Tracking knowing only C/A code Tracking is possible for two reasons P-code is written with 50% power P-code is written out of phase Phasor diagram shows how this works Assume that CIA code known, so that sign reversals from c/a code are removed Consider tracking in -0.1 usec(1/10.23 MHZ segments of data( no range change and frequencies match exactly) 02/27/02 12.540Lec0702/27/02 12.540 Lec 07 10 Tracking knowing only C/A code • Tracking is possible for two reasons: – P-code is written with 50% power – P-code is written out of phase • Phasor diagram shows how this works • Assume that C/A code known, so that sign reversals from C/A code are removed • Consider tracking in ~0.1 µsec (1/10.23 MHz) segments of data (no range change and frequencies match exactly)