This document contains slides from a lecture on electronic countermeasures (ECM) against radar systems. It discusses how ECM techniques like chaff, noise jamming and random pulses can be used to mask targets from radar detection by increasing clutter. It provides details on how chaff works, including its reflectivity properties and how it is dispensed. Examples are given of chaff masking an aircraft and deceiving trackers. The presentation also introduces how electronic counter-countermeasures (ECCM) can be used to counter ECM techniques.
Review of Radar Science, Technology, Applications, News, Publications, Industry, History, etc.
Sunday, March 12, 2017
Friday, March 10, 2017
Lecture 18 from the Radar System Engineering course by Dr. Robert O'Donnell.
This document provides an overview of a lecture on synthetic aperture radar (SAR). It begins with an introduction to SAR, including why it was developed due to limitations of conventional radar for imaging. It then discusses the basics of SAR and how it forms images using signal processing to synthesize a large antenna aperture. The document outlines the rest of the lecture topics which will cover SAR image formation techniques, examples, applications, and a history of the evolution of SAR from its origins in the 1950s to current systems.
Wednesday, March 8, 2017
Lecture 17 from the Radar System Engineering course by Dr. Robert O'Donnell.
This document provides an overview of radar transmitter and receiver systems. It begins with an introduction and block diagram of radar transmitters and receivers. The bulk of the document then focuses on different types of high power tube amplifiers used in radar transmitters, including klystrons, traveling wave tubes, crossed field amplifiers, and magnetrons. It also briefly discusses solid state RF power amplifiers. The document concludes with an outline of topics to be covered, including receivers and waveform generators, other transmitter and receiver subsystems, and radar receiver-transmitter architectures.
Saturday, March 4, 2017
Lecture 16 from the Radar System Engineering course by Dr. Robert O'Donnell.
This document summarizes a lecture on parameter estimation and tracking. It discusses tracking processes like track association, initiation, maintenance through prediction and updating, and termination. Filtering techniques like the Kalman filter are presented as ways to estimate target position and velocity while accounting for noise and maneuvers. Examples of civilian and military target maneuvers are provided to illustrate the challenges of tracking.
Thursday, March 2, 2017
Lecture 15 from the Radar System Engineering course by Dr. Robert O'Donnell.
The document discusses a lecture on parameter estimation and tracking in radar systems. It covers topics like observable estimation including range, angle, Doppler, and amplitude measurement accuracy. It also discusses single target tracking techniques such as amplitude monopulse, phase comparison monopulse, sequential lobing, and conical scanning. The outline indicates it will cover multiple target tracking and provide a summary. Diagrams are included to illustrate concepts like angular tracking error sources and Doppler estimation.
Tuesday, February 28, 2017
Lecture 14 from the Radar System Engineering course by Dr. Robert O'Donnell.
This document provides an overview of a lecture on airborne pulse Doppler radar systems. It discusses different airborne radar missions including fighter/interceptor radars like those used on F-16s and F-35s, as well as airborne early warning radars like AWACS. It covers topics like airborne radar clutter, pulse Doppler modes using different PRFs, and examples of military radars and their specifications. The goal is to explain the considerations and techniques involved in airborne pulse Doppler radar system design and operation.
Sunday, February 26, 2017
Lecture 13 from the Radar System Engineering course by Dr. Robert O'Donnell.
This document discusses Doppler filtering techniques for radar clutter rejection. It begins with an introduction to the problem of rejecting ground, sea, rain, and bird clutter for radar systems. It then covers pulse Doppler processing techniques including the use of burst waveforms and Doppler filter banks. It concludes with a discussion of implementations of Doppler filters and issues with airborne pulse Doppler radars.
Friday, February 24, 2017
Lecture 12 from the Radar System Engineering course by Dr. Robert O'Donnell.
This document contains lecture slides about radar clutter rejection techniques. It discusses the history of moving target indication (MTI) and how digital technology has enabled more advanced processing. MTI uses Doppler filtering to suppress stationary clutter and detect moving targets. Early MTI employed crude subtraction of stored pulses. Modern digital implementations allow complex signal processing over many pulses for improved clutter cancellation.
Wednesday, February 22, 2017
Lecture 11 from the Radar System Engineering course by Dr. Robert O'Donnell.
The document describes a lecture on radar waveforms and pulse compression. It introduces matched filters and how they are implemented by convolving a reflected echo with a time-reversed transmit pulse. This maximizes the signal-to-noise ratio. Pulse compression techniques like linear frequency modulation and phase coding are then discussed, which allow the use of longer pulses that increase energy while maintaining high range resolution. The goal is to reduce the high peak power needs of short pulses for applications like airborne radar.
Sunday, February 19, 2017
Lecture 10 from the Radar System Engineering course by Dr. Robert O'Donnell.
The first part of this lecture discusses radar clutter from unwanted objects like ground, sea, rain, and birds/insects. It provides examples of military radars for which clutter is an issue and outlines factors that affect ground clutter backscatter like terrain type, frequency, and depression angle. Median ground clutter strength values are shown for various terrain types and frequencies.
The second part of the lecture provides details on the attributes of rain clutter such as how it is affected by wavelength and circular polarization. Graphs are presented showing reflectivity of rain and its Doppler spectrum. Bird clutter properties around radar cross-section, velocity, and density are also covered. The document aims to explain the impact of various clutter sources on radar performance.
Saturday, January 21, 2017
Lecture 9 from the Radar System Engineering course by Dr. Robert O'Donnell.
The document is a lecture on radar antennas and discusses various antenna scanning techniques. It begins with an overview of radar systems and the radar equation. It then covers antenna fundamentals and different types of mechanical, electronic and hybrid scanning antennas used in radar systems. The lecture outlines electronic scanning with phased arrays, including linear and planar array beamforming. It discusses controlling the array pattern through element excitation phases and amplitudes. Properties of linear arrays like beamwidth and sidelobes are also covered. The document provides examples of increasing array gain by adding more elements.
Friday, January 20, 2017
Lecture 8 from the Radar System Engineering course by Dr. Robert O'Donnell.
This lecture provides an overview of radar antennas and scanning techniques. It begins with introductions to basic antenna concepts such as near and far field regions, electromagnetic field equations, polarization, and antenna gain. It then discusses reflector antennas, which use mechanical scanning to direct the antenna beam. The document outlines additional topics that will be covered, including phased array antennas, frequency scanning, and hybrid scanning methods. The goal is to provide an introduction to different types of radar antennas and how they are used to direct electromagnetic energy.
Thursday, January 19, 2017
Lecture 7 from the Radar System Engineering course by Dr. Robert O'Donnell.
The first part of this lecture provides an overview of radar cross section (RCS) and
techniques for predicting a target's RCS through both measurement and
theoretical calculation. It begins with definitions of RCS and factors
affecting it. Examples of typical RCS values for different targets are
given. Physical scattering mechanisms and contributors to a target's RCS
are described. Both full-scale and scale model target measurement
techniques are outlined. Theoretical prediction methods including
geometrical optics, physical optics, and diffraction theories are
introduced. Scaling laws for applying results from scale models to
full-scale targets are also covered.
The second part of the lecture discusses various methods for calculating radar cross section (RCS), including the finite difference time domain method, method of moments, geometrical optics, physical optics, geometrical theory of diffraction, and physical theory of diffraction. It provides overviews and comparisons of each method, explaining their approaches and areas of applicability. The document also includes examples of RCS calculations and summaries of key points about specific methods.
Wednesday, January 18, 2017
Lecture 6 from the Radar System Engineering course by Dr. Robert O'Donnell.
This document summarizes a lecture on radar signal detection. It discusses detecting signals in noise, the radar detection problem, basic target detection tests, and how detection performance is affected by factors like signal-to-noise ratio and number of integrated pulses. It outlines concepts like probability of detection, probability of false alarm, and the tradeoff between the two. Integration of multiple pulses can improve performance through coherent or non-coherent integration. Fluctuating targets are also addressed.
Tuesday, January 17, 2017
Lecture 5 from the Radar System Engineering course by Dr. Robert O'Donnell.
This document contains lecture slides about radar signal propagation through the atmosphere. It discusses various propagation effects including reflection from the Earth's surface, atmospheric refraction, multipath interference, and attenuation. It provides equations for calculating propagation losses and phase differences between direct and reflected signals. Examples are given of how propagation affects radar coverage and detection range for a shipborne surveillance radar system.
Monday, January 16, 2017
Sunday, January 15, 2017
Saturday, January 14, 2017
Friday, January 13, 2017
Thursday, January 12, 2017
A course in Radar System Engineering by Dr. Robert O'Donnell.
The course was initially developed in 2000 for engineers and scientists with little radar experience. It covers core topics in radar fundamentals and subsystems over multiple lectures. The course has evolved significantly and now includes additional material on radar applications. It is intended to provide students a broad understanding of radar principles and issues.
The course contents
- Lecture 1. Introduction
- Lecture 2. Review of Electromagnetism.
- Lecture 3. Review of Signals, Systems, and DSP
- Lecture 4.The Radar Equation
- Lecture 5.Propagation through the Atmosphere
- Lecture 6. Detection Signals in Noise
- Lecture 7.Radar Cross Section
- Lecture 8. Antennas I
- Lecture 9. Antennas II
- Lecture 10. Radar Clutter
- Lecture 11.Waveforms and Pulse Compression
- Lecture 12. Clutter Rejection I
- Lecture 13. Clutter Rejection II
- Lecture 14. Airborne Pulse Doppler Radar
- Lecture 15. Parameter Estimation and Tracking I
- Lecture 16. Parameter Estimation and Tracking II
- Lecture 17.
- Lecture 18.
- Lecture 19.
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