Optical Inertial Reference Unit

Optical Inertial Reference Units Overview 

Optical Inertial Reference Units (OIRUs) are at the heart of modern Acquisition, Tracking and Pointing (ATP) systems, and ATA has over 30 years experience solving the most challenging ATP problems through hardware and controls innovations. ATA develops and implements enabling component and system technology for both air and space programs such as the Airborne Laser, the Wide-Band Angular Vibration Experiment, Geostationary Operational Environmental Satellites, Advanced Land Observing Satellite, and the Mars Laser Communications Demonstration. ATA’s unique combination of practical experience and patented component technologies has enabled us to build custom, high-performing OIRUs for our customers.  For information on our recent success click here.

   Optical Inertial Reference Units

OIRU Features 

In general, ATA's OIRUs provide an inertially stabilized collimated optical beam with extremely low residual jitter when subject to typical ground, sea, air or space vibration environments. ATA OIRU custom products have advanced inertial sensors with low cross-axis and linear vibration sensitivity. 

ATA continues to advance and add additional features to its OIRUs.  Some of the advancements and additional features available include: 

--Space-Qualifiable Design

--Pyramid Sensor Head Allows Sensing in 3-Axis

-- Built-in Redundancy

-- Integrated Electronics

-- Flexible Processing Architecture

-- Optional High Precision Gyros for a Broad
   Bandwidth Solution (DC-1000 Hz)

OIRU Benefits 

One of the immediate applications of this technology is in the context of an optical inertial reference unit for laser communication. In this application, the OIRU provides an optical reference beam (laser) for use as a precisely controlled “virtual star” that enables precise pointing and stabilization of the communication beam to be received at the opposite terminal of the transmit/receive link. ATA also recognizes the versatility of an OIRU and determined additional applications in which a precise, small, and low-cost optical inertial reference unit is an enabling technology. Examples include:

   --Precise pointing and stabilization of large aperture passive and active imagers

   --Precise autonomous control of position and attitude control of spacecraft

   --Acquisition, tracking, and pointing of laser systems for target blinding and/or destruction

   --Target designation and geo-location systems operating from aircraft, high altitude airships, 
 helicopters, and UAVs

  OIRU-100 OIRU-500 OIRU-1000
  Product Datasheet Product Datasheet Product Datasheet
Jitter Performance
(1-1000 Hz)

100 nrad

  500 nrad

2 µrad

IAK Performance

1.2 mrad at 20 minutes

2.2 mrad at 20 minutes

6 mrad at 20 minutes

Mechanism Size

9.5” dia. x 5.5” high

 7” dia. x 5” high

3.1” dia. x 3.5” high

Mechanism Mass

18 lbs.

10 lbs.

3 lbs.

Electronics Mass

2 lbs.

2 lbs.

2 lbs.


45 W

30 W

18 W


(3) Emcore 1.3 k

 (3) KVH DSP-1750D

(1) 2-Axis NG G2000 DTG


(3) ARS-16

(3) ARS-16

(3) ARS-15


2 radians/s2

 2 radians/s2 10 radians/s2
(Open-Loop Crossover)
>100 Hz >100 Hz >150 Hz

Position Resolution

<1 µrad

<1 µrad

<1 µrad

Controller Type

Digital (FPGA)

 Digital (FPGA)

Digital (FPGA)