Optical strapdown inertia system

• US 4,315,693 A
• Filed: 12/31/1979
• Issued: 02/16/1982
• Est. Priority Date: 12/31/1979
• Status: Expired due to Term

• Current Assignee: Clifford G. Walker
• Original Assignee: Clifford G. Walker
• Inventors: Walker, Clifford G.
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Koren, Matthew W.
• Application Number:
  US06/108,972
• Time in Patent Office: 778 Days
• Field of Search: 356/350, 73/517 R
• US Class Current: 356/470
• CPC Class Codes: G01C 19/727 using a passive ring resonator

Abstract

An optical strapdown inertial system using passive laser gyros and passive laser accelerometers and a computer. These components may be disposed on "chips" in integrated optics format to provide an all solid-state system having no moving parts.

Claims

1. An optical strapdown inertial guidance system including:

a. A vehicle having a gyro and an accelerometer respectively mounted in three mutually perpendicular intersecting planes to sense acceleration components in each plane;

b. Said gyro including a passive ring Fabry-Perot interferemoter, and, a single frequency laser source to measure the difference in clockwise and counter clockwise lengths of the cavity caused by inertial rotation, electronic the cavity to resonance.

c. Said accelerometers comprising a single frequency laser source, a resonant cavity having a birefringent material therein, a proof mass carried by said birefringent material, a first polarizer for polarizing the laser beam, means disposed between said cavity and said polarizer for changing the optical frequency of the laser beam, focusing means for focusing the output laser beam from said cavity, detector means for receiving said output laser beam, feedback circuit means connected to said photo detector means and said SAW to vary the frequency of said laser beam.

2. An optical strapdown inertial system as in claim 1 wherein said means disposed between said cavity and said polarizer is a surface acoustical wave cell.

3. An optical strapdown inertial system as in claim 2 wherein said detector means is a photodiode.

4. An optical strapdown inertial system as in claim 3 wherein said focusing means is a lens disposed between said cavity and said detector.

5. An optical strapdown inertial system as in claim 4 wherein said laser source is a GaAs diode laser.

6. An optical strapdown inertial system as in claim 5 wherein said laser, polarizers, mirrors, birefringement material, proof mass and said detector are monolithically integrated on a substrate.

7. An optical strapdown inertial system as in claim 6 wherein said substrate is silicon.