Components of Remote Sensing
Remote Sensing Components is a main function to perform geospatial analysis. There are three major segments/components of Remote Sensing:
Remote Sensing platforms can be classified as follows, based on the elevation from the Earth’s surface at which these platforms are placed.
Thre are three types of platform in Remote Sensing-
- Ground borne platform
- Airborne platform
- Spaceborne platform
Ground borne platform
Ground borne remote sensors are very close to the ground. This platform used to record detail information about the Earth’s surface. very closely. The height of ground based platform is up to 50 meter from the Earth surface.
Some example of ground based platform are:
- Ground vehicle
- Air balloon
- Kite, and others
Airborne remote sensors is a low altitude or high altitude aerial remote sensing. This is used to collect very detailed images and facilities the collection of data over any portion of Earth’s surface. the height of airborne platform are above 50 km from earth surface. It is very expensive platform as compared to ground based platform.
There are some examples of airborne platform:
- High altitude aircraft
- Helicopters, and others
The space-borne remote sensors are orbiting spacecraft or space-shuttle on the earth. It is used for collect information both earth surface and atmosphere. Also it’s coverage large area and gather more information . Space borne imaging ranges from altitude 250 km to 36000 km.
There are some examples of Space-borne platform:
- Rocket satellite (height is 250 to 300 km above from the Earth surface)
- low level satellite (height is 700 to 1500 km)
- high level satellites (height is 36000 km)
There are two type of sensors available in Remote Sensing:
- Active Sensor
- Passive Sensor
Active Sensor is source of light or illumination and its sensor measures reflected energy. The energy is generated and sent from the Remote Sensing platform towards the targets.
Radar is an example of Active Sensor.
The MSS is an example of Passive Sensor.
There are three types of satellite Orbits:
A Geostationary Satellite Orbit is a very high altitudes (approximately 36,000 km), which view the same portion of the Earth’s surface.
This allows the satellites to observe and collect information continuously over specific areas. Weather and communications satellites commonly have these types of orbits.
Since there are 365 days in a year and 360 degrees in a circle, it means the satellites has to shift its orbit by approximately 1 degree per day. These satellites orbit at an altitude between 700 to 800 km.
A Polar orbit satellite travels north-south over the poles and takes approximately an hour and a half for a full rotation. Almost all the satellites that are in a polar orbit are at lower altitudes.
This satellite mostly used for Earth-mapping, observation, capturing the Earth as time passes from one point.