Atom interferometer with adaptive launch direction and/or position
Embodiments described herein provide for a method of launching atoms in an atom interferometer. The method includes determining a direction of the total effective acceleration force on the atoms, controlling a direction of launch of the atoms for measurement in the atom interferometer based on the direction of the total effective acceleration force, and obtaining measurements from the atoms.
1. An inertial sensor comprising:
an atom interferometer configured to launch atoms and obtain readings therefrom;
a non-atomic type accelerometer that is subject to the same input motion as the atom interferometer; and
control and measurement electronics configured to:
determine a direction of a total effective acceleration force on the atoms in the atom interferometer based on readings from the non-atomic type accelerometer;
control a direction of launch of the atoms in the atom interferometer based on the direction of the total effective acceleration force using one or both of a set of optical molasses lasers and a magneto-optical trap, wherein controlling the direction of launch includes adjusting the direction relative to a volume of a Raman laser beam to increase the amount of time the atoms are available for interrogation by the Raman laser beam; and
obtain output measurements based on the readings from the atom interferometer.
2. The inertial sensor of claim 1 , wherein the atom interferometer is configured to obtain readings corresponding to one of acceleration or rotation.
3. The inertial sensor of claim 1 , further comprising:
a non-atomic type gyroscope that is subject to the same input motion as the atom interferometer; and
wherein the control and measurement electronics are configured to obtain output measurements based on a combination of the readings from the atom interferometer and the non-atomic type gyroscope.
4. The inertial sensor of claim 1 , wherein the control and measurement electronics are configured to obtain output measurements based on a combination of the readings from the atom interferometer and the non-atomic type accelerometer, wherein the atom interferometer is configured to obtain readings corresponding to acceleration.
5. The inertial sensor of claim 1 , wherein the non-atomic type accelerometer comprises a micro-electro-mechanical system (MEMS) vibratory structure accelerometer.
6. The inertial sensor of claim 1 , wherein the control and measurement electronics are further configured to:
repeat the acts of determine a direction, control the direction of launch of the atoms, and obtain output measurements for subsequent atom launches such that the direction of an atom launch is adaptively determined based on an estimate of a current direction of the total effective acceleration force on the atom interferometer.
7. The inertial sensor of claim 1 , wherein control the direction of launch of atoms includes setting the direction of launch opposite to the direction of the total effective acceleration force.
8. The inertial sensor of claim 1 , wherein control the direction of launch of atoms includes setting the direction of launch orthogonal to the direction of the total effective acceleration force.
9. The inertial sensor of claim 1 , wherein the control and measurement electronics are further configured to:
control the position of launch of the atoms within the volume of the Raman laser beam to be nearer an edge of the volume of the Raman laser beam that is opposite the direction of a predicted trajectory of the atoms based on a predicted trajectory of the atoms after launch.
10. The inertial sensor of claim 9 , wherein the direction of the predicted trajectory of the atoms is based on the direction of launch of the atoms and the total effective acceleration force.
11. The inertial sensor of claim 9 , wherein control the position of launch of the atoms includes setting the position of the atoms near 1/e^2 of a radius of the volume of the Raman laser beam when the first pulse of the Raman laser occurs.
12. The inertial sensor of claim 1 , wherein the total effective acceleration force includes the force of gravity and any other acceleration forces on the atoms.
13. An inertial sensor comprising:
an atom interferometer configured to launch atoms and obtain readings therefrom;
a non-atomic type accelerometer that is subject to the same input motion as the atom interferometer; and
control and measurement electronics configured to:
determine a predicted trajectory of atoms for measurement in the atom interferometer after launch;
control a position of launch of the atoms within a volume of a Raman laser beam based on the predicted trajectory, wherein controlling the position includes adjusting the position relative to the volume of the Raman laser beam to increase the amount of time the atoms are available for interrogation by the Raman laser beam; and
obtain measurements from the atoms.
14. The inertial sensor of claim 13 , wherein control the position of launch of the atoms includes setting the position of launch nearer an edge of the volume of the Raman laser beam that is opposite the direction of the predicted trajectory of the atoms.
15. The method of claim 14 , wherein control the position of launch of the atoms includes setting the position of the atoms near 1/e^2 of a radius of the volume of the Raman laser beam when the first pulse of the Raman laser occurs.
16. The inertial sensor of claim 13 , wherein the control and measurement electronics are further configured to:
determine a direction of the total effective acceleration force on the atoms using readings from the a non-atomic type accelerometer;
wherein determine a predicted trajectory includes determining the predicted trajectory of the atoms based on the direction of a total effective acceleration force on the atoms and a direction of launch of the atoms.
17. The inertial sensor of claim 16 , wherein the total effective acceleration force includes the force of gravity and any other acceleration forces on the atoms.
18. The inertial sensor of claim 16 , wherein the control and measurement electronics are further configured to control a direction of launch of the atoms in the atom interferometer based on the direction of the total effective acceleration force.
19. The inertial sensor of claim 18 , wherein control the direction of launch of atoms includes setting the direction of launch opposite to the direction of the total effective acceleration force.
20. The inertial sensor of claim 18 , wherein control the direction of launch of atoms includes setting the direction of launch orthogonal to the direction of the total effective acceleration force.