Ring architecture for sequential operation of an atomic gyroscope

Patent metadata

Field	Value
Publication number	US-2016298967-A1
Application number	US-201414214767-A
Country	US
Kind code	A1
Filing date	Mar 15, 2014
Priority date	Mar 15, 2013
Publication date	Oct 13, 2016
Grant date	—

Abstract

Compact inertial measurement systems and methods based on atom interferometry. Certain examples provide a combination atomic accelerometer-gyroscope configured to recapture and cycle atom samples through atom interferometers arranged to allow the next measurement to use the atoms from the previous measurement. Examples of the apparatus provide inertial measurements indicative of rotation for different inertial axes by applying atom interferometry to a plurality of atom samples launched in opposite directions to allow for measurement of both acceleration and rotation rates. In some examples, the inertial measurement apparatus provide a combined atomic gyroscope and an atomic accelerometer in a compact six Degrees of Freedom (6 DOF) IMU.

First claim

What is claimed is:

1 . An inertial measurement apparatus based on atom interferometry and comprising:
a vacuum chamber; a plurality of atom interferometers including at least a first atom interferometer and a second atom interferometer, the first atom interferometer being configured to generate a first measurement corresponding to a common inertial input based on a first atom sample, and the second atom interferometer being configured to generate a second measurement corresponding to the common inertial input; and a plurality of atom capture sites housed within the vacuum chamber, the plurality of atom capture sites including at least a first atom capture site and a second atom capture site, the first atom capture site being configured to capture the first atom sample and to provide the first atom sample to the first atom interferometer, and the second atom capture site being configured to recapture the first atom sample from the first atom interferometer, following the first measurement, and to provide the first atom sample to the second atom interferometer, the second atom capture site being further configured to capture a second atom sample different from the first atom sample and to provide the second atom sample to a respective atom interferometer of the plurality of atom interferometers.

2 . The inertial measurement apparatus of claim 1 , wherein the second atom capture site is configured to provide the second atom sample to the respective atom interferometer along a propagation axis substantially parallel to that of the first atom sample and in a direction substantially counter-propagating relative to a direction of travel of the first atom sample.

3 . (canceled)

4 . The inertial measurement apparatus of claim 1 , wherein the first atom interferometer is disposed substantially orthogonal to the second atom interferometer, and the second atom capture site is disposed between the first atom interferometer and the second atom interferometer.

5 . (canceled)

6 . The inertial measurement apparatus of claim 1 , wherein the plurality of atom interferometers form an atomic gyroscope configured to:
sequentially provide a first plurality of phase shift measurements corresponding to a plurality of orthogonal inertial axes based on interference of the first atom sample, and sequentially provide a second plurality of phase shift measurements substantially simultaneously with providing the first plurality of phase shift measurements, the second plurality of phase shift measurements corresponding to the plurality of orthogonal inertial axes and being based on interference of the second atom sample; and combine the first and second pluralities of phase shift measurements to determine an inertial input to the inertial measurement apparatus.

7 - 9 . (canceled)

10 . The inertial measurement apparatus of claim 1 , wherein the plurality of atom interferometers further includes a third atom interferometer configured to generate a third measurement corresponding to the common inertial input based on the first atom sample, the third measurement providing information different from the first and second measurements; and
the plurality of atom capture sites further includes a third atom capture site configured to recapture the second atom sample received from the second atom interferometer and to provide the second atom sample to the third atom interferometer.

11 . The inertial measurement apparatus of claim 10 , wherein the plurality of atom capture sites are arranged in a ring configuration;
wherein each atom interferometer of the plurality of atom interferometers is disposed between a respective pair of atom capture sites of the plurality of atom capture sites; and wherein the first atom capture site is further configured to recapture the first atom sample received from the third atom interferometer and to provide the first atom sample that is recaptured to the first atom interferometer.

12 - 15 . (canceled)

16 . The inertial measurement apparatus of claim 10 , wherein the plurality of atom interferometers further includes a fourth atom interferometer configured to generate a further measurement corresponding to the common inertial axis based on the second atom sample, the fourth atom interferometer being aligned substantially parallel to the second atom interferometer;
wherein the plurality of atom capture sites further includes a fourth atom capture site configured to recapture the second atom sample from the third atom interferometer and to provide the second atom sample to the fourth atom interferometer; and wherein the first atom capture site is further configured to recapture the second atom sample from the fourth atom interferometer and to provide the second atom sample to the first atom interferometer.

17 - 19 . (canceled)

20 . The inertial measurement apparatus of claim 1 , wherein at least two atom capture sites of the plurality of atom capture sites are configured to launch distinct atom samples substantially simultaneously; and
wherein at least two atom interferometers of the plurality of atom interferometers are configured to receive the distinct atom samples and to operate substantially simultaneously to generate a plurality of phase shift measurements based on the distinct atom samples.

21 - 24 . (canceled)

25 . The inertial measurement apparatus of claim 1 , wherein each atom interferometer of the plurality of atom interferometers is configured to allow transfer of atoms between respective atom capture sites of the plurality of atom capture sites, and wherein each atom interferometer includes an optical assembly configured to provide a light pulse sequence to atoms being transferred between the respective atom capture sites.

26 . The inertial measurement apparatus of claim 25 , wherein the light pulse sequence is a pi/2-pi-pi/2 Raman pulse sequence.

27 . (canceled)

28 . The inertial measurement apparatus of claim 25 , wherein each atom interferometer is configured to provide the light pulse sequence configured to cause inertially sensitive atom interference.

29 - 35 . (canceled)

36 . A method for providing inertial measurements based on atom interferometry, the method comprising:
capturing a plurality of distinct atom samples by a plurality of atom capture sites, the plurality of atom samples including at least a first atom sample and a second atom sample; sequentially generating a first plurality of measurements corresponding to a plurality of orthogonal inertial axes based on interference of the first atom sample using a plurality of atom interferometers; and sequentially generating a second plurality of measurements corresponding to the plurality of orthogonal inertial axes based on interference of the second atom sample using the plurality of atom interferometers; wherein the plurality of atom capture sites and the plurality of atom interferometers are arranged in series in a ring configuration, each atom capture site being disposed between adjacent atom interferometers of the plurality of atom interferometers.

37 . The method of claim 36 , wherein sequentially generating the first plurality of measurements and sequentially generating the second plurality of measurements are performed substantially in parallel.

38 . (canceled)

39 . The method of claim 36 , further comprising:
determining at least one of rotation and acceleration relative to the inertial axes based on at least one of the first plurality o

Assignees

• Charles Stark Draper Laboratory Inc

Inventors

• Johnson David M S
• Butts David L
• Stoner Richard E

Classifications

• G01C19/62 Primary

  with optical pumping · CPC title

• G01C19/58 Primary

  Turn-sensitive devices without moving masses · CPC title

• G01C21/18

  Stabilised platforms, e.g. by gyroscope · CPC title

• G01B9/02

  Interferometers · CPC title

• G01P15/08

  with conversion into electric or magnetic values · CPC title