Solid State Radar

“Solid State” is the term that has been applied to modern Pulse Compression Radars. Such radars achieve improved range resolution and signal to noise ratio. This means that the radar can provide the range resolution benefit of short pulse transmission at greater ranges. In a traditional Magnetron based radar, short pulse transmission would normally result in insufficient power being returned to the receiver for the target to be detectable at long range. To detect targets at long range, the radar would normally be set to medium or long pulse but this would have the effect of reducing range resolution. Pulse Compression (Solid State) radars will therefore help users to resolve two targets in close range proximity at longer range. Azimuth (Bearing) resolution is unchanged as this is a function of the antenna.

Pulse Compression radars use a longer pulse length with frequency modulation or phase coding to resolve targets with overlapping returns. Using a longer pulse width also enables the radar to be of lower output power and this removes the need for the traditional, magnetron based, high power transmitter. In many traditional radars, particularly those based at remote sites, the reliability of the magnetron was a major reliability issue for users and therefore dual transceiver radar configurations are very common, particularly for remote radar sites (see radar sensors). Pulse Compression (Solid State) radars should therefore require less maintenance and may only need single transceiver configuration but site visits will still be necessary for most remote unmanned sites as other factors such as the antenna turning unit maintenance will still require regular preventative maintenance.

Pros & Cons for VTS

All sensor systems selected for VTS and Coastal Surveillance applications should be subject to a Cost Benefit Analysis and pulse compression radars clearly provide improved performance but also at a higher price. Therefore, it should be considered whether the improved performance will also improve the operational performance of the final system. The key question is whether the improved range resolution and small target detection capability at long range is required for the specific application. Is it important that small targets can be detected at greater range? and is it important to resolve two targets in close proximity to each other on the same bearing to the radar at longer range. Clearly there are applications where this capability is of benefit, such as applications where small vessels are used for illegal activities. If such vessels are fast moving, then earlier detection at greater range provides earlier warning and can increase to available interdiction response time. However, for other applications, potential users should assess whether the additional cost will deliver equivalent benefits.