UNIT 18MAP-MATCHING NAVIGATION

AIM OF THE TOPIC:- to describe map-matching navigation

- to understand grammar points ` Present perfect

passive, PresentСontinuous Passive.`

 

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 passive, Present Continuous Passive `

do the tasks and find the sentences with passives 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

work.

Brainstorming questions

 

 

1 When automatic map-matchers have been built?

2 What do aircraft and cruise missiles measure?

3 What does an on-board computer calculate?

On aircraft, mapping radars and optical sensors present an image of the terrain to the crew, whereas on unmanned aircraft, navigation must be autonomous. Automatic map-matchers have been built since the 1960s that correlate the observed image to stored images of patches of distinctive terrain, choosing the closest match to update the dead-reckoned state vector. Since 1980, aircraft and cruise missiles measure the vertical profile of distinctive patches of terrain below the aircraft and match it to a stored profile. Updating with the matched profile, perhaps hourly, reduces the long-term drift of the inertial navigator. The profile of the terrain is measured by subtracting the readings of a baro-inertial altimeter and a radio altimeter. An on-board computer calculates the cross-correlation function between the measured profile and each of many stored profiles on possible parallel paths of the vehicle. The on-board inertial navigator usually contains a digital filter that corrects the drift of the azimuth gyroscope as a sequence of fixes is obtained. Hence, the direction of flight through the stored map is known, saving the considerable computation time that would be needed to correlate for an unknown azimuth of the flight path.The most complex mapping systems observe their surroundings by digitized video (often stereo) and create their own map of the navigated space. In the 2000s, optical mappersare being developed that allow landings at fields that are not equipped with electronic aids.

 

EXERCISES FOR BETTER REMEMBERING THE TOPIC