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Code Issues Releases Wiki Activity

- Bug in carrier lock detector algorithm corrected

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- Code cleaning and DLL/PLL variable renaming in galileo_e1_dll_pll_veml tracking

git-svn-id: https://svn.code.sf.net/p/gnss-sdr/code/trunk@253 64b25241-fba3-4117-9849-534c7e92360d
This commit is contained in:
Javier Arribas
2012-10-20 16:11:31 +00:00
parent af92708c3d
commit 3628453c52
8 changed files with 68 additions and 72 deletions
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33
src/algorithms/tracking/libs/CN_estimators.cc
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@@ -131,40 +131,35 @@ float galileo_e1_CN0_SNV(gr_complex* Prompt_buffer, int length, long fs_in)
SNR_dB_Hz = 10 * log10(SNR) + 10 * log10(fs_in/2) - 10 * log10(Galileo_E1_B_CODE_LENGTH_CHIPS);
return SNR_dB_Hz;
}
/*
* The Carrier Phase Lock Detector block uses the normalised estimate of the cosine of twice the carrier phase error is given by
* \f{equation}
* C2\phi=\frac{NBD}{NBP},
* \cos(2\phi)=\frac{NBD}{NBP},
* \f}
* where \f$NBD=(\sum^{N-1}_{i=0}|Im(Pc(i))|)^2+(\sum^{N-1}_{i=0}|Re(Pc(i))|)^2\f$,
* \f$NBP=\sum^{N-1}_{i=0}Im(Pc(i))^2-\sum^{N-1}_{i=0}Re(Pc(i))^2\f$, and
* where \f$NBD=(\sum^{N-1}_{i=0}Im(Pc(i)))^2-(\sum^{N-1}_{i=0}Re(Pc(i)))^2\f$,
* \f$NBP=(\sum^{N-1}_{i=0}Im(Pc(i)))^2+(\sum^{N-1}_{i=0}Re(Pc(i)))^2\f$, and
* \f$Pc(i)\f$ is the prompt correlator output for the sample index i.
*/
float carrier_lock_detector(gr_complex* Prompt_buffer, int length)
{
/*
* Code lock detector
* carrier lock detector
*/
// estimate using buffered values
float tmp_abs_I, tmp_abs_Q;
float tmp_sum_abs_I, tmp_sum_abs_Q;
float tmp_sum_sqr_I, tmp_sum_sqr_Q;
tmp_sum_abs_I = 0;
tmp_sum_abs_Q = 0;
tmp_sum_sqr_I = 0;
tmp_sum_sqr_Q = 0;
float tmp_sum_I, tmp_sum_Q;
tmp_sum_I = 0;
tmp_sum_Q = 0;
float NBD,NBP;
for (int i=0; i<length; i++)
{
tmp_abs_I = std::abs(Prompt_buffer[i].real());
tmp_abs_Q = std::abs(Prompt_buffer[i].imag());
tmp_sum_abs_I += tmp_abs_I;
tmp_sum_abs_Q += tmp_abs_Q;
tmp_sum_sqr_I += (Prompt_buffer[i].real() * Prompt_buffer[i].real());
tmp_sum_sqr_Q += (Prompt_buffer[i].imag() * Prompt_buffer[i].imag());
tmp_sum_I += Prompt_buffer[i].real();
tmp_sum_Q += Prompt_buffer[i].imag();
}
NBD = tmp_sum_abs_I * tmp_sum_abs_I + tmp_sum_abs_Q * tmp_sum_abs_Q;
NBP = tmp_sum_sqr_I - tmp_sum_sqr_Q;
NBP = tmp_sum_I*tmp_sum_I + tmp_sum_Q*tmp_sum_Q;
NBD = tmp_sum_I*tmp_sum_I - tmp_sum_Q*tmp_sum_Q;
return NBD/NBP;
}