Space Shuttle navigation analysis using post flight reconstruction of onboard computer results

An approach to software verification and validation testing developed while testing the Shuttle's navigation system is described. The telemetry stream during the first flight was used to drive a simulation of the onboard navigation software. Agreement between the simulation and flight data was within 100 m during flight and 2 m during landing, as derived from postflight processing. The inertial navigation algorithm is provided for ascent and descent, noting that the latter employs a six-state Kalman filter to estimate the position and velocity statistics. Telemetry characteristics at 128 kbit/sec are given; an inhomogeneity of input parameters was found to be due to inconsistencies in the set comprising the navigation measurement data associated time lags. Detailed comparisons and solutions are presented for the three navigational regions: the drag-altitude phase, the TACAN phase, and the landing phase.