Abstract: A method for minimizing time error uses a drift-susceptible time clock at the receiver carried by an asset to be tracked in a high-accuracy reduced-order GPS asset localization system. Long-term accuracy of the time clock is maintained by periodically re-synchronizing the clock with the master GPS time clock so that absolute asset time clock errors are kept below a known limit over the wide temperature ranges expected in the asset tracking application. This is accomplished with only a short GPS signal reception time; i.e., GPS frame synchronization and time-stamp decoding are not needed, and the asset position ambiguity associated with using GPS data-bit or code-bit edges as signal time references is eliminated.

Abstract: A tungsten focal track is placed on a graphite substrate in such a manner as to reduce off focal spot radiation while maintaining a fixed focal spot size. The radial width of the focal tract is made smaller than that of the electron beam from the cathode such that the electron beam overlap will allow for misalignments between the electron beam and the focal track without affecting the focal spot size or location.