Open Library - открытая библиотека учебной информации

Открытая библиотека для школьников и студентов. Лекции, конспекты и учебные материалы по всем научным направлениям.

Категории

Химия Grammar Study
просмотров - 425

WHAT IS GPS?

Text C

GPS, short for Global Positioning System, is a space-based positioning system that uses satellites and computers to measure positions anywhere on the land, air, or sea at any time. This system is distinguished from other positioning systems by its 24-hour, seven-day per week availability and its pinpoint accuracy.

The system was born from communication problems U.S. troops experienced in the Vietnam conflict. During that time a localized system, LORAN, was used that was prone to problems inherent in radio communication such as poor reception during ominous weather or during the night. The U.S. Department of Defense responded to this problem by investing into a system known as the Navy Navigational Satellite System, TRANSIT, which most recently evolved into GPS.

GPS is a second generation, satellite-based, positioning system that is available anywhere and anytime and is capable of measuring land, air and sea positions with millimeter accuracy. GPS is referred to as a system because it is an assemblage of three distinct components or segments: Space, Control, and User.

The Space Segment refers to the constellation of satellites and the navigational data they provide. The Control Segment refers to monitoring and updating of the satellites’ clocks and navigational messages by a master control station that uses five regional monitoring stations distributed around the world. Lastly, the User Segment refers to the GPS receivers that calculate the time required for a radio signal to travel from the visible satellites to the receiver in order to measure its position using a technique called triangulation.

GPS has a civilian and military user community. Although GPS is funded by the U.S. DoD, civilians worldwide can use GPS’ Standard Positioning Service (SPS) provided a proper receiver is used. SPS provides positional accuracy of 100 meters in 2-Dspace with 95% confidence. The U.S. Military and its allies use a more highly accurate service called Precise Positioning Service (PPS) that is capable of accuracy within ten meters in 3-D space 95% confidence.

Инфинитив

The Infinitive

Инфинитив – неличная форма глагола, которая только называет действие, не указывая ни лица, ни числа.

Признаком инфинитива является частица “to”, которая в некоторых случаях опускается.

Инфинитив обладает свойствами глагола и существительного.

В русском языке ему соответствует неопределœенная форма глагола.

1. Формы инфинитива

Infinitive Active Passive Действие
Indefinite to ask to be asked Действие, одновременное действию, выраженному глаголом-сказуемым.
Continuous to be asking (to be + Participle I __ Длительное действие, одновременное с действием, выраженным глаголом-связкой.
Perfect to have asked (to have + Participle II) to have been asked (to have been + Participle II) Действие, предшествовавшее действию, выраженному сказуемым.
Perfect Continuous to have been asking (to have been + Participle I) Длительное действие, совершавшееся в течение отрезка времени, предшествовавшего действию, выраженному глаголом в личной форме.

Инфинитив может служить в предложении:

1. Подлежащим:

То skateis pleasant. Кататься на коньках приятно.

2. Именной частью сказуемого:

Your duty was to informme about it immediately. Вашей обязанностью было сооб­щить мне об этом немедленно.

3. Частью составного глагольного сказуемого:

She began to translatethe article. Она начала переводить статью.

4. Дополнением:

I asked him to helpme. Я попросил его помочь мне.

5. Определœением:

He expressed a desire to helpme. Он выразил желание помочь мне.

6. Обстоятельством:

I went to the station to see off a friend. Я поехал на вокзал, чтобы проводить приятеля.

Субъектный инфинитивный оборот (Complex Subject)

Конструкция субъектный инфинитивный оборот выражена существительным в общем падеже или местоимением в именительном падеже и инфинитивом, стоящим после сказуемого.


Читайте также


  • - Grammar Study

    Text C INSULATORS Insulating materials have a very low conductivity. They offer extremely high resistance to the flow of current. Insulators are used in electric devices to isolate conductors. Thus they should have a high dielectric strength and a high resistivity. Their mechanical properties are also important for practical use. Insulators are divided into gaseous, liquid and solid. They are also divided into groups according to their heat resistance. The main gaseous insulator... [читать подробенее]


  • - Grammar Study

    TELEGRAPH Text C Benjamin Franklin, an American who is famous for his interesting and useful inventions, published his ideas about electricity in 1752. Scientists in many countries became interested in this wonderful form of energy. They wanted to find the answer to a very important question: could the electricity be used to develop a fast, efficient system of long-distance communication? Experiments proved that electricity could travel instantly over a very long piece of wire.... [читать подробенее]


  • - Grammar Study

    Text C HARNESSING THE SPEED OF LIGHT When the American scientist Alan Huang revealed his plants to build an optical computer, most scientists considered this idea as hopeless. It was impractical, if not possible, they said, to create a general-purpose computer that could use pulses of light rather than electrical signals to process data. During one of the scientist’s lectures on the subject, a third of the audience walked out. At another one, some of the scientists laughed, calling... [читать подробенее]


  • - Grammar Study

    TALKING VIA SPACE Text C Communication has come a long way from the time when an Indian beat a drum in the forest to the time when a scientist receives messages from a satellite. In this space age communication has become a highly developed field. The system of communication in large countries is unthinkable today without space satellites. Besides large distances, there is a great time difference: the territories of some countries comprise up to 11 zones. Satellites help to... [читать подробенее]


  • - Grammar Study

    Text C NON-TRADITIONAL RENEWABLE SOURCES OF ENERGY It is known that much is being done in the world today for the development of non-traditional sources of energy. Without them the Earth cannot support its present population of 5 billion people and probably 8 billion people in the 21st century. Now we are using traditional power sources, that is oil, natural gas, coal and water power with the consumption of more than 50 billion barrels per year. It is evident that these sources are... [читать подробенее]


  • - Grammar Study

    Laser Text C Notes DIRECT CURRENT AND ALTERNATING CURRENT Text B When a cell or any other generator is connected so as to form a continuous path of conductors the electrons begin to move through conductors forming an electric current or an electric circuit. This phenomenon is known to be the electricity flow through a circuit. If broken anywhere, the electric circuit will stop carrying a current. There are two main types of current: direct and alternating. When... [читать подробенее]


  • - Grammar Study

    Text C ALEXANDER GRAHAM BELL Alexander Graham Bell was born in Edinburgh in 1847. His father was a world-famous teacher of speech and the inventor of a system which he called "Visible Speech". It helped deaf persons to pronounce words they could not hear. Alexander chose the same profession, and as his father became a teacher of the deaf, he moved to the United States and began to teach deaf children to speak. At the same time he worked at improving his father's invention. ... [читать подробенее]


  • - Grammar Study

    WHAT IS GPS? Text C GPS, short for Global Positioning System, is a space-based positioning system that uses satellites and computers to measure positions anywhere on the land, air, or sea at any time. This system is distinguished from other positioning systems by its 24-hour, seven-day per week availability and its pinpoint accuracy. The system was born from communication problems U.S. troops experienced in the Vietnam conflict. During that time a localized system, LORAN, was used... [читать подробенее]


  • - Grammar Study

    Laser Text C Notes DIRECT CURRENT AND ALTERNATING CURRENT Text B When a cell or any other generator is connected so as to form a continuous path of conductors the electrons begin to move through conductors forming an electric current or an electric circuit. This phenomenon is known to be the electricity flow through a circuit. If broken anywhere, the electric circuit will stop carrying a current. There are two main types of current: direct and alternating. When... [читать подробенее]