GPS correction methods, apparatus and signals
Granted: September 28, 2004
Patent Number:
6799116
Methods and apparatus are described and illustrated for producing GPS corrections, comprising: collecting measurements from a plurality of network reference stations; determining network corrections from the measurements; determining residual errors at one or more vernier-cell reference stations; and preparing vernier-cell corrections to compensate the residual errors within a vernier-cell region. Network correction streams are described and illustrated which contain network corrections…
Slow hopping data transmitter
Granted: September 21, 2004
Patent Number:
6795410
A method and apparatus for coupling data between communication devices in which data is transmitted over unoccupied radio channels. Multiple radio channels are monitored by a first communication device and a radio channel or a sequence of radio channels is assigned that is unoccupied. A message is then transmitted by the first communication device that includes the assigned radio channel or assigned sequence of radio channels. The first communication device then changes the radio channel…
Self-calibrating electronic distance measurement instrument
Granted: August 10, 2004
Patent Number:
6774839
A combined satellite positioning and electro-optical total station system includes a reference oscillator that provides local oscillator signals for a satellite navigation receiver and a precision frequency source for use by an electronic distance meter. When the satellite navigation receiver is locked onto and tracking orbiting navigation satellites, the highly precise cesium-rubidium clocks in the navigation satellite system can be used as standards to control the reference oscillator…
Web based data mining and location data reporting and system
Granted: July 27, 2004
Patent Number:
6768994
A database reporting and data mining system operates in one embodiment on a database of a location aware wireless gateway that processes message, location, event data obtained from an asset sensor or user, and other telemetry data from remote assets such as vehicles of a business enterprise fleet, and presents configurable reports on web pages displayed within the user's web browser in text or chart form. Reports, which may be user-customized, are created in response to user queries…
Electronic rotor pointing with high angular resolution
Granted: July 13, 2004
Patent Number:
6762575
A laser level with a sensorless DC motor controller having a feedback sampling circuit connected in parallel with the coil to sense back EMF. An integrator provides a feedback signal from the sensed back EMF, which the amplified difference from a reference level is used as a pulse width control signal. A pulse width modulation generator uses the control signal to generate variable “on” time pulse widths for each motor drive pulse such that high resolution is provided to the…
Handheld data collection device
Granted: June 29, 2004
Patent Number:
D492306
Photocell bias circuit
Granted: June 29, 2004
Patent Number:
6756578
Receiver circuits are provided for detecting a target light source. The circuits include a photocell arranged to detect light impinging thereupon, and a biasing circuit that maintains a constant reverse voltage across, the photocell irrespective of the photocell output. This maintains the capacitance of the photocell at a substantially constant value, and results in faster response times from the photocell. Further, the present invention provides circuits for effectively removing ambient…
Position detecting laser receiver
Granted: June 15, 2004
Patent Number:
6750953
Receiver circuits are provided for detecting a target light source such as a swept laser beam. The circuits include a photodetector adapted to produce a first detector output signal and a second detector output signal where the relative amplitudes of the first and second detector output signals are related to the position of a swept laser beam impinging thereon. A first log signal is determined, which is based upon a logarithmic and optionally scaled calculation utilizing the first…
Method and system for providing wide area augmentation system (WAAS) like corrections using a server and processor on the internet
Granted: May 25, 2004
Patent Number:
6741935
A method and system are disclosed for providing WAAS like corrections using a server and processor on the Internet. For one method, satellite measurement data is collected. Satellite position error corrections are computed using the collected satellite measurement data. The computed satellite position error corrections are stored. The stored satellite position error corrections can then be later retrieved and used by a server and processor on the Internet.
File system for avoiding loss of data
Granted: May 25, 2004
Patent Number:
6742079
An MS DOS and MS WINDOWS compatible file system for avoiding loss of data in a memory unit if power is interrupted while new data is being written. The file system uses an ATA write command for erasing a data reserve sector and writing the modified data including the new data into the data reserve sector; erasing a control reserve sector and writing control data into the control reserve sector; erasing the intended operational sector and writing the modified data into the intended…
Transducer arrangement for screed control
Granted: May 4, 2004
Patent Number:
6729796
A transducer arrangement and method that generates control signals indicating relative positions of the ends of a hydraulically movable screed head. The generated control signals of the present invention are used by a conventional control circuit controlling the hydraulically movable screed head with laser receivers in a column block situation, which interrupts the reception of a laser beam from a laser transmitter by one of the laser receivers, to provide an estimated absolute position…
Speech recognizing GIS/GPS/AVL system
Granted: May 4, 2004
Patent Number:
6732077
A speech recognition equipped geographic information recording apparatus and method. In one embodiment, a mobile data terminal has a communication node therein. A geographic mapping system is integral with the mobile data terminal, and is coupled to the communication node. A speech recognition system adapted to receive verbal information is also coupled to the mobile data terminal. The speech recognition system is adapted to receive attribute data verbalized by an operator of the mobile…
Seamless surveying system
Granted: May 4, 2004
Patent Number:
6732051
A survey system and method for determining the best source of position data for a particular application. The system includes both an optical unit and a satellite positioning system (SATPS) unit for obtaining position data. The optical unit includes a theodolite and an electronic distance meter for determining the position of a rover unit. The SATPS unit includes a SATPS antenna and a SATPS receiver for receiving signals from satellites of the SATPS and a radio for coupling the received…
GPS receiver having improved signal acquisition at a low signal to noise ratio
Granted: May 4, 2004
Patent Number:
6731672
A GPS receiver having a fast acquisition of a GPS signal having a low signal-to-noise ratio. The GPS receiver uses an adjustable local frequency for iteratively downconvertig raw GPS signal samples to baseband GPS signal code data, combining a plurality of code epochs of the GPS signal code data in chunks and superchunks for providing representative code epochs, and correlates the representative code epochs to a replica code epoch for providing correlation times. Two or more correlation…
Seamless surveying system
Granted: April 27, 2004
Patent Number:
6727849
A survey system and method for determining the best source of position data for a particular application. The system includes both a satellite positioning system (SATPS) and a non-SATPS unit for obtaining position data. The SATPS unit includes a SATPS antenna and a SATPS receiver for receiving signals from satellites of the SATPS and a radio for coupling the received signals to the rover unit. Data is collected using both the SATPS and non-SATPS methods to obtain a master data set. Data…
Method and system to connect internet protocol hosts via an application specific bus
Granted: April 27, 2004
Patent Number:
6728268
The present invention includes a system and method to implement Internet Protocol (IP) hosts on an application specific bus without disrupting the application specific bus. In one embodiment, an IP host determines the application specific bus address of a remote device, the remote device having an IP address in addition to the application specific bus address. The IP host formats a message conforming to the application specific bus, the message containing IP data and message identifiers.…
Indoor GPS clock
Granted: April 20, 2004
Patent Number:
6725157
An indoor GPS clock using GPS signals lower that −143 dBm for issuing disciplined frequency and time standard signals. The indoor GPS clock includes a correlation machine using long integration periods for enabling the indoor GPS clock to operate with low signal levels; a carrier-less tracking loop for tracking the low level signals without carrier offset feedback, a clock bias loop for providing clock bias feedback; and a reference oscillator using the clock bias feedback for…
Method for sending message that indicates position and message transmission device and message transmission server
Granted: April 6, 2004
Patent Number:
6717509
A method and system for sending messages that indicate position. In one embodiment, the message transmission device includes a message transmission unit that is coupled to a position determination system. A server is adapted to receive messages from the message transmission device. In operation, a first message is generated at the message transmission device. The position of the message transmission device is determined and is included in the message. The message is then sent to the…
Guiding vehicle in adjacent swaths across terrain via satellite navigation and tilt measurement
Granted: March 9, 2004
Patent Number:
6703973
A method of guiding a vehicle in adjacent swaths across terrain that may slope comprising the steps of: (1) determining the tilt of the vehicle with respect to Earth due to a slope of the terrain; (2) determining the position with respect to Earth of a predetermined location that is fixed relative to the vehicle; and (3) using the tilt and position determinations to provide information for guiding the vehicle to prevent gaps and overlaps between adjacent swaths as the slope changes.
Laser projector for producing intersecting lines on a surface
Granted: February 24, 2004
Patent Number:
6694629
A portable construction layout tool generates laser beams in two or more directions related by a specific angle, such as 90°. The instrument emits two fans of light in such a way as to project a pair of lines on the floor, wall or other surface on which the instrument is mounted or placed, with the intersection of the two being visible rather than being a virtual intersection hidden beneath the instrument itself, enabling easier setup. Compared to rotating-beam instruments, the…
