Abstract: The invention relates to methods, notably carried out by global or regional navigation satellite system (NSS) receivers, which involve receiving satellite-specific, nadir-angle dependent correction information associated with each of at least two NSS satellites among a plurality of NSS satellites. The correction information is useful to correct observed NSS signals, so as to mitigate the effects of satellite-specific, nadir-angle dependent biases in the NSS signals, and thus improve the performance of position determination systems. The invention also relates to methods for generating such correction information, to methods for designing a satellite, to NSS receivers, to apparatuses for generating correction information to be sent to the receivers, and to computer programs and storage mediums.

Abstract: The invention relates to methods, notably carried out by global or regional navigation satellite system (NSS) receivers, which involve receiving satellite-specific, nadir-angle dependent correction information associated with each of at least two NSS satellites among a plurality of NSS satellites. The correction information is useful to correct observed NSS signals, so as to mitigate the effects of satellite-specific, nadir-angle dependent biases in the NSS signals, and thus improve the performance of position determination systems. The invention also relates to methods for generating such correction information, to methods for designing a satellite, to NSS receivers, to apparatuses for generating correction information to be sent to the receivers, and to computer programs and storage mediums.

Abstract: The invention relates to methods, notably carried out by global or regional navigation satellite system (NSS) receivers, which involve receiving satellite-specific, nadir-angle dependent correction information associated with each of at least two NSS satellites among a plurality of NSS satellites. The correction information is useful to correct observed NSS signals, so as to mitigate the effects of satellite-specific, nadir-angle dependent biases in the NSS signals, and thus improve the performance of position determination systems. The invention also relates to methods for generating such correction information, to methods for designing a satellite, to NSS receivers, to apparatuses for generating correction information to be sent to the receivers, and to computer programs and storage mediums.

Abstract: The invention relates to methods, notably carried out by global or regional navigation satellite system (NSS) receivers, which involve receiving satellite-specific, nadir-angle dependent correction information associated with each of at least two NSS satellites among a plurality of NSS satellites. The correction information is useful to correct observed NSS signals, so as to mitigate the effects of satellite-specific, nadir-angle dependent biases in the NSS signals, and thus improve the performance of position determination systems. The invention also relates to methods for generating such correction information, to methods for designing a satellite, to NSS receivers, to apparatuses for generating correction information to be sent to the receivers, and to computer programs and storage mediums.

Abstract: A method of communicating satellite tracking information among a network of global navigation satellite system receivers is described. The method includes determining at a first GNSS receiver which satellites in a constellation of satellites have been continuously tracked over a preceding selected time period, and for each such satellite determining its elevation with respect to the zenith. Only the elevation value for the lowest satellite in the set of satellites for which all satellites of higher elevation values have been continuously tracked over the selected time period is then transmitted to the second GNSS receiver. That receiver can then reconstruct the set of satellites which have been continuously tracked.

Abstract: A surveying apparatus includes an antenna to receive a positioning signal. The surveying apparatus further includes a tilt sensor to obtain a tilt measurement that indicates a degree of tilt of the survey apparatus. The surveying apparatus further includes a processor to obtain a positioning measurement from the positioning signal, and to determine a degree of accuracy of the positioning measurement based on the tilt measurement.

Abstract: A method of communicating corrections for information related to satellite signals among global navigation satellite system (GNSS) receivers is described. An ionosphere correction for ionosphere signal path delay is determined for a first satellite. This ionosphere correction is then compared to an ionosphere correction for ionosphere signal path delay for a satellite assumed to be directly over the receiver. The receiver then sends a message which includes only the difference between the ionosphere correction for the actual observation and the ionosphere correction for a satellite assumed to be at the zenith.

Abstract: A format for providing messages among GNSS apparatus includes providing a message identification block and a message body. The message identification block includes information specifying a message length and a message type block specifying a message type. Rather than sending all data from one apparatus to another, ambiguous observation data is sent to conserve bandwidth. At the sender a deconstruction of GNSS code and carrier observations using knowledge of the signal structure and constellation geometry, together with simplifications of atmospheric models, allows removal from the observation data of that information which can be implicitly understood or recreated by the recipient. This enables only the necessary information to be packed for transmission to the recipient.

Abstract: A method of communicating corrections for information related to satellite signals among global navigation satellite system (GNSS) receivers is described. An ionosphere correction for ionosphere signal path delay is determined for a first satellite. This ionosphere correction is then compared to an ionosphere correction for ionosphere signal path delay for a satellite assumed to be directly over the receiver. The receiver then sends a message which includes only the difference between the ionosphere correction for the actual observation and the ionosphere correction for a satellite assumed to be at the zenith.

Abstract: A method of communicating satellite tracking information among a network of global navigation satellite system receivers is described. The method includes determining at a first GNSS receiver which satellites in a constellation of satellites have been continuously tracked over a preceding selected time period, and for each such satellite determining its elevation with respect to the zenith. Only the elevation value for the lowest satellite in the set of satellites for which all satellites of higher elevation values have been continuously tracked over the selected time period is then transmitted to the second GNSS receiver. That receiver can then reconstruct the set of satellites which have been continuously tracked.

Abstract: A format for providing messages among GNSS apparatus includes providing a message identification block and a message body. The message identification block includes information specifying a message length and a message type block specifying a message type. Rather than sending all data from one apparatus to another, ambiguous observation data is sent to conserve bandwidth. At the sender a deconstruction of GNSS code and carrier observations using knowledge of the signal structure and constellation geometry, together with simplifications of atmospheric models, allows removal from the observation data of that information which can be implicitly understood or recreated by the recipient. This enables only the necessary information to be packed for transmission to the recipient.

Abstract: A surveying apparatus includes an antenna to receive a positioning signal. The surveying apparatus further includes a tilt sensor to obtain a tilt measurement that indicates a degree of tilt of the survey apparatus. The surveying apparatus further includes a processor to obtain a positioning measurement from the positioning signal, and to determine a degree of accuracy of the positioning measurement based on the tilt measurement.

Abstract: In accordance with embodiments of the invention, a skyward-looking sensor enables classification of points in its hemispherical field of view as either sky, partial sky or not sky, which in turn enables determination from data supplied by the GNSS receiver of whether each satellite in the GNSS antenna's field of view is in a region of sky, partial sky or not sky. Pseudrange and phase data from GNSS satellites determined to be in a region of sky can be considered reliable and used with confidence in a positioning solution. Pseudrange and phase data from GNSS satellites determined to be in a region of partial sky can be considered suspect and can therefore only contribute to a position solution with limited confidence and decreased accuracy. Pseudorange and phase data from GNSS satellites determined to be in a region of no sky can be considered unreliable and excluded from use in a positioning solution.

Abstract: A method and system for variable data rate transmission in a real-time kinematic (RTK) positioning system. An RTK positioning system having a reference station and a rover utilizes wireless communications for data transfer. The data transmission rate between the reference station and the rover is dynamically controlled by a programmable transmission controller. The transmission rate is determined on the basis of specific parameters. Parameters that may be used to determine the data transmission rate include rover demand, required rover accuracy, satellite positioning system (SATPS) events, the required data for ambiguities, and the type and content of the data transmitted.

Abstract: In accordance with embodiments of the invention, a skyward-looking sensor enables classification of points in its hemispherical field of view as either sky, partial sky or not sky, which in turn enables determination from data supplied by the GNSS receiver of whether each satellite in the GNSS antenna's field of view is in a region of sky, partial sky or not sky. Pseudrange and phase data from GNSS satellites determined to be in a region of sky can be considered reliable and used with confidence in a positioning solution. Pseudrange and phase data from GNSS satellites determined to be in a region of partial sky can be considered suspect and can therefore only contribute to a position solution with limited confidence and decreased accuracy. Pseudorange and phase data from GNSS satellites determined to be in a region of no sky can be considered unreliable and excluded from use in a positioning solution.

Abstract: A method and system for variable data rate transmission in a real-time kinematic (RTK) positioning system. An RTK positioning system having a reference station and a rover utilizes wireless communications for data transfer. The data transmission rate between the reference station and the rover is dynamically controlled by a programmable transmission controller. The transmission rate is determined on the basis of specific parameters. Parameters that may be used to determine the data transmission rate include rover demand, required rover accuracy, satellite positioning system (SATPS) events, the required data for ambiguities, and the type and content of the data transmitted.

Abstract: A method and system for variable data rate transmission in a real-time kinematic (RTK) positioning system. An RTK positioning system having a reference station and a rover utilizes wireless communications for data transfer. the data transmission rate between the reference station and the rover is dynamically controlled by a programmable transmission controller. The transmission rate is determined on the basis of specific parameters. Parameters that may be used to determine the data transmission rate include rover demand, required rover accuracy, satellite positioning system (SATPS) events, the required data for ambiguities, and the type and content of the data transmitted.

Abstract: The system and method for long baseline RTK survey are disclosed. The system includes a primary base station (PBS), a secondary base station (SBS), a primary data link between the PBS and the SBS, and a secondary data link between the SBS and a rover. The PBS, the SBS, and the rover are equipped with satellite antennas for satellite navigational purposes, and with the wireless Internet data accesses devices (WIDAD). The long baseline vector between the PBS and the rover is established by combining the primary baseline vector between the SBS and the PBS and the secondary baseline vector between the SBS and the rover. The PBS is placed in a position with a known location. The PBS wirelessly downloads its logged set of data into the Internet server using the (PBS-WIDAD). The SBS determines its precise position coordinates by accessing wirelessly the PBS logged data on the Internet server using the (SBS-WIDAD).

Abstract: The system and method for long baseline RTK survey are disclosed. The system includes a primary base station (PBS), a secondary base station (SBS), a primary data link between the PBS and the SBS, and a secondary data link between the SBS and a rover. The PBS, the SBS, and the rover are equipped with satellite antennas for satellite navigational purposes. The long baseline vector between the PBS and the rover is established by combining the primary baseline vector between the SBS and the PBS and the secondary baseline vector between the SBS and the rover. The PBS is placed in a position with a known location. The final SBS position is accurately determined using the PBS position during two initialization steps.

Abstract: A first position determining device at a known position transmits a data signal identifying the known position. A second position determining device is responsive to the data signal and movable to a position near but displaced from a survey point. The position of the second position determining device is determined relative to the known position, and the range and bearing of the survey point is determined relative to the second position determining device.