• Synchro and analog outputs allow replacement of typical Directional Gyro and Vertical Gyro equipment
• AHC-1000A interfaces with Rockwell Collins FDU-70 or FDU-3000 flux detectors
• AHC-1000S interfaces with typical synchro style flux detectors-allowing existing flux detectors to remain
• Available with or without mounting flanges
• Available with Basic Mode only; no air data required
• Solid-state MEMS sensor technology for high reliability
• Rugged digital quartz gyro
• Low-power consumption
• Reduced installation cost
• Reduced weight and size
• High-integrity attitude information
• Automated compass swing
• Automated mount leveling (with or without flanges)
• Advanced EMI/HIRF/Lightning isolation
• Ideal for fixed-wing and helicopter applications

The AHS-1000A/S Attitude Heading Reference System 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-1000A/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 and linear acceleration outputs are provided for enhanced flight control system performance.

The AHS-1000A/S consists of the AHC-1000A/S Attitude Heading Computer, ECU-3000 External Compensation Unit, and an FDU-70 or FDU-3000 for the AHC-1000A or a synchro type flux detector such as the 323A-2G for the AHC-3000S.

The AHC-1000A/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-1000A/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 AHC-1000A/S outputs heading and attitude synchro information and analog data.

The 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-1000A/S. The FDU and the associated AHC-1000A/S circuits generate outputs that indicate the aircraft magnetic heading. This magnetic heading is used to slave the gyro stabilized heading in the AHC-1000A/S.

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-1000A. The FDU-3000 and associated AHC-1000A 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-1000A. 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-1000S. The FDU and the associated AHC-1000S circuits generate three outputs that indicate the aircraft magnetic heading. This magnetic heading is used to slave the gyro stabilized heading in the AHC-1000S.

The FDU, along with its compensation data, provides an accurate heading reference. The compensation data is used to reduce the aircraft 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-1000A/S determines and stores the compensation data as the aircraft is positioned at eight heading steps. If an index correction is required, the AHC-1000A/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-1000A/S is designed to be a bolt-down unit using either mounting flanges or blind screw holes. A precise alignment of the AHC-1000A/S mount surface is required for the AHC-1000A/S to provide accurate attitude information. It can be achieved through the AHC-1000A/S software compensation. With the aircraft level and the AHC-1000A/S switched into the leveling mode, the AHC-1000A/S will compute the values of the pitch and roll offsets between the AHC-1000A/S mounting plane and the aircraft level plane. These offset values will be stored in the ECU-3000. The AHC-1000A/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 aircraft during replacement of the AHC-1000A/S. The AHC-1000A/S provides power and signals to interface with the ECU-3000. In addition to storing the FDU compensation and leveling data, the ECU-3000 provides a means to configure various aspects of the AHS-1000A/S. Configuration options include scale factors for some analog inputs and outputs as well as length of time the AHC-1000A/S will operate on backup power.

Other input sources are primary and backup power sources, strut switch logic, orientation straps, Slave/DG mode select logic, heading slew command logic, SDI straps, and maintenance interfaces.