Currently, thanks to the introduction of GPS, accurate and inexpensive navigation receivers are widely used. How do these little smart assistants know where you are?
The basic principle underlying the entire GPS system is simple and has long been used for navigation and orientation: if you know exactly the location of a reference point and the distance to it, you can draw a circle (in the 3-dimensional case - a sphere), on which should be the point of your position. In practice, if the above distance, i.e. radius is large enough, you can replace the arc of a circle with a straight line segment. If you draw several of these lines corresponding to different reference points, then the point of their intersection will indicate your location. In GPS, the role of such benchmarks is played by two dozen satellites, each moving in its own orbit at an altitude of about 17,000 km above the surface of the Earth. The speed of their movement is very high, but the parameters of the orbit and their current location with high accuracy are known to on-board computers.
An important part of any GPS navigator is a regular radio receiver operating at a fixed frequency and constantly “listening” to the signals transmitted by these satellites. Each of the satellites constantly emits a radio signal, which contains data on the parameters of its orbit, the state of the onboard equipment and the exact time. Of all this information, the exact flight time data is the most important: the GPS receiver, using the integrated processor, calculates the time interval between sending and receiving the signal, then multiplies it by the speed of propagation of radio waves, etc. recognizes the distance between the satellite and the receiver. The result of subsequent calculations are the coordinates of your location.
Объяснение:
В настоящее время благодаря внедрению системы GPS получили широкое распространение точные и недорогие навигационные приемники. Каким же образом эти маленькие "умные" узнают, где Вы находитесь?
Основной принцип, лежащий в основе всей системы GPS, прост и давно используется для навигации и ориентирования: если Вы точно знаете местоположение какого-либо реперного ориентира и расстояние до него, то можно начертить окружность (в 3-х мерном случае - сферу), на которой должна быть расположена точка Вашего положения. На практике, если вышеуказанное расстояние, т.е. радиус, достаточно велик, то можно заменить дугу окружности отрезком прямой линии. Если провести несколько таких линий, соответствующих разным реперным ориентирам, то точка их пересечения укажет Ваше местоположение. В GPS роль таких реперов играют две дюжины спутников, движущихся каждый по своей орбите на высоте около 17 000 км над поверхностью Земли. Скорость их движения весьма велика, однако параметры орбиты и их текущее местонахождение с высокой точностью известны бортовым компьютерам.
Важной частью любого GPS-навигатора является обычный радиоприемник, работающий на фиксированной частоте и постоянно "прослушивающий" сигналы, передаваемые этими спутниками. Каждый из спутников постоянно излучает радиосигнал, в котором содержатся данные о параметрах его орбиты, состоянии бортового оборудования и о точном времени. Изо всей этой информации данные о точном бортовом времени являются наиболее важными: GPS-приемник с встроенного процессора вычисляет промежуток времени между посылкой и получением сигнала, затем умножает его на скорость распространения радиоволн и т.о. узнает расстояние между спутником и приемником. Результатом последующих вычислений являются координаты Вашего местоположения.
Объяснение:
10 Downing Street or «Number 10" as the British call it, is one of the most
famous uddresses in the world as it has been the home of British prime ministers since
1730, However, it is also a very busy place where hundreds of people work and where
many official functions. Cabinet meetings and state dinners take place. Many people
will immediately recognize the front of the building because the Prime Minister and
other well-known politicians often make important announcements in front of its
famous big black
Number 10 was originally given to the first prime minister, Sir Robert
Walpole, as a gift, but he wanted it to be used by all future prime ministers Before he
moved in, though, he joined 10 Downing Street to the large house behind it and had
some alterations made. So even though Number 10 looks like an ordinary terraced
house from the outside, inside it is an extremely erand place There are many
beautiful rooms with elegant decor and fine furniture including the State Dining
Room, the Study, the Terracotta Room and the White Drawing Room. There are
portraits ofevery past prime minister hanging on the walls of the Grand Staircase and
in the Cabinet Room, where government ministers meet to discuss important issues.
The table in this room is boat-shaped so that the Prime Minister can always see
everyone sitting around it!
The Prime Minister's private home is a furnished flat on the second floor, once
described by Margaret Thatcher (British Prime Minister from 1979-1940) as living
above the shop'. The Prime Minister also has his own study where he works and
reads. There, he offen meets colleagues, receives important guests, makes phone calls