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tracking_2nd_DLL_filter.h
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tracking_2nd_DLL_filter.h
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/*!
* \file tracking_2nd_DLL_filter.h
* \brief Interface of a 2nd order DLL filter for code tracking loop.
* \author Javier Arribas, 2011. jarribas(at)cttc.es
*
* Class that implements a 2nd order PLL filter for code tracking loop.
* The algorithm is described in:
* K.Borre, D.M.Akos, N.Bertelsen, P.Rinder, and S. H. Jensen,
* A Software-Defined GPS and Galileo Receiver. A Single-Frequency Approach,
* Birkhauser, 2007, Applied and Numerical Harmonic Analysis.
*
* -----------------------------------------------------------------------------
*
* GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
* This file is part of GNSS-SDR.
*
* Copyright (C) 2010-2020 (see AUTHORS file for a list of contributors)
* SPDX-License-Identifier: GPL-3.0-or-later
*
* -----------------------------------------------------------------------------
*/
#ifndef GNSS_SDR_TRACKING_2ND_DLL_FILTER_H
#define GNSS_SDR_TRACKING_2ND_DLL_FILTER_H
/** \addtogroup Tracking
* \{ */
/** \addtogroup Tracking_libs
* \{ */
/*!
* \brief This class implements a 2nd order DLL filter for code tracking loop.
*
* The algorithm is described in:
* K.Borre, D.M.Akos, N.Bertelsen, P.Rinder, and S. H. Jensen, A Software-Defined GPS
* and Galileo Receiver. A Single-Frequency Approach,
* Birkhauser, 2007, Applied and Numerical Harmonic Analysis.
*/
class Tracking_2nd_DLL_filter
{
public:
Tracking_2nd_DLL_filter();
~Tracking_2nd_DLL_filter() = default;
explicit Tracking_2nd_DLL_filter(float pdi_code);
void set_DLL_BW(float dll_bw_hz); //!< Set DLL filter bandwidth [Hz]
void set_pdi(float pdi_code); //!< Set Summation interval for code [s]
void initialize(); //!< Start tracking with acquisition information
float get_code_nco(float DLL_discriminator); //!< Numerically controlled oscillator
private:
void calculate_lopp_coef(float* tau1, float* tau2, float lbw, float zeta, float k);
// PLL filter parameters
float d_tau1_code = 0.0;
float d_tau2_code = 0.0;
float d_pdi_code = 0.0;
float d_dllnoisebandwidth = 0.0;
float d_dlldampingratio = 0.0;
float d_old_code_error = 0.0;
float d_old_code_nco = 0.0;
};
/** \} */
/** \} */
#endif