1. What does the ICA Commission on Maps and Society establised in August 2007 provide?
3
.
______ ..
____ _________ 2008.
: () ( )
: 6.070900
6.070900 㳿
Variant 6
I. Translate the following text in writing and put 5 questions to the underlined sentence.
A GPS antenna should cover a wide spatial angle to receive the maximum number of signals. The common requirement is to receive signals from all satellites about 5 degrees above the horizon. Combining satellites at low elevation angles and high elevation angles can produce a low value of geometric dilution of precision (GDOP). An interfering signal usually comes from a low elevation angle. In order to minimize the interference, sometimes an antenna will have a relatively narrow spatial angle to avoid signals from a low elevation angle. Therefore, in selecting a GPS antenna a trade-off between the maximum number of receiving satellites and interference must be carefully evaluated. If an antenna has small gain variation from zenith to azimuth, the strength of the received signals will not separate far apart.
An interfering signal usually comes from a low elevation angle.
II. Give the English equivalents to the following terms.
1. interfering signal 9. to separate
2. receiving satellites 10. to evaluate
3. low value of 11. to avoid
4. elevation angles 12. to minimize
5. low elevation 13. to combine
6. requirement 14. to produce
7. maximum number of 15. to receive
8. spatial angle 16. to cover
III. Translate sentences into English.
1. - ArcCadastre. 2. . 3. ϳ . 4. . 5. . 6. , ArcCadastre. 7. , ArcCadastre .
IV. Give extended answer to the following question.
1. Why do all the workshops of the ICA foster great networking among the participants?
3
.
______ ..
____ _________ 2008.
: () ( )
: 6.070900
6.070900 㳿
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Variant 7
I. Translate the following text in writing and put 5 questions to the underlined sentence.
In a GPS receiver the input is the GPS signal and a phase-locked loop must follow (or track) this signal. However, the GPS signal is a bi-phase coded signal. The carrier and code frequencies change due to the Doppler effect, which is caused by the motion of the GPS satellite as well as from the motion of the GPS receiver. In order to track the GPS signal, the C /A code information must be removed. As a result, it requires two phase-locked loops to track a GPS signal. One loop is to track the C /A code and the other one is to track the carrier frequency. These two loops must be coupled together. The C /A code loop generates three outputs: an early code, a late code, and a prompt code. The prompt code is applied to the digitized input signal and strips the C /A code from the input signal.
As a result, it requires two phase-locked loops to track a GPS signal.
II. Give the English equivalents to the following terms.
1. input signal 9. to be applied to
2. digitized signal 10. to strip
3. a prompt code 11. to generate
4. a late code 12. to require
5. early code 13. to be removed
6. code information 14. to track
7. bi-phase coded signal 15. the Doppler effect
8. phase-locked loop 16. receiver
III. Translate sentences into English.
1. - ArcCadastre. 2. . 3. ϳ . 4. . 5. . 6. , ArcCadastre. 7. , .
