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.
Review of Radar Science, Technology, Applications, News, Publications, Industry, History, etc.
Friday, February 24, 2017
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.
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