What is the use of satellites?

Satellite of different types, different uses, listed below:

1, meteorological satellites:

Used to monitor the cloud weather information, provide the latest weather conditions and long-term weather analysis. China's meteorological satellites have polar orbit and smooth sequence. This polar orbiting satellite flies around the north and south poles and crosses the equator. It takes about 102 minutes to fly around the orbit at an altitude of 830 kilometers above sea level.

Because the local time of the places where the satellite passes through is basically the same, it is also known as the "near-polar sun-synchronous orbit satellite". Its advantage is that it can observe any place in the world, mainly used for weather forecasting, ecology, environmental monitoring and climate change research. Military satellites: mainly used for military purposes, monitoring important military targets.

2. Communication satellites:

Mainly used for civilian purposes, providing a variety of communication purposes, such as television broadcasting, IP communication network, telephone network. Communication satellites use Ka-band, laser communications, electric propulsion and a series of new technologies, the total communication capacity of more than 20mbit / s.

This marks the entry of China's satellite communications into the era of high throughput, realizing the true meaning of independent communication satellite broadband applications, to fill the gaps of China's resource satellites in this field: mainly used for resource detection, etc..

3, low-orbit satellites:

Low-orbit satellites have an orbital altitude of 200-2000 kilometers, and satellites within this altitude range are low-orbit satellites.

Generally a large satellite system consisting of multiple satellites, capable of real-time information processing, capable of realizing communication, remote sensing, navigation and other functions. Constellation-sized groups may produce more benefits than large satellites with full functionality and superior performance.

Low-orbit satellites are also used for mobile communications because their low orbital altitude results in shorter transmission delays and fewer path losses. Communications systems consisting of multiple satellites can achieve truly global coverage with more efficient frequency reuse.

Technologies such as cellular communications, multiple access, spot beam, and frequency multiplexing also provide technical support for low-orbit satellite mobile communications. Low-orbit satellites are the newest and most promising satellite mobile communication system.

4, military satellites:

It can provide accurate position, speed and time information for ground combat vehicles, airplanes, surface ships, ground troops and even individual soldiers, and can carry out precise guidance for missiles and artillery shells, greatly improving the efficiency of the use of weapons.

Military satellites fast, accurate, continuous and flexible advantages of security, so often use adaptive antennae between the link to zero, on-star processing, star and other advanced technologies to improve reliability and survivability, anti-jamming, etc. to reduce dependence on the ground, against large-capacity, rapid information transfer plays a key role.

5, resource satellites:

Earth Resources Satellite is a medium-altitude "sun-synchronous satellites", its perigee is 905 kilometers, apogee of 918 kilometers, so the orbit is nearly circular; it is from north to south, from south to north around the Earth for one week, every 103.267 minutes per day rotating 14 times, every 25 seconds. 14 revolutions per day, every 25 seconds to "take" a picture.

The ERS carries two types of "photographic" instruments (called sensors): an anti-beam tube television camera, which is similar to a television camera, and a multispectral scanner, which separates electromagnetic waves reflected from the ground by wavelength and records them.

The instrument receives the light signal converted into a voltage signal recorded on a magnetic tape, waiting for the satellite ground receiving station through the station and use the tape to transmit back to record the voltage signal, and then processed by a computer, which will be converted into a light signal, imaged in the light-sensitive material, which is a satellite photo.