The Title of Invention is "Testing Method for Data Acquisition Electronic

Board for Inertial Measurement Unit".

2 Field ofthe Invention

The present Invention generally relates to Industrial applications and military Helicopters
for Automatic Flight Control System and in particular relates to the design and development of
testing methodology for Data Acquisition Electronic Board of Inertial Measurement Unit (IMU) in
Attitude Heading Reference Unit (AHRU).

3 Background ofthe Invention

HRU is a type of inertial system used in aerospace and aviation applications to determine the
orientation and movement of an aircraft, helicopter, spacecraft etc. It works by combining data
from different inertial sensors to calculate the aircrafts attitude (pitch, roll and yaw) and its
heading (direction of travel). IMU is the heart of AHRU which consists of hree axis Fiber Optic
Gyroscope (FOG), single axis Micro-Electro­ Mechanical-System (MEMS) based Accelerometers (3 Nos)
and electronic boards of various types. Multiplexing Electronic Board used to convert nalog
signals into digital data (ADC) conversion from 3 accelerometers hrough flexible printed circuit
board (flex PCB) and 3 channels magnetometer. Data Acquisition Electronic board used to acquire the
data rom fiber optic gyroscope, accelerometers, magnetometers of 3 channels nd communicate the
processing data to the interfacing input output lectronic board.

he present testing methodology for Data Acquisition Electronic Board overing 70% of the components
are tested functionally in the In-circuit ester without assembly in IMU. After assembly in IMU,
during good unctional checks the board is tested 100% and verified the functionality of he board
for three axes fiber optic gyroscope, 3 channel accelerometers and 3 channels magnetometer data acquisition and communication with
inertial sensors. During good functional checks observed communication
and acquisition problem with inenial sensors of accelerometers and fiber
optic gyroscopes. Also observed processed data communication error with
interfacing input output electronic board. The problem is limited test
parameters in the Data Acquisition Electronic Board testing method with
ln-circuit tester before assembly in the inertial measurement unit.
The proposed testing methodology for Data Acquisition Electronic Board
covering 100% of the components to be tested functionally without
assembly in IMU and to prevent the critical failure during data acquisition
and communication with Inertial measurement unit.
3.1 Prior Art
The present testing methodology covering 70% of the components are
tested functionally in the Data Acquisition Electronic Board without
assembly in IMU. During good functional checks of IMU, the Data
Acquisition Electronic Board is tested 100% and verified the functionality
of the board for three axes fiber optic gyroscopes. 3 channel
accelerometers and 3 channels magnetometer‘ Due to this testing
parameter limitation. some components related to data acquisition from
inertial sensors causes failure in good functional checks. During IMU
thermal calibration test observed critical failure in data acquisition
electronic board. Due to this critical failure troubleshooting time increases
for the data acquisition board with ln-circuit tester method. The proposed
testing methodology is covering 100% functional testing of the Data
Acquisition Electronic Boards without assembly in IMU and to prevent the
critical failure during inertial measurement calibration and functional test.
4 Brief Summary of the Invention
The 100% functional testing of the Data Acquisition Electronic Board
before assembly in IMU is the challenging task. The board is not designed by us. Knowing the schematic diagram of the board, the complete
functions of the board was studied. The challenging task is to verify the
data acquisition and communication functionality of the electronic board
without involving the inertial sensors fiber optic gyroscope, accelerometers
and magnetometers.
The Data Acquisition Electronic Board consists of 10 different sections; the
details are power supply, comparator, digital circuits, transceiver circuits,
Oscillators, Microcontroller section. Field programmable gate array
section, memory section, Input and output buffer section and connector
section. The board tested in ln-circuit tester for passive components check
and limited level of functional testing. The proposed testing methodology is
to test the board for all functional tests in the 10 sections and verify the
data acquisition and communication functionality of the gyroscope,
accelerometers and rmgnetometer for 3 channels. The present invention
enables to check the complete functionality of the Data Acquisition
Electronic Board without assembly in the inertial measurement unit.

We Claim,
1. The testing methodology for data acquisition electronic board is
designed and developed for 100% functional testing of the data
acquisition electronic board before assembly in inertial measurement
unit which comprising:
Ten different sections and the details are.Power supply section (21),
Oscillator section (22), Comparative section (23), Transceiver section
(24). Micro controller section (25), Field programmable gate array
section (26), Memory section (27), Input and output buffer section
(28), Digita! circuit section (29),Connector section (30a.30b,30c);
Developing a testing methodology for a data acquisition electronic
board can be challenging due to the complexity of the board and the
need to test multiple inputs and outputs simultaneously;
The proposed testing methodology to test the board for all functional
tests in the ten sections and verify the gyroscope. accelerometer and
magnetometer output for 3 channels before assembly in Inertial
measurement unit; and
The present invention enables to check the complete functionality of the
data acquisition electronic board without assembly in the inertial
measurement unit.
2. The proposed testing methodology as said in claim 1 prevents the
critical failure during thermal calibration test of inertial measurement
unit and functional test of the attitude heading reference unit.
3. The testing methodology for data acquisition electronic board as shown
in figure 3 requires a systematic approach and ensured that the board
meets the desired performance criteria and is reliable in operation.
4. The proposed testing methodology as said in claim 1, 2 and 3 reduces
the troubleshooting time cycles in the inertia| measurement unit as
mentioned in the flow chart of figure 4.
5. It is designed and developed for in-house testing of the data acquisition
5 electronic board before assembly in the inertial measurement unit.