Radar and waveforms

Citation

(2002), "Radar and waveforms", Aircraft Engineering and Aerospace Technology, Vol. 74 No. 1. https://doi.org/10.1108/aeat.2002.12774aab.003

Radar and waveforms

Keywords: Radar, Waveform

At any given moment, aircraft carrying synthetic aperture radar patrol airspace all over the world. The aircraft equipped with SAR can spot moving objects on the ground at a resolution of less than one square metre, which makes the radar effective for peacekeeping missions around the world. For example, the SAR-equipped aircraft currently patrol the airspace over Bosnia to monitor compliance with the peace agreement.

The Swedish Department of Defence Research Establishment in Stockholm is simulating various Swedish Armed Forces scenarios in order to test ways of creating countermeasures against SAR. The defence research establishment began its tests by simulating a scenario in which the SAR is jammed to prevent it from accurately reading objects on the ground. The establishment carried out a full-scale experiment using convincing dummy targets on the archipelago of southern Sweden. Researchers Per Hyberg and Fredrik Berefelt of the Defence Research Establishment found that large vessels could be totally concealed with the help of a jammer using specially shaped waveforms that had been generated in a software programme called Matlab. The programme is a mathematical modelling and analysis package developed by Comsol of Stockholm. The researchers also wrote a large SAR signal- processing model using Matlab against which they could test different jammer waveforms. The researchers even found another defence use for the technology; to model tactical situations in which objects change as the situation continues. For example, an aircraft might change its performance in midair or might be equipped with different guided missile than the one previously determined by radar. Their models show potential changes that might occur, which helps those in the defence department determine how to respond to each change.

But they have also created a broader application. The models show many different potential situations that occur during battle and researchers, along with others in the Swedish Armed Forces, can determine ways of responding to each of them. For instance, Hyberg and Berefelt created mathematical software models of the potential outcomes that might result when aircraft discover enemy aircraft.

"What happens when one or more fighters encounter one or more enemy planes of types?" Hyberg asked. "If you know beforehand what type of aircraft you're likely to encounter, you will also know what weapons the aircraft carries and – through simulations carried out in advance – how you will need to respond tactically."