Method and apparatus for providing integrity information for users of a global navigation system
First Claim
1. A method for providing integrity information for users of a global navigation system, said method comprising:
- a plurality of space vehicles transmitting information to a user device for position detection;
wherein the transmitted information includes,a first information from the global navigation system about the accuracy of a signal in space error SISE of a faulty space vehicle; and
a second information that specifies whether or not the global navigation system assesses the faulty space vehicle as faulty;
whereinthe first information comprises;
information about the quality of a signal in space SIS broadcast by the space vehicles, which is called signal in space accuracy SISA and corresponds to a prediction of a width of a statistical distribution of SISE;
information about accuracy of a monitoring of the signal in space SIS broadcast by the space vehicles by a ground segment of the global navigation system, which is called signal in space monitoring accuracy SISMA and corresponds to a width of a statistical distribution of a difference between an estimated and a true value of SISE; and
the second information comprises;
information about a signal in space SIS broadcast by space vehicles, which should not be used, which is called integrity flag IF.
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Abstract
In a method for providing integrity information for users of a global navigation system, which comprises several space vehicles like satellites transmitting information to a device for position detection, the transmitted information comprises first information from the global navigation system about the accuracy of a signal in space error SISE of a faulty space vehicle, and second information whether or not the global navigation system assesses the faulty space vehicle as faulty. The invention is based on the assumption how exact a fault can be detected, so that performance the global navigation system can be increased; and no unfounded assumption is used which improves the quality of service.
13 Citations
15 Claims
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1. A method for providing integrity information for users of a global navigation system, said method comprising:
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a plurality of space vehicles transmitting information to a user device for position detection;
wherein the transmitted information includes,a first information from the global navigation system about the accuracy of a signal in space error SISE of a faulty space vehicle; and a second information that specifies whether or not the global navigation system assesses the faulty space vehicle as faulty;
whereinthe first information comprises; information about the quality of a signal in space SIS broadcast by the space vehicles, which is called signal in space accuracy SISA and corresponds to a prediction of a width of a statistical distribution of SISE; information about accuracy of a monitoring of the signal in space SIS broadcast by the space vehicles by a ground segment of the global navigation system, which is called signal in space monitoring accuracy SISMA and corresponds to a width of a statistical distribution of a difference between an estimated and a true value of SISE; and the second information comprises; information about a signal in space SIS broadcast by space vehicles, which should not be used, which is called integrity flag IF. - View Dependent Claims (2, 3, 4, 13)
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5. A user device for position detection by means of a global navigation system in which a plurality of space vehicles transmit information to the device for determining the position of the device in space;
- wherein the device comprises;
receiving means, in the user device, for receiving an integrity information that includes a first information from the global navigation system about the accuracy of a signal in space error SISE of a faulty space vehicle; and
a second information that specifies whether or not the global navigation system assesses the faulty space vehicle as faulty;
whereinthe first information comprises; information about the quality of a signal in space SIS broadcast by the space vehicles, which is called signal in space accuracy SISA and corresponds to a prediction of a width of a statistical distribution of SISE; information about accuracy of a monitoring of the signal in space SIS broadcast by the space vehicles by a ground segment of the global navigation system, which is called signal in space monitoring accuracy SISMA and corresponds to a width of a statistical distribution of a difference between an estimated and a true value of SISE; and the second information comprises; information about a signal in space SIS broadcast by space vehicles, which should not be used, which is called integrity flag IF; processing means, in the user device, for calculating an integrity risk from the received first and second information, and from further information, wherein said integrity risk being a measure of the probability that a user should have been warned that said global navigation system should not be used for navigation, without having been warned; and alert means, in the user device, for raising an alert if the calculated integrity risk is larger than an allowed integrity risk. - View Dependent Claims (6, 7, 8, 9, 10, 14)
- wherein the device comprises;
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11. A method for determining integrity risk of information disseminated from space vehicles in a global navigation system which provides integrity information that includes a first information from the global navigation system about the accuracy of a signal in space error SISE of a faulty space vehicle;
- and a second information that specifies whether or not the global navigation system assesses the faulty space vehicle as faulty;
said method comprising;checking that the integrity information received for every integrity data stream is the integrity information generated by the integrity function of the ground infrastructure; selecting out of redundant and positively checked integrity data-streams the integrity data stream to be used; determining from selected and positive checked integrity information and the navigation information which signals are valid; computing an integrity risk at the alert limit for the critical operation period wherein only valid signals are considered; and computing a number of critical space vehicles for the critical operation period, considering only space vehicles that provide valid signals; and generating an alert for the user which indicates whether or not the received information should be used for position detection; wherein said integrity information comprises; information about the quality of a signal in space SIS broadcast by the space vehicles, which is called signal in space accuracy SISA and corresponds to a prediction of a width of a statistical distribution of SISE; information about accuracy of a monitoring of the signal in space SIS broadcast by the space vehicles by a ground segment of the global navigation system, which is called signal in space monitoring accuracy SISMA and corresponds to a width of a statistical distribution of a difference between an estimated and a true value of SISE; and information about a signal in space SIS broadcast by space vehicles, which should not be used, which is called integrity flag IF; wherein said integrity risk is a measure of the probability that a user should have been warned that said global navigation system should not be used for navigation, without having been warned; and wherein said method is carried out by a user device for position detection. - View Dependent Claims (12, 15)
- and a second information that specifies whether or not the global navigation system assesses the faulty space vehicle as faulty;
Specification