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Wednesday, 30 January 2013 18:00

Archangel Receives FAA TSO Approval for its AHR50 Attitude Heading Reference System

Archangel Systems Inc. announced today it has received FAA TSO-C4c & C6e approval to manufacture its AHR50 Attitude Heading Reference System (AHRS).  Despite extreme size and weight budgets of only 2.5” x 2.0” x 1.4” & 75 grams, the AHR50 core software is certified to DO178B Level A—identical to the certification level in our flagship AHR150A (ADAHRS).  According to Dr. Michael Greene, CEO of Archangel Systems, “the AHR50 is the most compact Level A AHRS in the marketplace.” 

The AHR50 can operate as a standalone Inertial Measurement Unit (IMU) providing body and inertial angles & rates with a maximum gyro rate of + 150°/s & an altitude ceiling of 52,000 feet.  When connected to Archangel’s AHR150A-2-A Magnetic Sensing Unit (MSU), the AHR50 becomes a complete AHRS with both attitude & heading output data.  Information on the AHR150A-2-A is available at

 The AHR50 complete package

The AHR50 was designed for two missions.  The first is for embedded applications where the host system provides EMI / EMC & input voltage protection.  With Level A software & DO-160E certifications for remaining categories, the AHR50 is ideal for primary flight system designs.  Second, impending FAA equipment requirements for UAS platforms operating in the domestic airspace will require some level of software certification.  Since both the AHR50 & the AHR150A-2 MSU carry Level A certifications, the combined system meets all possible scenarios. 

All customer data interfaces are via a single RS232 port with input & output data defined in the AHR50 ICD (User must confirm this is latest Rev. prior to use).  The input port has two functions.  First, during setup, commands for in-field magnetic compass calibration, orientation (8 options) & lever arm corrections are defined.  Second, during operation, directional gyro (DG mode) heading select & compass slewing are received through the RS232 port.   In addition, the ICD supports an air data message input.  If received, the AHR50 blending algorithms can achieve FOG-equivalent attitude performance & echo the air data to downstream systems. Software customizations for other sensor inputs can be developed by Archangel.

For further information on Archangel’s products, contact Bill Dillard at (334) 826-8008 x14 or via our website

Archangel Systems, Inc. is a private, closely held Alabama Corporation, headquartered in Auburn, Alabama. Formed in 1992, the company specializes in Inertial Sensing Systems & Solutions for Aerospace, Automotive, & Military applications. Areas of expertise include inertial sensor research, hardware & software development, as well as FAA certification of both hardware & software to any DAL criticality level. For additional information, please visit