System for determining the location of mobile objects
First Claim
1. A system for determining the position of mobile objects (5) with the assistance of position-finding and navigation satellites (GPS satellites 1, 2, 3, 4) which continuously change their position relative to a stationary point on the earth and emit GPS signals (11, 21, 31, 41) that permit a GPS receiver (120) installed on the mobile object (5) to determine its instantaneous position coordinates, the system comprisingat least one GPS receiving and processing unit (50) operating as a reference whose precise position coordinates are known, with the unit determining continuous error values from the continuously received GPS signals (12, 22, 32, 42) and from the known position coordinates of its location (6) and generating correction data (7) therefrom, with the correction data (7) comprisingpseudo range correction values (PRC data) valid for the moment of their calculation, andvalues (RRC data) for the instantaneous rate of change of the RRC data;
- at least one radio station (80) with RDS coder (70) which emits the generated correction data (7) as data of a radio data system signal (RDS signal) which are inserted into its program signal;
a radio receiver (90) present on the mobile object (5) and having an RDS decoder (100) for receiving and decoding the RDS signal that is provided with the correction data (7), anda computer (110) for separating the correction data (7) from the decoded RDS signal and for feeding the correction data (7) into the GPS receiver (120) mounted on the mobile object (5), with the receiver correcting its measurement results according to the separated correction values (7),characterized in thata) downstream of the GPS receiving and processing unit (50) an evaluating device (60) is arranged whichcalculates back the PRC data, which were calculated at a specific moment, with the assistance of the associated rate of change values (RRC data) to the moment of the last full minute, and,for each GPS satellite, inserts into a single RDS group of an RDS signal cycle the calculated-back PRC data together with the associated RRC data and an identification of the satellite concerned, but while abandoning a header provided in a standard format for GPS correction signals;
b) in a computer (110) arranged downstream of the RDS decoder (100) of the radio receiver (90), the calculated-back PRC data are extrapolated to the actual time for each GPS satellite with the assistance of the associated rate of change values (RRC data) and computer-internally generated time information (internal Z count), andc) the non-transmitted header is reconstructed with check words and continuous time information in the computer (110) and, together with the extrapolated PRC data for each GPS satellite and the associated RRC data, is put together to form the standardized format of the correction data (7).
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Accused Products
Abstract
To reduce the transfer capacity requirements for correction data in a differential GPS system, while notably improving the interpretability of any correction data having suffered transmission interference and ensuring that such correction be as up to date as possible, continuous error readings (7) are calculated from a steady stream of GPS signals (12, 22, 32, 42) received from a reference GPS receiver (50) and from the known co-ordinates of its location (6). According to the invention, an evaluation system (60) is provided which, at a specific point in time recalculates the correction readings rounded off to the last full minute. The correction reading (8), calculated by the evaluation system, is then transmitted by at least one radio transmitter (80) in a radio data signal (RDS) included in its program signal. Attached to the mobile object (5), whose situation co-ordinates are determined by a mobile GPS receiver (120), is a radio receiver (90) to which are connected an RDS decoder (100) for receiving and decoding the received RDS signals incorporating the processed correction readings (8) and a computer (110) which extracts the correction readings (7) from the decoded RDS and updates them to the present time. The computer also reconstructs a standard correction signal (7) complying with the RTCM standard. The reconstructed, standard correction data are finally fed to the GPS receiver which then corrects its reading according to the reconstructed correction readings (7) received.
89 Citations
8 Claims
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1. A system for determining the position of mobile objects (5) with the assistance of position-finding and navigation satellites (GPS satellites 1, 2, 3, 4) which continuously change their position relative to a stationary point on the earth and emit GPS signals (11, 21, 31, 41) that permit a GPS receiver (120) installed on the mobile object (5) to determine its instantaneous position coordinates, the system comprising
at least one GPS receiving and processing unit (50) operating as a reference whose precise position coordinates are known, with the unit determining continuous error values from the continuously received GPS signals (12, 22, 32, 42) and from the known position coordinates of its location (6) and generating correction data (7) therefrom, with the correction data (7) comprising pseudo range correction values (PRC data) valid for the moment of their calculation, and values (RRC data) for the instantaneous rate of change of the RRC data; -
at least one radio station (80) with RDS coder (70) which emits the generated correction data (7) as data of a radio data system signal (RDS signal) which are inserted into its program signal; a radio receiver (90) present on the mobile object (5) and having an RDS decoder (100) for receiving and decoding the RDS signal that is provided with the correction data (7), and a computer (110) for separating the correction data (7) from the decoded RDS signal and for feeding the correction data (7) into the GPS receiver (120) mounted on the mobile object (5), with the receiver correcting its measurement results according to the separated correction values (7), characterized in that a) downstream of the GPS receiving and processing unit (50) an evaluating device (60) is arranged which calculates back the PRC data, which were calculated at a specific moment, with the assistance of the associated rate of change values (RRC data) to the moment of the last full minute, and, for each GPS satellite, inserts into a single RDS group of an RDS signal cycle the calculated-back PRC data together with the associated RRC data and an identification of the satellite concerned, but while abandoning a header provided in a standard format for GPS correction signals; b) in a computer (110) arranged downstream of the RDS decoder (100) of the radio receiver (90), the calculated-back PRC data are extrapolated to the actual time for each GPS satellite with the assistance of the associated rate of change values (RRC data) and computer-internally generated time information (internal Z count), and c) the non-transmitted header is reconstructed with check words and continuous time information in the computer (110) and, together with the extrapolated PRC data for each GPS satellite and the associated RRC data, is put together to form the standardized format of the correction data (7). - View Dependent Claims (2, 3, 4, 5)
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6. A receiving arrangement for determining the position of mobile objects (5) with the assistance of position-finding and navigation satellites (GPS satellites) which continuously change their position relative to a stationary point on the earth and emit GPS signals that permit a GPS receiver (120) installed on the mobile object (5) to determine its instantaneous position and altitude coordinates, wherein the receiving arrangement is designed to receive correction data--comprised of pseudo range correction values (PRC data), valid for the moment of their calculation, as well as of values (RRC data) for the rate of change of the PRC data--wherein the correction data are emitted as data of a radio data system signal (RDS signal) inserted into a radio program signal, the receiving arrangement comprising
an arrangement (90, 100) to continuously receive and decode the RDS signal provided with the correction data, and a computer (110) to separate the correction data from the decoded RDS signal and to feed the correction data into the GPS receiver (120) installed on the mobile object (5), which GPS receiver corrects its measurement results according to the separated correction data, characterized in that, for the evaluation of processed correction data (8), wherein the PRC data calculated at a specific moment are calculated back to the moment of the last full minute with the assistance of the associated rate of change values (RRC data), the computer (110) is designed such that a) the calculated-back PRC data are extrapolated to the actual time for each GPS satellite with the assistance of the associated rate of change values (RRC data) and computer-internally generated time information (internal Z count), and b) a non-transmitted header provided in a standardized format for correction data is reconstructed with check words and continuous time information and, together with the extrapolated PRC data for each GPS satellite and the associated RRC data, is put together to form the standardized format of the correction data.
Specification