OVERVIEW:  The UAA-1 aka "Abbey Hill" is a shipborne ESM suite operating in the 1-18 GHz range. 

DETAILS:  The UAA-1 aka UAA (1) is a follow on to the UA-13.  It was the first British ESM set designed to use Instantaneous Frequency Measurement (IFM) to identify threats, and can do so with an accuracy of 1.5 Mhz.    It also integrated bearing and frequency information by tagging each pulse with the Time of Arrival (ToA), allowing it to rapidly identify frequency agile radars and automatically measure pulse width of the detected pulses.  If a detected signal is on the alarm list, the UAA-1 notifies the operator who can manually analyze the signal. 

Specifications:

	Frequency:	 1-18 GHz 
	Accuracy:		±2 °
			
NOTES:  IOC 1978.  The UAA-1 and UAA-2 were reportedly very effective during the Gulf War. 


SOURCES: Friedman, The Naval Institute Guide to World Naval Weapons Systems 1997-98, pg. 524.
