Section 3 – Technical Description
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Section 3 – Technical Description
3.1 Introduction
Sonardyne International Limited has applied its comprehensive experience in producing advanced
and dependable marine solutions to the development of the Lodestar Attitude and Heading
Reference System (AHRS) / Inertial Navigation System (INS).
The Lodestar is a solid state AHRS/INS that includes three Ring Laser Gyroscopes (RLGs) and
three linear accelerometers. These inertial-grade components provide raw data to the Sonardyne-
developed gyrocompass algorithm, which uses them to produce a full range of accurate real-time
motion and attitude measurements in all sea states.
Developed originally to provide accurate heading and attitude measurements for Sonardyne’s family
of acoustic positioning systems, Lodestar is equally suited to a variety of other applications where
the accuracy of heading and attitude measurements is of critical importance. Lodestar can operate
either as a stand-alone AHRS or as part of an integrated system.
The Lodestar 500 provides the following as standard:
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Industry standard output telegrams
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Battery backup to maintain uninterrupted operation in the event of brief power failure
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8 GB of internal memory.
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Upgrade capability to a full INS that provides additional outputs of position, velocity,
orientation and angular velocity at high update rates.
•
0.04° (dynamic) to 0.1° secant-latitude.
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0.01° roll and pitch measurement accuracy.
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Fast follow-up speed of >500° per second.
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A settling time of less than five minutes.
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Support for all industry standard telegrams.
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MTBF inertial sensors (RLG and Accelerometer) > 400,000 hours
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Flexible mounting arrangements
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Heave measurement accuracy the greater of 5 cm or 5% of measured heave.
•
Robust heave algorithm.
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Data output through RS232 serial, RS485 serial or Ethernet interfaces.
The Lodestar 500 has undergone independent and exhaustive testing against an industry-
recognised reference and has proved capable of delivering accurate measurements in highly
dynamic marine environments.
Lodestar 500 benefits from Sonardyne’s world-class manufacturing, support and training
organisation, which has a well-established record for providing trusted solutions.
