Quiz 2

• Radar


  Radio Detection and Ranging
• Radar


  • Form of Active microwave remote sensing
  • Produces the microwave energy and gets the back scattered portion of the signal from the target
  • Can detect energy signals through both night and day
• LIDAR


  Light Detection and Ranging
• LIDAR


  • Data can be collected from the ground, air or space
  • Sensor detects reflected pulses of the laser light that is used to illuminate the target
  • Uses Green/infrared light to do scanning and detection since it is highly reflected off vegetation
• Radar and LIDAR


  Both do detection and ranging but the difference is Radar comes for the radio waves and Lidar utilizes the light waves to make detection and ranging
• Active microwave sensors


  Provide their own source of microwave radiation to illuminate the target
• Types of active microwave sensors

  • Imaging (e.g. RADAR)
  • Non-imaging (e.g. altimeters, scatterometers)
• RADAR


  • Transmits a microwave (radio) signal towards the target and detects the backscattered portion of the signal
  • Measures the strength of the backscattered signal to discriminate between different targets
  • Measures the time delay between the transmitted and reflected signals to determine the distance (or range) to the target
• Non-imaging microwave sensors


  • Take measurements in one linear dimension, as opposed to the two-dimensional representation of imaging sensors
  • Radar altimeters transmit short microwave pulses and measure the round trip time delay to targets to determine their distance from the sensor
  • Scatterometers make precise quantitative measurements of the amount of energy backscattered from targets, which can be used to estimate wind speeds based on the sea surface roughness