Abstract: Differential correction signals for a global positioning system (GPS), which operates with signals from a plurality of orbiting satellites, are provided in a first standard format, such as a RTCM SC-104 format, for each satellite in view of a reference receiver station. The differential correction signals include range error correction signals and range rate error correction information. The differential correction signals are then encoded according to a second standard format, such as the RDS format. The transmission time of the signals in the second standard format are then prioritized. A broadcast transmitter, such as a broadcast FM transmitter, is then modulated by the prioritized signals in the second standard format and a receiver receives and demodulates the broadcast signal. The broadcast prioritized signals in the second standard format are then decoded to provide differential correction signals in the first standard format.

Abstract: A global positioning system (GPS) receiver having a radio frequency (RF) circuitry to receive position signals from a plurality of satellites and to provide an intermediate frequency (IF) signal to a correlator circuitry for generating a pseudo range and a Doppler measurement for calculating a position fix. The GPS receiver further has a power supply system which has at least one battery and an alternative external power connector for connecting to an external power source. The GPS receiver further has a microprocessor having a read only memory (ROM). The microprocessor is electrically connected to the RF circuitry and the power supply system. Since the GPS receiver does not need to constantly process all the GPS position signals that are available to it to provide a useful tool, the ROM includes a program for automatically controlling the power supply to the RF circuitry so that battery power is conserved.

Abstract: An embodiment of the present invention includes a GPS receiver capable of concurrently tracking up to eight GPS satellites. The GPS receiver comprises computer-implemented methods for parallel search, split search and precomputation. The parallel search method causes the apparent Doppler frequency spectrum to be sectioned into several segments and a first GPS satellite signal is searched for in parallel in each of the segments. When the first GPS fix is not found after a predetermined time has expired, a split search is begun.

Abstract: A system, according to an embodiment of the present invention, comprises a coupler, a remote antenna, and a handheld GPS receiver. The remote antenna has a microstrip RHCP receiving element and a low noise amplifier (LNA) powered by the coupler over an interconnect cable. The coupler has a slotline antenna and a driver circuit. The coupler re-radiates GPS satellite signals received by the remote antenna with a slotline antenna to the GPS receiver. In a typical installation, such as a car, a user holds the GPS receiver while in the front seat. The coupler mounts to the windshield and the cable runs to remote antenna mounted on the roof of the car. The coupler can then re-radiate GPS satellite signals effectively to the GPS receiver even when the two are separated by as much as six feet. The shielding of GPS signals by the metal of the car is thereby avoided as a problem that can prevent operation of the GPS receiver.

Abstract: A wafer transfer mechanism used for transferring wafers between cassettes and a boat uses sensors to detect and to measure any offset of the actual center of each wafer being transferred with respect to the expected or precalibrated center of that wafer. An appropriate adjustment is made to effectively eliminate such offset so that each wafer can be transferred throughout the system without any edge contact between a wafer and the boat or the cassette. The system also includes a boat exchange unit having a rotatable turntable which is used in association with two boats. The boat exchange unit permits a continuous mode operation in which one boat can be undergoing a loading or unloading of wafers at one station on the turntable while another boat is at or is moving to or from a heating chamber loading or unloading station on the turntable.

Abstract: A spectrophotometer optical section is presented which employs a fine positioning beam director which corrects for any deflections of the output beam path and accurately positions the optical beam on the detector slit of the spectrograph. The detector slit is chosen to have a size slightly smaller than the size of the optical beam at the detector slit to have high slit throughput without introducing spurious absorption. The sample cells need not be rigidly mounted thereby enabling use of a sample cell and cell holder which allows quick, easy interchange of cells.

Abstract: A beam directing device is provided which employs one or more mirrors mounted on a single rotatable shaft. The orientation of the shaft controls the rotational orientation of these directing mirror(s) to direct the beam toward any of a number of sample or reference cells. Behind each cell is a cube corner which reflects the beam back to the directing mirror(s) for reflection toward the detector. In one embodiment, a shaft encoded senses the orientation of the shaft, the encoder output being servoed against a position signal to coarsely rotate the shaft in order to direct the beam to a sample cell and thence to a spectrograph slit. A pair of slit diodes detect the beam overlap on each side of the slit and their output is used to accurately position the beam on the slit to within one second of arc and correct for deviations in beam direction.