Fiber optic gyroscope mixed signal application specific integrated circuit

• US 9,568,317 B2
• Filed: 01/31/2013
• Issued: 02/14/2017
• Est. Priority Date: 01/31/2013
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Croker, Chuck, Keith, Gregory W, Tarleton, Norman Gerard
• Primary Examiner(s): Chowdhury, Tarifur
• Assistant Examiner(s): NIXON, OMAR H
• Application Number:
  US13/755,139
• Publication Number:
  US 20140211210A1
• Time in Patent Office: 1,475 Days
• Field of Search: 356/326
• US Class Current: 1/1
• CPC Class Codes: G01C 19/662 signal readout; dither compensators
• CPC Class Codes: G01C 19/721 Details
• CPC Class Codes: G06F 30/30 Circuit design

Abstract

A system comprising a fiber optic gyroscope and a mixed signal application specific integrated circuit (ASIC) connected to the gyroscope is provided. The mixed signal ASIC comprises a digital logic unit, a relative intensity noise (RIN) analog-to-digital converter (ADC) coupled to the digital logic unit and configurable to receive a signal from a RIN detector, and a rate ADC coupled to the digital logic unit and configurable to receive a signal from a rate detector. The mixed signal ASIC also includes a light source digital-to-analog converter (DAC) coupled to the digital logic unit, and a thermo-electric cooler DAC coupled to the digital logic unit, both of which are configurable to send control signals to a light source of the gyroscope. The mixed signal ASIC further includes an integrated optical chip DAC, an eigen-frequency servo DAC, and a heater servo DAC, all of which are coupled to the digital logic unit.

Claims

1. A mixed signal application specific integrated circuit (ASIC), the mixed signal ASIC comprising:

a single printed circuit assembly configured for connection to a fiber optic gyroscope;

a digital logic unit on the printed circuit assembly, wherein the digital logic unit implements modulation and compensation algorithms for one or more servo loops, and provides configuration, control, and communication services;

a relative intensity noise (RIN) analog-to-digital converter on the printed circuit assembly, the RIN analog-to-digital converter operatively coupled to the digital logic unit, wherein the RIN analog-to-digital converter is operatively coupled to an external RIN detector in optical communication with an optical coupler of the fiber optic gyroscope;

a rate analog-to-digital converter on the printed circuit assembly, the rate analog-to-digital converter operatively coupled to the digital logic unit and configurable to receive a signal from an external rate detector in optical communication with the optical coupler;

a light source digital-to-analog converter on the printed circuit assembly, the light source digital-to-analog converter operatively coupled to the digital logic unit and configurable to send a control signal from the digital logic unit to a light source of the fiber optic gyroscope to control a current of the light source;

a thermo-electric cooler digital-to-analog converter on the printed circuit assembly, the thermo-electric cooler digital-to-analog converter operatively coupled to the digital logic unit and configurable to send a control signal from the digital logic unit to the light source to control thermo-electric cooling of the light source;

an integrated optical chip digital-to-analog converter on the printed circuit assembly, the integrated optical chip digital-to-analog converter operatively coupled to the digital logic unit and configurable to send a control signal from the digital logic unit to an integrated optical chip of the fiber optic gyroscope to modulate an optical signal;

an eigen-frequency servo digital-to-analog converter on the printed circuit assembly, the eigen-frequency servo digital-to-analog converter operatively coupled to the digital logic unit and configurable to send a control signal from the digital logic unit to the integrated optical chip to synchronize sampled rate data to a proper eigen-frequency of the fiber optic gyroscope;

a heater servo digital-to-analog converter on the printed circuit assembly, the heater servo digital-to-analog converter operatively coupled to the digital logic unit and configurable to send a control signal from the digital logic unit to a heater element of the fiber optic gyroscope;

a monitor multiplexer and analog-to-digital converter on the printed circuit assembly, the monitor multiplexer and analog-to-digital converter operatively coupled to the digital logic unit and configurable to receive a signal from one or more external monitors;

a digital-to-analog converter on the printed circuit assembly and operatively coupled to the digital logic unit to form a direct digital synthesizer that outputs a tunable modulation clock signal to an external analog filter, wherein the external analog filter outputs a single dominant frequency sine wave that is returned to an analog comparator on the printed circuit assembly to generate a bias modulation clock; and

a digital serial input/output on the printed circuit assembly that provides signal communication between the digital logic unit and a host;

wherein the mixed signal ASIC provides all electronic functions associated with operation of the fiber optic gyroscope on a single integrated device.

2. The mixed signal ASIC of claim 1, wherein the mixed signal ASIC is configured for connection to an interferometric fiber optic gyroscope.

3. The mixed signal ASIC of claim 1, wherein the digital logic unit is configured to receive a clock signal from an external oscillator.

4. The mixed signal ASIC of claim 1, wherein the digital logic unit is configured for connection to an external memory unit comprising one or more non-volatile memory devices.

5. The mixed signal ASIC of claim 1, wherein the external analog filter comprises a low pass filter.