OVERVIEW: The AN/SSQ-101 ADAR (Air Deployed Active Receiver) is an "A-size" command activated, expendable, passive buoy used as the receiver in a multi-static sonobuoy field. 
 
DETAILS:  A multistatic sonar network (MSN) is characterized by one receiver receiving transmissions from more than one transmitter, each placed at different locations.  This provides improved triangulation and increased covertness of the receiving platform, multi-platform operations and  multi-angle observations and can improve target tracking accuracy. 

The AN/SSQ-101 ADAR sonobuoy provides a commandable passive search capability, and functions as the receiver in a multistatic active receiver system. The device uses a pentagon-shaped horizontally oriented pattern of hydrophones to detect and beam form underwater sound waves. The ADAR sonobuoy is designed to receive active search signals (i.e., long-range echo detection of quiet, slow moving targets).

 Once activated, the ADAR sonobuoy receives, beamforms, and transmits real-time acoustic data in the selected frequency band to the monitoring unit. The separately deployed acoustic source will be commanded to "ping," ensonifying the water and any target present, generating an acoustic "return" that is received and transmitted by the ADAR receiver. Aboard the monitoring unit, the data is processed and displayed (visual and aural), providing the operator a means of determining range, bearing, amplitude and possibly Doppler (coherent acoustic sources only) on submarine targets.

The AN/SSQ-101 transmitter can be set to operate in one of 47 UHF channels.  

Specifications:
	
	Operating Life:		4.5-6 hours
	Sonic Frequency:	250-1000 Hz 
	Operating depth(s)	65, 300, 500 feet (19.8, 91.4, 152 meters)

 

NOTES:   

SOURCES: AN/SSQ-101 Sonobuoy. Sonobuoy TechSystems. https://www.yumpu.com/en/document/read/25976991/an-ssq-101-adar-sonobuoy ; References
Rogoway, T. (2021, November 27). Watch a P-3 submarine hunter's sonobuoy dramatically transform once in the water. The Drive. https://www.thedrive.com/the-war-zone/43279/watch-a-p-3-submarine-hunter-launched-sonobuoy-dramatically-transform-once-in-the-water
 