Compass-M1 broadcast codes in E2, E5b, and E6 requency bands

Grace Xingxin Gao, Alan Chen, Sherman Lo, David De Lorenzo, Todd Walter, Per Enge

Research output: Contribution to journalArticlepeer-review


With the launch of the Compass-M1 satellite on 14 April 2007, China is set to become the latest entrant into global navigation satellite systems (GNSS). Understanding the interoperability and integration of the Chinese Compass with the current GNSS, namely the U.S. Global Positioning System (GPS), the European Galileo, and the Russian GLONASS, requires knowing and understanding its signal structures-specifically its pseudorandom noise (PRN) codes and code structures. Moreover, the knowledge of the code is a prerequisite for designing receivers capable of acquiring and tracking the satellite. More important is determining if the signal may degrade performance of the current GNSS in the form of interference. Finally, we are eager to learn from the code and signal design of our Chinese colleagues. For this research, we set up a 1.8-m dish antenna to collect the broadcast Compass-M1 signals. Even with the dish antenna, the received signal is still weak and buried in thermal noise. We then apply signal processing and are able to extract the PRN code chips out of the noise in all three frequency bands. The PRN codes are thousands of bits long. In addition, we find that the Compass-M1 PRN codes in all frequency bands are Gold codes. We also derive the Gold code generators to represents thousands of code chips with fewer than a hundred bits. Finally, we implement these codes in our software receiver to verify and validate our analysis.

Original languageEnglish (US)
Pages (from-to)599-612
Number of pages14
JournalIEEE Journal on Selected Topics in Signal Processing
Issue number4
StatePublished - 2009
Externally publishedYes


  • Global navigation satellite system (GNSS)
  • Pseudorandom noise codes
  • Spread spectrum

ASJC Scopus subject areas

  • Signal Processing
  • Electrical and Electronic Engineering


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