Sonardyne Lodetar 500 AHRS

Lodestar is a combined solid state Attitude and Heading Reference System (AHRS), which is upgradable to SPRINT Acoustically Aided Inertial Navigation System [AAINS].


Lodestar is a combined solid state Attitude and Heading Reference System (AHRS), which is upgradable to SPRINT Acoustically Aided Inertial Navigation System [AAINS]. The unit is comprised of three high grade, high reliability, commercially available, Ring Laser Gyros (RLG) and accelerometers. The sensors used are the standard for commercial aviation with a proven 15+ year track record and MTBF of 400,000 hrs+.

Lodestar AHRS supports serial, Ethernet and industry standard telegrams for easier interfacing. In addition, advanced outputs such as acceleration and rotation rates are also available. On-board data storage and backup battery functionality ensures continued operation and no data-loss even if communications or external power is lost .

The instrument is available in a surface housing and a variety of depth ratings from 1000m to 6,000 metre depth ratings. The latest third generation Lodestar is one of the smallest form factor subsea inertial instruments available.

The Lodestar Surface AHRS version is fully MED Wheelmark approved.

Lodestar AHRS has built-in field upgradability to the higher performance SPRINT INS. This feature allows operators to equip their vehicles with a cost effective AHRS whilst ensuring commercial and operational flexibility to upgrade as and when needed in the field. The optional SPRINT upgrade provides a dual algorithm capability, which is unique in the market and allows for dual use from one inertial instrument, e.g. Lodestar AHRS for ROV, SPRINT INS for Survey teams.


  • An ideal replacement for your ship’s gyrocompass
  • Also suitable for subsea vehicle guidance
  • 3 performance levels; 200, 300 and 500
  • Fast settling time so you can get straight to work
  • Upgradeable to SPRINT INS

Technical information



Heading Accuracy (Secant Latitude) 0.1º (Lodestar AHRS)
Settle Time 5 minutes in dynamic conditions (Lodestar AHRS)
Follow Up Speed 900º / second**
Roll and Pitch Accuracy 0.01º
Maximum Acceleration 10.0 g**




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