18. The newton's first law of gravitation
Newton's law of gravitation, statement that any particle of matter in the
universe attracts any other with a force varying directly as the product of
the masses and inversely as the square of the distance between them.
20. Kepler's law just the statements would make you
good then we will go with the derivation you will then
understand the beauty of it.
They are good to analyse the planetary aspects of the motion in the space and
also dealing with the computational motion planning.
22. Orbital parameters
● Ascending and the descending nodes
● Semi major axis
● Right ascension of the ascending
● Argument of perigee
● True anamoly of satellite
● Angle defining the direction of the satellite
23. Type of orbit
● Orientation of the orbital plane
● Distance from earth
24. Parameters defining the satellite orbit
● Right ascension of ascending node
● Inclination angle
● Position of major axis of the orbit
● Shape of elliptical orbit
● Position of the satellite in its orbit
25. Modifying the orbital parameters
● Right ascension of the ascending node
● Inclination angle
● Position of major axis of orbit
● Shape of elliptical orbit
● Position of the satellite in its orbit
42. Satellite : satellite orientation
• Satellite orientation in space is important for continuous solar cell and
• The satellite antenna must also be pointed at the appropriate earth
• Spin stabilization operates on the principle that direction of the spin axis of
a rotating body tends to remain fixed in space.
43. • An example of spin stabilization is the effect of the rotation of
the earth in keeping its axis fixed in space.
• Satellite that has a spin axis parallel to the axis of the earth will
maintain this position since both axes are fixed in space.
• Figure illustrates the use of this principle.
44. • Once the system is in motion, spin stabilization requires virtually no
• A spin-stabilized satellite is usually constructed like a flywheel.
• After reaching its orbit, the radial jets are pulsed to start the satellite
• The satellite spin axis is oriented to the axis of the earth by means of small
• Velocity jets are used to place the satellite in orbit position and provide
46. Satellite : Orbits & Swaths
bits & Swaths
• The path followed by a satellite is referred to as its orbits
• Satellite orbits are matched to the capability and objective of the sensor(s)
• Orbit selection can vary in terms of altitude (their height above the Earth's
surface) and their orientation and rotation relative to the Earth.
• Satellites at very high altitudes (altitudes of approximately 36,000
kilometers ) revolve at speeds that match the rotation of the Earth.
• Weather and communications satellites commonly have these types of
47. • Many remote sensing platforms are designed to follow an orbit
(basically north-south) .
• Allows them to cover most of the Earth's surface over a certain
period of time.
• Many of these satellite orbits are also sun-synchronous such that
they cover each area of the world at a constant local time of day
called local sun time.
• At any given latitude, the position of the sun in the sky as the
satellite passes overhead will be the same within the same season.
• This ensures consistent illumination conditions when acquiring
images in a specific season over successive years, or over a
particular area over a series of days.
48. • Most of the remote sensing satellite platforms today are in near-polar orbits.
• The satellite travels northwards on one side of the Earth and then
toward the southern pole on the second half of its orbit.
• If the orbit is also sun-synchronous, the ascending pass is most likely
on the shadowed side of the Earth while the descending pass is on the
• Sensors recording reflected solar energy only image the surface on a
descending pass, when solar illumination is available.
• Active sensors that provide their own illumination or passive sensors
that record emitted (e.g. thermal) radiation can also image the surface
on ascending passes.
49. • The area imaged on the surface, is referred to as the swath.
• Imaging swaths for space borne sensors generally vary between
tens and hundreds of kilometers wide.
• As the satellite orbits the Earth from pole to pole, its east-west
position wouldn't change if the Earth didn't rotate.
• The satellite's orbit and the rotation of the Earth work together to
allow complete coverage of the Earth's surface, after it has
completed one complete cycle of orbits.
• “Sensor” is preferred because it refers to a broader way of getting
information than a camera(only be seen by the eye).
• Is a device.
• Used to acquire data i.e. to measure the radiation arriving to the satellite
51. TYPES OF SENSOR
● Have 2 types of sensor, they are Passive Sensor and Active Sensor
● Passive sensor
- In remote sensing, many different sensor are used that varying
sensitivities to radiations at different wavelengths in the electromagnetic
52. Passive Sensor:
● Passive sensors detect electromagnetic radiation emitted from an object.
● Record incoming radiation that has been scattered, absorbed and
transmitted from the Earth in transit from its original source, the Sun.
53. ● Some sensor are designed to receive all ‘green’ wavelengths, other that
more targeted toward infrared wavelengths.
● In infrared viewer, is specially made to ‘see’ objects emitting infrared
radiation (even in the dark).
● In general terms, sensor that use external energy sources to “observe” an
object are called “Passive Sensor”.
● Sun is main sources.
54. Types of Passive Sensor:
● Have 5 types of Passive Sensor, they are:-
1) Gamma-ray spectrometer
○ Passive sensor that detects gamma rays.
○ The sources for the radiation is are generally upper-soil layers as well as rock layers.
○ Caused by radioactive decay.
○ Used to explore mineral deposits.
55. Passive Sensor:
2) Aerial cameras
○ Used in aerial photography.
○ Aircraft serve as a platform as well as many low-earth orbiting satellites deploy many aerial
○ Used for topographic mapping.
56. Passive Sensor:
3) Thermal infrared video cameras
○ Equipped to detect radiation in the near-infrared range.
○ Sometimes combined with active sensors, such as radar, to provide additional information.
○ Aircraft as well as satellites can serve as platforms.
57. Passive Sensor:
4) Multispectral scanner
○ Records information in the visible and infrared spectrum.
○ Scans the Earth's surface for various wavelength bands.
○ Satellites act as platforms for such passive sensors.
○ Used for geological purposes.
58. Passive Sensor:
5) Imaging Spectrometer
○ Similar to the multispectral scanner.
○ Scans very narrow wavelength bands of the spectrum.
○ Satellites are used as platforms.
○ Used for determining the mineral composition of the Earth's surface and concentrations of
suspended matter in surface water.
60. Active sensor:
● Sensor that able to direct energy at an object in the form of electromagnetic
● Object is scanned and the sensors detect any radiation reflected back from
● Types of active remote sensing:
○ Active Optical Remote Sensing
○ Active Thermal Remote Sensing
○ Active Microwave Remote Sensing
61. Active Optical Remote Sensing
● Active optical remote sensing involves using a laser
beam upon a remote target to illuminate it, analyzing
the reflected or backscattered radiation in order to
acquire certain properties about the target.
● The velocity, location, temperature and material
composition of a distant target can be determined
using this method.
○ LIDAR( Light Detection and Ranging)
62. Active Optical Remote Sensing
● LIDAR( Light Detection and Ranging)
■ The instrument works by using a transmitter and a receiver.
■ The laser generates pulses which excite the specified target, causing it to absorb
radiation at certain wavelengths.
■ The target then reflects radiation in the form of photons which are detected by the
LIDAR sensors and converted to an electrical signal.
63. Active Thermal Remote Sensing
● Thermal remote sensing deals with information acquired primarily in the
thermal infrared range.
● The majority of the thermal remote sensing is done using passive sensors.
64. Active Microwave Remote Sensing
● Active microwave remote sensing uses sensors that operate in the
microwave region of the electromagnetic spectrum.
○ RADAR (Radio detection and ranging)
65. Active Microwave Remote Sensing
○ The sensor transmits a microwave (radio) signal upon a specified target.
○ The reflected or backscattered radiation from the target is then detected by the active
sensors which measure the round trip time delay to targets allowing the system to calculate
the distance of the target from the sensors.
● A satellite platform is the service module section of a
● Or the vehicles or carriers for remote sensors
types of platform:
● Ground Based Platforms
● Airborne Platforms
● Spaceborne Platforms
67. Ground Based Platform:
● Is the remote sensing platform that position the sensor
at the Earth's surface
● Used for close-range, high-accuracy applications,
such as architectural restoration, crime and accident
scene analysis, landslide and erosion mapping,...
● It is either static (tripod or mast) or dynamic (moving
68. ● These systems are fixed to the Earth
● And the ground-based sensors are often used to record detailed information about the surface
● or measure environmental conditions such as air temperature, wind characteristics, water salinity,
earthquake intensity and such.
-DOE ARM (Atmospheric radiation Program)
-NASA AERONET (Aerosol Robotic
69. Airborne platforms:
● Are primarily stable wing aircraft, although helicopters are occasionally
● Used to collect very detailed images and facilitate the collection of data.
● Up to 50 km from earth.
Examples:NCAR, NOAA, and NASA research aircrafts.
70. Spaceborne platforms:
● Platforms that located about 100 km to 36000 km from earth.
Examples:-rockets, satellites, shuttle
● Types of spaceborne platforms:
■ -Space shuttle: 250-300 km
■ -Space station: 300-400 km
■ -Low-level satellites: 700-1500 km
■ -High-level satellites: about 36000 km
74. Basic concepts
● The hyperspectral data in contiguous 10 nm wide
spectral bands with sufficient resolution can
provide the direct identification of those materials
with diagnostic features.
● Traditional remote sensing uses a few wide
spectral bands (50-300 nm)
○ Less sensitive to subtle spectral changes such as
phenological changes, mineral mixture proportional
changes, vegetation stress, etc.
○ Harder to extract quantitative information
● Typical development stages of imaging spectroscopy
○ The 1st generation of airborne imaging spectrometer system, AIS, 1983,
~10 nm, 128 bands, 0.8 – 2.4 μm.
○ The 2nd generation of airborne imaging spectrometer system, AVIRIS,
1987, 10 nm, 224 bands, 0.4 – 2.5 μm. (CASI).
● Earth Observation System (EOS) and EO-1 mission
○ EO-1 carries three sensors: ALI, Hyperion and AC,
○ Hyperion, space-based imaging system, similar to AVIRIS, 220 bands,
10 nm bandwidth, 30 m pixel size.
○ See sample image for ALI, Hyperion, AC and AVIRIS (Argentina
study site, Fig. 5).
● In the future, Landsat 8 may carry imaging
spectroscopy system similar to Hyperion.
● Hyperspectral remote sensing will be very
useful for assessment of various Earth
system processes, including:
○ Hydrological processes, e.g., water vapor,
○ Biogeochemical processes, e.g., land
○ Atmospheric processes, e.g., aerosols