HRG and marine applications

Sagem improvements made in the design, the process and the control of the HRG help to reach high performance while keeping the intrinsic simplicity of the Coriolis Vibrating Gyros family. Therefore it allows the HRG to challenge the laser gyros for strapdown inertial navigation. The simplicity derives from many patented innovations which lead to a very compact gyro with a very low number of components. The manufacturing takes advantage of this simplified design and of a new automatic tuning and balancing process which reduces sensitivities to mechanical environment. While using a Whole Angle mode of control which leads to very good scale factors, a new full digital electronics provides gain and phase accuracy at the level needed by the 0.01°/h class of bias performance. The paper explains these choices and presents the results obtained by the Sagem HRG during tests. Thanks to these characteristics, new applications are developed, especially when compactness, low consumption, reliability and maintenance free long term performance are needed as it is the case with Marine Gyrocompass or Marine Attitude and Heading Reference Systems. The architecture of the Sagem marine AHRS BlueNaute™ is presented and many test results are given, including those obtained on marine vessel.