gps tracking

Transmitter • Use DSSS signal model: oversampled code (4 samples per chip) and Doppler sinusoidal modulation (no code Doppler). Signal duration is one code period. Receiver • Carrier Tracking Discriminators. Set the code delay equal to 0 (no delay) which means a perfect alignment of code and replica. Implement an ordinary correlator (integrate&dump unit) for one code duration wiping-off the code. On the output of the correlator implement carrier loop discriminators and get characteristic curves: o Costas PLL (atan based) discriminator o FLL (atan based) discriminator. For FLL characteristic one should take two consecutive correlator outputs. So take two code periods. • Code Tracking Discriminator. Set the Doppler shift effects in frequency to 0 or disable these feature. Implement two correlators (early and late) by correlating the transmiter signal with shifted replica codes. Use the correlator outputs to obtain (early minus late envelop normalized by early plus late envelope) discriminator characteristic curves. Combine both figures using Matlab “hold on” command and include the figure in the report.