Podcast
Questions and Answers
Which platform is typically used for multispectral scanning systems?
Which platform is typically used for multispectral scanning systems?
What is the primary difference between a multispectral scanner and a line camera?
What is the primary difference between a multispectral scanner and a line camera?
Which of the following is a type of multispectral scanner?
Which of the following is a type of multispectral scanner?
What is the primary function of a thermal scanner?
What is the primary function of a thermal scanner?
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What is the operating wavelength range of thermal scanners?
What is the operating wavelength range of thermal scanners?
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Which of the following is an example of a thermal multispectral scanner?
Which of the following is an example of a thermal multispectral scanner?
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What is the primary function of a passive microwave scanner?
What is the primary function of a passive microwave scanner?
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Which platform is typically used for thermal scanners?
Which platform is typically used for thermal scanners?
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What is the key advantage of using a multispectral scanner over a line camera?
What is the key advantage of using a multispectral scanner over a line camera?
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Which platform is typically used for passive microwave scanners?
Which platform is typically used for passive microwave scanners?
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What is the key difference between a multispectral scanner and a thermal scanner?
What is the key difference between a multispectral scanner and a thermal scanner?
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Study Notes
Types of Sensors
- Active sensors have their own source of energy and can work both day and night, e.g., Radar and Lidar
- Passive sensors measure reflected radiation during the day and emit at night, e.g., ASTER
Remote Sensing Platforms
- A remote sensing platform is a vehicle that carries one or more remote sensors, e.g., satellite, aircraft, or field equipment
- Platforms can be operated at altitudes ranging from a few centimeters above the ground to beyond the atmosphere
- Platforms can be moving (e.g., satellite, aircraft) or static (e.g., high-rise building)
Classification of Remote Sensing Platforms
- Ground-based platform: includes moving vehicles, cranes, cherry-pickers, and tall buildings, used for collecting detailed information
- Airborne platform: includes aircraft, helicopters, hot air balloons, and UAVs, flying higher than 1000m and up to approximately 20km
- Spaceborne platform: includes satellites and space shuttles, producing images with high temporal resolution at low cost
Orbits of Satellites
- Low Earth orbit (LEO): 1-2,000 km above the earth, with high temporal resolution and small coverage area
- Medium Earth orbit (MEO): 5,000-10,000 km above the earth, e.g., communication satellites (GPS)
- Geostationary orbit (GEO): ~35,786 km above the earth, precisely over the equator, with high temporal resolution and large coverage area, e.g., weather satellites
- Polar Orbit: Travels from north pole to south pole, with a special type being Sun-synchronous orbit (SSO)
Multispectral Scanning Systems
- Pushbroom: Multispectral system
- Whiskbroom: Multispectral scanning system, operated from spaceborne and airborne platforms, sensing in broad spectral range from visible to microwave
Thermal Scanners
- Special types of multispectral scanners that provide information related to objects' temperature
- Operates between 7.0µm – 14µm (Thermal infrared region)
- Examples: Thermal Infrared Multispectral Scanner (TIMS) with 6 bands between 8.2 – 12.2 micrometre, ASTER on board of Terra-1 satellite with 5 thermal infrared bands
Passive Microwave Scanner
- A radiometer that detects naturally emitted radiation of the Earth's surface in 10-1000mm
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Description
Test your knowledge about remote sensing platforms and sensors used for measuring reflected and emitted radiation. Learn about active sensors with their own energy sources like radar and lidar, and understand the concept of remote sensing platforms such as satellites and aircraft.
