Aerospace and Electronic Systems Magazine December 2017 - 2

In This Issue - Technically

OTH RADAR PHENOMENOLOGY: SIGNAL INTERPRETATION AND TARGET CHARACTERIZATION AT
HF
The extraction of information from radar echoes is based on a physical model of the interaction between
the radar system and the target, the study of which is often referred to as radar phenomenology. Not only
does this model serve as the basis for echo interpretation, it impacts on the design, siting, operation,
processing and performance of the radar. As radar technology advances and the achievable dynamic
range increases, so must the fidelity of the phenomenological model. In this article we present a number
of examples of model refinements that succeed where standard models fail to capture essential physics
that has an observable impact on the radar returns.

PERFORMANCE PREDICTION FOR DESIGN OF A NETWORK OF SKYWAVE OVER-THE-HORIZON
RADARS
We introduce a methodology to address the challenge of designing a network of skywave over-thehorizon radar (OTHR). The approach can be used to investigate the number of radars in the network, the
location of each radar, and their respective sensitivity as required by the chosen mission objectives. The
approach postulates these parameters and evaluates radar performance based on ionospheric propagation and noise models and a model of the radar detection and tracking sensitivity. We demonstrate the
method with a case study of a three-radar network directed at the eastern region of Australia from OTHR
located in New Zealand, Norfolk Island and New Caledonia. This OTHR network is evaluated for performance for commercial aircraft flights operating between several major Australian cities and Sydney.

SPECTRUM UTILIZATION: SENSE AND ADAPT: OPERATION ON A NONINTERFERENCE AND
NONPROTECTED BASIS
Canada has been investigating the use of High Frequency Surface Wave Radar (HFSWR) for surveillance of the 200 nautical mile Exclusive Economic Zone (EEZ) for more than 20 years. The effort
cumulated in the deployment of two operational radars that provided persistent surveillance of Canada's
East Coast, Grand Banks region. Additional systems were sold internationally, however in 2007 operation of the Canadian systems was terminated and further development halted due to concerns over
the potential for harmful interference with primary spectrum users. In 2010 the unique capability of
HFSWR to provide low cost surveillance of the EEZ resulted in a re-evaluation of the technology and
subsequent development of a 3rd Generation, (3rd Gen) HFSWR system based on the principle of
sense-and-adapt. The objective of this article is to outline the sense-and-adapt capabilities of Canada's
Third-Generation High Frequency Surface Wave Radar (3rd Gen HFSWR). This system is an evolution
of Raytheon's pioneering SWR503 radar.

HIGH-LATITUDE APPLICATION OF THREE-DIMENSIONAL OVER-THE-HORIZON RADAR
Over-the-Horizon Radar (OTHR) operations at high latitude must contend with intense backscatter from
ionospheric plasma irregularities, referred to as auroral clutter. This article describes the backscatter effect and then examines how Three-Dimensional (3D) OTHR techniques, which provide simultaneous
resolution of range, azimuth, and elevation, can mitigate the effect. Experimental results are shown that
illustrate the advantages of applying 3D OTHR techniques at high latitude.

ESTIMATING THE SENSITIVITY AND LINEARITY REQUIREMENTS OF AN OTH RADAR
RECEIVING SYSTEM
This article describes a methodology for the collection of appropriate environmental RF spectrum data
and the use of these data in predicting the performance of an OTHR receive and processing chain. The
method can be extended to examine the requirements of a receiver to meet desired performance criteria.
An example of a data collection and the application of the technique is provided.
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IEEE A&E SYSTEMS MAGAZINE

DECEMBER 2017

Table of Contents for the Digital Edition of Aerospace and Electronic Systems Magazine December 2017