Abstract: A method of determining a location is provided. The method comprises placing a plurality of radio frequency (RF) tags within an area, mapping the placement of the plurality of RF tags within the area, detecting one or more of the plurality of RF tags in the area, and determining a location based in part on the mapping and on probability distributions associated with each of the one or more detected RF tags.

Abstract: A navigation system includes an inertial navigation unit. The navigation system also includes a Kalman filter that generates corrective feedback for use by the inertial navigation unit. The Kalman filter generates the corrective feedback as a function of at least one of GPS/DGPS information, sensor information, user input, terrain correlation information, signal-of-opportunity information, and/or position information output by a motion classifier.

Abstract: A navigation system with resume logic and mode logic provides as an output an accurate navigation solution using multiple RF sensors. The resume logic determines which sensors are currently providing good data to the navigation system. The mode logic selects an operating mode of the navigation system and selects which data to use for calculating corrections to the navigation solution. The mode logic makes the selections based on the results of the resume logic. The resume logic continues to test data from the sensors. If a sensor that has previously provided erroneous data starts providing good data, the mode logic will automatically select that data for use in calculating the corrections to the navigation solution. The tracking of RF transmitters by the multiple RF sensors is controlled using a plurality of available inertial and non-inertial sensors.

Abstract: A GPS receiver acquires GPS data from at least one GPS satellite. A code offset and a frequency offset are determined based on the acquired GPS data. A change in GPS position of the GPS receiver during the determination of the code offset is determined, and a change in rate of the GPS receiver during the determination of the frequency offset is also determined. The code offset is updated based on the change in GPS position, and the frequency offset is updated based on the change in rate. The updated code offset and the updated frequency offset are handed over to a tracking function.

Abstract: A navigation system includes an inertial measurement unit, a navigation computer, a GPS receiver, and a clock controller. The inertial measurement unit has a first clock and a first switch, the navigation computer has a second clock and a second switch, and the GPS receiver has a third clock. The clock controller controls the first and second switches. Accordingly, the inertial measurement unit, the navigation computer, and the GPS receiver may use their own clocks, or the inertial measurement unit and the navigation computer may use the second clock, or the inertial measurement unit, the navigation computer, and the GPS receiver may use the third clock.

Abstract: A system and method for classifying and measuring human motion senses the motion of the human and the metabolism of the human. A motion classification unit determines the motion type being carried out by the human and provides the motion classification information to an energy estimator and a health monitor. The energy estimator also receives the metabolism information and therefrom provides an estimate of energy expended by the human. The health monitor triggers an alarm if health related thresholds are traversed. The motion classification is also provided to a processing unit that in turn provides the data to a Kalman filter, which has an output that is provided as feedback to the motion classification unit, the energy estimator and health monitor. Altimeter, GPS and magnetic sensors may also be provided for monitoring the human motion, and initial input and landmark input data inputs are provided to the system.