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ЗТК III курс soil management.doc
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III. Fill in the blanks:

1. The primary function of the field surveyor is … .

2. Total station incorporates a distance meter for … and a theodolite for … into one instrument.

3. Global Positioning System (GPS) is the only fully functional … .

4. Satellites transmit precise microwave signals, enabling a GPS receiver to determine its … .

5. President Ronald Reagan issued a directive making the system available for … .

6. GPS has become a widely used aid to … , and a useful tool for … .

7. GPS is used in many applications including for scientific studing of … , and synchronization of …

IV. Read and translate the text: Global Positioning System (gps)

The primary function of the field surveyor is measuring, mapping, and observing. Our most important tool for these purposes is total station. It's given this name because it incorporates a distance meter for measuring distances and a theodolite for measuring angles into one instrument.

The total station measures by sending a beam of infrared light toward a prism, usually supported either by a tripod or a pole.

The light reflects off the prism directly back to the total station. By measuring the time it takes for the light to return, the total station calculates the distance away that the prism is.

The information that the total station measures (angles and distances) is recorded in a data collector for later downloading into a computer in the office. The data collector also doubles as a field computer, enabling us to calculate coordinate geometry in the field and figure out the proper position in which to put stakes.

GPS is a tool used for precise positioning of points. Speaking scientifically the Global Positioning System (GPS) is the only fully functional Global Navigation Satellite System (GNSS). Utilizing a constellation of at least 24 Medium Earth Orbit satellites that transmit precise microwave signals, the system enables a GPS receiver to determine its location, speed, direction, and time. Other similar systems are the Russian GLONASS (incomplete as of 2008), the upcoming European Galileo positioning system, the proposed COMPASS navigation system of China, and IRNSS of India.

It operates through satellites which send out signals to the receiver. The receiver then transmits those signals to the data collector which stores the data. After it is got into the office, the data is downloaded into the computer, and the computer software resolves from the data the exact position of any point within a few millimeters.

Developed by the United States Department of Defense, GPS is officially named NAVSTAR GPS (Contrary to popular belief, NAVSTAR is not an acronym, but simply a name given by John Walsh, a key decision maker when it came to the budget for the GPS program). The satellite constellation is managed by the United States Air Force. The cost of maintaining the system is approximately US$750 million per year, including the replacement of aging satellites, and research and development.

Following the shootdown of Korean Air Lines Flight 007 in 1983, President Ronald Reagan issued a directive making the system available for free for civilian use as a common good. Since then, GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying, commerce, and scientific uses. GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks.

Other satellite navigation systems in use or various states of development include:

  • Beidou — China's regional system that China has proposed to expand into a global system named COMPASS.

  • Galileo — a proposed global system being developed by the European Union, joined by China, Israel, India, Morocco, Saudi Arabia, South Korea, and Ukraine, planned to be operational by 2011–12.

  • GLONASS — Russia's global system which is being restored to full availability in partnership with India

Indian Regional Navigational Satellite System (IRNSS) — India's proposed regional system

QZSS - Japanese proposed regional system, adding better coverage to the Japanese Traditional Total Station Surveying.