AHRS & Synthetic Vision Guide
What is AHRS?
An Attitude and Heading Reference System (AHRS) uses a combination of sensors to determine an aircraft's orientation in space. Unlike traditional gyroscopic instruments, AHRS uses solid-state sensors with no moving parts, making it reliable and maintenance-free.
The data from an AHRS enables synthetic vision displays on EFB apps-showing an artificial horizon with pitch and roll information. While not a replacement for certified flight instruments, it provides valuable situational awareness, especially for VFR pilots or as a backup reference.
9-Axis Sensor Explained
3-Axis Accelerometer
Measures: Linear acceleration (X, Y, Z)
Purpose: Detects gravity direction and movement forces
3-Axis Gyroscope
Measures: Angular velocity (roll, pitch, yaw rate)
Purpose: Measures rotation speed around each axis
3-Axis Magnetometer
Measures: Earth's magnetic field (X, Y, Z)
Purpose: Provides magnetic heading reference
The Stratux software uses sensor fusion algorithms to combine data from all 9 axes, compensating for drift and providing stable attitude information. The accelerometer determines 'down', the gyroscope tracks changes, and the magnetometer provides heading.
Mounting & Calibration
- Mount Stratux level on the glareshield, aligned with aircraft longitudinal axis
- Avoid locations near magnetic interference (compasses, speakers, metal structures)
- The device should remain stationary during flight-vibration affects accuracy
- Initial calibration happens automatically when the device detects stable, level conditions
- Some EFB apps allow manual AHRS calibration-useful if mounting isn't perfectly level
AHRS Use Cases
VFR Backup Horizon
Partial Panel Training
Synthetic Vision Display
Flight Data Recording
Stratux AHRS Hardware
| Sensor Model | Generation | Features |
|---|---|---|
| ICM-20948 | Latest (Recommended) | 9-axis, I²C, best drift performance |
| GY-91 | Plug & Play | MPU-9250 + BMP280 combo board, easy setup |
| MPU-9250 | Standard | 9-axis sensor, widely available |
| MPU-9255 | Alternative | 9-axis, good performance |
AHRS Products
Important Limitations
Stratux AHRS is NOT a certified flight instrument and must not be used as the primary attitude reference. It's designed as a situational awareness tool and backup reference only. Always rely on certified instruments for attitude information in IMC conditions. The AHRS may experience drift during aggressive maneuvering or near magnetic interference.
Frequently Asked Questions
Related Technology Guides
Get AHRS-Equipped Stratux
All our Stratux devices include 9-axis AHRS sensors for synthetic vision.
Disclaimer
Stratux is not certified aviation equipment. It does not replace a transponder or relieve the pilot of traffic awareness responsibilities. Use as supplementary situational awareness only. Dross:Aviation assumes no responsibility or liability for the use of Stratux devices, firmware flashing, or hardware modifications. All DIY guides are provided without warranty-use at your own risk.