Application of LDPC codes in satellite navigation systems
- Paper number
IAC-08.B2.4.11
- Author
Dr. He Shanbao, China Academy of Space Technology (CAST), China
- Coauthor
Mrs. Liu Chonghua, China
- Coauthor
Mr. Lin Yiming, China
- Year
2008
- Abstract
Low Density Parity Check (LDPC) codes are being accepted in many applications as a type of advanced channel codes approaching Shannon limit. For example, LDPC codes have being used in DVB-S2 and will be adopted in telemetry channel coding standard of CCSDS. This paper will discuss an application of LDPC codes in satellite navigation systems, including encoding on spacecrafts and decoding in user receivers. GPS Joint Program Office has presented LDPC codes of L1 message structure in Interface Specification (Draft IS-GPS-800, Navstar GPS Space Segment/User Segment L1C Interfaces, 19 April 2006). Subframe2 and 3 shall utilized 24-bit Cyclic Redundancy Check (CRC) algorithm with a separate CRC for each subframe. Each of the two subframes shall be further encoding using LDPC codes with length 1200/548 and rate 1/2. This paper will give a different kind of LDPC codes from above FEC codes with same length and rate. They exhibit excellent decoding performance, simple encoding structure and low decoding complexity. The parity check matrix being denoted without a series of redundant tables is another advantage. At last, this construction method of LDPC codes can be extended to other satellite navigation systems, such as Galileo system of Europe and Compass system of China.
- Abstract document
- Manuscript document
IAC-08.B2.4.11.pdf (🔒 authorized access only).
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