VI Skim the text with your partner to decide if the sentences are true or false.
1 Navigation software is not embedded in a central processor with other avionic software or confined to one or more navigation computers. 2 The navigation software does not contain algorithms and data. 3 It contains calibration constants, initialization sequences, self-test algorithms, reasonability tests, and alternative algorithms for periods when sensors have failed or are not receiving information. 4 In the simplest systems, a state vector is not calculated independently from each sensor while the navigation software calculates the best estimate of position and velocity. 5 Prior to 1990, the best estimate was calculated from a least-squares algorithm with constant weighting functions or from a frequency-domain filter with constant coefficients. 6 Now, a Kalman filter does not calculate the best estimate from mathematical models of thedynamics of each sensor. 7 Digital maps, often stored on compact disc, are carried on an increasing number of aircraft; position can be visually displayed to the crew and terrain warnings issued. 8 Military aircraft superimpose their navigated position on a stored map of terrain and cultural features to aid in the penetration of and escape from enemy territory 9 Algorithms for waypoint steering and for control of the vehicle’s attitude are not contained in the software of the flight management and flight controlsubsystems. 10 Specially equipped aircraft are seldom used for the routine calibration of radio navigation aids, speed and velocity sensors, heading sensors, and newalgorithms. 11 Airborne test beds and hardware-software integration laboratories are routinely used to develop algorithms and sensor-software interfaces.
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