Research and development history of GLONASS

The development of GLONASS began in the mid-1970s. After more than 20 years of twists and turns, although it was hit by the disintegration of the former Soviet Union and the economic depression in Russia, it never stopped the development of the system and the launch of satellites. Finally, on June 5438+099665438+1October 18, 24 working satellites in the space constellation broadcast navigation signals normally, which made the system reach an important milestone.

The GLONASS working test began in June/KOOC-0/982+/KOOC-0/2/KOOC-0/0, and the whole test plan was completed in two stages. ( 1982- 1990)

By 1984- 1985, the experimental system consisting of four satellites has reached the basic performance index of the verification system. The space constellation is gradually expanded from 1986 to 1990, and the test plan of the first phase of the system is completed. At that time, there were 10 satellites in the space constellation, which were arranged on the orbital plane 1(6) and the orbital plane 3(4) respectively. The constellation can provide at least 15 hours of two-dimensional positioning coverage every day, while the three-dimensional coverage can reach at least 8 hours. ( 1990 - 1995)

The GLONASS Phase II test plan mainly completes the test of user equipment, and ends with the space constellation1996 65438+1October 18, which finally reaches 24 working satellites. Then the system begins to enter the comprehensive working stage.

GLONASS consists of three basic parts: space satellite system (i.e. space part), ground measurement and control subsystem (i.e. ground control part) and user equipment (i.e. user receiving equipment).

The GLONASS space constellation consists of 24 satellites, including six kinds of satellites, namely Block Ⅰ, Block Ⅱ A, Block Ⅱ B and Block Ⅱ, and the next generation of improved satellites, GLONASS-M Ⅰ and GLONASS-M Ⅱ, which are being developed. Each GLONASS satellite transmits two carrier signals L 1 and L2 in L-band, and the civil code is only modulated on L 1, while the military code is on (L- 1 and L2) dual frequency. GLONASS uses frequency division multiple access (FDMA) to distinguish satellite signals.