US 12,174,020 B2
System and method for heading error correction in a pulsed Rb-87 magnetometer at geomagnetic fields
Wonjae Lee, Princeton, NJ (US); Michael Romalis, Princeton, NJ (US); Vito Giovanni Lucivero, Barcelona (ES); Mark Limes, Princeton, NJ (US); Elizabeth Foley, Plainsboro, NJ (US); and Tom Kornack, Plainsboro, NJ (US)
Assigned to THE TRUSTEES OF PRINCETON UNIVERSITY, Princeton, NJ (US)
Filed by The Trustees of Princeton University, Princeton, NJ (US)
Filed on May 28, 2021, as Appl. No. 17/333,474.
Claims priority of provisional application 63/031,993, filed on May 29, 2020.
Prior Publication US 2022/0221277 A1, Jul. 14, 2022
Int. Cl. G01R 33/26 (2006.01); G01C 17/28 (2006.01)
CPC G01C 17/28 (2013.01) [G01R 33/26 (2013.01)] 17 Claims
OG exemplary drawing
 
8. A magnetometer, comprising:
a multipass cell containing Rb-87 vapor;
a pump laser operated in a pulse mode that is synchronous with a Larmor frequency and oriented to pass a pump beam through the multi-pass cell in a first direction;
a horizontal probe laser configured to pass a first probe beam through the multipass cell in a direction parallel to the pump beam; and
a vertical probe laser configured to pass a second probe beam through the multipass cell in a direction perpendicular to the pump beam; and
one or more processing units configured to:
determine a direction of a magnetic field based on a ratio of an AC signal to an DC signal measured based on the vertical probe laser and/or horizontal probe laser; and
determine heading error-free magnetic field based on

OG Complex Work Unit Math
wherein B is the magnetic field strength, gs and gl are the electronic and nuclear Landé factors, respectively, μB is the Bohr Magneton, υ=ω/2π is a measured precession frequency, υhf is a hyperfine splitting frequency, P is a degree of initial spin polarization, and θ is an angular deviation of the pump beam from a nominal magnetometer orientation where the pump beam is perpendicular to the magnetic field.