Signature Сontrol & Ocean Physical Field Division

MAGNETIC SIGNATURE CONTROL

The Institute performs research aimed at ensuring stealth and protection against magnetometer detection systems above and below the water, development, fabrication and supply of technical means for reduction and monitoring of magnetic signature for the ship and various components of ship-board equipment.

In the field of ship magnetic signature management the Institute offers:

• Fabrication and testing of ship models using magnetic test shed;
• Computations of ship and marine equipment magnetic characteristics;
• Computations of ship magnetic field and modes of deperming with due account of results obtained using magnetic test shed;
• Magnetic model tests of
  -ship equipment and systems including ferromagnetic and low-magnetic hulls, propeller shafts, machinery and equipment, electric devices, automatic control units;
  -mobile instrumentation suits for degaussing and -magnetic control ranges;
  -magnetic field compensation systems;
  -deperming devices.
  

In the field of general-purpose industrial magnetic protection the Institute offers:

• Investigation of magnetic environment in production, laboratory and ship spaces, their certification, development of recommendation and tools for reduction of static and alternating (up to 1000 Hz) magnetic fields affecting magnetic-sensitive instrumentation and personnel;
• Certification measurements of magnetic characteristics of various equipment;
• Deperming of marine equipment components;
• Deperming of automatic control units, electronics and microprocessors;
• Testing and recommendations to enhance performance stability (interference immunity) of instrumentation, equipment and devices under magnetic field effects.

Unique land-based fixed-type magnetic test facility was developed in the Institute for experiments in the field of magnetic protection.

Principal characteristics: – Earth’s magnetic field cancellation within the measurement zone; – latitude simulation up to ± 60 µT for the vertical component and up to 40 µT for the horizontal component of Earth's mаgnetic field; – magnetic model lateral dimensions within 1×1 m; – external field strength for deperming: static field – up to 10 mT, alternating field – up to 4 mT.

Instrumental suite used by the Institute to equip mobile rigs for magnetic signature measurements of naval ships and commercial vessels in any water areas is based on:

• long instrumental array (instrumental girder) for ships of up to 2000 t displacement;
• instrumental seabed stations for ships of over 2000 t displacement.

The suite includes:

• primary instrumental transducers system;
• integrated system for referencing the measured data to the monitored ship coordinate grid;
• computer-aided system for data processing and visualization and enables to measure ship magnetic signature at specified depth.

Various laboratory facilities for determination of magnetic signature of ship-board equipment and ship models and laboratory experiments are used in the Institute.

They include: – primary instrumental transducers positioned with the help of a special traversing system; – computer-aided system for data processing and visualization; – software and enable to: – measure magnetic induction; – measure magnetic moments; – define parameters of magnetic models for designs under study.

Research and development activities of the Institute have enabled to develop the following:
In support of ship design:

• magnetic silencing rules;
• guidelines on magnetic signature calculations;
• guidelines on the design of degaussing systems for ships of various types and classes;
• guidelines on magnetic signature physical modeling and numerical simulation;
• guidelines on magnetic signature extrapolation to various distances;
• guidelines on calculations of magnetic characteristics for conductive and ferromagnetic masses of shipboard equipment;
• guidelines on measuring of magnetic characteristics for shipboard equipment.

In support of ship construction:

• guidelines on the control of magnetic characteristics for equipment to be supplied on board;
• guidelines on ship and marine equipment deperming;
• guidelines on ship degaussing system adjustment and tuning;
• onboard automatic controls for electric currents in degaussing systems, power sources and local electromagnetic compensation loops.

In support of ship trials:

• guidelines on full-scale magnetic signature measurements at stop and underway;
• design documentation for marine deperming and magnetic signature monitoring facilities;
• control instrumentation and equipment for deperming facilities;
• instrumentation for signature monitoring and degaussing system tuning.

One of the most significant Krylov's developments in the field of magnetic signature management, which found wide interest of the customers, is a package of scientific and methodological documentation supporting the new generation of on-board automatic control systems for ship and submarine degaussing systems known as KDS-type systems. These systems have enhanced interference immunity and reliability, ensure automatic cancellation of ship magnetic fields, thus improving ship magnetic silencing. These systems are available in configurations specifically designed for surface ships of various classes (KDS-703) and submarines (KDS-701).

Purpose:
generation of control signals to regulate the currents in degaussing coils and local compensators for reducing ship magnetic field.

The systems support:

• significant reduction of ship magnetic field by its automatic compensation in function of the Earth's magnetic field;
• on-line operation with the navigation systems providing digital inputs on ship location, heading, roll and pitch;
• on-line operation with the Earth's magnetic field sensors;
• high accuracy of compensation current under disturbing factors (error within 2%);
• wide range of ship operating conditions.

The systems employ the following control methods:

• proportional control based on the Earth's magnetic field components in the ship-fixed coordinate system using three-component flux-gate probes of magnetic induction (control "in function of the Earth's field");
• proportional control based on the Earth's magnetic field components in the ship-fixed coordinate system found automatically in function of ship's current heading, roll and pitch, ship's geographical coordinates (latitude & longitude) provided by the ship navigation system (control "in function of indirect parameters");
• control based on manual setting of constant signal component found using measurements of the ship magnetic field at the magnetic test facility;
• combined control method.