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Radar Fundamentals

Radar Fundamentals. Prof. Bierng-Chearl Ahn Director of Applied Electromagnetics Laboratory College of Electrical and Computer Engineering Chungbuk National University. CONTENTS. 1. What is a Radar? 2. Radar Concept 3. Radar History 4. Radar Classification 5. Radar Design

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Radar Fundamentals

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  1. Radar Fundamentals Prof. Bierng-Chearl Ahn Director of Applied Electromagnetics Laboratory College of Electrical and Computer Engineering Chungbuk National University

  2. CONTENTS 1. What is a Radar? 2. Radar Concept 3. Radar History 4. Radar Classification 5. Radar Design 6. Emerging Radar Technologies 7. Pulse Radar 8. Summary

  3. 1. What is a Radar? • Radar • Radio detection and ranging : objects detection, location and speed measurement • Radar waves : ultrasonic, radio, infrared, laser • Ladar : laser detection and ranging • Sonar : sound detection and ranging • Radar applications • Military : target detection (land vehicle, aircraft, ship, projectiles, personnel), terrain imaging (SAR), tracking and targeting, fire control, land mine detection • Civil : police speed gun, marine navigation, automobile anti-collision, liquid level measurement, industrial speed measurements, motion sensor, meterology(weather radar), remote sensing(earth monitoring, satellite radar), industrial imaging(cancer, concealed weapon, wood)

  4. 2. Radar Concept • Radar Principle

  5. 3. Radar History • Evolution of Radar Technology - 1886 : Heinrich Hertz`s demonstration of radiowave - 1920`s : Aircraft (bomber) detection and early warning - 1930`s : Bi-static CW(continuous wave) radar - 1940`s : Mono-static pulse radar - 1950`s : Pulsed Doppler radar and signal processing concept - 1960`s : Phased array radar - 1970`s : Digital MTI(moving target indicator) and imaging radar - 1980`s : SAR(synthetic aperture radar) and OTH(over-the-horizon) radar - 1990`s : Multifunction radar (Patriot Missile Defense Radar) - 2000`s : Space borne radar(SIR-E/SRTM) SRTM(Shuttle Radar Topography Mission) PESA(passive electronically scanned array): single source per radar AESA(active electronically scanned array): one source per an element

  6. 4. Radar Classification • Radar Classification - Parameters and Functions - Range: short, medium, long range - Frequency: HF, UHF, L, S, C, X, Ku, Millimeter (‘radar bands’) - Function: surveillance, tracking, imaging - Information: 1d, 2d, 3d, 4d, image - Object: aircraft, ship, missile, vehicle, weather - Processing: MTI, pulse, Doppler, LPI, SAR - PRF: low, medium, high LPI(low probability of intercept) <Raytheon APG-27 AESA aircraft radar> <Bosch LPR3 77GHz car radar>

  7. 5. Radar Design • Radar Design Steps Mission Analysis •Environmental limits • Applicable technology & components limits • Radar frequency selection • Antenna selection: mechanical or electrical scanning • Choice of radiowavepolalization • Radar waveform • Type of signal processing : MTI or pulse Doppler MTD • Transmitting power :Tube/MPM (microwave power module) or solid-state Sensor Requirement Sensor Design System Parameters Weight, Volume, Size, Power, Reliability Subsystem/module Parts/ SW design Implementation

  8. 6. Emerging Radar Technologies • Trends in Radar Technology - Ultra-wideband radar - Laser radar, optical signal processing/photonics - Microwave and millimetric radiometry - SDR(software defined radar) - COTS(commercial off-the-shelf) Technologies - Radar networks - Computer modeling and simulation - Performance prediction of radar systems - Computer modeling for design - Scenario/engagement modeling for EW - New applications: landmine and underground objects, concealed weapon, vital signs, breast cancer

  9. 7. Pulse Radar(1) • Structure of a Pulse Radar

  10. 7. Pulse Radar(2) • Example of a Pulse Doppler Radar • Samraksh BumbleBee Radar (Oct. 2008): velocity only, monitoring and classifying human activities, 10m range, USD 100/each, 5.8GHz, 40mW power consumption, for use with USN sensor node (Crossbow’s TelosB Motes), detects sub-centimeter displacement, 300 measurements per second

  11. 7. Pulse Radar(2) • Example of a Pulse Doppler Radar • M/A-COM Short Range Radar Sensor

  12. 7. Pulse Radar(2) • Example of a Pulse Doppler Radar • M/A-COM Short Range Radar Sensor

  13. 7. Pulse Radar(2) • Example of a Pulse Doppler Radar • Siemens VDO Blind Spot Detection Sensor

  14. 7. Pulse Radar(3) • Radar Measurements - Range: measured by time of flight R = cτ/2 - Elevation and azimuth angles: measured by antenna beam pointing direction - Speed (= range rate): measured by Doppler frequency shift fd = 2v/λ= 2vf/c <Shuttle Topography Radar – Tutuila Island of American Samoa and Continental US>

  15. 7. Pulse Radar(4) • Radar Range Equation SNR = 14.38 dB

  16. 7. Pulse Radar(5) • Pulse Repetition Frequency • Spectrum of Transmitted Signal

  17. 7. Pulse Radar(6) • Range Resolution ΔR = cTp/2 = c/(2 x BW) • Angular Resolution Δθ = θ3dB • Minimum Range (Blind Range) • Rmin = cTp/2 • Maximum Unambiguous Range • Rmax = c/(2xPRF) • Pulse Radar Bandwidth • BW = 1/Tp

  18. 7. Pulse Radar(7) • Radar Signal Processing Issues - Space-time adaptive processing - CFAR detection and clutter rejection - MTI/MTD - SAR/ISAR processing, high-resolution radar signal processing - Interferometric techniques - Target classification - Radar data fusion - Polarimetric techniques - Radar waveform design - Fusion with other sensors - Real-time digital signal processing

  19. 7. Pulse Radar(8) • Applications of Pulse Radar - Military radars: search radar, tracking radar, artillery locating radar - Weather radar - Marine navigational radar - Industrial level meter - Aircraft altimeter - Automotive radar - Vital signs radar - Ground penetrating radar - Time domain impulse radar

  20. 8. Summary • Radar Technology - Old and high technology - Constantly evolving - Many diverse applications • Pulse Radar - Most prevalent and versatile - More complicated than CW types - Sophisticated signal processing

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