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

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 = dB

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

17. 7. Pulse Radar(6) Range Resolution Angular 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