R&D and Consultancy
WHR is happy to discuss contract research and development, or consultancy work. WHR can offer unprecedented impartiality in reviewing research literature or assessing product descriptions.
Perhaps we can help you with your own product development. WHR has an extensive high-fidelity modelling and simulation capability which enables parametric studies of design options. Much of our modelling capability employs processing algorithms which may be used in actual systems. Our unique blend of expertise in radar systems, radar electronic warfare, computer optimisation, and signal processing enables us to propose vastly superior design solutions than would be possible using conventional techniques.
WHR has recently completed successful projects in the following areas:
- Design of missile seekers: including feasibility studies of the potential of low THz missile seekers, and design studies of K and W-band systems.
- Design of pulse Doppler modes for short-range ground surveillance radar.
- Study into future ground-based, long-range, air surveillance radars.
- Study and review of weapons locating radars.
- WHR is a small to medium (sized) enterprise (SME) with a background in both industry and academia. As such, WHR would form ideal research partners with universities.
- International projects entailing primary research or product development would be subject to the approval of an export licence from the UK authorities.
Much of our R&D experience has been in the field of active radar seekers used in missile guidance. As a consequence, we have built up a considerable suite of high-fidelity modelling/simulation software for such systems. This software permits runs of multiple engagements; each run with variations in the design parameters which enables multiple design options to be tested. The simulation software structure allows parametric reconfiguration of both large system components such as changing the entire seeker type, through to manipulation of individual algorithm parameters. The software is designed to handle multiple entities in the simulation simultaneously and is also capable of modelling many targets, countermeasures as well as detailed surface and volume clutter.
The example video above depicts a simulated engagement of the terminal phase of a radar-guided anti-ship missile. The missile is sea-skimming at 850m/s over a moderate sea. There are three ships within the radar beamwidth, the closest is moving to the left, the furthest is moving away to the right and the middle ship is stationary and is the designated target for the missile. The missile seeker has been modelled to also have an imaging infra-red (IIR) sensor slaved to the radar boresight so that the scene is more easily comprehended. Although the animation of the IIR sensor shows the activity of IIR target extraction and tracking, no pointing information is used for the missile guidance and only the radar provides steering commands in this simulation. Multi-sensor fusion, however, is an active area of WHR research.
Although WHR simulations normally employ intelligent frequency and waveform agility, when waveform and frequency agility are employed, the location of the target in the range-velocity space is not constant. The radar simulation has therefore been conducted at a single 15GHz carrier frequency and has been simplified to use a single pulse repetition frequency. The pulse repetition frequency used is of the low-PRF category and provides an unambiguous detection range out to 10km, but at the expense of the velocity information becoming ambiguous. For the sea-skimming scenario, operating in the low-PRF regime is often desirable to prevent the strong sea clutter returns at close ranges wrapping ambiguously and obscuring weaker targets at the longer ranges. In the velocity domain, there is often then a sufficiently unambiguous velocity space to prevent the sea clutter causing too much disruption of target velocities of interest. Although platform motion compensation (PMC) can be applied in the velocity domain to centre the sea clutter returns around zero velocity, this particular simulation has been run without PMC applied to demonstrate how the tracking algorithms are capable of tracking targets within ambiguities, as well as making the behaviour of the sea clutter easier to observe.
The radar model employs a pulse-level simulation with full pulse-Doppler processing of each coherent processing interval. A non-linear Frequency Modulation is employed on each pulse which is processed using pulse compression to provide a finer range resolution than the transmitted pulse would normally produce. The ship target radar cross section is modelled using a scatterer model approach. The ship RCS has been calculated from a CAD model using an electromagnetic simulation package over the full upper hemisphere of view positions (at over 20,000 positions). The upper hemisphere has then been split into many smaller regions, and in each region, a scattering centre model fitted to allow a representative complex scattering behaviour to be generated quickly. The ship RCS model therefore recreates an appropriate scintillation pattern not only with small changes in angle, but importantly for modelling missile seekers, the RCS scintillation is range dependant.
The ultra-high fidelity sea clutter is modelled using an intelligent scatterer approach which allows the internal clutter motion to remain both spatially and temporally coherent across multiple radar processing intervals. Representative atmospheric attenuation is employed for both targets and clutter alike.
The radar uses an amplitude comparison monopulse seeker, with both azimuth and elevation axes gimballed, with the azimuth component used for guidance and the missile autopilot controlled to produce a constant sea-skimming altitude. Although the target is simulated as being stationary in the animation to provide a worst-case signal-to-clutter scenario for the radar, the proportional navigation guidance is capable of engaging moving craft too. The radar signal processing model simulates automatic gain control, digitisation, pulse compression, background estimation and constant false alarm rate detection, detection clustering and target data extraction, and multi-target tracking.
The videos shows the last 5km of the engagement and in the main radar range-velocity plots, the pulse-Doppler processed data are overlaid with small circles which indicate the detection centroids for each CPI, the triangles represent tracks being initiated, the diamonds indicate existing tracks, and the large circle indicates the location of the ‘key’ track which the missile is engaging. Additional animations show the view through the co-located IIR sensor, a magnified view of the local range-velocity cells around the key target, and an averaged range profile along with the azimuth monopulse boresight error ratio indicating the angular directions to the three targets and clutter returns.