InertialReferenceUnits - RAF Instruments

Measurements Made and Methods Used

Measurements Provided: Aircraft position (Latitude, longitude, baro-inertial altitude), N-S, E-W ground speeds, baro-inertial (pressure damped) vertical aircraft speed, and aircraft attitude angles (pitch, roll, true heading/yaw).
Manufacturer or Builder of the Instrument: Honeywell Aerospace

Operational Status:
- requestable, ready for deployment
General Description:
- Strap-down, ring laser gyro micro inertial systems on each aircraft.
- GV: Three units on the aircraft. Data from 2 of the 3 units recorded via ARINC data bus to the standard data files.
- C-130: Two units on the aircraft, both recorded. Later model of the system on the GV; SM=special missions for hand selected components
Measurement Characteristics:Position and ground speed data subject to Shuler Oscillation drift errors until blended with GPS data in post processing. Additionally there are "transport delays" and digital filtering in the IRU computer that are accounted for in post processing to align measurements with other recorded data.

Description of Software, Data Handling, and Data Flow:
- Software Components (data acquisition, display, processing, and analysis):
- Data Processing Chain (from flight to archival): Standard aeros data acquisition and processing via nimbus to archived netCDF data files. "Raw" data from aircraft are blended with GPS data in post processing (nimbus) and transport delays are accounted for. See the StandardDataPath page for more information on data processing.
QA Procedures and Needs: check of final position errors post flight

Lead Contacts

Documentation

Descriptive Publications
Documentation of the Processing Algorithm(s): See the Technical Note on Processing Algorithms at this URL (fix when available)

Internal users: See http://wiki.eol.ucar.edu/rafscience/InertialReferenceUnits (last edited 2012-12-08)