STL Magnetometers, Digital Magnetometers and Gradiometer Systems

STL Systemtechnik Ludwig specialises in complex and demanding measurement technologies for underwater and land applications, such as magnetometers, digital magnetometers, gradiometer technologies, magnetic field simulators, signature measurement systems and magnetic multi-channel test ranges.

STL’s core competence is the measurement and analysis of magnetic fields, electric fields, and other signature parameters through uncompromising data acquisition tools with powerful numerical methods. STL systems have been delivered to different prestigious navies around the world.

DIGITAL MAGNETOMETERS AND GRADIOMETER SYSTEMS

STL is a digital magnetometer innovator. The new generation of 26Bit digital magnetometers are applicable for land and underwater operation fulfilling the NATO requirement for DC to 3kHz bandwidth.

Advantages of our digital magnetometers include:

• 26Bit digitization close to the fluxgate (integrated concept)
• High linearity, very-low noise, high dynamic-range
• Very-low temperature drift due to internal digital-temperature compensation
• ‘Ideal sensor’ due to digital real time error correction for scaling, offset and orthogonality
• Digital sensor alignment
• Simultaneous vector and total field information
• PCMCIA and Ethernet interfaces for communication and power
• Array capability up to 3,000 channels with ns simultaneous sampling

U212 / 214 SUBMARINE DIGITAL MAGNETOMETERS

STL supplied digital magnetometers as part of its complete magnetic measurement system, including data acquisition and data management, for the German Navy’s new earth magnetic field simulator. Close to 1,000 digital three-axis underwater magnetometers in two layers simultaneously measure the precise magnetic signatures of the new U212 / 214 submarines.

All earth magnetic field intensities around the world and any possible manoeuvre in any operation can be simulated with this ultimately challenging measurement system and its digital magnetometers.

MOBILE SIGNATURE MEASUREMENT SYSTEMS

Mobile signature measurement systems provide precise measurement of all relevant signatures from submarines and ships. STL have produced a second-generation system with 4kHz bandwidth and a 10kHz sample rate.

• Automatic system alignment
• No need for divers during deployment
• Mobile – easy to set up
• No saturation effects
• Simultaneous low and high-frequency acquisition of all sensors
• Real-time visualisation of all data
• DGPS integration

STL’s mobile novel underwater system measures magnetic, electric and other signatures from submarines and ships. Several sensor platforms are connected to an underwater relay station connecting data and power to a distant base station by mixed fibre
optic / copper cable.

Three pairs of UEP carbon electrodes form the analogue sensor front end, followed by ultra low noise isolation preamplifiers, a three axes digital low-noise fluxgate and environmental temperature and pressure sensors

The digital part is based upon a novel high-performance 26-bit analogue-to-digital converter. Consequent digital signal processing provides high bandwidth, compensated for temperature and geometry errors.

High-resolution tilt sensors complement the three magnetic and electric field vector components to achieve precise software alignment of the sensor platform with respect to magnetic north and the earth’s gravity centre. This unique feature makes a
deployment of the entire system very easy, with no need for divers.

Additional sensors are possible to measure acoustic signatures and additional environmental information. The system also includes DGPS, allowing centimetre-precise tracking of the ship.

The system runs under Windows® XP Professional. Data acquisition and analysis software is programmed under Lab View.

MAGNETIC MULTI-CHANNEL LAND TEST RANGES

The objectives of the magnetic multi-channel land test ranges are:

• Measurement and analysis of magnetic stray fields of military machineries covering the range from DC to over 3kHz
• Formulation and analysis of new magnetic treatment and compensation methods
• Analyses of magnetic stability
• Fundamental research for generating small magnetic signatures

STL have successfully realised several magnetic multi-channel land test ranges. Systems with 75-150 channels are the international standard. A complete degaussing range consists of:

• Strictly built with non-magnetic materials
• High resolution digital magnetic measurement system, including data acquisition, data analysis and system control units
• ‘Transportation system’ to move the machinery over the sensor arrangement
• Earth field simulator
• Degaussing unit
• High power current sources

Depending on the customer’s request, STL have the know how to deliver a complete turnkey system. Upgrades of existing system parts are also possible.