« Previous Next »

Anti-Circling Unit

Technical Information

Catalogue No: C0243
Category: Gyro
Object Type: Sensor/Transducer
Object Name: Anti-Circling Unit
Part No: ?
Serial No: ??
Manufacturer: Marconi Underwater Systems Ltd
Division: Unknown
Platform(s): Tigerfish Torpedo
Year of Manufacture: 1967
Dimensions: Width (mm): 135
Height (mm): 85
Depth (mm): 195
Weight (g): 2,410
Location: Rack RAA09 [Main Store]

Anti Circling
Serial No ???
G.E.C. 1967


When a submarine launches a Torpedo the sensors in the weapon will seek the target and the weapon may seek over a wide area before locking on. It is important that the sensors do not home in on the launch vehicle so the anti-circling unit was developed to prevent this. An anti-¬circling device acts independently of the main heading reference, to detect 180° turns immediately after launch. Such devices were mechanical, relying on the inertial aspects of a gyroscope to detect the turn. FARL were asked by Gyro Division to investigate alternative means of implementing an anti-circling device. The most promising solution appears to be a monitor system to incorporate the integrity of the main strapdown attitude sensing unit (ASU). The monitor consists of a fourth rate gyro mounted skewed to the three orthogonal rate gyros of the ASU such that the output of the gyros can be compared; and a microprocessor to perform the inverse of the strapdown transformation.
The Mk 24 Tigerfish torpedo was a heavyweight acoustic homing torpedo used by the Royal Navy (RN) for several years and it is likely that this unit was developed for that programme. Marconi Avionics also developed the Attitude/Heading Reference System for both the UK Sting Ray and Spearfish heavyweight Torpedoes.
This item is also marked: "LCON 0347"

Click to enlarge Click to enlarge Click to enlarge