北斗卫星导航系统-地信.ppt

BEIDOU Catalog Basic situation BEIDOU-1 BEIDOU-2 Application and development Basic situation Beidou satellite navigation system is a global satellite navigation system of independent research and development, independent operation, abbreviated as BDS. Beidou satellite navigation system, GPS, GLONASS and Galileo system compatible with global satellite navigation system, shared, and said the four major global satellite navigation system. Basic situation The?space?segment?of?this?system?consists of?3 (2?operational?+1?spare)?geo-synchronous satellites orbiting?360,000km?high?above ?the?Earth. The?two?operational?satellites?were?both?launched in?2000. The?spare?one?was?successfully?launched?on?May 25,?2003. * * * BEIDOU-1 BEIDOU-1 October 31, 2000 140 degrees east longitude December 21, 2000 80 degrees east longitude May 25, 2003 110.5 degrees east longitude BEIDOU-1 Compared?with?Global?Navigation Satellite?Systems?(GPS,?GLONASS?and?GALILEO), BEIDOU?should?in fact?be?called?a?Local?Navigation Satellite?System. The?positioning?principles?of?BEIDOU?and?GNSS?are?different.. GPS,?GLONASS?and?GALILEO?are?all?passive?positioning?systems?that?do?not?require?the?transmission?of?signals?from?users?to?satellites. But?BEIDOU?is?an?active?positioning?system. To?make?use?of?this?system?for?positioning?or?navigating,?users?need?to?transmit?signals?t?the?satellites?at?first?and?then?signals?are?re-transmitted?to?the?Ground?Control?Center. BEIDOU-1 Ground?Control?Center ?computes?out the?users’?position?based?on?the signals transmitted?from?the?satellites. So?it?is?required?that?both?satellites?and?receivers own the functions of receiving and sending or re-transmitting the?signals. BEIDOU-1 Limitations: 1、A two-dimensional position.Elevation to use the pressure gauge or DEM digital terrain model. 2、The central station location, does not favor the user autonomous navigation, poor safety. 3、Positioning speed limit. 4、The use