Specifics of GPs signal GPS transmits at two frequencies L11575.42MHz(2×77×1023MHz) L2122760MHz(2X60X10.23MHz) Wavelengths L1-190 mm: L2 -244 mm Codes Course acquisition code( C/A) Chip rate(rate at which phase might change)1.023 MHZ Precise positioning code(P code)10.23 MHz Y-code(Antispoofing code) also 10.23 MHZ derived by multiplying P-code by-20KHz code(highly classified 02/27/02 12.540Lec0702/27/02 12.540 Lec 07 3 Specifics of GPS signal • GPS transmits at two frequencies – L1 1575.42 MHz (2x77x10.23 MHz) – L2 1227.60 MHz (2x60x10.23MHz) – Wavelengths L1 ~190 mm; L2 ~244 mm • Codes: – Course acquisition code (C/A) Chip rate (rate at which phase might change) 1.023 MHz – Precise positioning code (P code) 10.23 MHz – Y-code (Antispoofing code) also 10.23 MHz derived by multiplying P-code by ~20KHz code (highly classified)