remote sensing and its applicattion with proper findings

1. BASIC COMPONENTS OF REMOTE SENSING-
SIGNALS, SENSORS AND SENSING SYSTEMS;
ACTIVE AND PASSIVE REMOTE SENSING

2. CONTENTS
Remote sensing – an introduction
Components of remote sensing
Active and passive remote sensing
Applications of remote sensing
Advantages and disadvantages of
remote sensing
References

3. Fig: Remote sensing

4. Remote sensing – an introduction
Technique of collecting information about objects or areas
from a distance without physical contact
Used in diverse fields: geography, geology, ecology, glaciology,
hydrology and oceanography
Provides a means of observing large areas at finer spatial and
temporal frequencies
Its integration with GIS enables: Map-based queries, Statistical
analysis and efficient spatial data management

5. Elements of remote sensing
Source: Lillesand, T.M., Kiefer, R.W., & Chipman, J.W. (2015). Remote Sensing and Image Interpretation, 7th ed., Wiley

6. Components of remote sensing
Remote sensing components is
a major function to perform
geospatial analysis

7. COMPONENTS OF REMOTE SENSING
There are three major segments/components of Remote Sensing:
Platforms
Sensors
Orbits

8. Platforms
The vehicle or carrier for a remote
sensor to collect and record energy
reflected or emitted from a target or
surface
These platforms can be ground-based,
airborne or space-borne based
As the platform height increases the
observational area increases. Thus, the
higher the sensor is mounted; the
larger the synoptic view is obtained
Fig: Platforms
Source : AI generated

9. Platforms
Types
 Ground- borne platform
 Air- borne platform
 Space- borne platform
Fig: Types of remote sensing platforms

10. Platforms

11. Platforms
There are three types of platforms in Remote Sensing-
Ground- borne platform
 Ground borne remote sensors are very
close to the ground
 Used to record detail information
about the Earth’s surface closely
 Height is up to 50 meter from the
Earth surface
Examples of ground-based platform
 Ground vehicle
 Tower
 Air balloon
 Kite, and other
Air- borne platform
A low altitude or high altitude aerial
remote sensing
used to collect very detailed images and
facilities the collection of data over any
portion of Earth’s surface
Height of the airborne platform is above
50 km from earth’s surface
Very expensive platform as compared to a
ground-based platform
Examples of airborne platform:
 Aeroplane, Helicopters
 Drone

12. Space-borne platform
 The space-borne remote sensors are orbiting
spacecraft or space-shuttle on the earth
 Used to collect information on both the earth’s
surface and atmosphere
 It covers large area and gather more information
 Space borne imaging ranges from altitude 250
km to 36000 km
 Examples of Space-borne platform:
 Rocket satellite (height is 250 to 300 km above
from the Earth’s surface)
 Satellites
• low-level satellite (height is 700 to 1500 km)
• high-level satellites (height is 36000 km)
Platforms

13. Sensors
A device that detects and
responds to some type of input
from the physical environment
 The specific input could be light,
heat, motion, moisture, pressure,
or any one of a great number of
other environmental phenomena
Different types of sensors are
used in remote sensing, each with
their own unique characteristics
and capabilities
Fig: Sensors

14. Sensors
There are two types of sensors
available in Remote Sensing:
 Active Sensor
 Passive Sensor
Fig: Types of sensors

15. Sensors
Active Sensor
Provide their own source of energy to
illuminate the objects they observe
Active Sensor is a 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
Fig: Active sensing

16. Sensors
Passive sensor
Rely on external energy sources, like the
sun, to illuminate the target and then
detect the reflected or emitted radiation
Most of the Remote Sensing systems work
in passive mode using solar energy as the
source of EMR
Most passive systems used in remote
sensing applications operate in the visible,
infrared, thermal infrared, and microwave
portions of the electromagnetic spectrum
Fig: Passive remote sensing

17. Orbits
An orbit is a curved path followed
by a satellite as it revolves around
a celestial body like Earth
For remote sensing, satellites are
placed in specific orbits to achieve
particular objectives, such as
global coverage or frequent
imaging of specific areas
Fig: Orbits

18. Orbits
There are three types of satellite Orbits:
 Geostationary orbit
 Sun-synchronous
 Polar orbit
Fig: Types of Orbits

19. Orbits
 Geostationary Orbit
A Geostationary satellite orbit is a very high
altitude (approximately 36,000 km), which
views 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

20. Orbits
 Sun-synchronous Orbit
Geo-synchronous Satellite is placed in the
geosynchronous orbit, and Earth-
centered orbit with an orbital period that
matches Earth’s rotation on its axis
These satellites orbit at an altitude
between 700 to 800 km

21. Orbits
 Polar Orbit
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
Mostly used for Earth-mapping,
observation, capturing the Earth as time
passes from one point

22. Active and Passive Remote Sensing
Fig: Active and Passive Remote Sensing

23. Active and Passive Remote Sensing
Active remote sensing
Performed with the help of
artificial energy sources
Generally done when there is dark
or during the period of night
It has the advantage of obtaining
data any time of day or season
Most of the microwave remote
sensing is done through active
remote sensing
Relatively independent of
atmospheric scatterings
Passive remote sensing
Remote sensing done through naturally
available energy sources like the sun
The sensors can measure the energy of
the sun only during daytime when it is
illuminating the Earth
Depends on natural energy (sunrays)
bounced by the target
Difficult to record a data during night
time
Atmospheric impact is high

24. Environmental
assessment
Water source
management
Farm
condition
assessment
Pest/disease
outbreaks
Soil sensing
Applications of Remote sensing

25. Advantages and Disadvantages of
Remote Sensing
Advantages
Provides data from large areas
Provides data on very remote and
inaccessible regions
Able to obtain imagery of any area
over a continuous period
Relatively inexpensive when
compared to employing a team of
surveyors
Easy and rapid collection of data
Disadvantages
The interpretation of imagery requires a
certain skill level
Needs cross verification with ground
(field) survey data
Data from multiple sources may create
confusion
Objects can be misclassified or confused
Distortions may occur in an image due to
the relative motion of sensor and source

26. Thank you