Noise Radar allows active surveillance with a provable level of protection from interception and exploitation. The non-deterministic nature of the waveforms protects the signals from any clever schemes to intercept or exploit the radar or to perform intelligent jamming against it. It is therefore possible to plan accurately the extent to which expeditionary forces can obtain autonomous situational awareness without suffering from interception or intelligent jamming.
Noise radar can also be used for improving the spectral efficiency of radars by allowing multiple radars to share the same spectrum, in a method analogous to the Code-Division Multiple Access (CDMA) techniques used in communication systems, offering new approaches to spectrum sharing.
The work of SET 225, building on the work of the previous groups, SET-101, “Noise Radar Technology” and SET-184, ”Capabilities of Noise Radar,” has demonstrated that it is possible to design a noise radar with equivalent form fit and function to a low-power military radar such as a small marine navigation radar or a battlefield surveillance signal.
The group made these demonstrations by cooperatively building and trialling three radar systems.
Figure 1 shows a Plan Position Indicator (PPI, map) display obtained with one of the demonstrators at the Pendik naval base in Turkey. Land clutter can be seen at short range and several ships and other targets can be seen at ranges of several kilometres.
Figure 1: Noise Radar PPI
Another innovation is that this result was obtained with a waveform which, whilst remaining unpredictable, had been ‘tailored’ to improve the dynamic range of the system. This is believed to be the first practical demonstration of this technique.
The theoretical performance of the radar is comparable to that of a low-power marine radar or a battlefield surveillance radar.
Figure 2 shows a shorter-range PPI obtained during the same trials.
Figure 2: Noise Radar PPI – Short Range
The picture is about 500m across. At very short range, the red square is the edge of the building on which the radar was sited. The land clutter returns outline the shore, except in a few directions where it is hidden by dead ground.
Another demonstrator enabled us to prove that we understood how the power budget of a noise radar is built up. This demonstrator also showed that moving targets could be detected with the expected sensitivity. Figure 3 shows the range-velocity plot obtained with a moving vehicle.
Figure 3: Detection of Moving Targets: (a) Range-Velocity Map; (b) Physical Map
The physical map shows the route of the car and a corner reflector at the end of the track along which the vehicle was travelling. The left-hand display shows ‘clutter’ at short range, the corner reflector at 150m and zero speed and the return from the car. The labels show that the ranges and speeds of the targets are as expected.
The first demonstrator which had been built by the group had shown the practicability of building the demonstrators as cooperative projects within a NATO Research and Technology Group. This demonstrator is shown in figure 4.
Figure 4: First Demonstrator
This figure shows the scanning receiver, using a marine radar antenna, on top of the cabin at the trials site at Wachtberg, Germany. The floodlight transmit antenna can be seen by the side of the cabin, with several members of the group working together to align it for the particular experiment which was being carried out. The collaboration which was achieved between the members of the group, in order to build and test three demonstration radars in four years, was itself one of its major achievements.
As well as showing that the system works as a radar, this first demonstrator was also used as an emitter which could be tested against experimental electronic surveillance receivers to assess whether the detectability of the radar in practice matched what was expected in theory.
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