An artificial satellite is an object that has been put into orbit in outer space by human effort. A remote sensing satellite contains within it sensors that enable it to collect information about an object without physical contact with the object.
There are two types of sensors i.e. passive sensors and active sensors. Passive sensors are designed to acquire information about natural phenomena while active sensors acquire information concerning artificial objects. The following is a compilation of some import satellites:
- ‘SPOT’ – boasts two high resolution geometrical (HRG) instruments which offer high resolutions of between two and a half, and five meters (in panchromatic mode), and ten meters (in multispectral mode), twenty meters (on short wave infrared). Due to its high resolution capabilities, the SPOT-5 can be used in monitoring and assessment of crops (F. Achard, 1995).
- ‘LANDSAT 7’- it was equipped with both MSS and TM sensors. It has a panchromatic band with fifteen meters (49 feet) spatial resolution (band 8), (reflected light) bands in the spectrum of blue, green, red, near-infrared (NIR), and mid-infrared (MIR) with thirty meters (98 feet) spatial resolution (bands 1-5, 7), and a thermal infrared channel with sixty meters spatial resolution (band 6). The Landsat 7 was designed to capture and refresh cloud-free images of the earth (Irons, 2013).
- ‘NOAA’ – is equipped with AVHRR/2 (Advanced Very High Resolution Radiometer), TOVS, SSU, and MSU sensors. The instruments on NOAA observe the earth’s cloud cover and temperature changes to study climate change patterns. Other applications for the sensors include the surveillance of land terrain and oceans. The AVHRR instruments are currently capable of capturing ground images with resolutions of up to 1100 meters (National Environmental Satellite, Data, And information Service , 2013).
- ‘IKONOS’- boasts spoting 0.8 meters panchromatic (1-meter PAN), four meter multispectral (4m MS), and a one meter pan-sharpened (1-m PS) sensors (Kramer, 2002). It was created with the main purpose of capturing high-resolution images of the earth.
- ‘ADEOS 2’ – was designed to monitor the biomass in the carbon cycle, earth’s water cycle and the trends in climate variation. To do this it was loaded with an Ocean Color and Temperature Scanner (OCTS), an Advanced Visible and Near Infrared Radiometer (AVNIR), Improved Limb Atmospheric Spectrometer (ILAS), Retroreflector in Space (RIS), Total Ozone Mapping Spectrometer (TOMS), and Interferometric Monitor for Greenhouse Gases (IMG) sensors (Earth observation satellite, 2003).
- ‘RADARSAT’- this Satellite has a Synthetic Aperture Radar (SAR). Its highest resolution is one meter in Spotlight mode, three meters in Ultra Fine mode with a hundred meter positional accuracy requirement (Radsat-2, 2011). Radarsat is implemented in marine surveillance, mapping, and monitoring of resources.
- ‘Quickbird’- this satellite is capable of capturing high quality and high-resolution images (between 2.4 meters to 2.8 meters), thanks to its PAN (panchromatic) sensor. Due to the high level of detail that can be captured, the images are mainly utilized in map making, and mapping of resources.
Satellites provide useful and accurate information that would otherwise be inaccessible; this has led to increased safety and efficiency in human activities. The integration of Global Positioning Systems into portable devices is the most is a good example. With the information collected by these satellites governments have been able to predict natural disasters and take preemptive measures, thereby avoiding human suffering and massive loss of life.
References
Earth observation satellite. (2003). Web.
F. Achard, J. M. (1995). A Mission for the Global Monitoring of the Continental Biosphere. Web.
Irons, J. R. (2013). about. National Aeronautics and Space Administration. Web.
Kramer, H. J. (2002). Survey of missions and sensors. Observation of the earth and its environment (p. 286).
National Environmental Satellite, Data, And information Service. (2013). NOAA Satellite and Information Service. Web.
Radsat-2. (2011). Canadian Space Agency. Web.