IMU Sensors

 In addition to the GPS output, the Tapestry system can generate high rate Strapdown Inertial Measurement Unit (IMU) data comprised of  Dn (incremental velocity) and Dq (incremental attitude) using our proprietary multi-function I/O card (MFIO). The card will generate the data in one of our predefined binary formats in addition to a complete simulation of the hardware clock and handshaking signals. The supported formats, LSB’s, and electrical interfaces include:

Honeywell HG-1700 (SDLC)

Rockwell Collins GNP-10, GIC-100, IMU-202

Boeing DQS

Litton LN-200 (SDLC)

For the SDLC systems, the full CRC is generated along with the navigation, autopilot, data interleaving, zero bit insertion, etc.  The user may define and configure the following model elements for the system:   

IMU Case-to-BODY axis alignment
Accelerometer Bias, Scale Factor, White and Correlated noise.
Gyro Bias, Scale Factor, White noise and Random walk.

Our PCI multifunction I/O card (MFIO) resides within the computer system expansion bus using high speed dual ported RAM. This interface, combined with a 5-element ring buffer, virtually eliminates timing error between the generated RF and IMU data outputs. The differential data interface is via a DB25 connector on the feature card. 

The six-degree-of-freedom vehicle motion generator included with the Tapestry system, constructs the Dn and Dq data automatically reflecting the simulated dynamics of the host vehicle. This data is synchronized with the GPS RF signal and output to the feature card by the run time executive. A 1-PPS reflecting the epoch timing of the synchronized RF and IMU outputs is provided. The IMU electrical interface can be derived from either and internal or external clock.  

 

Navigation Laboratories Inc. (949) 766-0444, (949) 495-9551, Fax (949) 713-2479