Abstract:
A method and system for delivery of location-dependent time-specific corrections. In one embodiment, a first extended-lifetime correction for a first region is generated. A distribution timetable is used to determine a first time interval for transmitting the first extended-lifetime correction to the first region. The first extended-lifetime correction is then transmitted via a wireless communication network to said first region in accordance with said distribution timetable.
Abstract:
A combination laser system and global navigation satellite system has a laser detector positioned in a known and fixed relationship with the nominal phase center of an included global navigation satellite antenna. The outputs of the laser system and the global navigation satellite system are used together to determine position.
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:
A machine control system uses a laser system and global navigation satellite system to determine the position of the machine. The laser system has a laser detector positioned in a known and fixed relationship with the nominal phase center of a global navigation satellite antenna. The laser detector receives laser light transmitted from a laser transmitter. The outputs of the laser system and the global navigation satellite system are used together to determine the position of the transmitter prior to being used to determine the position of the machine.
Abstract:
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 in the combined satellite positioning and electro-optical total station system. Baseline measurements made by the electronic distance meter are therefore not subject to mis-calibrations and drift as long as the satellite navigation receiver is locked onto and tracking the orbiting navigation satellites.
Abstract:
Apparatus for measuring surveying parameters, such as distances and angular displacements between an instrument survey station and a mobile survey station, with improved accuracy. The invention combines a differential satellite positioning system (DSATPS), available with positioning systems such as GPS and GLONASS, with electromagnetic measurements of distances and optically encoded angles by a conventional electro-optical survey instrument to provide survey measurements that can be accurate to within a few millimeters in favorable situations. The DSATPS relies upon pseudorange measurements or upon carrier phase measurements, after removal of certain phase integer ambiguities associated with carrier phase SATPS signals. The SATPS may be retrofitted within the housing of the conventional electro-optical instrument. In a first approach, a remote station provides DSATPS corrections for the mobile station and/or for the instrument station. In a second approach, the mobile station provides DSATPS corrections for itself and for the instrument station. In a third approach, the instrument station provides DSATPS corrections for itself and for the mobile station.
Abstract:
A combined satellite positioning and electro-optical total station system including a satellite navigation receiver and a reference oscillator with a reference frequency output that can be related to precision time standards obtained from orbiting navigation-satellite transmissions. Such time standards are output by the satellite navigation receiver and are highly precise. An electronic distance meter (EDM) is included and has an EDM-transmitter for launching an out-bound signal to a distant target, and an EDM-receiver for receiving a reflected signal from the distant target. A phase measurement device is connected to the reference oscillator, and also to both the EDM-transmitter and EDM-receiver. It provides for a measurement of the difference in the number of cycles of the reference frequency between the out-bound signal and the reflected signal. A post-processor is connected, such as by radio link or floppy disk, to receive the measurement of the difference in the number of cycles of the reference frequency and the precision time standards obtained from orbiting navigation-satellite transmissions. Post-processing is then able to relate the corresponding measurements and time standards such that a distance-to-target measurement can ultimately be computed. Therefore routine calibration of the EDM is unnecessary. The measurement of the difference in the number of cycles of the reference frequency is time-tagged and stored for later retrieval to construct a time-ordered log. The precision time standards obtained from the orbiting navigation-satellite transmissions are similarly time-tagged and stored. Thus a series of distance-to-target measurement can be computed according to the order they were originally collected in the field by the EDM, as might be necessary in a legal inquiry.
Abstract:
Apparatus for measuring surveying parameters, such as distances and angular displacements between survey stations, with improved accuracy. The invention combines a differential satellite positioning system (SATPS), available with positioning systems such as GPS and GLONASS, with electromagnetic measurements of distances and optically encoded angles by a conventional electro-optical survey instrument to provide survey measurements that can be accurate to within a few millimeters in favorable situations. The differential satellite positioning system relies upon carrier phase measurements, after removal of certain phase integer ambiguities associated with carrier phase SATPS signals. The SATPS may be retrofitted within the housing of the conventional electro-optical instrument.
Abstract:
In a method for refining a position estimate of a low earth orbiting (LEO) satellite a first position estimate of a LEO satellite is obtained with a GNSS receiver on-board the LEO satellite. The first position estimate is communicated to a Virtual Reference Station (VRS) processor. VRS corrections are received at the LEO satellite, the VRS corrections having been calculated for the first position estimate by the VRS processor. The VRS corrections are processed on-board the LEO satellite such that a VRS corrected LEO satellite position estimate of the LEO satellite is generated for the first position estimate.
Abstract:
In a method for refining a position estimate of a low earth orbiting (LEO) satellite a first position estimate of a LEO satellite is obtained with a GNSS receiver on-board the LEO satellite. The first position estimate is communicated to a Virtual Reference Station (VRS) processor. VRS corrections are received at the LEO satellite, the VRS corrections having been calculated for the first position estimate by the VRS processor. The VRS corrections are processed on-board the LEO satellite such that a VRS corrected LEO satellite position estimate of the LEO satellite is generated for the first position estimate.