Transmission of satellite navigation message into multiple pages encoded for optimal retrieval at receiver in a fully interchangeable way
AssigneeThe European Union, Represented By the European Commission
InventorIgnacio Fernàndez-Hernàndez
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Abstract
Described herein is a method for improving the reception of a satellite navigation message divided in several pages and transmitted by one or several satellites. A satellite navigation message M of k pages is encoded inn pages, and any k retrieved pages from any satellite enables decoding of the original satellite navigation message M. An implementation of the method uses parallel block encoding for a binary erasure channel with high parity and zero overhead, where symbols at a fixed position of all pages are encoded in parallel into shorter codes. This method achieves full page interchangeability in the message transmission, optimizes message reception and reduces decoding cost.
Claims12
A method of generating an encoded satellite navigation message, in the form of a number of pages, for transmission to at least one user receiver via a plurality of satellites, the method comprising the steps of:
- a) dividing, at a ground station, a satellite navigation message M into k pages;
- b) dividing, at the ground station, each page into j symbols, the satellite navigation message M being divided into k×j symbols;
- c) for each symbol position, encoding the symbols of the k pages at the ground station by encoding each column of the symbols of the pages separately for a total of j block codes, wherein each of n pages comprises symbols from the j block codes, n being larger than k;
- d) generating, at the ground station, an encoded satellite navigation message M′ for the n pages;
- e) allocating, at the ground station, at least a subset of the n pages of the encoded satellite navigation message to each of the plurality of satellites;
- f) transmitting, by the ground station, the allocated pages to respective ones of the plurality of satellites;
- and
- g) transmitting the allocated pages by the plurality of satellites to the at least one user receiver.
A satellite navigation system for generating, transmitting and decoding an encoded satellite navigation message in the form of a number of pages, the system comprising:
- a plurality of satellites;
- at least one user receiver;
- and
- a ground station configured for generating an encoded satellite navigation message, in the form of a number of pages, for transmission to the plurality of satellites, the encoded satellite navigation message being generated by:
- dividing a satellite navigation message M into k pages;
- dividing each page into j symbols, the satellite navigation message M being divided into k×j symbols;
- for each symbol position, encoding the symbols of the k pages by encoding each column of the symbols of the pages separately for a total of j block codes;
- generating an encoded satellite navigation message M′ for n pages, n being larger than k, wherein each of the n pages comprises symbols from the j block codes;
- allocating at least a subset of the n pages of the encoded satellite navigation message to each of the plurality of satellites;
- and
- transmitting the allocated pages to respective ones of the plurality of satellites,
- wherein the plurality of satellites comprises means for transmitting the allocated pages to the at least one user receiver.
Dependencies are inferred from the claim text.