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Radar

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Pankaj Jagadale

RADAR is a system that uses radio waves to detect distant objects by transmitting pulses and measuring their reflection. It can determine a target's range, direction, speed and size. RADAR signals are processed to measure distance using transit time or frequency modulation. Speed is measured using changes in distance over time or the Doppler effect. Signal processing reduces interference like clutter using techniques like MTI and pulse Doppler.

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PRESENTED BY:PRESENTED BY: Pankaj jagdalePankaj jagdale
WHAT IS RADAR?WHAT IS RADAR? RADAR (Radio Detection And Ranging) is aRADAR (Radio Detection And Ranging) is a way to detect and study far off targets byway to detect and study far off targets by transmitting a radio pulse in the direction oftransmitting a radio pulse in the direction of the target and observing the reflection of thethe target and observing the reflection of the wave.wave.
Radar observables: Target range Target angles (azimuth & elevation) Target size (radar cross section) Target speed (Doppler) Antenna Transmitted Pulse Target Cross Section Propagation Reflected Pulse (echo)
RADAR SIGNAL PROCESSINGRADAR SIGNAL PROCESSING a) Distance Measurementa) Distance Measurement 1. transit time1. transit time 2. frequency modulation2. frequency modulation b) Speed measurementb) Speed measurement c) Reduction of interference effectsc) Reduction of interference effects d) Plot and track extractiond) Plot and track extraction
DISTANCE MEASUREMENT Transit time: 1.The round trip time for the radar pulse to get to the target and return is measured. 2.The distance is proportional to this time. 3. The distance is one half the product of the round trip time and the speed of the signal.
Radar Range Measurement Transmitted Pulse Reflected Pulse Range Target Target range = c 2 where c = speed of light = round trip time
FREQUENCY MODULATION Another form of distance measuring radar is based on frequency modulation. Frequency comparison between two signals is considerably more accurate, even with older electronics, than timing the signal. By measuring the frequency of the returned signal and comparing that with the original, the difference can be easily measured.
2. Speed measurement Speed is the change in distance to an object with respect to time. Thus the existing system for measuring distance, combined with a memory capacity to see where the target last was, is enough to measure speed. There is another effect that can be used to make almost instant speed measurements known as the Doppler effect.
REDUCTION OF INTERFERENCE EFFECTS: Signal processing is employed in radar systems to reduce the radar interference effects. Signal processing technique include MTI, pulse Doppler, constant false alarm rate and digital terrain model(DTM) are also used in clutter environments.
Doppler effect: The Doppler effect is a frequency shift that results from relative motion between a frequency source and a listener. The Doppler shift is directly proportional to speed between source and listener, frequency of the source, and the speed the wave travels.
RADAR SIGNAL PROCESSOR
The signal processor is that part of the system which separates targets from clutter on the basis of Doppler content and amplitude characteristics. In modern radar sets the conversion of radar signals to digital form is typically accomplished after IF amplification and phase sensitive detection.
Military application Navigational radars Radar altimeters Air traffic control Law enforcement and highway safety
Radar

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Radar

  • 1. PRESENTED BY:PRESENTED BY: Pankaj jagdalePankaj jagdale
  • 2. WHAT IS RADAR?WHAT IS RADAR? RADAR (Radio Detection And Ranging) is aRADAR (Radio Detection And Ranging) is a way to detect and study far off targets byway to detect and study far off targets by transmitting a radio pulse in the direction oftransmitting a radio pulse in the direction of the target and observing the reflection of thethe target and observing the reflection of the wave.wave.
  • 3. Radar observables: Target range Target angles (azimuth & elevation) Target size (radar cross section) Target speed (Doppler) Antenna Transmitted Pulse Target Cross Section Propagation Reflected Pulse (echo)
  • 4. RADAR SIGNAL PROCESSINGRADAR SIGNAL PROCESSING a) Distance Measurementa) Distance Measurement 1. transit time1. transit time 2. frequency modulation2. frequency modulation b) Speed measurementb) Speed measurement c) Reduction of interference effectsc) Reduction of interference effects d) Plot and track extractiond) Plot and track extraction
  • 5. DISTANCE MEASUREMENT Transit time: 1.The round trip time for the radar pulse to get to the target and return is measured. 2.The distance is proportional to this time. 3. The distance is one half the product of the round trip time and the speed of the signal.
  • 6. Radar Range Measurement Transmitted Pulse Reflected Pulse Range Target Target range = c 2 where c = speed of light = round trip time
  • 7. FREQUENCY MODULATION Another form of distance measuring radar is based on frequency modulation. Frequency comparison between two signals is considerably more accurate, even with older electronics, than timing the signal. By measuring the frequency of the returned signal and comparing that with the original, the difference can be easily measured.
  • 8. 2. Speed measurement Speed is the change in distance to an object with respect to time. Thus the existing system for measuring distance, combined with a memory capacity to see where the target last was, is enough to measure speed. There is another effect that can be used to make almost instant speed measurements known as the Doppler effect.
  • 9. REDUCTION OF INTERFERENCE EFFECTS: Signal processing is employed in radar systems to reduce the radar interference effects. Signal processing technique include MTI, pulse Doppler, constant false alarm rate and digital terrain model(DTM) are also used in clutter environments.
  • 10. Doppler effect: The Doppler effect is a frequency shift that results from relative motion between a frequency source and a listener. The Doppler shift is directly proportional to speed between source and listener, frequency of the source, and the speed the wave travels.
  • 12. The signal processor is that part of the system which separates targets from clutter on the basis of Doppler content and amplitude characteristics. In modern radar sets the conversion of radar signals to digital form is typically accomplished after IF amplification and phase sensitive detection.
  • 13. Military application Navigational radars Radar altimeters Air traffic control Law enforcement and highway safety