RLG SIGMA 40 is based on Ring Laser Gyroscope technology. It is gyroscope based on the principles of interferometry and the Sagnac Effect, which is a relativistic phenomenon in the theory of electromagnetic fields. In this article, we will understand the details about  RLG SIGMA 40, its features, core aim, and the units.

What is RLG Sigma 40

RLG SIGMA 40 is an inertial navigation system which is based on Ring laser gyro technology. This system has state-of-the-art technology which is completely advanced and rugged. This system has been designed by Sagem, especially for Navy applications and it fulfills the most demanding navigation criteria and weapon stabilization requirements.

It provides all the critical navigational data like heading, roll and pitch, angular velocities, position and heave, horizontal/vertical velocities, and accelerations.

It consists an Inertial Navigation Unit (INU), a Control and Display Unit (CDU) and an Installation Support (SDI) enabling quick assembly and disassembly without any alterations/adjustments. This Ring Laser Gyroscope sigma 40 is upgradable and is quite easy to install, maintain and operate.

Features of RLG Sigma 40

 The main features are :

  • It has got high-level performance
  • It has very simple installation requirements
  • It has very convenient operation procedure.
  • It does not requires any preventive maintenance.
  • It consists both Synchro and digital interfaces. There is no need to provide any extra hardware interface.
  • It is IMO approved and military standards certified.
  • It is very reliable and rugged.

What does It Provides?

The core aim of RLG Sigma 40 is :

  • To provide the target navigational data like heading, roll, itch etc in real time.
  • To regularly update the target navigational data like speed and velocity.
  • Interfacing of other navigational inputs from/to other Navigational equipments like EM Log, GPS, DGPS, Radar, Anemometer etc.

Sub-Units of Ring Laser Gyroscope Sigma 40

The RLG Sigma 40 system contains four basic sub-units. They are as follows:

Components of Ring Laser Gyro Sigma 40
Components of Ring Laser Gyro Sigma 40
  1. INU (Inertial Navigation Unit)
  2. CDU (Control and Display Unit)
  3. DDU (Data Distribution Unit)
  4. UPS (Uninterrupted Power Supply)

Basic Units of Inertial Navigation Unit in RLG Sigma 40

The Inertial Navigation Unit of basic unit consists of the following sub-units:

  • Inertial Sensor Block (referred as BSI)
  • Basic Synchro Module
  • EB Module
  • UTR-SP Module
  • Interface module (or RS 422 Module)
  • Power Supply Unit
  • HT/ THT Module
Composition of Inertial Navigation Unit
Composition of Inertial Navigation Unit

Sensors in Inertial Sensor Block (BSI) of INU

The Inertial Sensor Block (BSI) consists of the three core sensors which are :

  1. Laser Gyros (Model GL S32) 03 in numbers : It senses Angle of Rotation and Speed of Rotation.
  2. Accelerometers (Model A-600)   : It senses the acceleration.
  3. EACC : It consists the circuitry for controlling the Pendulum of Accelerometer using servo elements. In addition to that, It also contains the EEPROMs which stores the sensor’s calibration data.

Way Ahead for RLG Sigma 40

The Sigma 40 navigation systems are advanced maritime tools centered around a ring laser gyro (RLG) inertial core, ensuring sustained high precision and operational adaptability. These systems are not only compact and user-friendly but also offer scalable hardware and software, allowing for expansion and evolution.

In addition to providing accurate navigation, they play a vital role in enhancing the ship’s sensor capabilities and self-defense systems. The integration of a sophisticated RLG inertial core, coupled with a focus on flexibility and performance, makes these navigation systems well-suited for a variety of maritime applications.

RLG Sigma 40 inertial navigation systems are currently integrated into the combat systems of more than 500 warships. This includes cutting-edge vessels like the Charles-de-Gaulle aircraft carrier, Europe’s advanced Fremm and Horizon frigates, and helicopter carriers. Beyond these, Sigma units are also under use in Norway’s ocean-going patrol boats and find application in various attack submarines globally. Notable examples include the ULA submarines in Norway, Collins in Australia, and the Scorpène and Barracuda submarines in France.

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