Daisy 7 and Fox G20 - AHRS KIT

FOX AHRS demo system by Federico Lolli. Open source software demo that integrate data incoming from the DAISY-7 gyroscope, accelerometer and magnetometer using a Kalman filter and provide a stream of orientation/position data on USB gadget port, serial port, UDP socket. The software include a windows based graphic user interface that shown all data in real-time.screenshot.jpg

FOX AHRS is a small size and low weight measurement unit, excellent for control and navigation of (un)manned systems and other equipments.

The FOX AHRS is a GPS aided MEMS based Inertial Measurement Unit (IMU) and static pressure sensor. It delivers unprecedented performance for its size, weight, cost and low complexity in use.

It was designed to be the most versatile IMU and AHRS platform available. Its host of on-board sensors, algorithms, real-time communication via USB device port and Ethernet. The on-board SD card, real-time clock/calendar and motion trigger wake up also make the FOX AHRS an ideal standalone data logger.

A window based AHRS graphic user interface can be used to configure, shows real-time measurements and export data to othet softwares as like as Microsoft Excel, Matlab, etc.


  • 3D Orientation (360°)
  • 3D Position
  • 3D acceleration, 3D rate of turn, 3D magnetic field

On-board sensors

  • Digital triple axis accelerometer magnetometer and gyroscope
  • Digital-output X, Y, and Z-Axis ±2g ±4g ±8g dynamically selectable full-scale acceleration
  • Digital-output X, Y, and Z-Axis angular rate sensors (gyros) on one integrated circuit with a range of 250/500/2000 °/sec
  • Digital-output X, Y, and Z-Axis ±0.88/1.33/1.9/2.5/4.0/4.7/5.6/8.1Ga dynamically selectable full-scale magnetometer
  • Fast and low noise 10hz GPS
  • Digital pressure sensor 0.03hPa (resolution 0.25m) ultra high resolution
  • Fast Mode I2C (400kHz) and serial interface
  • 16 bit data output ADCs provide simultaneous sampling of gyros and acceleration while requiring no external multiplexer
  • 10000 g high shock survivability
  • Enhanced bias and sensitivity temperature stability reduces the need for user calibration
  • RoHS and Green compliant

On-board algorithms

  • IMU and AHRS algorithms provide real-time measurement of orientation relative to the Earth
  • Internal states updated at 256 Hz
  • Selectable kalman filtering algorithms
  • Open source code and algorithms


  • USB
  • ethernet
  • Micro SD card
  • UART

Power options

  • USB
  • LiPo battery
  • External source from 5V

AHRS GUI Software

The AHRS GUI (Graphical User Interface) provides interface to all features and functionality of the FOXAHRS USB. The AHRS GUI is open source and so is intended to serve as a comprehensive template for those using the AHRS to develop their own applications


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  • @Federico

    Try the MS5611, up to 0.1 m resolution  :)

  • Moderator

    Hi Federico,

    good news for your new development A8 dual core is great micro , so i'm working on same platform for next revision of my BRAIN :) We can join force ?

    Visto che siamo tutti italiani ... Spada mi ha parlato molto bene di te' e dei vostri prodotti .

    Un saluto


  • I'm using the barometer and I can get a resolution of 0.5 m.what is the best?

    I am currently using this Kalman filter

    yes probably at the moment the beast solution for compute EKF is the Cortex STM32F4, but I prefer the flexibility of Linux solutions for future use. (wireless Bluetooth webcam )

    migrating to a cotrex A8 2x1Ghz is even possible to process ad example the video from a camera ecc..

  • Hi Roberto, Federico has all support code here (EKF too):

    The Fox Board G20 (400Mhz Atmel AT91SAM9G20 - 256KB FLASH, 64MB RAM, 16GB SD)

    running linux is powerful.  The ARM926EJ-S has built in fixed point DSP support via ARMv5T instruction

    extensions, the primitives can be used to speed up floats, but your 168Mhz Cortex STM32F4

    MultiPilot32 with native floating point DSP is probably faster doing floating point EKF,

    would be interesting to compare.

    FedericoLolli - Overview
    FedericoLolli has 4 repositories available. Follow their code on GitHub.
  • Moderator

    Hi Federico,

    change Barometer is not so good :) What about your EKF ?



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