Abstract

A GNSS receiver (100) receives radio signals (S(SV)) transmitted from an active set of signal sources (SV1, SV2, SV3, SV5) and based thereon produces position/time related data (DPT). The receiver (100) has a tracking channel resource for each signal source (SV1, SV2, SV3, SV5) in the active set, and the tracking channel resources process the radio signals (S(SV)) in parallel with respect to a real-time signal data rate of the signals. The receiver (100) also includes a signal-source database (140), a signal-masking database (150) and a control unit (130). The signal-source database (140) describes the movements of the signal sources (SV1, SV2, SV3, SV4, SV5) over time relative to a given reference frame, and the signal-masking database (150) reflects, for positions (P) within a predefined geographic area, visibility/blockage to the sky with respect to a direct line of sight in terms of spatial sectors (M1(P), M2(P) M3(P)). The control unit (130) derives data describing a current position/time (PTR(t)) and a current velocity vector (VR(t)) for the receiver (100) based on the position/time related data (DPT); and derives an estimated visibility of the signal sources (SV1, SV2, SV3, SV5) in the active set at a second position/time (PTR(t+Δt)) representing an expected future position/time for the receiver (100) based on the signal-source and signal-masking databases (140; 150). If at least one signal source (SV1) in the active set is estimated not to be visible at the second position/time (PTR(t+Δt)), the control unit (130) initiates a modification of the active set aiming at replacing the at least one non-visible signal source (SV1) with at least one signal source (SV4) which, based on the signal-source and signal-masking databases (140; 150), is estimated to be visible at the second position/time (PTR(t+Δt)).

IPC Classes  ?

• G01S 1/00 - Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmittersReceivers co-operating therewith

Abstract

A GNSS receiver design is tested, which design includes software (135) for generating position/time related data (DPT) based on raw digital data (dRAw) when the software (135) is executed in a processing unit (130) of the receiver. GNSS signals (SRF) are received via a radio frequency input device (105) while moving the radio frequency input device (105) along a route trajectory. The received GNSS signals (SRF) are fed to a radio-frequency front end (110) of a representative example of a receiver unit built according to the design to be tested. The radio-frequency front end (110) produces raw digital data (dRAw) representing the received GNSS signals (SRF), and the raw digital data (dRAw) are stored in a primary data storage (210) as a source file (Fsc). The source file (Fsc) is read from the primary data storage (210), and the source file (Fsc) is processed by means of the software (135) to generate at least one set of position/time related data (DPT). Each set of position/time related data (DPT) is stored to a respective result file (Fres), and the result file(s) (Fres) is(are) evaluated against reference data (Dref) to determine the perfor mance of the design.

IPC Classes  ?

• H04B 17/00 - MonitoringTesting
• G01S 1/00 - Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmittersReceivers co-operating therewith

Abstract

A method is provided of synchronising a receiver with a signal transmitted by a remote transmitter on-board a satellite. The signal comprises the repeated transmission of time data defining the transmission time and orbit data relating to the orbit of the satellite. The method comprises receiving the transmitted signal at the receiver; obtaining reference data at least a part of which corresponds to the data within the transmitted signal; and estimating a receipt time relating to the transmitted signal. A predicted signal is selected based upon the reference data and the estimated receipt time, this being compared with the received signal. The time synchronisation of the received signal is then determined based upon the comparison and the time data.

IPC Classes  ?

• G01S 1/00 - Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmittersReceivers co-operating therewith
• G01S 5/14 - Determining absolute distances from a plurality of spaced points of known location

Abstract

A method is provided of calculating the position of a receiver with respect to a transmitter on-board each of at least four satellites. The method comprises synchronising a receiver time of the receiver with a transmission time of a first transmitter of the plurality of transmitters. The time of transmission of signals received from each of the other satellites is then estimated based upon the receiver time, an estimated user position and orbit data relating to the orbit of each satellite. Pseudoranges for each satellite are then calculated and then used to calculate a revised user position. The method is repeated until the user position meets a predetermined convergence criterion.

IPC Classes  ?

• G01S 1/00 - Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmittersReceivers co-operating therewith
• G01S 5/14 - Determining absolute distances from a plurality of spaced points of known location

Abstract

A proposed GNSS receiver includes a radio signal processing unit adapted to process radio signals transmitted from an active set (Sact) of signal sources (SV1 , SV2, SV3, SV4, SV8, SV9) and based thereon produce position/time related data. The signals of the active set (sact) are processed in parallel with respect to a real-time signal data rate of the signals by a respective tracking channel resource (T1 , T2, T3, T4, T5, T6) allocated for each signal source. The processing unit also has a monitoring channel resource (M) adapted to process radio signals transmitted from each of at least two signal sources (SV5, SV6, SV7, SV10) in an additional set (sadd) of signal sources different from the signal sources (SV1 , SV2, SV3, SV4, SV8, SV9) in the active set (sact)- The processing unit is adapted to process the radio signals of the additional set sadd according to a cyclic processing sequence (&sgr;) involving: processing signals from a first additional signal source (SV5) during a first phase (ph1 ) of the sequence (&sgr;); processing signals from at least one second additional signal source (SV6, SV7, SV10) during at least one second phase (ph2, ph3, ph4) of the sequence (&sgr;); and determining in each of said phases (ph1 , ph2, ph3, ph4) a respective set of parameters (P1 , P2, ... , Pn) regarding the radio signals (SHF) received from one signal source (SV5, SV6, SV7, SV10) in the additional set (sadd). The set of parameters (P1 , P2, ... , Pn) includes tracking-parameter data. Thus, the signals from any of the signal sources (SV5, SV6, SV7, SV10) in the additional set (sadd) can be included into the navigation solution without delay at any time.

IPC Classes  ?

• G01S 1/00 - Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmittersReceivers co-operating therewith
• G01S 5/14 - Determining absolute distances from a plurality of spaced points of known location