31. Some systems may incorporate the input from a gyrocompass to rotate the display and once again display north as " up ". 32. Since magnetic and gyrocompasses show the course to steer, the officer must be able to determine and correct for compass errors. 33. A helmsman relies upon visual references, a magnetic and gyrocompass , and a rudder angle indicator to steer a steady course. 34. Some products continue to be sold under the SG Brown banner; principally gyrocompass and hand-steering units for military vessels. 35. Airspeed and heading can be measured with a fair degree of accuracy using onboard measurements, namely the airspeed indicator and gyrocompass . 36. This was solved with the introduction of a selsyn connected to the aircraft's gyrocompass , whose output modified the scan rotation. 37. By the time these stabilizers were abandoned, gyroscopes had already found their place in ship navigation as gyrocompasses and in control systems. 38. The gyrocompass guided the torpedo to the target, allowing even rear-launched torpedoes to turn around and hit a target in front. 39. Non-magnetic methods of taking bearings, such as with gyrocompass , GPS ) or radio navigation, are not subject to magnetic deviation. 40. In such cases, the ship's gyrocompass sends a disabling signal that closes a solenoid valve to block mercury flow between the tanks.
