LOGO The Principle of BeiDou Navigation System and Its Receiver Modification Course Code: GMAT9205 By LeShu Wu - Chinese Independent research and development of regional positioning system

LeShu Wu Contents Introduction 1 Positioning Principle 2 Compare with GPS 3 Receiver Modification 4 Conclusion 5 Reference 6

LeShu Wu 1.Introduction  1960s First Generation of Global navigation system based on Doppler principle  ， based on RNSS principle U.S. and U.S.S.R. started to establish new generation global navigation system  GPS – U.S.  GLONASS – U.S.S.R.

LeShu Wu Low cost & Short Circle - only 6 satellites can achieve Chinese region positioning Why China Choose Beidou? Communication – integrate positioning and communication on one platform which is important in disaster relief, search and rescue.

LeShu Wu 2.Positioning Principle BeiDou Navigation System (BDSS) “Double satellites positioning principle” GEOSTAR system “active satellite navigation and Communication system” 1970s American scientist G. K. Oneill

LeShu Wu Positioning Process and Principle Fig.1. Working Schematic Diagram of BDSS

LeShu Wu 1 st Time Delay Table.1. Signal Transport Part-1

LeShu Wu 2 nd Time Delay Table.2. Signal Transport Part-2

LeShu Wu Fig.2. Calculation Components 2(Ds1 + D1) ( D s1 + D1 + D s1 + D2 )

LeShu Wu 3. Compare with GPS

LeShu Wu

LeShu Wu Receiver Modification Fig.3. Overall Receiver System Schematic

LeShu Wu Modulation  OQPSK Modulation ： can avoid 180° phase shift I slip ： Sinusoidal modulation Q slip ： Cosine modulation Binary signal modulation ： NRZ“1 ， -1” Initial phase of “1” ： 0° Initial phase of “-1” ： 180°

LeShu Wu Fig.4. BDSS Signal modulation diagram

LeShu Wu 1 Encode signals I slip & Q slip Generator – 16kb/s NRZ bipolar signals 2 Multiply with 4.08Mb/s Short PN1 code (Kasami Sequence) 4.08Mb/s Long PN2 code (Gold Sequence) 3 Spread spectrum signal I slip delay half PN code period – Sin modulation Q slip – Cos modulation directly 4 I slip + Q slip send into the channel

LeShu Wu  Final transmit signals

LeShu Wu Demodulation Input Signal Q slip  Only demodulate I slip which includes satellite position and time. Q slip has nothing useful signals. I Slip Costas Central

LeShu Wu

LeShu Wu Control VOC output frequency Multiple I & Q Multiple with local PN code After Low-pass filter （ LPF ） I slip ： Q slip ：

LeShu Wu 5. Conclusion The Next Generation Of BDSS Same Principle as GPS More accurate on timing and positioning Combination with old system

LeShu Wu 6. Reference  [1]"The construction of BeiDou navigation system steps into important stage, "Three Steps" development guideline clear and certain" (China National Space Administration html. Retrieved "The construction of BeiDou navigation system steps into important stage, "Three Steps" development guideline clear and certain" 56.html  [2]"Comparable with American and Russian in terms of performance, BeiDou-1 navigates for China" (in Chinese). China National Space Administration Retrieved "Comparable with American and Russian in terms of performance, BeiDou-1 navigates for China"  [3]Pike, John. "BeiDou (Big Dipper)". Space. GlobalSecurity.org. Retrieved [dead link]"BeiDou (Big Dipper)"GlobalSecurity.org link  [4]Marks, Paul ( ). "China's satellite navigation plans threaten Galileo". NewScientist.com. navigation-plans-threaten-galileo.html. Retrieved "China's satellite navigation plans threaten Galileo" NewScientist.comhttp:// navigation-plans-threaten-galileo.html  [5]"China puts new navigation satellite into orbit" Retrieved "China puts new navigation satellite into orbit"  [6]"BeiDou 1 Experimental Satellite Navigation System" Retrieved "BeiDou 1 Experimental Satellite Navigation System"  [7]"60-day works in space -- Story of reparation of the BeiDou satellite" (in Chinese). Sohu Retrieved "60-day works in space -- Story of reparation of the BeiDou satellite" Sohuhttp://news.sohu.com/ /n shtml  [8]"Compass due Next Year". Magazine article. Asian Surveying and Mapping. May 4, Retrieved "Compass due Next Year"  [9]"China successfully launched the third BeiDou satellite" (in Chinese). Sohu Retrieved "China successfully launched the third BeiDou satellite"  [10]"China sends Beidou navigation satellite to orbit" Retrieved "China sends Beidou navigation satellite to orbit"  [11]"China successfully launches fifth satellite for its own global navigation network". Xinhuanet /01/c_ htm. Retrieved "China successfully launches fifth satellite for its own global navigation network" Xinhuanethttp://news.xinhuanet.com/english2010/china/ /01/c_ htm

LOGO Thanks for listening.