Earth Observation From Space: Active
Remote Sensing Systems Question and
answers 100% correct
Passive Remote Sensing - correct answer ✔- Passive remote sensing
measures energy that is naturally emitted
- Passive sensors sense naturally occurring energy that ultimately
comes from the sun
- Energy (such as thermal infrared) can be detected day or night, the amount
of energy has to be large enough for it to be recorded
Active Remote Sensing - correct answer ✔- Active sensors provide their own
energy source for illumination
- A sensor emits a form of radiation that is directed towards a target
in a particular area
- The radiation that is reflected back from the target is then detected and
measured by the sensor
- There are three types of active remote sensing 1. LiDAR
2. RADAR
3. SONAR
Advantages and Disadvantages of Active Remote Sensing - correct answer
✔Pros:
- Weather independent (in the case of RADAR)
- Sunlight independent
- Active forms of remote sensing can penetrate vegetation and soil: can gain
information about surface layers from mm to m depth
- Wide variety of applications
, Cons:
- Power of pulse is low so it can be influenced or interfered by other sources
of radiation
- Limited spectral information
- Complicated analysis, cost-intensive
Wide variety of applications
Three Types of Active Remote Sensing - correct answer ✔RADAR - uses
high frequency radio / microwaves to detect the speed, direction, distance and
speed of motor vehicles
2. LiDAR - uses a light waves to measure the distance to an object
3. SONAR - uses sound waves propagated to navigate, communicate and
detect objects under the water surface
RADAR - correct answer ✔RADAR = Radio Detection and Ranging
- RADAR technology emerged during World War II as a way of detecting the
presence of ships and aircraft
- At this time the military considered information obtained about weather as
noise
- Since World War II there have been many advances in technology and it is
now also used in space
RADAR is a distance measurement - correct answer ✔- RADAR uses the
microwave portion of the electromagnetic spectrum
- RADAR creates an electromagnetic wave that is focused by an antenna and
then transmitted into the atmosphere
- The transmitted electromagnetic waves are then scattered by various objects
in the atmosphere or from the ground
Remote Sensing Systems Question and
answers 100% correct
Passive Remote Sensing - correct answer ✔- Passive remote sensing
measures energy that is naturally emitted
- Passive sensors sense naturally occurring energy that ultimately
comes from the sun
- Energy (such as thermal infrared) can be detected day or night, the amount
of energy has to be large enough for it to be recorded
Active Remote Sensing - correct answer ✔- Active sensors provide their own
energy source for illumination
- A sensor emits a form of radiation that is directed towards a target
in a particular area
- The radiation that is reflected back from the target is then detected and
measured by the sensor
- There are three types of active remote sensing 1. LiDAR
2. RADAR
3. SONAR
Advantages and Disadvantages of Active Remote Sensing - correct answer
✔Pros:
- Weather independent (in the case of RADAR)
- Sunlight independent
- Active forms of remote sensing can penetrate vegetation and soil: can gain
information about surface layers from mm to m depth
- Wide variety of applications
, Cons:
- Power of pulse is low so it can be influenced or interfered by other sources
of radiation
- Limited spectral information
- Complicated analysis, cost-intensive
Wide variety of applications
Three Types of Active Remote Sensing - correct answer ✔RADAR - uses
high frequency radio / microwaves to detect the speed, direction, distance and
speed of motor vehicles
2. LiDAR - uses a light waves to measure the distance to an object
3. SONAR - uses sound waves propagated to navigate, communicate and
detect objects under the water surface
RADAR - correct answer ✔RADAR = Radio Detection and Ranging
- RADAR technology emerged during World War II as a way of detecting the
presence of ships and aircraft
- At this time the military considered information obtained about weather as
noise
- Since World War II there have been many advances in technology and it is
now also used in space
RADAR is a distance measurement - correct answer ✔- RADAR uses the
microwave portion of the electromagnetic spectrum
- RADAR creates an electromagnetic wave that is focused by an antenna and
then transmitted into the atmosphere
- The transmitted electromagnetic waves are then scattered by various objects
in the atmosphere or from the ground
