• Solid-state MEMS sensor technology for high reliability
• Rugged digital quartz gyro (DQG)
• Low power consumption
• Reduced installation cost
• Reduced weight and size
• High-integrity attitude information
• Automated compass swing
• ARINC 429 digital interface capabilities
• Automated mount leveling
• GPS growth capable
• Advanced EMI/HIRF/Lightning isolation
• Ideal for fixed-wing and helicopter applications
• Analog and synchro interface for retrofit applications
• AHC-3000S Interfaces with five wire synchro type flux detectors
• Provides ease of replacement for non Collins gyros and AHRS

The AHS-3000A/S Attitude Heading Reference System is truly the next generation of AHRS that combines an innovative new solid-state sensor technology with leading edge avionics design techniques to take a significant step forward in AHRS technology. The primary function of the AHS-3000A/S is to provide measurements of the aircraft pitch, roll and heading Euler angles for use by the flight deck displays, flight control system, flight management system and other avionics equipment. In addition, high quality body rate, Euler rate and linear acceleration outputs are provided for enhanced flight control system performance.

The AHS-3000A consists of the AHC-3000A Attitude Heading Computer, FDU-3000 Flux Detector Unit and ECU-3000 External Compensation Unit.

The AHS-3000S consists of the AHC-3000S Attitude Heading Computer, ECU-3000 External Compensation Unit and a synchro type flux detector such as the 323A-2G.

The AHC-3000A/S measures angular rates and linear accelerations about the body axes of the aircraft and digitally processes this data to obtain three-axis angle, rate and acceleration information.

The AHC-3000A/S includes a solid-state sensor cluster located near the rear of the unit for maximum stability in a high-dynamic environment. The inertial measurement unit card receives the low-level analog signals from the cluster and converts them into a digital output that provides superior performance to alternative analog demodulation techniques. The output is processed utilizing proprietary Rockwell Collins algorithms to compute pitch, roll and heading Euler angles along with acceleration information. The data is output via four high-speed ARINC 429 devices. The AHC-3000A/S also outputs this data in synchro and analog forms.

The FDU-3000 is a gimbaled two-axis magnetic sensor that detects the horizontal component of the earth's magnetic field. The excitation signal to the FDU-3000 is provided by the AHC-3000A. The FDU-3000 and associated AHC-3000A circuits generate outputs proportional to the sine and cosine of the aircraft magnetic heading angle. Magnetic heading is derived and used to slave the computed heading angle in the AHC-3000A. The FDU-3000 is electrically compatible with the FDU-70( ) with packaging modifications to improve index error adjustment.

The synchro type flux detector unit (FDU) is a gimbaled magnetic sensor that detects the horizontal component on the earth's magnetic field. The excitation signal to the FDU is provided by the AHC-3000S. The FDU and the associated AHC-3000S circuits generate three outputs that indicate the aircraft magnetic heading. This magnetic heading is used to slave the gyro stabilized heading in the AHC-3000S.

The FDU, along with its compensation data, provides an accurate heading reference. The compensation data is used to reduce the hard and soft iron errors and flux detector misalignment. The compensation data is aircraft specific and will be stored in the ECU-3000. When operated in the FDU compensation mode, the AHC-3000A/S determines and stores the compensation data as the aircraft is positioned at eight heading steps. If an index correction is required, the AHC-3000A/S determines and stores the correction during the last step of the compensation procedure while the aircraft is aligned to a known heading.

The AHC-3000A/S is designed to be rack mounted in an MMT-3010 mounting tray. Guide pins are used to maintain mounting accuracy. The mounting tray is designed to allow repeatable high-accuracy installations, better than 0.1 degrees. A precise alignment of the AHC-3000A/S mount surface is required for the AHC-3000A/S to provide accurate attitude information. It can be achieved by shimming the MMT-3010 to the aircraft level surface. Another option is through the AHC-3000A/S automated leveling function. With the aircraft level and the AHC-3000A/S switched into the MMT leveling mode, the AHC-3000A/S will compute the values of the pitch and roll offset between the AHC-3000A/S mounting plane and the aircraft level plane. These offset values will be stored in the ECU-3000. The AHC-3000A/S will then read these offset values during the initialization process and compensate the computed attitude accordingly during normal operation.

The ECU-3000 contains two EEPROM chips and is designed to stay with the MMT-3010 during replacement of the AHC-3000A/S. The AHC-3000A/S provides power and signals to interface with the ECU-3000. In addition to storing the FDU compensation and MMT leveling data, the ECU-3000 provides a means to configure various aspects of the AHS-3000A/S. Configuration options include scale factors for some analog inputs and outputs, source of air data information and length of time the AHC-3000A/S will operate on backup power.

The AHC-3000A/S is capable of receiving input from one of the following air data sources: ARINC  429, Manchester or analog air data. The AHC-3000A/S determines which air data source it is receiving through the data set stored in the ECU-3000 and performs the corresponding air data interface function.

Another ARINC 429 input port is reserved for future GPS data interface that will be used to supplement air data input. Other input sources are primary and backup power sources, strut switch logic, orientation straps, Slaved/DG heading mode select logic, heading slew command logic, SDI straps, and maintenance interfaces.