Abstract: The system includes a method and apparatus for transmitting a spread spectrum signal from each of a plurality of base stations. The spread spectrum signal has a predetermined timing and has a ground wave component and a sky wave component. The signal is transmitted with a repetition time at least as great as a maximum anticipated delay time of the sky wave component such that the ground wave component of the transmitted spread spectrum signal can be distinguished from the sky wave component. The signal is detected at each of a plurality of mobile stations and the timing of the detected signal is compared to a local timing signal. The phase difference between these signals is indicative of the range of the base station from the mobile station.

Abstract: A wide-range load cell is installed within a press in line with the work load. The load cell measures the actual force applied to the load irrespective of any friction, binding or drag in the press mechanism. The sensitivity of the load cell is adjusted in order to provide an accurate measurement over a wide range of pressures. In some embodiments of the load cell the least sensitive of the pressure or traction bearing elements become active as the applied force approaches the maximum limit of the more sensitive element. In other embodiments of the invention the most sensitive of the pressure or traction sensing elements are switched out of operation as the applied force approaches their maximum limits. A hydraulic version of the load cell uses a combination of pressure-sensing transducers of different ranges and sensitivities.