Each transmitter would transmit on stepped frequencies so that receivers could tell where a signal came from. This made it possible to determine the length of the signal path, so that if a signal was picked up at several nodes it was possible to determine the target's location precisely.
One disadvantage: the transmitter and receiver had to be on opposite sides of the target, so it could not be detected until it had entered the defended airspace. To get around that problem and still intercept targets in a timely manner, Swedish planners expected to exploit the system's accuracy - it could locate targets within 1.5 m
- and command-guide a high-speed missile on to the target.
But because the system used range rather than bearing to locate its targets, the antennas did not need to have accurate bearing resolution.
Also, the system's use of UHF, its independence from target RCS [radar cross-section] and the fact that bistatic systems have long pulse times meant that the necessary power was modest....
We've seen many anti-stealth ideas come and go over the years, such as the UK's cell-phone radar concept or the Russian Nagira high-powered radar. But AASR is the first advertised system-level attack on stealth to emerge from a full-up combat radar house.
