For some time now, radar sensing has been an indispensable tool for military surveillance and civil remote sensing.
The ability to function day and night, in all weathers and to cover wide areas rapidly shows that radar has found wide applications from short ranges of a few hundred meters to space based operations.
Over the past few years, radar systems have gone through something of a revolution with the advent of high speed, wide dynamic rage A to D converters and corresponding digital processors. This has led to array based antennas, ultra-high range resolution and imaging, advanced adaptive processing for enhanced detection, tracking and target classification.
And radar systems continue to evolve and be extended in new areas such as cognitive sensing and sensing for autonomous applications.
Conventional radar systems comprise a collocated transmitter and receiver, which usually share a common antenna to transmit and receive. A pulsed signal is transmitted and the time taken for the pulse to travel to the object and back allows the range of the object to be determined.
But in a passive radar system, there is no dedicated transmitter. Instead, the receiver uses third-party transmitters in the environment, and measures the time difference of arrival between the signal arriving directly from the transmitter and the signal arriving via reflection from the object. This allows the bistatic range of the object to be determined. In addition to bistatic range, a passive radar will typically also measure the bistatic Doppler shift of the echo and also its direction of arrival.
In the modern battlefield, passive radar systems are thought of as an anti-stealth technology. These systems exploit existing radio emissions, such as FM, TV and cellular telephony signals, trying to detect echoes which would indicate the potential presence of a flying target.
Also, passive radars cannot be detected, allowing for covert operation.
Want to know more? Tonex offers Radar Systems Design and Engineering Training, a 4-day course that covers the design and engineering of modern radar systems including analysis, high level architecture, design of critical components, transmitter/receiver, antenna, verification and validation, operations and maintenance.
Additionally, Tonex offers another 45 courses in Aerospace & Defense Engineering, including:
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