Abstract: A means of accurately determining the position of a selected location such as at the end of a center-pivot irrigation system by using two Global Positioning System (GPS) receivers. The first GPS receiver is located at a fixed, known position such as at the center of the pivoting irrigation system while the second GPS receiver is located on a moving portion of the irrigation system. The first GPS receiver compares the GPS receiver reported position against the actual position and reports by wire or radio link the position differences to the second GPS, where the differences are used to remove errors from the second receiver's measured position.

Abstract: An integrated guidance system for use in swath guidance applications combines the display of swath navigation information with swath guidance system information. A processor receives information from an external positioning system such as a Global Positioning System receiver and generates course correction data derived from swath parameters selected by the user from a displayed menu of options using a control interface that is integrated with the display and processor or is located externally. The swath navigation information is displayed graphically and numerically. The entire apparatus is compact and mountable within the operative view of the user as he operates the equipment to be guided, thereby reducing hazard and navigational error.

Abstract: A method and apparatus for demodulating and decoding an MSK signal utilizing synchronous accumulation and simultaneous synchronization of reference carrier and MSK data clocks enables a GPS correlator channel in a multi-channel GPS receiver to be used for processing MSK signals. The PRN code epochs are synchronized with the MSK data clocks and the process of de-spreading with a PRN code is disabled in order to obtain coherent MSK demodulation without corrupting the MSK signal with a PRN code within the channel.

Abstract: An integrated guidance system for use in swath guidance applications combines the display of swath navigation information with swath guidance system information. A processor receives information from an external positioning system such as a Global Positioning System receiver and generates course correction data derived from swath parameters selected by the user from a displayed menu of options using a control interface that is integrated with the display and processor or is located externally. The swath navigation information is displayed graphically and numerically. The entire apparatus is compact and mountable within the operative view of the user as he operates the equipment to be guided, thereby reducing hazard and navigational error.

Abstract: An apparatus for extending the practical lengths over which coaxial cables can be used to transfer signal information from a Global Positioning System (GPS) antenna to a GPS receiver. The apparatus converts the GPS signal frequency of 1.57542 GHz to a frequency low enough to be transferred long distances over coaxial cables without significant signal attenuation and then converts the signal back to the original frequency without the introduction of frequency errors. The invention is not restricted from being used at other frequencies where system design parameters makes it practical.

Abstract: A portable laser pulse detection device. Optical pulses are sensed by a photodiode, and if the pulse width is narrow enough to yield sufficient spectral energy within the bandpass of the tuned circuits, a "laser occurred" indication will be produced by the processing circuitry. Automatic adjustment of the detected output for non-laser incident radiation is made by varying the signal level into a sequential detection logarithmic amplifier by a voltage proportional to the integral of the incident radiation over a short period of time. The device is shielded against electromagnetic interference and adapts automatically to variations in background noise.