Abrégé

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)).

Classes IPC  ?

• G01S 1/00 - Radiophares ou systèmes de balisage émettant des signaux ayant une ou des caractéristiques pouvant être détectées par des récepteurs non directionnels et définissant des directions, situations ou lignes de position déterminées par rapport aux émetteu; Récepteurs travaillant avec ces systèmes

Abrégé

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.

Classes IPC  ?

• H04B 17/00 - Surveillance; Tests
• G01S 1/00 - Radiophares ou systèmes de balisage émettant des signaux ayant une ou des caractéristiques pouvant être détectées par des récepteurs non directionnels et définissant des directions, situations ou lignes de position déterminées par rapport aux émetteu; Récepteurs travaillant avec ces systèmes

Abrégé

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.

Classes IPC  ?

• G01S 1/00 - Radiophares ou systèmes de balisage émettant des signaux ayant une ou des caractéristiques pouvant être détectées par des récepteurs non directionnels et définissant des directions, situations ou lignes de position déterminées par rapport aux émetteu; Récepteurs travaillant avec ces systèmes
• G01S 5/14 - Localisation par coordination de plusieurs déterminations de direction ou de ligne de position; Localisation par coordination de plusieurs déterminations de distance utilisant les ondes radioélectriques déterminant des distances absolues à partir de plusieurs points espacés d'emplacement connu

Abrégé

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.

Classes IPC  ?

• G01S 1/00 - Radiophares ou systèmes de balisage émettant des signaux ayant une ou des caractéristiques pouvant être détectées par des récepteurs non directionnels et définissant des directions, situations ou lignes de position déterminées par rapport aux émetteu; Récepteurs travaillant avec ces systèmes
• G01S 5/14 - Localisation par coordination de plusieurs déterminations de direction ou de ligne de position; Localisation par coordination de plusieurs déterminations de distance utilisant les ondes radioélectriques déterminant des distances absolues à partir de plusieurs points espacés d'emplacement connu

Abrégé

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.

Classes IPC  ?

• G01S 1/00 - Radiophares ou systèmes de balisage émettant des signaux ayant une ou des caractéristiques pouvant être détectées par des récepteurs non directionnels et définissant des directions, situations ou lignes de position déterminées par rapport aux émetteu; Récepteurs travaillant avec ces systèmes
• G01S 5/14 - Localisation par coordination de plusieurs déterminations de direction ou de ligne de position; Localisation par coordination de plusieurs déterminations de distance utilisant les ondes radioélectriques déterminant des distances absolues à partir de plusieurs points espacés d'emplacement connu

Abrégé

The programmable graphics processor processing a signal from a global navigation satellite system ('GNSS'); has a rasterizer unit, a pixel shader unit and a memory unit. GNSS satellite, received signal converted into a digitized form of the received signal, and transformed by a programmable graphics processor, wherein an array of a corresponding data of the digitized form signal is stored in the memory unit and operated by the pixel shader unit forming a resulting array, written into the memory unit at the first address (see figure 3). A first address and values of the endpoints of the array of the corresponding data of the digitized form signal are supplied to the rasterizer unit. The rasterizer unit interpolates values between values of endpoints of the array. The values of the endpoints and the interpolated values of the array correspond to addresses in the memory unit for the array of the corresponding data of the digitized form signal.

Classes IPC  ?

• G06T 15/00 - Rendu d'images tridimensionnelles [3D]

Abrégé

A proposed data processing device (100) includes at least two processor units (141, 142, 143), which each is adapted to process digitized precorrelation navigation satellite signal data (dF) as well as to process alternative data and/or signals (DA) rela ting to at least one function being uncorrelated with the satellite signal data (dF) . The device (100) includes at least one data buffer (131, 132) adapted to store data sets (⏧dF]) , where each set includes a number of instances of the satellite signal data (dF) . A control module (150) in the device (100) controls execution of a processing job with respect to a stored data set (⏧dF]) by allocating individual processing tasks to at least one of the at least two processor units (141, 142, 143) based on a current processing load on each processor unit (141, 142, 143).

Classes IPC  ?

• G06F 9/46 - Dispositions pour la multiprogrammation
• G01S 1/00 - Radiophares ou systèmes de balisage émettant des signaux ayant une ou des caractéristiques pouvant être détectées par des récepteurs non directionnels et définissant des directions, situations ou lignes de position déterminées par rapport aux émetteu; Récepteurs travaillant avec ces systèmes
• G01S 19/24 - Acquisition ou poursuite des signaux émis par le système
• G01S 19/37 - Récepteurs - Détails de construction ou détails de matériel ou de logiciel de la chaîne de traitement des signaux - Détails de matériel ou de logiciel de la chaîne de traitement des signaux
• H04B 1/707 - Techniques d'étalement de spectre utilisant une modulation par séquence directe

Abrégé

A proposed spread spectrum signal receiver includes a radio signal processing unit, which is at least partly implemented in software running on a processor. The processing unit is adapted to determine a candidate collection of subsets of signal sources among a group of potential signal sources (S1 -S9). Each member of the collection is a subset of the group of potential signal sources, which is defined by a criterion that an anticipated processing intensity required to derive the position/time related data from that subset is equal to or less than a maximum specified processing intensity. Each subset also contains at least a minimum number of signal sources necessary to produce the position/time related data. The processing unit is further adapted to select a set of preferred signal sources based on a candidate subset, which is associated with a highest estimated quality of the position/time related data attainable during a subsequent operating period for the receiver without exceeding the maximum specified processing intensity. Then, during the subsequent operating period, the receiver receives spread spectrum signals from the selected set of signal sources, and based on the received signals produces position/time related data.

Classes IPC  ?

• G01S 1/00 - Radiophares ou systèmes de balisage émettant des signaux ayant une ou des caractéristiques pouvant être détectées par des récepteurs non directionnels et définissant des directions, situations ou lignes de position déterminées par rapport aux émetteu; Récepteurs travaillant avec ces systèmes

Abrégé

A proposed spread spectrum signal receiver includes a radio signal processing unit, which is at least partly implemented in software running on a processor. The processing unit is adapted to estimate a respective processing demand required to produce position/time related data based on each subset of a number of candidate subsets of signal sources among a group of potential signal sources (S1 -S9). Each candidate subset contains at least a minimum number of signal sources, which is necessary to produce the position/time related data of a desired quality. The processing unit is further adapted to select a set of preferred signal sources from the group of potential signal sources (S1 -S9) based on a candidate subset, which is associated with a lowest estimated processing demand during a subsequent operating period for the receiver. Then, during the subsequent operating period, the receiver receives spread spectrum signals from the selected set of signal sources, and based on the received signals produces position/time related data.

Classes IPC  ?

• G01S 1/00 - Radiophares ou systèmes de balisage émettant des signaux ayant une ou des caractéristiques pouvant être détectées par des récepteurs non directionnels et définissant des directions, situations ou lignes de position déterminées par rapport aux émetteu; Récepteurs travaillant avec ces systèmes

Abrégé

The present invention relates to reception and processing of spread spectrum signals (SHF) to produce position/time related data (DPT). A proposed receiver (100) includes a radio signal processing unit (115), which is at least partly implemented in a software (115s) running on a microprocessor (110). The processor (110) is adapted to effect at least one separate software-controlled function (117) in addition to the at least-part implementation of the radio signal processing unit (115). The receiver (100) is also adapted to operate the radio signal processing unit (115) on at least two processing intensity levels each at which an amount of processing per time unit is different. Thereby, during periods when the radio signal processing unit (115) operates on a relatively low processing intensity level, a first amount of processing capacity is available for the at least one separate software-controlled function (117); and during periods when the radio processing unit (115) operates on a relatively high processing intensity level, a second amount of processing capacity is available for the at least one separate software- controlled function (117). Provided that the processor's (110) over-all processing1 capacity is constant, the second amount is smaller than the first amount.

Classes IPC  ?

• G01S 1/00 - Radiophares ou systèmes de balisage émettant des signaux ayant une ou des caractéristiques pouvant être détectées par des récepteurs non directionnels et définissant des directions, situations ou lignes de position déterminées par rapport aux émetteu; Récepteurs travaillant avec ces systèmes
• G01S 5/14 - Localisation par coordination de plusieurs déterminations de direction ou de ligne de position; Localisation par coordination de plusieurs déterminations de distance utilisant les ondes radioélectriques déterminant des distances absolues à partir de plusieurs points espacés d'emplacement connu

Abrégé

The present invention relates to production of a decoded signal (A&tgr;) based on in an incoming stream of data samples (d(k)) representing at least one downconverted digitized spread spectrum source signal. A number (NM) of the received data samples (d(k)) are divided into a first number (N) of data blocks, where each data block contains a second number (M) of samples. The second number (M) is an integer larger than or equal to two. Each of the data blocks is then correlated with a respective local code replica segment (p(k)) to produce a first number (N) of intermediate accumulation results (∑&igr;; ΣQ). To enable production of a decoded signal (Ax) being compensated for a Doppler shift relative to a downconverting frequency for the least one spread spectrum source signal, the intermediate accumulation results (∑&igr;; ΣQ) are correlated with a carrier vector (s⏧z]&igr;; s⏧zQ) expressing such a Doppler shift. However, according to the invention, the carrier vector (s⏧z]&igr;; s⏧z]Q) only contains a target number (Z) of carrier . values (sn:sZ!; s1Q:sZQ) (i.e. different carrier amplitude levels), where the target number (Z) is smaller than or equal to the first number (N). Normally, the target number (Z) is substantially smaller than the first number (N). Thus, depending on the first number (N) and the target number (Z) for the relevant carrier vector (s⏧z]&igr;; s⏧z]Q), a number of consecutive results of the intermediate accumulation results (∑&igr;; ΣQ) are combined into a number of aggregated accumulation results (cn:cZ&igr;; c1 Q:c2Q), which is equal to the target number (Z). Thereafter, the aggregated accumulation results (c-&pgr;Xzi; c1Q:cZQ) are correlated with the carrier vector (s⏧z]&igr;; s⏧z]Q) to produce the decoded signal (Ax). The invention is well adapted for implementation of software GNSS receivers.

Classes IPC  ?

• H04B 1/707 - Techniques d'étalement de spectre utilisant une modulation par séquence directe