The satellite which carry the sensors that help to acquire information about an object without physically coming in contact with the object is called remote sensing satellite . Altitude, orbit and sensor are the three vital characteristic of a remote sensing satellite .
Characteristics of a remote sensing satellite:
• Altitude: Altitude is the height of operation of a remote sensing satellite . The nature of an imagery captured by a remote sensing satellite varies depending on the altitude.
• Orbit: Orbit is the elliptical path followed by a remote sensing satellite around the earth. They are of three types- Geostationary orbit, Near polar orbits and Sun synchronous orbits. A remote sensing satellite generally follows Sun synchronous orbit. In this orbit the remote sensing satellite always crosses the same point at the same time everyday because of the altitude. The time taken by the remote sensing satellite to complete one revolution is called orbital period. The time interval after which a remote sensing satellite repeats its path is called repeat circle.
• Sensors: Sensors are of two kinds-passive and active. Passive sensors are those which accept reflectance from natural object whereas active sensors accept reflectance from man-made objects. These passive and active sensors can also be divided into many parts.
Function of a remote sensing satellite systems :
• Tracking and control system: Determinig the orbit along with controlling it.
• Operation control system: Planning of the main goal, data evaluation etc.
• Data acquisition system: Acquisition of data and processing the data
Geostationary remote sensing satellite: When the remote sensing satellite follows the earth orbit parallel to the equator and takes the time of 24 hrs, then the orbit of the remote sensing satellite is called geostationary. Some of them are:
• GMS : These are meteorological satellites launched on 17 th March of 1995.
• FY-2: Launched on 10June, 1997, this remote sensing satellite contains visible and infrared scan radiometer.
• INSAT: These are Indian sattelites launched for meteorological observations.
• GOES: These are launched over America.
• METEOSAT: European remote sensing satellite launched over Europe and Africa.
Some of the Important remote sensing satellites are:
|
Name |
Type |
Altitude(km) |
Inclination(°) |
Period(min) |
Repeat Circle(days) |
Sensors |
|
SPOT |
Sun synchronous |
832 |
98.7 |
101 |
26 |
HRV |
|
LANDSAT |
Sun synchronous |
705 |
98.2 |
99 |
16 |
MSS, TM |
|
MOS |
Sun synchronous |
908 |
103 |
17 |
MESSR, VTIR, MSR |
|
|
EO-1 |
Sun synchronous |
705 |
98.2 |
99 |
16 |
Hyperion |
|
IRS |
Sun synchronous |
817 |
98.69 |
101 |
24 |
LISS, PAN, WIFS |
|
RESURS |
Sun synchronous |
678 |
98.04 |
98 |
21 |
MSU-SK |
|
NOAA |
Sun synchronous |
870-833 |
98.7-98.99 |
101.4 |
AVHRR/2, TOVS, SSU, MSU |
|
|
EROS-A1 |
Sun synchronous |
475-491 |
97.3 |
94 |
CCD |
|
|
IKONOS |
Sun synchronous |
681 |
98.1 |
98 |
PAN |
|
|
ADEOS2-GLI |
Sun synchronous |
803 |
98.6 |
101 |
4 |
GLI |
|
SPOT-5 |
Sun synchronous |
832 |
98.7 |
101 |
26 |
HRV |
|
Quickbird-2 |
Sun synchronous |
450 |
98 |
93.4 |
PAN |
|
|
ADEOS |
Sun synchronous |
800 |
98.6 |
101 |
41 |
OCTS |
|
RADARSAT |
Sun synchronous |
798 |
98.6 |
100.7 |
24 |
SAR |
The remote sensing satellite monitors the different aspects of a country and helps the government to carry out development projects. It also forecasts the threats to the country and is important base for telecommunication system.
In other words, remote sensing satellite accelerates development.
Image Mapping