Abstract: A method and system for accurately determining the position coordinates of a mobile GPS receiver by resolving the double difference GPS carrier phase integer ambiguity. A reference station is provided at precisely known coordinates and carrier phase data and pseudoranges for each received GPS satellite are calculated at both the reference station and the mobile GPS receiver. A communications link couples carrier phase data, pseudorange data and the known reference station position from the reference station to the mobile GPS receiver. A first Kalman filter within the mobile GPS receiver operates on GPS satellite ephemeris parameters and the calculated pseudoranges to obtain an error state vector for position and time. The GPS satellite ephemeris parameters and calculated carrier phase data are then applied to a second Kalman filter to obtain a predicted vector of velocity and clock rate error.

Abstract: A pulsed-field walk-through metal detector contains circuitry to reduce several different types of external noise, or interference due to external stationary or moving metal, and signals due to small objects, such as jewelry. A self-test fixture monitors system performance. The detector has digitally controlled timing means operated at an odd half-multiple of the power mains frequency. A gated integrator is active for periods equal to a multiple of the TV retrace frequency. A switched-capacitor FIR filter removes signals due to steady power line hum, and a subtractive means removes signals due to stationary metal, prior to averaging or lowpass filtering. A peak limiter controls transient noise bursts. A voting circuit reduces the likelihood of false alarm triggering. A simple self-test circuit, consisting of a wire loop and a switch, tests the entire signal path and has no moving parts.

Abstract: A radio ranging system has at least one receiver which receives pulses over a direct path and over a longer delayed path from each of two or more fixed repeater stations. From the reception times of pulses which have traveled over these paths at different travel times from the fixed stations, a computer calculates the hyperbolic distances separating the passive receiver and the several fixed reference stations. By interchanging the roles of the various fixed stations, the computer compares the results of timing calculations of the same distances based on the different sets of data. From this comparison, the systematic timing errors of the system can be isolated and added or subtracted from the time measuring results, leaving differential time measurements without systematic error.

Abstract: A pulse position detector responding to the leading and trailing edges of a pulse at a point where it crosses a threshold level. Responsive to the leading edge, a capacitor begins to charge with a characteristic which is represented by a slope of a first line. Responsive to the trailing edge of pulse, the capacitor begins to charge at a second rate which is represented by a second line having a slope which is twice the slope of the first line. An one-shot multivibrator responds to the change in the charge rate to measure a time period which depends upon the slopes of the two lines. That time period is substracted from a standard time period in order to indicate where the center of the pulse appeared.

Abstract: A ferrite transformer is coupled between a two-wire array of geophones or other suitable vibration detectors (such as hydrophones). An oscillator is coupled across the secondary of the transformer in order to provide a carrier on which the output of the array may be modulated. A low level leakage current appears in the array so that a continuity test may be conducted to monitor the line for opens and shorts and to detect the operativeness of system components. The modulated output of the transformer is connected to a signal processing system.

Abstract: A radar system is used to locate a vehicle's position on a predetermined X, Y grid, which could be latitude and longitude. Several paths of different lengths link the vehicle with a master station which transmits cyclically recurring pulses. Equipment on the vehicle compares the propagation time required for the pulses to travel over each of the several paths. The compared times are then used by a microprocessor to calculate the position of the vehicle. The several paths are identified by a use of repeater stations which may selectively drop predetermined ones of the cyclically recurring pulses and retransmit the rest. For example, one repeater may retransmit every second recurring pulse and another repeater may retransmit every third recurring pulse.

Abstract: A microprocessor controls a radar trilateralization system, used on board an aircraft to provide pattern flying. A suitable hard wired board may be added to the microprocessor to enable it to read out any suitable flight pattern. A plurality of transponders are set up at known positions to establish a baseline. Then, by using known radar techniques, the system feeds radar derived, distance information into the microprocessor. The microprocessor calculates the airplane's position from these radar signals, relates that position to the X, Y grid locations in a desired flight pattern, and then gives an instrument readout. The pilot keeps a display of the instrument over an appropriate index, and the airplane flies over the entire predetermined flight pattern.

Abstract: A radio locator system uses transceivers located in a mobile and at least two stationary stations. Each stationary station serves as one end of a surveyor's baseline. Therefore, since the transceivers are located at opposite ends of a line having a known length, their broadcast signals provide direct distance measurements of two other lines extending between the individual stationary stations and the mobile unit, thereby cooperating with the known line to complete a trilateralization. Each station in the system is identified by a uniquely encoded stream of pulse bursts, each burst encompassing a wide, preprogrammed change of frequency for eliminating interference between the signals used in the locator system and the signals of other users of the same frequency band. An inversion of the preprogrammed frequency change is used for the return of the ranging system signal in order to substantially eliminate or suppress echo returns to the mobile or interrogator station.

Abstract: A pair of inverted, concentrically mounted cups are lowered into a pool of liquid at the bottom of a well. The outer cup is a housing connected to atmospheric pressure via a capillary tube extending upwardly to the top of the well. The inner cup is a closed dome. Liquid passes through a check valve in the bottom of the housing and rises in the outer cup, since the capillary tube is open to the atmosphere and bleeds off the air inside the outer cup. Since the inner cup is closed, air is entrapped therein to limit the rise of liquid in it. When the capillary tube and, therefore, the two cups are pressurized, the check valve closes to prevent escape of liquid from the housing. The liquid rises in the dome to compress the air entrapped therein. When the capillary tube is suddenly opened again to atmospheric pressure, the compressed air entrapped in the closed dome of the inner cup drives the liquid violently up the capillary tube.

Abstract: A disaster valve for downhole use in a gas or oil well is built into a unitary housing having a wireline running tool connector at one end and a control package at the other end. In the center of the housing, a ball valve (in one embodiment) or a piston and cylinder valve (in another embodiment) is arranged to be operated by a new and improved mandrel driven by a motor for rotating a feed screw. The housing includes passages and parts configured so that the lower end of the housing lies along the axis of the tubing to enable a peripheral fluid flow, coaxially around the housing. Near the valve, the fluid is diverted from the peripheral flow into an axial flow. The valve controls the fluid flow at the point where the peripheral flow converts into the axial flow. During catastrophic conditions, a quick release feature enables the valve to be driven to a closed position under spring tension.

Abstract: A standard amplitude pulse is transmitted as a cyclically recurring pulse in a radar ranging system. At a receiver, identified by the pulse repetition rate of the recurring pulses, each pulse is analyzed for its deterioration from the standard in order to detect fading. An amplifier, having a controlled gain, is adjusted responsive to the analysis, and the uniformity is restored to the pulse despite variations in fading. In some cases, a threshold detection is used to prevent response to minor variations. A pulse repetition rate detector insures that the pulses are so controlled at only the identified station, and that the identified station responds only to pulses with the proper repetition rate.

Abstract: A wireline running tool enables a module to be lowered into or removed from a production tubing or pipe line, especially one extending downhole in an oil or gas well. A kickover arm in the tool deflects the module into a side pocket in the tubing or pipe. The power for so deflecting such module comes from a pressurized pneumatic cylinder. If something goes wrong and the tool or module becomes stuck in the tubing or pipe, the gas slowly leaks from the pneumatic cylinder, after which the tool or module becomes unstuck.

Abstract: An acoustically controlled system includes means for transmitting any of several different forms of sonic energy signals through the walls of a tubing extending down into a gas or oil well. There, any of several functions may be performed, such as a control of a disaster valve located at the lower end of the tubing. Depending upon the function selected, the valve may hold itself open irrespective of the continuity of the sonic signal, or may slam shut if the sonic energy ends. Preferably, the selection control depends upon the pulse repetition rate of the sonic energy pulses.

Abstract: A radar position locator system uses a mobile and at least two stationary transceivers. The signals are validated by being stored and compared with previously received signals. If the comparison indicates that the received signal is within a range of a reasonably possible change, as compared to the previously received signals, it is accepted. Otherwise, it is rejected and the memory circuit which stored the signal for validation is backed up to the last previously stored valid signal. The stationary transceivers function somewhat as a surveyor's bench mark. Each transceiver is individually identified by a coded stream of radar pulses, as, for example, a stream of pulses transmitted at a predetermined transceiver identifying pulse repetition rate. A selected number of validated radar signals are transmitted between the mobile and stationary transceivers. The round trip transmission times of several of these signals are averaged, and a digital read out indicates the distance represented by such averaging.

Abstract: A sonic energy signal is transmitted continuously through the walls of tubing extending down into an oil or gas well, in order to control a disaster valve at the lower end of the tubing. If the signal disappears, the valve shuts automatically. In one embodiment, the tubing functions as the core of a transformer. In another embodiment, the tubing conducts an acoustic signal. The sonic energy may be transmitted by either a hydraulic ram or a tuned hammer, which transmits energy vertically into the tubing walls.

Abstract: A signal is transmitted through the walls of tubing extending down into an oil well in order to control a disaster valve at the lower end of the tubing. If the signal disappears, the valve shuts. In one embodiment, the tubing functions as the core of a transformer. In another embodiment, the tubing conducts an acoustic signal.

Abstract: A system for radar station identification depends primarily upon the encoding growing out of a pulse repetition rate of interrogation pulses. To secure the encoding, one or more pulses arm the system and succeeding pulses must be detected during an extremely narrow time of acceptance. Hence, the pulses are logically interpreted in order to reject randomly occurring stray signals.