MXPA06005288A - Method and apparatus for monitoring the integrity of satellite tracking data used bya remote receiver - Google Patents

Abstract

A method and apparatus for monitoring the integrity of satellite tracking data used by a remote receiver is described. In one example, a first set of satellite tracking data is received at a server. Integrity data for a second set of satellite tracking data is generated using the first set of satellite tracking data. The integrity data is then transmitted to at least one remote receiver having the second set of satellite tracking data.

Description

METHOD AND DEVICE FOR MONITORING THE INTEGRITY OF SATELLITE TRACKING DATA USED BY T3N REMOTE RECEIVER FIELD OF THE INVENTION The present invention relates generally to satellite position location systems and, more particularly, to monitoring the integrity of satellite tracking data used by a remote receiver. BACKGROUND OF THE INVENTION The receivers of the Positioning System Global (GPS, for its acronym in English) use measurements from several satellites to calculate the position. GPS receivers usually determine their position by calculating time differences between the transmission and reception of signals transmitted from satellites and received by the receiver at or near the surface of the Earth. The time differences, multiplied by the speed of light, provide the receiver's distance to each of the satellites in view of the receiver. GPS satellites transmit satellite positioning data to the receivers, known as ephemeris or orbital position data. In addition to the ephemeris data, the satellites transmit to the receiver absolute time information associated with the satellite signal, that is, the absolute time signal is sent as a second to the week signal.

Ref.: 172958 This absolute time signal allows the receiver to unambiguously determine a time stamp for the time when each satellite transmitted each received signal. Knowing the exact transmission time of each of the signals, the receiver uses the ephemeris data to calculate where each satellite was when it transmitted a signal. Finally, the receiver combines the information of the positions of the satellites with the calculated distances to the satellites to calculate the position of the receiver. More specifically, GPS receivers receive GPS signals, transmitted from in-orbit GPS satellites, which contain unique pseudo-random noise (PN) codes. The GPS receivers determine the time differences between the transmission and reception of the signals, comparing time shifts between the sequence of PN code signals received and sequences of PN signals generated internally. Each GPS signal transmitted is a signal in spread spectrum of direct sequence. The signals available for commercial use are provided by the Standard Positioning Service. These signals use a direct sequence spreading signal with a spreading rate of 1.023 MHz on a carrier wave at 1.575.42 MHz (the Ll frequency). Each satellite transmits a code P? unique (known as C / A code) that identifies a particular satellite, and allows signals transmitted simultaneously from several satellites to be received simultaneously by a receiver, there being very little interference between one signal and another. The sequence length of the PN code is 1,023 chips, which corresponds to a time lapse of 1 ilisecond. A cycle of 1,023 chips is known as a PN frame. Each received GPS signal is constructed from the repetitive 1,023 MHz PN pattern of 1,023 chips. At very low levels of signal, one can still observe the pattern P ?, to provide measurements of unambiguous time differences, when processing, and essentially average, many PN frames. These measured time differences are known as "sub-millisecond pseudo-ranges", since they are known as a module of the borders of PN frames of 1 millisecond. By solving the whole number of milliseconds associated with each difference for each satellite, true and unambiguous pseudo-ranges are obtained. The process of resolving unambiguous pseudo-ranges is known as "ambiguity resolution of whole milliseconds". To solve the position of the GPS receiver, a series of four pseudo-ranges suffices, together with the knowledge of the absolute times of transmission of the GPS signals and the positions of the satellites in these absolute times. The absolute transmission times are necessary to determine the positions of the satellites at the moments of transmission, and therefore to determine the position of the GPS receiver. The GPS satellites move at approximately 3.9 km / s, and therefore the satellite range, observed from the Earth, changes at a rate of more than ± 800 m / s. Errors in absolute times cause range errors of up to 0.8 m for every millisecond in the time error. These range errors produce an error of similar magnitude in the position of the GPS receiver. Therefore, an absolute time accuracy of 10 ms is sufficient for a position accuracy of approximately 10 m. Absolute time errors of more than 10 ms will cause large position errors, and for this reason typical GPS receivers require an absolute time accuracy of approximately 10 milliseconds or less. That a GPS receiver downloads ephemeris data from a satellite is always slow (takes at least 18 seconds), and is often difficult, if not impossible (in environments with very low signal strength). For these reasons, it has long been known that it would be advantageous to send orbital and satellite time data to a GPS receiver by other means, instead of waiting for transmission from the satellite. This technique of providing orbital data and satellite time, or "help data", to a GPS receiver is known as "assisted GPS" or A-GPS.

The aid data in an A-GPS system can be short-term data, such as information to assist in the acquisition of satellite signals, medium-term data, such as ephemeris data, or long-term data, such as ephemeris groups or other types of orbital models and long-term satellite time (generally known as "satellite tracking data"). For example, the aid data for the acquisition of satellite signals are typically valid for several minutes; satellite ephemeris data are typically valid for a few hours; and the orbital and satellite time data may be valid for a few days. A remote receiver can then use the help data to acquire satellite signals and, in some cases, calculate the position. Between the time the help data is sent, and the time when the remote receiver uses the help data, the orbital and satellite time data on which the help data were based may already be invalid. For example, the clock within a given satellite may have left the expected range, or the orbit of a given satellite may have changed beyond the expected range. If the remote receiver uses previously obtained help data, and associated with invalid orbital data and satellite time, the calculated position for a device could have a very significant error.

Accordingly, there is a need in the art for a method and device that monitors the integrity of a satellite's help data sent to remote receivers in an assisted location location system. SUMMARY OF THE INVENTION A method and a device for monitoring the integrity of the satellite tracking data used by a remote receiver are described. In one embodiment of the present invention, a first series of satellite tracking data is received on a server. For example, the first series of satellite tracking data can be received from one or more of a network of reference stations, a satellite control station, or another type of communication network. The satellite tracking data may comprise satellite orbital data, satellite clock data, or both. Integrity data for a second series of satellite tracking data is generated using the first series of satellite tracking data. The integrity data is then transmitted to at least one remote receiver that possesses the second series of satellite tracking data. For example, integrity data can identify one or more satellites with problems. BRIEF DESCRIPTION OF THE FIGURES In order that the above-described features of the present invention may be understood in detail, a more particular description of the present invention, which was briefly summarized above, can be obtained by reference to some embodiments, some of which are illustrate in the attached figures. However, it should be noted that the appended figures illustrate only typical embodiments of the present invention, and therefore should not be considered as limitations on their scope, since the invention may admit other equally effective modalities. Figure 1 is a block diagram showing an exemplary embodiment of a position location system. Figure 2 is a block diagram showing an exemplary embodiment of a position location system receiver for use with the position location system of Figure 1. Figure 3 is a block diagram showing an exemplary embodiment of a location location system server for use with the location location system of Figure 1. Figure 4 is a flow diagram showing an exemplary embodiment of a process for monitoring the integrity of the satellite tracking data used by a remote receiver in accordance with the present invention. Figure 5 is a flow diagram showing an exemplary embodiment of a process for identifying satellites with problems, in accordance with the present invention.

Figure 6 is a flow diagram showing another exemplary embodiment of a process for identifying satellites with problems, in accordance with the present invention. Figure 7 is a flow chart showing another exemplary embodiment of a process for identifying satellites with problems, in accordance with the present invention. Figure 8 is a flow diagram showing an exemplary embodiment of a process for requesting integrity data from a server, in accordance with the present invention. Figure 9 is a flow chart showing another exemplary embodiment of a process for identifying satellites with problems, in accordance with the present invention. To facilitate understanding, identical reference numbers are used, when possible, to designate identical elements common to the Figures. DETAILED DESCRIPTION OF THE INVENTION Figure 1 is a block diagram showing an exemplary embodiment of a position location system 100. The system 100 comprises a server 102 and a remote receiver 104. For purposes of clarity, and as an example, the system 100 is shown with a single remote receiver 104. However, it will be understood that the server 102 may be in communication with one or more remote receivers. The remote receiver 104 may be in communication with the server 102 by a wireless communication system 106 (i.e., a cellular telephone network) or another type of communication link 108, such as the Internet, or both. The remote receiver 104 acquires satellite signals transmitted by a plurality of satellites 105 in a constellation, and measures pseudo-ranges to the satellites 105 in order to locate their unknown position. For example, remote receiver 104 may measure pseudo-ranges to a plurality of GPS satellites in the GPS constellation. To assist in the acquisition of satellite signals, position calculations, or both, the remote receiver 104 receives satellite tracking data (hereinafter referred to as "help data") from the server 102. In one embodiment of the present invention, the remote receiver 104 uses server support data 102 to assist in the acquisition of the satellite signals, and transmits the measured pseudo-ranges to the server 102 using the wireless communication system 106. The server 102 then uses the pseudo- ranges for resolving the unknown position of the remote receiver 104. The position can be transmitted to the remote receiver 104 by the wireless communication system 106, or be made available to a third requester 199 by another mode, such as over the Internet. In another embodiment, the remote receiver 104 may use the measured pseudo-ranges to calculate its own position without transmitting the pseudo-ranges to the server. The remote receiver 104 uses help data from the server 102 to assist in the acquisition of the satellite signals, calculate the position, or both. The server 102 uses various measurements and information associated with the constellation (hereinafter referred to as "satellite tracking information") to generate the help data sent to the remote receiver 104. The server 102 receives the satellite tracking information of a external source, such as a network of satellite signal receivers ("reference network 110"), a satellite control station 112 (ie, the Master Control Station in GPS), or another source of such information (i.e. , by Internet) . The reference network 110 may include several tracking stations that collect tracking information from satellites of all satellites in the constellation, or a few tracking stations, or a single tracking station that only collects satellite tracking information for a region. particular of the world. The satellite tracking information includes, for example, at least one of the satellite navigation message (i.e., ephemeris), code phase measurements, phase measurements of the carrier wave, and Doppler measurements. In one embodiment of the present invention, the server 102 receives the ephemeris portion of the satellite navigation data for at least the plurality of satellites 105. In the United States Patent No. 6,411,892, issued June 25, 2002, an exemplary system for distributing ephemeris data is described, which is hereby incorporated by reference in its entirety. In the United States patent application serial number 10 / 081,164, filed on February 22, 2002 (File No. GLBL 020), an exemplary system for obtaining ephemeris information directly from a satellite control station is described, which is incorporated herein by reference in its entirety. The help data generated using the satellite tracking information can be valid in the short, medium or long term, and contains information to assist in the acquisition of satellite signals or calculate their position. For example, the help data may comprise the acquisition of help data, such as code phase and Doppler measurements, or a pseudo-range model expected in the remote receiver 104 ("pseudo-range model"). In the United States patent? 6,453,237, issued September 17, 2002, an exemplary system for distributing and using a pseudo-range model for acquiring satellite signals is described, which is hereby incorporated by reference in its entirety. In another example, the help data may comprise ephemeris information or a long-term orbital model. In the patent of the United States No. 6,542,820, issued April 1, 2003, describes an exemplary system for distributing and using ephemeris information or a long-term orbital model, which is incorporated herein by reference in its entirety. Regardless of the type of help data, if the tracking information of satellites on which the help data is based becomes invalid, the remote receiver 104 may not be able to properly acquire satellite signals or calculate the position using this data. of help, or could calculate positions with severely degraded accuracy. Thus, in one embodiment of the present invention, the server 102 monitors the integrity of the help data used by the remote receiver 104. As described in detail below, the server 102 obtains satellite tracking data and generates data from integrity for the help data using the satellite tracking data. The satellite tracking data obtained by the server 102 is more updated than the help data. The integrity data produced by the server 102 can then be transmitted to the remote device 104. FIG. 2 is a block diagram showing an exemplary embodiment of a position location system receiver 200. The receiver 200 can be used as the remote receiver 104 shown in Figure 1. The receiver 104 comprises illustratively a satellite signal receiver 202, a wireless transceiver 204, a microcontroller 206, a memory 208 and a modem 210 (or other communication port). The satellite signal receiver 202 receives satellite signals via an antenna 212. The satellite signal receiver 202 processes the satellite signals to form pseudo-ranges in a manner known per se. An exemplary GPS assisted receiver that can be used with the present invention is described in U.S. Pat. 6,453,237. The pseudo-ranges can be coupled with the wireless transceiver 204 via the microcontroller 206. The wireless transceiver 204 can transmit the pseudo-ranges for a position calculation on a server using an antenna 214. Alternatively, the pseudo-ranges can be stored in the memory 208 so that the receiver 200 calculates the position. The memory 208 can be a random access memory, read-only memory, removable storage, hard disk storage, or any combination of these memory devices. The memory 208 can store help data 216 provided by a server that can be used to assist in the acquisition of satellite signals, the position calculation, or both. The help data 216 may be received by wireless links using the wireless transceiver 204, or by a computer network (ie, Internet) using the modem 210 (or another communication port that connects the device to a computer network). Figure 3 is a block diagram showing an exemplary embodiment of a location location system server 300. The server 300 can be used as the server 102 shown in Figure 1. The server 300 illustratively comprises a central processing unit (CPU) 302, input and output (I / O) circuits 304, support circuits 306, a memory 308, and a server clock 310.

The server 300 may include, or be coupled to, a device database 312. The support circuits 306 comprise well-known circuits that facilitate the operation of the CPU 202, such as clock circuits, associated memory, power sources and the like. The memory 308 may be random access memory, read-only memory, removable storage, hard disk storage, or any combination of these memory devices. The server clock 310 can be used to provide a timestamp, indicating the arrival time of the pseudo-ranges transmitted by a remote receiver. The satellite tracking information (ie, ephemeris, phase-code measurements, carrier wave phase measurements, and Doppler measurements) is received from an external source of this information (i.e., a reference network, satellite control, Internet) using the 1/0 304 circuits. The server 300 uses the satellite tracking information to calculate help data to be used by remote devices. To monitor the integrity of the help data sent to the remote receivers, the server 300 tracks the type of help data distributed to each remote receiver, at what time, and when such help data will expire. In one embodiment, a table 350 may be stored within the database of the device 312 that has entries (that is, three are shown) defined by a remote device identification ("ID"), the time of day that they were sent. the data of help to the remote device, the type of help data sent, and the time of expiration of the help data. For example, an entry 352 indicates that the acquisition of help data was sent to a device with an ID of "1" at time ti, and that the acquisition of help data will expire 10 minutes after you. An entry 354 indicates that the ephemeris data was sent to a device with an ID "2" at time t2, and that the ephemeris data will expire four hours after t2. An entry 356 indicates that long-term orbital data (LTO) was sent to a device with ID "3" at time t3, and that LTO data will expire two days after t3. The server 300 monitors the integrity of the help data in use by the remote devices identified in the database of the device 312 to produce integrity data 314. The integrity data 314 can be stored in the memory 308 and transmitted to the remote devices , as described below. Figure 4 is a flow chart showing an exemplary embodiment of. a process 400 for monitoring the integrity of the satellite tracking data used by a remote receiver in accordance with the present invention. The process 400 can be executed by a satellite positioning system server to monitor the integrity of the help data used by the receivers of the satellite positioning system. The process 400 is initiated in step 402, in which satellites with problems are identified, associated with one or more series of help data used by remote receivers. For example, one or more of the processes 500, 600, 700 and 900 described below can be used to identify satellites with problems. In optional step 403, an interruption period is determined for each satellite with problems that is identified. For example, an interruption period can be obtained for each problem satellite identified from the interrupt notification data generated by a satellite control station, as will be discussed later with respect to the process 900 of Figure 9. In step 404, integrity data is generated that includes the identity of each satellite with problems and a corresponding interruption period, if known. If the interruption periods are unknown, then the integrity data may not include an interruption period, or the interruption period may be set at a pre-defined value or a value based on the particular type of aid data in use (ie say, four hours if the help data is valid for four hours). The integrity data can then be transmitted to the remote receivers using the help data series. In an embodiment of the present invention, in step 406, the integrity data can be transmitted to the affected remote receivers, in response to a satellite with identified problems. That is, if satellites are identified as problematic, the integrity data is transmitted to the remote receivers that have help data affected by such satellites with problems. Thus, integrity data is sent only if satellites with problems are identified, and only to remote receivers affected by such troubled satellites. In another embodiment, in step 405, integrity data can be transmitted to all remote receivers, in response to satellites with identified problems. In another embodiment, in step 408, the integrity data is transmitted to remote receivers in accordance with a predefined transmission program. For example, integrity data can be transmitted to all remote receivers using the help data series periodically, whether or not satellites with problems have been identified. In yet another embodiment, in step 410, the integrity data can be transmitted to the remote receivers in response to requests from the remote receivers. Figure 5 is a flow diagram showing an exemplary embodiment of a process 500 for identifying satellites with problems, in accordance with the present invention. The process 500 is started in step 502, in which a series of satellite tracking data is obtained. The series of current satellite tracking data can be received from a reference network, a satellite control station, or other information source, such as over the Internet. In step 504, satellite orbital data, satellite clock data, or both (hereinafter referred to in general as orbital / clock data) are extracted from the satellite tracking data. In step 506, the orbital / clock data is compared with the orbital / clock data of one or more series of aid data used by the remote receivers to identify discrepancies. For example, you can change a satellite's orbit, or there may be errors in a satellite's clock, from the time the help data was generated. Thus, there may be some discrepancy between the orbital / clock data extracted from the current series of satellite tracking data and the orbital / clock data underlying the aid data. In step 508, it is determined if there is any identified discrepancy that has exceeded a predefined threshold. For example, the orbit of a satellite may have changed beyond a predefined threshold, or the clock of a satellite may have left a predefined threshold. If so, process 500 proceeds to step 510. Otherwise, process 500 ends in step 512. In step 510, the affected satellite (s) associated with the identified discrepancies are marked as problematic. Figure 6 is a flow diagram showing another exemplary embodiment of a process 600 for identifying satellites with problems, in accordance with the present invention. The process 600 is started in step 602, in which a series of satellite tracking data is obtained. The series of current satellite tracking data can be received from a reference network, a satellite control station, or other information source, such as over the Internet. In step 604, health data from the satellite is extracted from the current series of satellite tracking data. As described above, the ephemerides contain precise information of the orbit of the satellite and the time model of a particular satellite. In addition, the ephemerides also contain an indication of the health of the satellite ("state of health"). In GPS, for example, the MCS announces the changes in the ephemeris by changing the state of health in the transmission ephemeris. In step 606, the health data of the satellite is analyzed to identify the presence of satellites with problems. Figure 7 is a flowchart showing another example embodiment of a process 700 for identifying satellites with problems, in accordance with the present invention. The process 700 is initiated in step 702, in which satellite signals are received at one or more reference stations having a known position. In step 704, the position of each reference station is calculated using one or more series of help data used by the remote receivers. In step 706, the calculated positions are compared with the known positions of the reference stations. If a series of given aid data used to calculate the position of a reference station is invalid due to a satellite with problems, the calculated position will be erroneous. Accordingly, in step 708, it is determined whether the calculated positions exceed the respective known positions in a pre-defined threshold. If so, process 700 proceeds to step 710. Otherwise, process 700 culminates in step 712. In step 710, the affected satellite (s) associated with the identified discrepancies are marked as problematic. Figure 8 is a flow diagram showing an exemplary embodiment of a process 800 for requesting integrity data from a server, in accordance with the present invention. The process 800 is started in step 802, in which pseudo-ranges from a remote receiver to a plurality of satellites are measured. In step 804, a position of the remote receiver is calculated using the pseudo-ranges and satellite tracking data stored in the remote receiver. For example, the satellite tracking data may be help data supplied by a server. In step 806, "the validity of the calculated position is estimated.There are several well-known techniques with which the validity of the calculated position can be estimated.For example, residues can be formed a posteriori that are associated with the pseudo-ranges The residuals can be analyzed afterwards to identify some erroneous pseudo-range If one of the pseudo-ranges is found to be erroneous, the calculated position is estimated as invalid Other techniques can be used to estimate the validity. , you can compare the expected pseudo-ranges (based on the a priori position and time and the satellite tracking data stored in the remote receiver) with measured pseudo-ranges, to obtain pseudo-rank residuals a priori. A priori pseudo-range above a particular threshold may indicate invalid satellite tracking data Another example to estimate validity is to compare the calculated position with a po a priori A position difference above a particular threshold may indicate invalid satellite tracking data. Other examples may use variations of these methods (compare altitudes, times, etc., calculated and expected), as well as any combination of these methods. In step 808, it is determined whether the calculated position is valid. If so, process 800 returns to step 802 and may be repeated. Otherwise, the process 800 proceeds to step 810, where server integrity data is requested. The integrity data can be used to determine if the satellite tracking data stored in the remote receiver is still valid. Figure 9 is a flow diagram showing another exemplary embodiment of "a 900 process for identifying satellites with problems, in accordance with the present invention. The process 900 is started in step 902, in which interrupt notification data generated by a satellite control station is received. For example, interrupt notification data can be received directly from the satellite control station, or through another source, such as the Internet. For example, in GPS, the constellation of satellites is monitored by stations throughout the world, under the control of a Master Control Station (MCS). The MCS announces satellite outages, whether planned for the future, or unplanned and immediate, by providing Notification Ads for Navstar Users (NA? U) over the Internet. In step 904, the interrupt notification data is compiled to identify satellites with problems. In step 906, an interruption period is determined for each satellite with identified problems. For example, an interruption period can be obtained for a problem satellite identified by NANU. Using the interrupt notification data, the present invention ensures that the help data in use by the remote receivers always reflects the most up-to-date integrity status of the GPS constellation, regardless of whether changes in integrity were planned for the future, or unplanned and immediate. Although the methods and devices of the present invention were described with reference to GPS satellites, it will be appreciated that the teachings herein are equally applicable to positioning systems using pseudolites or a combination of satellites and pseudolites. Pseudolites are ground transmitters that transmit a PN code (similar to the GPS signal) that can be modulated in a carrier signal of the L band, generally synchronized with GPS time. The term "satellite", as used herein, may include pseudolites or pseudolite equivalents, and the term "GPS signals", as used herein, include signals similar to GPSs of pseudolites or equivalents. of pseudolites. In addition, in the foregoing discussion, the present invention was described with reference to its application to the United States Global Positioning System (GPS). However, it is clear that these methods are equally applicable to similar satellite systems, and in particular to the Russian Glonass system and the European Galileo system. The term "GPS" used herein includes alternative satellite positioning systems, including the Russian Glonass system and the European Galileo system. Although the foregoing was directed to illustrative embodiments of the present invention, other embodiments of the present invention can be devised without departing from its basic scope, and its scope is determined by the following claims.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (32)

1. CLAIMS Having described the foregoing invention, the content of the following claims is claimed as property: 1. A method characterized in that it comprises: receiving a first series of satellite tracking data in a server; generate integrity data for a second series of satellite tracking data using the first series of satellite tracking data; and transmitting the integrity data to at least one remote receiver having the second series of satellite tracking data. The method according to claim 1, characterized in that it further comprises: generating additional integrity data for additional series of satellite tracking data using the first series of satellite tracking data; and transmitting the additional integrity data to remote receivers that possess the additional series of satellite tracking data. The method according to claim 1, characterized in that it further comprises: receiving additional series of satellite tracking data in the server during a time lapse; and update the integrity data using the additional series of satellite tracking data. The method according to claim 3, characterized in that the integrity data is transmitted periodically to at least one remote receiver. The method according to claim 1, characterized in that the integrity data is transmitted at least one remote receiver in response to a request from the at least one remote receiver. 6. The method according to claim 1, characterized in that it further comprises: receiving satellite signals at a reference station; calculating a position of the reference station using the satellite signals and the second series of satellite tracking data; and comparing the position with a known position of the reference station, to increase the integrity data. The method according to claim 6, characterized in that the integrity data is transmitted to the remote receiver in response to a deviation of the position from the known position exceeding a threshold. The method according to claim 1, characterized in that the first series of satellite tracking data comprises at least one of first orbital or clock data, and the second series of satellite tracking data comprises at least one of between seconds orbital or clock data. 9. The method according to claim 8, characterized in that the step of generating comprises at least one of: comparing the first orbital data with the second orbital data to identify an orbital discrepancy; and comparing the first clock data with the second clock data to identify a clock discrepancy. The method according to claim 9, characterized in that the integrity data is transmitted to the remote receiver in response to at least one of an identified orbital discrepancy exceeding a threshold, and an identified clock discrepancy that exceeds another threshold. 11. The method according to the claim I, characterized in that the first series of satellite tracking data comprises satellite health data. 12. The method in accordance with the claim II, characterized in that the step of generating comprises analyzing the health data of the satellite to identify satellites with problems. The method according to claim 12, characterized in that the integrity data is transmitted to the remote receiver in response to a satellite with identified problems. 14. The method according to claim 1, characterized in that the first series of satellite tracking data is received from at least one of a network of reference stations and a satellite control station. 15. The method according to claim 1, characterized in that the first series of satellite tracking data comprises ephemeris data. 16. The method according to claim 1, characterized in that the second series of satellite tracking data comprises at least one of a pseudo-range model, ephemeris data, and long-term satellite orbital data. The method according to claim 1, characterized in that the integrity data comprises at least one of an identity of at least one satellite with problems and a period of interruption of at least one satellite with problems. 18. A method, characterized in that it comprises: measuring pseudo-ranges of a remote receiver to a plurality of satellites in a constellation; calculating a position of the remote receiver using the pseudo-ranges and satellite tracking data stored in the remote receiver; estimate if the position is valid; and requesting a server integrity data for the satellite tracking data, in response to an invalid position. The method according to claim 18, characterized in that the integrity data is generated using another series of satellite tracking data received by the server. 20. The method according to claim 18, characterized in that the estimation step comprises: forming post-hoc residues associated with the pseudo-ranges; and analyze the residuals a posteriori to identify an erroneous pseudo-range. The method according to claim 20, characterized in that the integrity data is requested in response to an identified erroneous pseudo-range. 22. A server in accordance with satellite positioning system, characterized in that it comprises: a device for receiving a first series of satellite tracking data; a database for storing a second series of satellite tracking data and an identity of at least one remote receiver having the second series of satellite tracking data; a processor for generating integrity data for the second series of satellite tracking data using the first series of satellite tracking data; and a device for transmitting the integrity data to at least one remote receiver. 23. The server according to claim 22, characterized in that the first series of satellite tracking data comprises ephemeris data. 24. The server according to claim 22, characterized in that the second series of satellite tracking data comprises at least one of a pseudo-range model, ephemeris data, and long-term satellite orbital data. 25. The server according to claim 22, characterized in that the integrity data comprises at least one of an identity of at least one satellite with problems and a period of interruptof at least one satellite with problems. 26. A satellite positng system receiver, characterized in that it comprises: a satellite signal receiver for measuring pseudo-ranges of the satellite positng system receiver to a plurality of satellites in a constellat a memory for storing satellite tracking data; a processor for calculating a positof the receiver of the satellite positng system using the pseudo-ranges and satellite tracking data, and estimating whether the positis valid; and a wireless transceiver for transmitting to a server a request for integrity data associated with the satellite tracking data, in response to an invalid posit 27. A positlocatsystem, characterized in that it comprises: a remote receiver having a wireless transceiver and a memory for storing a first series of satellite tracking data; and a server in wireless communicatwith the remote receiver; wherein the server receives a second series of satellite tracking data, generates integrity data for the first series of satellite tracking data using the second series of satellite tracking data, and transmits the integrity data to the remote receiver; and where the remote receiver receives the integrity data using the wireless transceiver. 28. A method characterized in that it comprises: receiving interrupt notificatdata generated by a satellite control stat compile disruptnotificatdata to identify satellites with problems and corresponding interruptperiods for satellites with problems; generate integrity data for a series of satellite tracking data in response to satellites with identified problems and periods of interrupt and transmitting the integrity data to at least one remote receiver that possesses the satellite tracking data series. The method according to claim 28, characterized in that the satellite control statis a master control stat(MCS) for the global positng system (GPS) of satellites, and where the interruptnotificatdata comprises one or more Notice Notificat for Navstar Users (NANU). 30. The method of compliance with the claim 28, characterized in that the integrity data is transmitted periodically to at least one remote receiver. 31. The method according to claim 28, characterized in that the integrity data is transmitted to at least one remote receiver in response to a request from the at least one remote receiver. 32. The method according to claim 28; characterized in that the interrupt notificatdata is received by the Internet.