Abstract: A gas separator connectable between the seating nipple/pump and the mud anchor of a well production line takes advantage of gravitational, shear and centrifugal forces to detrain gas from the formation fluid. An outer cylindrical tube is concentrically secured by upper and lower couplings in relation to an inner cylindrical tube having an axial flow passage and a plurality of radial perforations. The upper coupling is adapted for connection to the seating nipple/pump and the lower coupling is adapted for connection to the mud anchor. The couplings each have a passage therethrough to extend the inner tube axial flow passage in fluid communication between the pump and the mud anchor. The outer cylindrical tube has a plurality of inwardly downwardly centrifugally oriented passages for admitting liquid entrained with gas into an annulus between the tubes and for causing the admitted liquid to flow in a downward spiral in the annulus.

Abstract: A shared channel GPS (Global Positioning System) receiver for receiving a plurality of coded satellite signals. The plurality of satellite signals is transmitted by a corresponding plurality of satellites. Since these satellites are moving rapidly with respect to the receiver, Doppler shifting of the signals is exhibited. The signals are converted from analog to digital at intermediate frequency levels. The signals are then separated simultaneously into a plurality of digital signals corresponding to channel information for each transmitting satellite. One channel of the receiver sequence through a number of the satellites on a time division multiplexed basis. The channel estimates a plurality of parameter pertaining to each satellite so that re-acquisition of the satellite's transmission may be facilitated. A processor then converts these channel information signals to pseudo-range and broadcast data for navigation and time purposes.

Abstract: A method and apparatus for operating a two channel digital global positioning system receiver for receiving coded satellite signals from each of a plurality of satellites, where the signals exhibit Doppler shifts. The method comprises the steps of continuously tracking of a particular one of the satellites for receiving information included in the coded satellite signals by one channel of the receiver, and sequentially tracking of each of the plurality of satellites, except the one particular satellite, by the other channel of the receiver for receiving information included in the coded satellite signals.

Abstract: A digital GPS (Global Positioning System) receiver for receiving a plurality of coded satellite signals. The plurality of satellite signals are transmitted by a corresponding plurality of satellites. Since these satellites are moving rapidly with respect to the receiver, Doppler shifting of the signals is exhibited. The signals are converted from analog to digital at intermediate frequency levels. The signals are then separated simultaneously into a plurality of digital signals corresponding to I and Q channel information for each transmitting satellite. A processor then converts these I and Q channel information signals to pseudo-range and broadcast data for navigation and time purposes.

Abstract: A system for measuring Doppler frequency cycle count over a predetermined time period wherein a phase locked VCO is operated at N times the Doppler to allow measurement of both integral and fractional cycles. The resolution of the measurement is a function of the factor N.

Abstract: A system for stabilizing the amplitude and, thus, the delay of a signal pulse subsequent to the first interrogating signal pulse to a transponder used in a range measurement system. AGC level in the transponder is set responsive to the first interrogating pulse and is held for a time period encompassing the subsequent pulse.

Abstract: A comparator is connected to the output of a variable gain amplifier and, when the output signal exceeds a predetermined threshold, pulses are applied to a plural stage shift register in series, with incremental voltages being generated in parallel at the outputs of the various stages. The incremental voltages are applied to the amplifier to vary the amplification thereof, and a threshold detector and timer also sense the output of the amplifier and reset the shift register when the output of the amplifier is below a predetermined value for at least preset period of time. One or more additional comparators may be included in the circuit to cause the shift register to activate one or more of the higher stages directly when the output of the amplifier exceeds a second predetermined amplitude. A step control circuit for shaping the response curve of the amplifier is also included.