This paper describes recent advances with our earlier developed Personal Dead-reckoning (PDR) system for GPS-denied environments. The PDR system uses a foot-mounted Inertial Measurement Unit (IMU) that also houses a three axismagnetometer. In earlier work we developed methods for correcting the drift errors in the accelerometers, thereby allowing very accurate measurements of distance traveled....

Optical pumping was originally suggested by Kastler [I] in 1950 and since the early 1960's numerous helium magnetometers based upon that technique have been developed. Since then the main evolution has consisted in the advent in 1986 of tunable lasers suitable for helium optical pumping. They led to a renewed interest in helium magnetometry essentially because the magnetometer resolution is exp...