter then introduces clock bias or timing error terms to absorb this mismatch, and these errors propagate into the estimated position and velocity. With ongoing dynamics, even a tiny time offset can accumulate and appear as non-negligible errors in the fused solution. Since the timing error affects both how fast you think you’re moving and where you think you are, it is not limited to altitude and it degrades the overall accuracy of the solution.