KVH C100 compass engine for direction or pointing reference

Abstract

To meet the needs of product designers for a reliable, accurate source of direction and pointing information, KVH Industries has introduced a small, versatile heading sensor subsystem called the KVH C100 Compass Engine. Exceptionally accurate and capable of operating under a wide range of conditions, the KVH C100 is also compact and affordable. Typical applications for this versatile new sensor are diverse, including antenna aiming, vehicle navigation systems, oceanographic buoys, current meters, weapon fire control systems, robotics, remotely piloted vehicles, and optic instruments such as laser rangefinders, night vision scopes, and binoculars.

To meet the needs of product designers for a reliable, accurate source of direction and pointing information, KVH Industries has introduced a small, versatile heading sensor subsystem called the KVH C100 Compass Engine. Exceptionally accurate and capable of operating under a wide range of conditions, the KVH C100 is also compact and affordable. Typical applications for this versatile new sensor are diverse, including antenna aiming, vehicle navigation systems, oceanographic buoys, current meters, weapon fire control systems, robotics, remotely piloted vehicles, and optic instruments such as laser rangefinders, night vision scopes and binoculars.

The KVH C100 makes it very easy for the product designer to add the direction determining sensor to a larger system. Operating totally autonomously of the host system, the C100 requires only a power connection to output exceptionally accurate heading data. Simple menu driven software enables custom configuration of a variety of the product's performance parameters and outputs. Proprietary electronic automatic compensation corrects for both hard and soft iron sources of permanent deviation in each individual installation, assuring the C100 heading sensor is accurate not only on the lab bench but, more importantly, after it is installed in the final product.

The physical circuit board of the C100 including both the electronics and the fluxgate sensor element measures only 1.2in.(h) X 1.8in.(w) X 4.5in.(1). The mechanical design of the electronics board permits one-piece mounting for simple installations, as well as a detachable sensor element. This feature is useful for installations which have either size constraints too tight for the connected unit or where large sources of magnetic interference from the host platform make it desirable to mount the sensor coil remotely, away from the other electronics.

The C100's fluxgate sensor is a saturable ring core, free floating in an inert fluid within a cylindrical lexan housing. The lexan housing is surrounded by windings which electrically drive the coil into saturation. Pulses, whose amplitude is proportional to the sensed magnetic field of the earth, are detected by two secondary windings. The secondary windings are at right angles providing data on the x and y components of the earth's magnetic field. The fluxgate sensor takes ten measurements of the earth's magnetic field every second, converts these signals to a DC level, and then sends them to a microprocessor to be evaluated. The C100' s microprocessor uses sophisticated filtering and averaging algorithms to ensure the collected measurements are translated into extremely accurate heading information. The sensing coil is free floating within the lexan housing to ensure measurements are taken of the earth's horizontal magnetic field, a critical consideration in magnetic compass accuracy.

The C100 compass sensor was designed not only to be accurate when sitting stationary in the free field of the laboratory, but more importantly to be accurate after it is installed in the final application. To achieve this goal, every C100 unit features sophisticated automatic compensation enabling it to correct for the unique magnetic disturbances of the host system. This is an important consideration, as identical products may have vastly different magnetic characteristics which must be taken into consideration if a heading sensor subsystem of the final product is expected to be accurate. KVH's proprietary compensation procedure is simple to perform, does not require an external reference such as a compass rose, and takes less than three minutes to complete. Compensation algorithms are stored in nonvolatile memory in the C100's EEPROM. KVH's compensation procedure unequivocally demonstrated its effectiveness when it was used to correct for the significant platform induced errors on US Army M1A1 tanks, and the US Navy's aircraft carriers.

The C100 Compass Engine is built in the USA by KVH Industries, using advanced technology which was the result of ten years of research and development work on fluxgate compasses for sophisticated US military applications. The C100 Compass Engine uses industrial grade components to ensure years of trouble free operation, and is built to military quality standards. KVH Industries is one of the world's leading manufacturers of electronic compass systems. The company's products have been selected to replace conventional card compasses in all the US Navy's new vessels and landing craft. KVH also supplies the compasses used on the US Marine Corps Amphibious and Light Armored Vehicles, and the US Army's Bradley Fighting Vehicles. In addition to military and industrial compasses, the company also markets the Azimuth, Sailcomp and DataScope product lines to the marine industry.

For further information on the C100 and a free colour brochure, contact: KVH Industries, Inc., 110 Enterprise Center, Middletown, RI 02842, USA. Tel: [phone]; Fax: [phone].

UK Distributor: Burmarc Ltd, Unit 12, Beaver Industrial Estate, Liphook, Hants GU30 7EU, UK. Tel: [phone]; Fax: [phone].