X. Choose the correct option. 1. Current navigation systems used in aircraft cost several times the price of an average car

1. Current navigation systems used in aircraft cost several times the price of an average car.

a. much time b. several times c. as many as

2. Our effort focuses _____ vehicle navigation systems.

a. of development b. on developing c. developed

3. During the past several years, Professors Boser and graduate students _____ to implement new technology in micromachined inertial sensors.

a. have worked b. was working c. have been working

4. Last year Analog Devices _____ such sensors on a commercial basis.

a. has provided b. provided c. was provided

5. Currently we _____ on the first generation six-sensor module that could replace single axis accelerometers.

a. are focusing b. are focused c. focus

6. To achieve the required performance, complex calibration and processing ____ be performed on the data provided by each sensor.

a. should b. can c. must

7. The first inertial sensors _____ by rocket designers such as Goddard and Braun in the early 1930's.

a. were developed b. developed c. were developing

8. If the device were stationary for one day the calculated position after one day ____ 1800 meters away from the sensors actual position.

a. will be b. would be c. would have been

9. Sensors provide the best overall performance ____ both determining position and orientation.

a. in terms of b. relative c. in order

10. Tactical grade Inertial Measurement Units are used extensively in the industry ____ their cost effective performance.

a. despite b. due to c. hence

XI. Each of these words is used with the navigation. Separate them into words which go before and words which come after navigation. Make up your own sentences with these collocations.

sensor celestial airborne system

ship aids equation radio

data en-route air variable