Introduction to Radar Signals and Systems

This article is part of a series on Radar Signals and Systems. I intend to cover the following topics in this series.

Basics of Radar

1. Radio wave propagation

2. Continuous wave (CW) Radar : The simplest of all Radars. Provides information about relative velocity thanks to Doppler effect. There are a number of applications where relative velocity is sufficient.

3. Frequency modulated CW (FMCW) Radar: CW radar, but modulated in frequency. Introduces range measurement capability

4. Pulse modulated Radar: Used in high power and long range radars.

5. Pseudo-noise(PN) Radar: Has a correlation receiver

6. Monopulse direction finding: Simple and fast in finding the direction of a radar echo.

7. Fundamental system parameters: Resolution, Accuracy, Duty cycle etc.

Hardware Components of Radar systems

1. Basics of microwave electron tubes: Electron tubes are attractive when it comes to high power. Long range radars require 100 kW to MW of Power. This is difficult with solid state devices. Can measure electron mobility in vacuum.
2. Magnetron oscillator
3. Klystron amplifier
4. Solid-state amplifiers
5. Low-Power Radar chip sets
6. Antennas and phased array techniques

Target detection

1. Noise in Radar receivers
2. Phase noise in oscillators
3. Detection theory
4. Matched filter: Optimum receiver in communications
5. Ambiguity function
6. Pulse compression: Concept to maximise signal to noise ratio
7. Clutter: Background of disturbing or blinding targets.
8. Moving target indication(MTI): Clutter background is very often static.
9. PRF staggering: Pulse Repetition frequency is not static.
10. Constant false-alarm rate(CFAR): CFAR is an algorithm that aims to detect the properties of the detector
11. Target tracking: Can also be seen as a concept to suppress the clutter.
12. RCS(Radar cross-section) fluctuation: Issue for target detection. Fluctuation of radar cross-section occurs typically with large targets.

4. Synthetic aperture Radar(SAR): A very advanced principle in Radar. Working principle: Mount a radar sensor on a moving platform. Record all the data received and process it afterwards as if it’s received by a very large antenna.

Example: Aircrafts, Satellites

5.Radar meteorology (Weather radars)

Polarimetric properties (Rain, Snow, Drizzle) are important

Here is an overview on some related fields

Related fields

1. Electrical Engineering — Electrodynamics, Fourier analysis, Signals and Systems
2. High-Frequency Engineering — Electromagnetic wave propagation, Antenna parameters
3. Communications Engineering-Modulation, Frequency conversion(mixing), Filtering