Abstract: A locator system for use in connection with at least one mobile person includes a mobile locator system adapted to be worn by the person, wherein the mobile locator system includes an inertial navigation system. The locator system further includes a reference locator system to provide information about a position of the mobile locator device relative to a coordinate system. In several embodiments, the reference locator system comprises an ultrasonic system. For example, the reference locator system can include at least one ultrasonic transmitter and at least one ultrasonic receiver. One of the at least one ultrasonic receiver and the at least one ultrasonic transmitter can be positioned at a known position on the coordinate system and the other of the at least one ultrasonic receiver and the at least one ultrasonic transmitter can be worn by the person. The reference locator system can also include a plurality of ultrasonic transmitters and a plurality of ultrasonic receivers.

Abstract: Digitized heterodyne signals in a ring laser gyroscope are processed to determine the phase and acceleration of heterodyne signals at turnarounds in the angular motion of the frame of the ring laser. A hybrid analog/digital design that incorporates the necessary logic processes the turnaround data to produce a phase correction that can be added to the gyroscope count to correct phase errors that at each turnaround. Separation of high speed data processing from lower rate data simplifies the code and permits evaluation of turnaround correction performance. A fully digital system determines a phase distribution for the detected turnarounds and processes the phase distributions of the heterodyne signals for a multiplicity of turnarounds to determine an angle towards which the phase distributions are skewed and the amount of that skew.