TDRSS constellation _dsc constellation

Basic types of remote sensing satellites

Meteorological satellite is a kind of remote sensing satellite, whose main task is to collect meteorological data and provide a large number of real-time data for meteorological forecast, typhoon formation and movement monitoring, ice and snow coverage monitoring and atmospheric and space physics research. Meteorological satellites can be divided into sun-synchronous satellites and geostationary satellites according to their orbital characteristics. ① Sun-synchronous satellites orbit the earth's north and south poles and cross the equator. American satellites TIROS, NOAA and Nimbus belong to the sun synchronous meteorological satellites. ② Geostationary satellites are stationary relative to the Earth over the equator. In the 1980s, three geostationary operational environment satellites (GOES) launched by the United States (located above the equator of 75 W,135 E and 75 E respectively), the meteorological satellite (METEOSAT) launched by the European Space Agency (located above the equator of 0 longitude) and the geostationary meteorological satellite (GMS) launched by Japan.

Tiros meteorological satellite

Some countries began to carry out meteorological satellite experiments in the 1960s, and such satellites gradually formed operational systems. As early as the 1960s, two satellites in the TIROS series and the ESSA series launched by the United States could provide daily live broadcast and global television image recording and playback respectively. The "ITOS" and "NOAA" satellites launched in the early 1970s are the second generation meteorological satellites. They are equipped with live and recording cameras and radiometers, which can provide images at intervals of 65,438+02 hours every day and night. Since ITOS-D, very high resolution radiometer, medium resolution radiometer and solar proton monitor have been added. Tiros-N and NOAA satellites launched in 1978 are the third generation meteorological satellites. They carry advanced instruments, such as very high resolution radiometer, high resolution infrared radiation detector, stratospheric detector, microwave detector data acquisition system and solar environmental monitor, for monitoring protons, electrons and particles. The "Rain Cloud" satellite launched by the United States in the 1960s and 1970s is equipped with multi-band microwave scanning radiometer, stratosphere and mesosphere detectors, ultraviolet and ozone detectors, ground radiometer, coastal zone color scanner and other atmospheric sounding instruments, so as to monitor the atmosphere on a daily basis and further develop advanced technologies for observing the planetary atmosphere and the earth's environment. A series of Defense Meteorological Satellites (DMSP) launched since 1966 can provide real-time military meteorological data. GOES satellite launched since 1974 is mainly equipped with visible and infrared rotating scanning radiometers, which can provide two-dimensional cloud images in visible light band, measure the temperature field on the cloud surface and cloud top in infrared band, and obtain the three-dimensional structure of atmospheric temperature and water vapor distribution. "Cosmos" and "Meteor" series of sun-synchronous meteorological satellites launched by the Soviet Union in 1960s are equipped with moderate resolution radiometers and wide-angle cameras to provide meteorological data for the Soviet Union and eastern European countries. Resources-1 (ZY- 1) Earth Resources Satellite

The Earth Resources Satellite (ERS) photographed the ground of the manned spacecraft "a sub-constellation mainly collecting information on earth resources and environment". After discovering the existence of abundant information on earth resources and environment, ERS plan was developed. 1972 launched the first ERTS, which was later renamed Landsat- 1. Landsat 2, 3, 4 and 5 were launched in the middle and late 1970s and early 1980s. "Landsat" can provide periodic and relatively cheap remote sensing data, so it is widely used. Landsat satellite remote sensing data has been widely used in land, forest and water resources survey, crop yield estimation, mineral and oil exploration, coastal survey, geological mapping, natural disaster monitoring, agricultural zoning, preliminary work of major projects and environmental dynamic monitoring. By 1984, many countries, including China, have established or are establishing land satellite ground stations, which cover almost the whole land area. Land satellite

"Landsat" is a sun-synchronous satellite orbiting the north and south poles of the earth, with a nearly circular orbit. At about 9: 30am, it crossed the equator "Landsat" 1 3km (Landsat1,2, 3) or 804km (Landsat 4, 5). Landsat-4 and Landsat-5 cover the earth once every 16 days, and the interval between adjacent strips is 7 ~ 9 days. Satellite-borne remote sensors, such as multispectral scanner (MSS), inverse beam photoconductive camera (RBV) and thematic imager (TM), can scan185km wide ground belt from north to south at one time. Using two RBVs to shoot panchromatic images on the ground, the resolution is twice as high as that of MSS. The image data of TM is 1 1 times that of MSS. Because it contains infrared band, its geometric accuracy and radiation accuracy are higher than MSS, and the information and image quality of TM is much better than MSS. A "land satellite" equipped with a broadband video recorder can be accepted into the world according to the instructions of the Space Center.

The MSS and RBV image data there will be played back and collected when the satellite runs to the ground receiving station. The satellite also carries a data acquisition system to collect telemetry data and forward it to the data processing center. The satellite can also be equipped with no video recorder, and the remote sensing image data collected outside the receiving range of the ground receiving station will be transmitted to the ground receiving and processing station for processing through the Tracking and Data Relay Satellite System (TDRSS). Ocean satellite is a kind of remote sensing satellite, whose main task is to collect marine resources and their environmental information. The ocean accounts for more than two-thirds of the earth's area and is rich in resources, which has a great influence on meteorology. Therefore, it is of great significance to study the ocean through satellite remote sensing. The ocean satellite A (SEASAT-A) launched by the United States in 1978 was equipped with remote sensors such as altimeter, L-band side-looking radar, scatterometer, microwave radiometer and visible and infrared radiometer, and received and recorded a considerable amount of remote sensing data, especially the image data of side-looking radar. The synthetic aperture side-looking radar on the satellite can work day and night. Radar waves penetrate clouds and dense vegetation to obtain surface images. It can distinguish ice and snow from water, and plays a great role in the study of marine ice floes and land snow, geological structures, floods and flooding.