UNIT 19 NAVIGATION SOFTWARE
AIM OF THE UNIT: - to describe navigation software -to understand the grammar point ` Present perfect tense`
TASKS 1 Do your best to answer the brainstorming questions. 2 Read the text for general understanding. 3 Make up questions to the text. 4 Find the sentences with the new words in the text. Give the Kazakh or Russian equivalents of the words. 5 Write sentences with the new vocabulary. 6 Do the given exercisesfor better remembering the topic.7 Study grammar point ‘present perfect tense ` do the tasks and find the sentences with present perfect tense in the text. 8 Speak on the topic. Given schemes and questions will help you to remember and understand the topic. 9 Find more information about the text and prepare a presentation or a project
1 What is navigation software? 2 What does the navigation software contain?
Navigation software is sometimes embedded in a central processor with other avionic software or confined to one or more navigation computers. The navigation software containsalgorithms and data that process the measurements made by each sensor (e.g., GPS, inertial, or air data). 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. In the simplest systems, a state vector is calculated independently from each sensor while the navigation software calculates the best estimate of position and velocity. Prior to 1970, the best estimate was calculated from a least-squares algorithm with constant weighting functions or from a frequency-domain filter with constant coefficients. Now, a Kalman filter calculates the best estimate from mathematical models of the dynamics of each sensor. 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. 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. Algorithms for waypoint steering and for control of the vehicle’s attitude are contained in the software of the flight management and flight control subsystems. Specially equipped aircraft are often used for the routine calibration of radio navigation aids, speed and velocity sensors, heading sensors, and new algorithms. Airborne test beds and hardware-software integration laboratories are routinely used to develop algorithms and sensor-software interfaces.
EXERCISES FOR BETTER
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