Optical Inertial Reference Units (IRU's)

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Applied Technology Associates, Inc. (ATA) has over 30 years experience solving difficult state-of-the-art acquisition, tracking and pointing (ATP) problems. ATA has developed and implemented technologies such as components and systems that have enabled essential advances in precision ATP for the Airborne Laser Laboratory, the Wide-band Angular Vibration Experiment (WAVE), Geostationary Operational Environmental Satellites (GOES), Advanced Land Observing Satellite (ALOS), and the Mars Laser Communications Demonstration. ATA’s unique experience base and patented component technologies have lead to the development of the best performing family of optical IRUs in the world today.
All IRUs Provide: – Inertial angular rates, ΔVs and ΔΘs – An Optical Reference Beam (ORB) for optical system alignment, pointing and stabilization – Relative angular rates and positions for gimbal/platform control feedback signals – Lowest noise floor of any optical IRU ever produced –Vibration isolation better than 40 dB (1-1000 Hz) and better than 80 dB at 1 Hz – Very low linear acceleration susceptibility	All IRUs Feature: – Mission Specific DC Sensor (Gyro, GPS, etc.) – Flexible host communication interface (Low Voltage Differential System (LVDS), Ethernet, 1394 (b) Firewire, etc.) – ATA’s MHD Angular Rate Sensors – Your Choice of ORB Wavelength and Power – Separate Inertial and Electronics Units for Flexible Mounting

Magneto-hydrodynamic Stable Reference (MSTAR)+Inertial Reference Unit (IRU)=MIRU II
MIRU II is a second generation design that has been subjected to linear and angular base motion disturbances and has proven performance in line with engineering predictions and design goals. To date, three MIRU IIs have been built with one delivered to Massachusetts Institute of Technology/Lincoln Lab (MIT/LL), the second to the ATA vibration test lab, and the third is slated to be installed in the Starfire Optical Range (SOR) at Kirtland AFB.


The aIRU incorporates the stable platform design legacy of MIRU, with a flexible approach for gyro integration, thus providing both LOS stabilization and inertial attitude knowledge (IAK). The designs for aIRU included three variants for airborne and space applications.	The MIRU III is being developed for MIT/LL to provide line of sight stabilization for Mars Laser Communications Demonstration. MIRU III is a direct descendant of MIRU II but comes in at less than half the weight and could be space qualified in 2006 if the MLCD program is funded.
Hybrid Airborne Design - This design features modular gyro integration and Separate electronics unit for integration flexibility. The first Hybrid aIRU is slated for installation on a large telescope used for ATP.
Air-on-Platform Design - This design was developed to be used on optical payloads carried by large aircraft. In this case, the gyros are integrated directly on the stable platform.
Space-on-Platform Design This design was developed to be used on spacecraft with precision inertial attitude knowledge requirements coupled with stringent line of sight stabilization requirements.