Most people are probably more familiar with radar being used to detect aircraft.
Static walls could detect aircraft up to 30 miles away.
The essence of air defence is to detect hostile aircraft and destroy them.
Passive acoustic sensors can detect aircraft flying low over the sea.
But the system never entered active service, as radar became the principal means of detecting aircraft.
Casually, she added, "And our scouts say they detect aircraft heading this way."
Submarines also carry radar equipment to detect surface ships and aircraft.
The corps was created to provide a system for detecting, tracking and reporting aircraft over Britain.
But we haven't detected surface ships or aircraft at the time of every incident.
The planes would be effective in detecting Iranian aircraft.