Interface of a library with a set of code and carrier phase lock detectors. More...

#include <gnuradio/gr_complex.h>

Functions
float	cn0_svn_estimator (const gr_complex *Prompt_buffer, int length, float coh_integration_time_s)
	cn0_svn_estimator is a Carrier-to-Noise (CN0) estimator based on the Signal-to-Noise Variance (SNV) estimator More...

float	cn0_m2m4_estimator (const gr_complex *Prompt_buffer, int length, float coh_integration_time_s)
	cn0_m2m4_estimator is a Carrier-to-Noise (CN0) estimator based on the Second- and Fourth-Order Moments Method (M2M4) More...

float	carrier_lock_detector (gr_complex *Prompt_buffer, int length)
	A carrier lock detector. More...

Detailed Description

Interface of a library with a set of code and carrier phase lock detectors.

SNV_CN0 is a Carrier-to-Noise (CN0) estimator based on the Signal-to-Noise Variance (SNV) estimator [1]. Carrier lock detector using normalised estimate of the cosine of twice the carrier phase error [2].

[1] Marco Pini, Emanuela Falletti and Maurizio Fantino, "Performance Evaluation of C/N0 Estimators using a Real Time GNSS Software Receiver," IEEE 10th International Symposium on Spread Spectrum Techniques and Applications, pp.28-30, August 2008.

[2] Van Dierendonck, A.J. (1996), Global Positioning System: Theory and Applications, Volume I, Chapter 8: GPS Receivers, AJ Systems, Los Altos, CA 94024. Inc.: 329-407.

Authors

Javier Arribas, 2011. jarribas(at)cttc.es
Luis Esteve, 2012. luis(at)epsilon-formacion.com

Copyright (C) 2010-2020 (see AUTHORS file for a list of contributors)

GNSS-SDR is a software defined Global Navigation Satellite Systems receiver

This file is part of GNSS-SDR.

SPDX-License-Identifier: GPL-3.0-or-later

Definition in file lock_detectors.h.

Function Documentation

◆ carrier_lock_detector()

float carrier_lock_detector	(	gr_complex *	Prompt_buffer,
		int	length
	)

A carrier lock detector.

The Carrier Phase Lock Detector block uses the estimate of the cosine of twice the carrier phase error is given by

$\begin{equation} C2\phi=\frac{NBD}{NBP}, \end{equation}$

where $NBD=(\sum^{N-1}_{i=0}|Im(Pc(i))|)^2+(\sum^{N-1}_{i=0}|Re(Pc(i))|)^2$ , $NBP=\sum^{N-1}_{i=0}Im(Pc(i))^2-\sum^{N-1}_{i=0}Re(Pc(i))^2$ , and $ Pc(i) $ is the prompt correlator output for the sample index i. Ref: Van Dierendonck, A.J. (1996), Global Positioning System: Theory and Applications, Volume I, Chapter 8: GPS Receivers, AJ Systems, Los Altos, CA 94024. Inc.: 329-407.

◆ cn0_m2m4_estimator()

float cn0_m2m4_estimator	(	const gr_complex *	Prompt_buffer,
		int	length,
		float	coh_integration_time_s
	)

cn0_m2m4_estimator is a Carrier-to-Noise (CN0) estimator based on the Second- and Fourth-Order Moments Method (M2M4)

Signal-to-Noise (SNR) ( $\rho$ ) estimator using the Moments Method:

$\begin{equation} \hat{\rho}=\frac{\sqrt{2 \hat{M}_2^2 - \hat{M}_4 }}{\hat{M}_2-\sqrt{2 \hat{M}_2^2 - \hat{M}_4 }}, \end{equation}$

where $\hat{M}_2=\frac{1}{N}\sum^{K-1}_{k=0}|P[k]|^2$ , $\hat{M}_4 = \frac{1}{K}\sum^{K-1}_{k=0}|P[k]|^4$ , $|\cdot|$ is the absolute value, and $ P[k] $ is the prompt correlator output for the sample index k.

The SNR value is converted to CN0 [dB-Hz] taking into account the coherent integration time, using the following formula:

$\begin{equation} CN0_{dB}=10*log(\hat{\rho})-10*log(T_{int}), \end{equation}$

where $T_{int}$ is the coherent integration time, in seconds.

Ref: D. R. Pauluzzi, N. C. Beaulieu, "A comparison of SNR estimation techniques for the AWGN channel," IEEE Trans. on Comm., vol. 48, no. 10, pp. 1681–1691, Oct. 2000.

◆ cn0_svn_estimator()

float cn0_svn_estimator	(	const gr_complex *	Prompt_buffer,
		int	length,
		float	coh_integration_time_s
	)

cn0_svn_estimator is a Carrier-to-Noise (CN0) estimator based on the Signal-to-Noise Variance (SNV) estimator

Signal-to-Noise (SNR) ( $\rho$ ) estimator using the Signal-to-Noise Variance (SNV) estimator:

$\begin{equation} \hat{\rho}=\frac{\hat{P}_s}{\hat{P}_n}=\frac{\hat{P}_s}{\hat{P}_{tot}-\hat{P}_s}, \end{equation}$

where $\hat{P}_s=\left(\frac{1}{N}\sum^{N-1}_{i=0}|Re(Pc(i))|\right)^2$ is the estimation of the signal power, $\hat{P}_{tot}=\frac{1}{N}\sum^{N-1}_{i=0}|Pc(i)|^2$ is the estimator of the total power, $|\cdot|$ is the absolute value, $Re(\cdot)$ stands for the real part of the value, and $ Pc(i) $ is the prompt correlator output for the sample index i.

The SNR value is converted to CN0 [dB-Hz], taking into account the coherent integration time, using the following formula: