Attitude & Heading Reference System
AHRS-‐II-‐M Datasheet Rev. 1.2
AHRS-‐II-‐M Datasheet Revision 1.2
Inertial Labs, Inc. Address: 39959 Catoctin Ridge Street, Paeonian Springs, VA 20129 U.S.A. Tel: +1 (703) 880-‐4222, Fax: +1 (703) 935-‐8377 Website: www.inertiallabs.com
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AHRS-‐II-‐M Datasheet Rev. 1.2 The Inertial Labs Attitude and Heading Reference System, AHRS-II-M is marine version of enhanced, high-performance strapdown AHRS-II system that determines absolute orientation (Heading, Pitch and Roll), Heave, Sway and Surge for any device on which it is mounted. Orientation is determined with high accuracy for both motionless and dynamic applications. The Inertial Labs AHRS-II-M utilizes 3-axes each of precision accelerometers, magnetometers, gyroscopes and barometric sensors to provide accurate Heave, Sway, Surge, Heading, Pitch and Roll of the device under measure. Integration of gyroscopes’ output provides high frequency, real-time measurement of the device rotation about all three rotational axes. Accelerometers and Fluxgate magnetometer measure absolute Pitch, Roll and magnetic Azimuth at AHRS initial alignment as well as providing ongoing corrections to gyroscopes during operation. KEY FEATURES AND FUNCTIONALITY • State-of-the-art algorithms for different dynamic motions of Vessels & Ships control, Helideck Monitoring Systems, UUV, ROV, AUV, Buoys and Offshore Platforms; • Highly accurate, sensitive, and temperature stable Fluxgate magnetometers (in-house technology) • 0.3 deg Gyro-Stabilized Slaved Magnetic Heading and <0.1 deg Attitude accuracy • 5% or 0.05 meters RMS (whichever is greater) Heave accuracy • 4 deg/hr gyroscopes and 0.05 mg accelerometers Bias in-run stability • Advanced, extendable, embedded Kalman Filter based sensor fusion algorithms • Embedded 2D and 3D magnetic calibration on hard and soft iron • RS-232, RS-422, USB and CAN 2.0 interfaces • Full temperature calibration of all sensing elements • Up to 200Hz data update rate • Environmentally sealed (IP67) • Compact design
One of the key elements to the success of Inertial Labs AHRS-II-M is its use of Inertial Labs 8mm Fluxgate Magnetometers. Inertial Labs Fluxgate Magnetometer has distinct advantages over commonly used magneto-inductive or magneto-resistive magnetometers. In operation over time and temperature fluxgate magnetometers have superior stability and repeatability. In terms of sensitivity, fluxgate magnetometers provide up to two orders of magnitude increased sensitivity. In addition to the performance advantages, unlike the chip-level magnetometer technology, fluxgate magnetometer technology has been depended on for over 70 years to provide an accurate reference to North. It remains the most reliable magnetic sensor technology for determining an object’s heading.
Inertial Labs, Inc. Address: 39959 Catoctin Ridge Street, Paeonian Springs, VA 20129 U.S.A. Tel: +1 (703) 880-‐4222, Fax: +1 (703) 935-‐8377 Website: www.inertiallabs.com
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AHRS-‐II-‐M Datasheet Rev. 1.2 AHRS-II-M Specifications Parameter
Units
Value
Hz sec sec
Euler angles; Quaternion; Heave; Sway; Surge; Accelerations; Angular rates; Magnetic field; Pressure; Delta Theta and Delta Velocity 1 … 200 (user settable) <1 30
Heading Range Angular Resolution Static Accuracy (2) Dynamic Accuracy (3) Noise (at 200 Hz output)
deg deg deg deg RMS deg RMS
0 to 360 0.01 0.25 0.4 0.03
Attitude Range: Pitch, Roll Angular Resolution Static Accuracy Dynamic Accuracy (3) Noise (@100 Hz)
deg deg deg deg RMS deg RMS
±90, ±180 0.01 0.08 0.1 0.02
Heave Measurement range Resolution Accuracy, RMS
meters meters % (meters)
±10 0.01 5% or 0.05 meters (whichever is greater)
Output signals Update rate Start-up time Full Accuracy Data (Warm-up Time)
(1)
Sensors Technology type Measurement range Bandwidth Resolution Bias in-run stability (RMS, Allan Variance) SF accuracy Noise density Non-linearity Axis misalignment
(1) (2) (3)
Accelerometers MEMS ±2 g 50 0.1 mg (at ±2 g range) 50 ug 0.1 % 40 ug√Hz 0.05% 0.15 mrad
Gyroscopes MEMS ±250 deg/sec 50 0.01 deg/sec (at ±250 deg/sec range) 4 deg/hr 0.01 % 0.009 deg/sec√Hz 0.01% 0.15 mrad
Magnetometers Fluxgate ±1.6 Gauss 50 10 nT 0.1 nT 0.02 % 3 uG/√Hz 0.02% 0.15 mrad
Pressure MEMS 300 – 1100 hPa 50 2 Pa 0.8 Pa – 1 Pa/√Hz – –
Environment Operating temperature Storage temperature MTBF
deg C deg C hours
-40 to +70 -50 to +85 55,500
Electrical Supply voltage Power consumption Connector Output Interface Output data format
V DC Watts -
9 to 40 0.6 Binder Series 723 RS-232, RS-422, CAN 2.0 and USB (with external converter) Binary, TSS-1, NMEA 0183 ASCII characters
Mechanical Size Weight
mm gram
120 x 50 x 53 170
including time of initial alignment, it may be decreased on request. in homogeneous magnetic environment, for latitude up to ±65 deg vessel motion
Inertial Labs, Inc. Address: 39959 Catoctin Ridge Street, Paeonian Springs, VA 20129 U.S.A. Tel: +1 (703) 880-‐4222, Fax: +1 (703) 935-‐8377 Website: www.inertiallabs.com
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AHRS-‐II-‐M Datasheet Rev. 1.2 AHRS-II-M available models and part numbers
AHRS-II-M - G250/500/1000/2000 - A2/6 - TMGA - C1 - V1.1/V1.2/V1.3 model
Model AHRS-II-M +
G250 ±250 deg/sec
gyro range
Gyroscopes measurement range G500 G1000 ±500 deg/sec ±1000 deg/sec
acc range
G2000 ±2000 deg/sec
AHRS-II-M mechanical interface drawing
calibration
Accelerometers measurement range A2 A6 ±2 g ±6 g
case
Temperature calibration TMGA YES
interfaces
Aluminum case C1 YES
Interfaces V1.1 RS-232
V1.2 RS-422
V1.3 CAN 2.0
AHRS-II-M electrical interface description
Pin A B C D E F G H J K L M
Signal RS422 – A RS422 – B RS422 – Y RS422 – Z Power Ground RS232 – RX RS232 – TX PPS GPIO Do not connect Do not connect
Notes: 1. All dimensions are in millimeters. 2. All dimensions within this drawing are subject to change without notice. Customers should obtain final drawings before designing any interface hardware.
Connector type: Binder Series 723. Male receptacle, 12 pin, shielded, rear-mounting
Inertial Labs, Inc. Address: 39959 Catoctin Ridge Street, Paeonian Springs, VA 20129 U.S.A. Tel: +1 (703) 880-‐4222, Fax: +1 (703) 935-‐8377 Website: www.inertiallabs.com
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