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.