Abstract: The invention relates to a device, system, and method for providing a multi-mode navigation device. In a first mode of operation, the navigation device provides position information based on a radio frequency navigation signals. If radio signals become unavailable, the navigation device enters a second mode of operation. In the second mode of operation the navigation device stores the most recent elevation and associates it with a reference elevation, the reference elevation is associated with an entry floor. The difference between a current elevation and the reference elevation is determined and this difference is divided by a floor height to obtain a floor number. The navigation device provides the floor number while reliable global position information is unavailable.

Abstract: A method and apparatus for providing dead reckoning position data, orientation, and heading of a person is disclosed. The apparatus uses an algorithm that automatically determines the appropriate set of navigation functions for personal navigation based upon the orientation of the apparatus. Dead reckoning is accomplished by combining electronic heading and motion signals from human ambulation. Individual orientation and human motion measurement is accomplished with motion sensing devices. In one implementation of the invention, a navigation device provides different heading, position, and/or orientation functionality depending on whether the navigation device is affixed to the user in a vertical position or horizontal position, or the navigation device is not affixed to the user.

Abstract: One embodiment of the invention provides a compact navigation device assembly that is rugged, compact and does not require independent connector components to interconnect multiple circuit boards. According to one implementation of the compact navigation device assembly, an electrical or electromechanical circuit may be laid-out among a plurality of circuit boards that are electrically joined along their edges in a three-dimensional structure without the use of discrete connectors or components. Each circuit board may have one or more crenelated, serrated, and/or notched edge to electrically join the circuit board to other circuit boards. Such crenelated edges may be plated for electrical conductivity and may be joined to corresponding crenelated edges with solder or other electrically conductive materials.

Abstract: An improved method, system, and device for a compass combining an electronic magnetic compass and an angular velocity sensing gyroscope. One aspect of the invention integrates an angular velocity output signal from an angular velocity sensor or rate gyroscope to determine the angle of motion. An initial magnetic heading is obtained from a geomagnetic sensor and used as a reference for the integrated angular velocity signal. A geomagnetic heading signal is blended with the angular velocity output signal at an adaptive time interval. The adaptive time interval is increased if the reliability of the magnetic field improves and decreased if the reliability of the magnetic field degenerates. Additionally, dynamic calibration of the angular velocity sensor may be performed to correct for gyroscope bias (zero offset), and/or gyroscope scale factor or gain.

Abstract: Performing dead reckoning navigation for persons on foot with improved accuracy. Accelerometers in a navigation device are used to deduce when abnormal steps are being taken and modify navigation calculations accordingly. Running and walking sideways or backwards are among the situations which can be detected and compensated. One embodiment of the invention is a pedometer which is attached to the user's waist or torso. Various correlations are used to distinguish between running versus walking, forward steps versus backward steps, left turn versus right turn, and the slope of the terrain being traveled. Various algorithms are used to distinguish between such motions and accurately track the distance and direction traveled.

Abstract: Performing dead reckoning navigation for persons on foot with improved accuracy. Accelerometers in a navigation device are used to deduce when abnormal steps are being taken and modify navigation calculations accordingly. Running and walking sideways or backwards are among the situations which can be detected and compensated. One embodiment of the invention is a pedometer which is attached to the user's waist or torso. Various correlations are used to distinguish between running versus walking, forward steps versus backward steps, left turn versus right turn, and the slope of the terrain being traveled. Various algorithms are used to distinguish between such motions and accurately track the distance and direction traveled.

Abstract: A method and apparatus for providing dead reckoning position data, orientation, and heading of a person is disclosed. The apparatus uses an algorithm that automatically determines the appropriate set of navigation functions for personal navigation based upon the orientation of the apparatus. Dead reckoning is accomplished by combining electronic heading and motion signals from human ambulation. Individual orientation and human motion measurement is accomplished with motion sensing devices. In one implementation of the invention, a navigation device provides different heading, position, and/or orientation functionality depending on whether the navigation device is affixed to the user in a vertical position or horizontal position, or the navigation device is not affixed to the user.

Abstract: An improved method, system, and device for a compass combining an electronic magnetic compass and an angular velocity sensing gyroscope. One aspect of the invention integrates an angular velocity output signal from an angular velocity sensor or rate gyroscope to determine the angle of motion. An initial magnetic heading is obtained from a geomagnetic sensor and used as a reference for the integrated angular velocity signal. A geomagnetic heading signal is blended with the angular velocity output signal at an adaptive time interval. The adaptive time interval is increased if the reliability of the magnetic field improves and decreased if the reliability of the magnetic field degenerates. Additionally, dynamic calibration of the angular velocity sensor may be performed to correct for gyroscope bias (zero offset), and/or gyroscope scale factor or gain.

Abstract: A microcomputer-assisted position finding system that integrates GPS data, dead reckoning sensors, and digital maps into a low-cost, self-contained navigation instrument is disclosed. A built-in radio frequency transponder allows individual positions to be monitored by a central coordinating facility. Unique dead reckoning sensors and features are disclosed for ground speed/distance measurement and computer-aided position fixes.

Abstract: Methanol and nitrogen are injected into a furnace utilized for annealing or spheroidizing metal articles. The methanol reacts inside the furnace to provide an atmosphere with a carbon potential that will minimize or prevent carbon removal or carbon addition to the surface of the ferrous metals being treated.