Component Frequency(MH) Fundamental Frequency fo=10.23 Carrier li 1546=157542(190cm) Carrier l2 120=122760(244cm) P-Cod =10.23 C/A-Code J10=1023 W-Code f20=0.5115 Navigation message f204600=50X106 The unmodulated carriers by Li(t)=acos(it) The C/A-code is placed on the Li carrier in phase quadrature (i.e, 90 offset)with the P-code 電 Principles of the Global Positioning System 2005-3-18(13 A Random code? The Pseudo random Code(PrC)or Pseudo random Noise code, PRN, is a fundamental part of GPS Physically it's just a very complicated digital code, or in other words, a complicated sequence of "on"and"off pulses. The signal is so complicated that it almost looks like random electrical noise. Hence the name "Pseudo- Random Principles of the Global Positioning System 2005-3-1814147 Principles of the Global Positioning System 2005-3-18 13 Principles of the Global Positioning System 2005-3-18 14 14 A Random Code? The Pseudo Random Code (PRC) or Pseudo Random Noise code, PRN, is a fundamental part of GPS. Physically it's just a very complicated digital code, or in other words, a complicated sequence of "on" and "off" pulses. The signal is so complicated that it almost looks like random electrical noise. Hence the name "Pseudo￾Random