For Undergraduate Electrical Engineering Students
Tracking radar is a specialized type of radar system designed to follow the movement of a target and continuously provide its position, velocity, and other parameters over time. Unlike surveillance radar that scans a volume of space, tracking radar maintains a focused beam on a specific target.
The primary purpose of tracking radar is to maintain continuous contact with a target and provide accurate, real-time data about its position and motion.
Tracking radar technology evolved significantly during World War II, with early systems using conical scanning techniques. Modern tracking radars employ sophisticated digital signal processing and monopulse techniques for higher accuracy.
Tracking radar operates on the same fundamental principles as other radar systems but with specialized techniques for maintaining target lock.
Where:
The Doppler effect is crucial for tracking moving targets. The frequency shift in the returned signal provides information about the target's radial velocity.
Where:
Tracking radar performance depends on three types of resolution:
Various techniques have been developed for tracking radar systems, each with advantages and limitations.
Monopulse radar simultaneously compares signals received from multiple antenna beams to determine angular error in both azimuth and elevation.
[Diagram: Four overlapping beams with sum and difference patterns]
Monopulse systems use simultaneous lobing to eliminate errors caused by target fluctuations.
In conical scanning, the antenna beam is rotated around the target axis. The amplitude modulation of the returned signal indicates the angular error.
If the target is off-axis, the received signal amplitude varies at the scan frequency. The phase of this modulation indicates the direction of the error.
This technique sequentially switches between different antenna beam positions and compares signal strengths to determine angular errors.
TWS systems perform surveillance while maintaining tracks on multiple targets. They update target positions during each scan cycle.
| Tracking Technique | Accuracy | Complexity | Resistance to Jamming |
|---|---|---|---|
| Monopulse | High | High | High |
| Conical Scan | Medium | Medium | Low |
| Sequential Lobing | Medium | Medium | Medium |
| Track-While-Scan | Low to Medium | High | High |
Different types of tracking radar systems are designed for specific applications and operational requirements.
CW radar transmits continuously and uses the Doppler shift to detect moving targets. It's simple but cannot measure range without modulation.
Pulsed radar transmits short pulses and measures the time delay for range determination. Most tracking radars use pulsed transmission.
Phased array radars use multiple antenna elements with electronically controlled phase shifters to steer beams without physical movement.
Pulse Doppler radar combines pulsed transmission with Doppler processing to provide both range and velocity information with high accuracy.
Tracking filters estimate target position and velocity while reducing measurement noise. Common approaches include:
Tracking radar systems are used in various military, civilian, and scientific applications.
The AEGIS combat system uses sophisticated tracking radar (AN/SPY-1) to simultaneously track hundreds of targets. It employs phased array technology and advanced signal processing to provide comprehensive air and missile defense for naval vessels.
Test your understanding of tracking radar concepts with this quiz.
1. What is the primary advantage of monopulse tracking over conical scan tracking?
2. In the radar range equation, received power is inversely proportional to:
3. Which tracking technique uses electronic phase shifting to steer the beam without mechanical movement?
4. The Doppler frequency shift in radar is proportional to:
5. Which tracking filter is considered optimal for linear systems with Gaussian noise?