Gyro Compass type AlphaMidicourse

Gyro Compass For Marine
Gyro Compass For Marine

The AlphaMidiCourse is highly reliable, has an enhanced follow-up performance and several interfacing features to connect to external equipment. The Gyro compass AlphaMidiCourse complies with requirements of IMO A.424(XI), ISO 8728 and is Marine Equipment Directive 96/98/ЕС or Wheelmark approved.

A gyrocompass is a type of non-magnetic compass which is based on a fast-spinning disc and rotation of the Earth to automatically find geographical direction, true north. The AlphaMidiCourse exploits this property and uses earth gravitational attraction and rotation to align the gyroscope spin axis with the meridian, i.e. in the true north direction. The AlphaMidiCourse is designed to meet the needs of the marine market Highly accurate performance derived from the aerospace industry, combined with a ruggedized construction in order to cope with the most severe circumstances at sea.


The AlphaMidiCourse is a reliable, type-approved gyrocompass for merchant vessels. This gyrocompass is easy to install and requires little maintenance since there’s no fluid inside. Alphatron Marine can also supply all peripheral equipment such as repeaters and converters to ensure compatibility with existing installations.

• Small size and versatility.
• Automatic speed error correction.
• Short initial settling time (within 3 hours).
• High reliability.
• High static and dynamic accuracy.

• Easy installation and adjustment.
• Built-in testing facility.
• No compass fluid or extra cooling required.
• No periodic compensation of azimuth drift.
• IMO compliant.

The AlphaMidiCourse provides heading data against the geographical meridian (latitude up to 70°) at vessel speeds up to 50 knots. Roll and pitch angles up to maximum ± 45°.

Main unit

The AlphaMidiCourse is a self-contained precision navigation instrument capable of supplying heading reference information to a wide range of equipment located on board the vessel. To support this wide range of equipment, the AlphaMidiCourse can supply heading information through multiple channels using common transmission formats.
On a typical vessel heading information is used by :
• Autopilot.
• Radars.
• Electronic chart systems.
• Satellite communication systems.
• Satellite television.
• AIS.

AlphaLine Repeater

The AlphaLine Repeater displays range provides a heading repeater connectable to gyro, magnetic and GPS compass showing the ship’s heading information. This advanced compass repeater has an analog moving compass card and fixed line. The LCD information screen displays in 5-inch (horizontal and vertical), 6.5-inch and 8.4-inch digital course trend, alarm and rate of turn.

Next to the heading repeater we have a more advanced heading+ instrument available, that, in addition to the ship’s heading information, shows an extended scale with accurate analog representation in tenths of degrees.

Control unit

The control unit, supplied with the AlphaMidiCourse, provides all the functions and indicators necessary to power up, control and operate the AlphaMidiCourse. The control unit displays all information on an integrated display which can show the following information :
• Heading in degrees from 0.0 to 359.9
• Heading source.
• Latitude from 70S to 70N.
• Speed from 0 to 50 knots.
• Speed source.
• Steering source.
• Rate of Turn.
• Alarms and status information.
• Presence of power readiness for operation.
• Timer.

The control unit is used for connecting the AlphaMidiCourse but also to connect ships’ cabling, like power and data cable to aggregate all relevant data for input and output.


A range of accessoires are available for the AlphaMidiCourse.

Repeater compass

The repeater compass receives and displays the ship’s heading signal transmitted from the master compass.
The case is made of Glass fiber Reinforced Plastic (GRP), thus corrosion free and has a waterproof construction, suitable for open deck installation.

Advanced gyro element

The high precision dynamically tuned gyroscope and gimbal suspension is derived from aerospace technology and is now available to the marine industry.
• Unique technology without annual servicing.
• Very low RPM reduces wear, increasing life time.
• No oil change.
• Quick installation.

Advanced gyro element gyro compass
Advanced gyro element gyro compass

Bridge Alert Management

The optional annunciator unit can be connected to the AlphaMidiCourse to comply to Bridge Alert Management system (BAM). It harmonizes the priority, classification, handling, distribution and presentation of alerts, meaning that the bridge team can devote its full attention to the safe operation of the ship and immediately identify any alert situation requiring action to maintain the safe operation of the ship.


Gyro Compass Insatallation
Gyro Compass Insatallation

Unlike a magnetic compass, it can output without influence of the steel hull, the heading signal to repeaters around the vessel at critical positions. The gyrocompass is typically located below decks as close as possible to the center of roll, pitch and yaw of the ship, minimizing errors caused by the ship’s motion.

Repeaters are located at convenient places throughout the ship, such as at the helm for steering, in after steering for emergency steering, and other places. Bearing repeaters installed on the bridge wing used for taking bearings will likely be equipped with removable bearing and azimuth circles, and telescopic alidades, which allow one to sight a distant object and see its exact gyrocompass bearing.


3107.9134 AlphaMidiCourse (including control unit).
3107.9138 Bearing repeater compass, serial data.
3107.9140 BB repeater holder, bearing bracket, serial data.
3107.9142 BH repeater stand.
3107.9146 Azimuth circle.


3803.0226 AlphaLine Repeater MFS-H grey.
3803.0230 AlphaLine Repeater MFS-V grey.
3803.0242 AlphaLine Repeater MFM grey.
3803.0246 AlphaLine Repeater MFL grey.
3803.0228 AlphaLine Repeater MFS-H black.
3803.0232 AlphaLine Repeater MFS-V black.
3803.0244 AlphaLine Repeater MFM black.
3803.0248 AlphaLine Repeater MFL black.

0 to 50 knots Follow up speed >75°/sec Settling time within 3 hours Settle point accuracy <±0,3° Dynamic accuracy <±0,5°/sec Settle point repeatability <±0,2°/sec Service life 35.000 hours

1x step; 24V DC, 6 steps/° 4x serial data; RS422/485 Serial data transfer rate; IEC61162-1/2 (4800/38400 bps) 24V backup supply Failure/alarm; NO relay/NC relay Power 24V DC, 70W

4 display sizes available Alarm signal loss (audible/visual) Indication; heading, magnetic or true Rate of Turn (ROT) IEC61162-1 serial port interface Input; DDC, ROT, HDT (default), HDG, HDM, THS

3099.0000 Annunciator for response to INS/BAM.
3401.0240 NMEA distribution module Mk2.


Read more : GPS Sensor For MarineInmarsat C VMS


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