signal and the input data is performed and the output contains 5000 points the maximum of all the 21 correlation outputs is selected this maximum value provides the starting point in time of the c a code in the input signal and the selected coarse demodulation frequency with a resolution of 500 hz from the true gps satellite doppler shifted carrier frequency during the second part of the acquisition procedure the coarse carrier frequency is refined and initial phase angle determined since the starting point of the c a code in the data is known one millisecond of data beginning at the starting point of the c a code is selected multiplying in time domain the c a code with the data will strip the c a code from the data leaving an output sinusoidal wave the next step is to find the frequency of this sinusoidal wave representing the gps satellite signal carrier in this operation twenty one refined demodulation frequencies are locally generated and range from u2212 500 hz to 500 hz centered around the coarse carrier frequency in 50 hz steps the dft output equation equation 1 above is used to calculate the output frequency the highest output will be the desired frequency this operation improves the frequency resolution to 50 hz the phase angle equation equation 2 above is used to determine the initial phase angle of the carrier frequency it appears that if finer carrier frequency resolution is used to start the tracking procedure better results can be obtained the third part of the acquisition procedure is to generate the fine carrier frequency the approach is to take seven milliseconds of consecutive data beginning with the starting point of the c a code then to use the refined coarse frequency.