Abstract: A GPS antenna comprises an antenna body that can rotate between horizontal and vertical positions between the handle horns on the top of an optical total station. A GPS receiver embodiment comprises an integrated body and antenna that can similarly be rotated between horizontal and vertical positions between the handle horns on the top of an optical total station to avoid interference with the total station optics.

Abstract: A video cassette recorder includes a tape transport and servo that records digital data at one tape speed and plays back the digital data at one twentieth of the recording speed, both with a fixed speed of rotation of a drum head. On playback, each recorded segment of data on the tape is read from ten slightly different longitudinal positions on the magnetic tape, with the highest amplitude read-back signal being selected. The drum head comprises two playback heads that each have playback widths that are approximately twice as wide as each of four recording heads in the drum head.

Abstract: A surveying instrument comprises a tripod with a tribrach that receives both a theodolite and a C-bracket that half vertically encircles the theodolite. The C-bracket and the theodolite are each independently pivotable on the same vertical axis and the C-bracket is able to completely orbit around the theodolite such that it can be positioned so as not to optically interfere with the use of the theodolite. The top of the C-bracket provides a mount for a navigation satellite receiver antenna that positions the axis of rotation of the C-bracket through the electrical center of the antenna.

Abstract: A system embodiment of the present invention comprises a fixed and a roving pair of four-observable GPS receivers and a communication link between them for double differencing code and carrier measurements. Carrier phase integer ambiguities are resolved efficiently by searching the simultaneous narrow-lane intersections of both the L1 and L2 wave fronts propagated by the GPS satellites being tracked. External constraint information, such as elevation, is additionally used to speed up integer ambiguity resolution. Data between the reference station and the rover is communicated in compressed form at a regular interval, e.g., once a second at each epoch, and demi-measurements of carrier phase are obtained more frequently, e.g., ten times a second, and used to propagate solutions between epochs.

Abstract: An insulation material comprising the double salt of aluminum potassium sulphate and method of producing such. Aluminum sulphate materials and potassium sulphate materials are combined to form aluminum potassium sulphate which is then dehydrated to remove the water of hydration. Porous forms are made by mixing the hydrated aluminum potassium sulphate with a binder before dehydration. The resultant dehydrated sulphate expands greatly to provide an insulative material which is of lightweight and inorganic.

Abstract: A drop-in arc lamp assembly comprising an arc lamp with fitted cathode and anode heat sinks each including a thin-wall copper strip that is brazed in pleated folds between inner and outer cylindrical rings to create cooling fins. The drop-in lamp assembly also includes an insulative sleeve in which the arc lamp and heat sinks are disposed and a pair of connection bushings piercing the wall of the sleeve and providing an electrical connection to the arc lamp outside the sleeve. A flush-mount receptacle for the drop-in lamp assembly includes a housing with a fan axially positioned behind the arc lamp and heat sinks when they are in place in the sleeve and dropped-into the housing. A glass epoxy board attached to the housing supports and insulates electrical terminals that contact the bushings to power the arc lamp. The arc lamp includes a copper heat conduction flange that surrounds a front window reduced in diameter from the diameter of the arc lamp.