WRE 327 (GIS and Remote Sensing)
Assignment #2
July 2022 Semester
Q.1 (i) The sun radiates maximum energy at 0.483 μm. Determine the luminosity and flux density
of sun. Given the radius of sun is 6.96 x 108 m.
(ii) A planet is 1.5 x 108 km away from the sun; its albedo is 0.45. What is its emission temperature?
Use the data given in part (i) if necessary.
Q.2 The sun radiates maximum energy at 0.483 μm. Determine the emitted energy at this
wavelength. Reflectance of blue band =0.04. Calculate the emission temperature of the earth. For
sun, find out the ratio of emittance at 0.483 μm to total emittance. Given, sun emits maximum
radiations at 0.483 μm.
Q.3 Imagine a planet near a bright star (which can be assumed as a blackbody). The temperature
of the star is 1000 K. The diameter of the atmospheric particles varies from 15 to 100 μm. Based
on the maximum wavelength of the emitted radiation, what type of atmospheric scattering will
occur? Given that, A = 2898 μm K
Q.4 An object emits temperature 1000 K in an atmosphere. The atmospheric particle diameter
ranges 5 μm - 100 μm. Which type of scattering occurs from the object?
Q.5 What is the range resolution of a real aperture radar if the depression angle is 30° and pulse
length is 0.1 microsecond? What should be the minimum distance between two distinct features
on the surface if they are to be resolved as separate object in the image?
Q.6 What is the range resolution of a real aperture radar if the depression angle is 35° and pulse
length is 0.1 microsecond? What should be the minimum distance between two distinct features
on the surface if they are to be resolved as separate object in the image?
Q.7 A side looking airborne radar (SLAR) is operating at a height of 6km. Given, depression angle
= 30°, pulse length = 10.3 microsecond, wavelength = 1 cm, antenna length = 3 m. Calculate the
range resolution and along track resolution of the SLAR? What should be the minimum distance
between two features on the surface if they are to be resolved as separate object in the image?
Q.8 A side looking airborne radar (SLAR) is operating at a height of 10 km. Given, depression
angle=25˚, pulse length=0.001 microsecond, wavelength=2 cm, antenna length=4m. Calculate the
range resolution and along track resolution of the SLAR. What should be the minimum distance
between two features on the surface if they are to be resolved as separate object in the image?
Q.9 Determine the height of a mountain from the information of radar shadows of that object:
aircraft altitude= 2 km, slant range to far end of shadow = 8 km, slant range length of near end of
shadow = 5.5 km.
Q.10 An aircraft is taking radar image from 1000 m above the ground. Slant range from the plain
to the furthest point of the shadow of an object is 3000 m. Slant range of the shadow is 50 m. What
is the height of the object?
Q.11 A cross-track scanner captures 3500 cells on a single line at 0.03 sec.cell -1. while an along
track scanner moving at a velocity of 300 m/s captures cells of dimension 15 m cell -1. Calculate
dwell time for both scanner.
Q.12 What is azimuthal/along track resolution of a 10 foot Side Looking Airborne Radar (SLAR)
array operating at a frequency of 10 GHz and at a distance 300,000 feet.
Roll wise problem distributions:
Roll 1 to 15: Q.1, Q.3, Q.5, Q.7, Q.9, Q.11, Q12
Roll 16 to 30: Q.2, Q.4, Q.6, Q.8, Q.10, Q.11, Q12