Signature Сontrol & Ocean Physical Field Division

RADAR, INFRA-RED AND LASER SIGNATURE CONTROL

The Krylov Institute has developed methods and tools for radar, infra-red and laser signature control to protect ships and other marine structures and land objects from weapon homing and guidance systems.

In the area of ship radar, infra-red and laser signature control the Krylov Institute offers:

• Manufacturing and testing of ship models in the sonar basin for radar image simulation and the electrodynamic scale range with tank for marine radar modelling;
• Model measurements and calculations of ship radar cross-sections;
• Model measurements and calculations of ships radar images;
• Calculations of ship overall luminance coefficient;
• Determination of laser images and calculations of infra-red ship images;
• Determination of ship electromagnetic field in laser band, calculations of ship overall luminance coefficient as component of ship laser cross-section;
• Determination of ship electromagnetic field in the infra-red band of wavelengths as component of ship infra-red image;
• Development of tools and techniques for ship infra-red signature control;
• Development of design documents for special-purpose test facilities.

The methods and tools for radar, infra-red and laser signature control make it possible to acquire:

– radar and laser cross-section characteristics (RCS and LCS) for ships and other marine structures through physical simulations and calculations taking into consideration sea surface wave, pitch, yawing, polarisation of the radiated and received electromagnetic fields and other conditions;
– heat radiation characteristics of ships and marine structures in infra-red spectrum;
– reflective properties of absorbing ship coatings in radar and visible spectra under various radiation and observation conditions based on limited scope of input experiment data;

and perform:

– physical simulations of the laser field as well as wake field of surface ships and submarines;
– goniophotometer analysis of LCS for surface ship and submarine models and wake fields;
– spectrophotometric analysis of the LCS for paints and other materials used for ships;
– development of physical and mathematical models and computer-based simulations of the sea laser location with complex route "atmosphere-hydrosphere";
– analytical LCS calculations for multi-layer paint structures including backscattering.

Experimental facilities include indoor model test ranges and measurement equipment suites.

The sonar basin for radar image simulation	The electrodynamic scale range with tank for marine radar modelling
This facility serves for acquisition radar characteristics of marine targets (using models of naval and commercial ships, low-flying aircraft and missiles, submarine masts), land targets (tanks, armoured personnel vehicles, etc.), and aircraft, including RCS in wavelength ranges 2.5 to 80 cm, pulse durations 0.05 to 1 μs and grazing angles 0.5 to 70°, and radar images with 20×20m to 1×1m resolution with reference to full-scale conditions.	It is designed for measuring ship model radar signatures with extrapolation to full-scale conditions at wavelengths from 30 cm to 10 m; modelled grazing angles: 0.5 to 7°; modelled sea states 0 to 4; minimum detectable RCS is 10-5 to 10-2 m2; working frequency is 200 GHz.

Laser simulation test facility

Laser image of the model Each cell of the measurement grid shows value of its mean LCS.

Measured bistatic backscattering indicatrix lines for varnish and paint ship coating, where: ß – luminance coefficient, λ – radiated wavelength, Θr – observation angle, Θi – laser angle coincidence angle measured from vertical line.

Radiated wavelength:
for measurements of object laser characteristics: 0.63 μm and 1.15 μm;
for measurements of material reflectivity coefficients: 0.2 to 1.2 μm and 3.5 to 14 μm.
Sensitivity in terms of reflectivity coefficient: -40 to -30 dB.

Infra-red imaging complex for measurement of ship infra-red signatures is used for research studies and practical tasks.

This complex provides capabilities to: – obtain the infra-red (IR) 2D images of ships; – determine radiation temperatures at any point of the ship surface; – estimate the efficiency of the IR radiation control tools to be used; – find of non-typical ship heat radiation sources and their sizes; – obtain statistic characteristics of the ship infra-red images; – set up the data bank of IR images and other heat radiating characteristics of ships.

Spectral ranges of the IR imaging complex are 2 to 5 μm and 8 to14 μm, range of measured temperatures is from -30°C to +1200°C, temperature resolution is 0.08°C. Operation conditions: ambient air temperature is from -20°C to +50°C, relative air humidity is up to 98%.

Based on R&D efforts the Krylov Institute has elaborated:
For radar signatures:

• Guidelines on estimation of the ship radar “visibility”;
• Guidelines on calculation of shadow zones for the ship-borne radars;
• Guidelines on model measurements of the ship RCS;
• Guidelines on full-scale measurements of the ship RCS;
• Guidelines on determining ship radar images;
• Guidelines on calculation of the ship radar electromagnetic fields in the near zone;
• Guidelines on development of tools for ship radar signature control.

For laser signatures:

• Guidelines on calculation of laser signatures of ships and other marine structures;
• Guidelines on measurements of laser signatures of full-scale ships and other marine objects;
• Guidelines on laboratory measurements of laser signatures of the marine objects using physical models;
• Guidelines on designing tools for ship laser signature control.

For infra-red signatures:

• Guidelines on full-scale measurements of the ship IR signature parameters;
• Guidelines on designing ships with reduced IR signatures;
• Guidelines on calculations of the ship IR signatures.

The above-mentioned investigations make it possible to develop and update the rules for design of tools for control of ship radar, infra-red and laser signatures.

with improved ship architecture

with IR signature reduction measures

COHERENT X-BAND, SHORT PULSE RESEARCH INSTRUMENTAL RADAR COMPLEX