HFSWR different to microwave radars because of their operating frequencies, energy from microwave radars travels in straight lines, and the curvature of the earth limits detection range for surface targets and detection range and altitude for aircraft.
However, by locating the radar on the shoreline and using the HF spectrum, HFSWR’s transmissions couple to the ocean surface and coverage extends over the ‘visible’ horizon, from sea level to the ionosphere. HFSWR also uses separate fixed transmit and receive antennas that are each optimised for their function and located physically apart. Target information is determined by advanced signal processing techniques.
What is the intended role of the radar?
Conventional surveillance is usually associated with assets like aircraft, patrol vessels, microwave radar, and sometimes satellite imagery. Each has optimum performance in a specific role but none can cost-effectively undertake complete surveillance of a large coastal area. Because HFSWR operates continuously in all weather conditions and has a wide area of coverage, it can operate both as a trip-wire or tracker for monitoring and reporting the behaviour and location of targets of interest. Therefore it complements conventional assets providing cueing information, to focus patrol boat or aircraft tasks when further action is required.
What does HFSWR cost?
Life cycle costs for the radar are well below equivalent surveillance assets. Capital outlay is less than that for a corresponding network of microwave radars and because of its extended range, HFSWR is better than a 6 to 1 force multiplier. The radar has a very low demand for manpower and high reliability, so the operating cost is negligible compared to any other assets providing 24/7 surveillance of the same coverage area.
Who are your customers?
HFSWR is based on research by the Australian Defence Science and Technology
Organisation, who have a long history of pioneering advances in HF radar. Daronmont was first engaged to commercialise the technology. As a result, SECAR was built, tested and deployed in northern Australia in late 2000. Based on a series of operational trials and technical evaluations by Australian Defence staff, Daronmont was contracted to supply and install a variant of the first radar for deployment in the Torres Strait. This radar enabled remote and unattended operations and was jointly funded by the Australian Customs (Coastwatch) and Defence departments.
Target size and characteristics impact detection range but are rarely referenced in describing microwave radar performance. For HF radars, the radar cross section is very similar to the physical size of the target. Daronmont chartered a range of vessels of different size and material as targets to verify performance. Detection range for a 10m fibreglass fishing boat was up to 120 km from the radar. Results from larger vessels show that detection range for a 1000 GRT fishing boat is in the order of 300 km and for larger vessels range is greater. Operational data from the Torres Straits shows vessels detected and tracked to 500km. For aircraft targets, trial data against cooperative and non-cooperative targets verifies that HFSWR will detect small aircraft (e.g. light twins) at very low altitudes; at ranges in the order of 165 km. Larger commercial aircraft have been detected and tracked at ranges greater than 500km from the radar. Unlike many other sensors, HFSWR processes surface and air targets simultaneously, is not adversely affected by rain and can operate 24/7.