diff --git a/src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc b/src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc
index 3513a41da..f4aea64d8 100644
--- a/src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc
+++ b/src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc
@@ -222,6 +222,7 @@ void pcps_acquisition::init()
     d_gnss_synchro->Flag_valid_pseudorange = false;
     d_gnss_synchro->Flag_valid_word = false;
 
+    d_gnss_synchro->Acq_doppler_step = d_doppler_step;
     d_gnss_synchro->Acq_delay_samples = 0.0;
     d_gnss_synchro->Acq_doppler_hz = 0.0;
     d_gnss_synchro->Acq_samplestamp_samples = 0;
@@ -282,6 +283,7 @@ void pcps_acquisition::set_state(int state)
         {
             d_gnss_synchro->Acq_delay_samples = 0.0;
             d_gnss_synchro->Acq_doppler_hz = 0.0;
+            d_gnss_synchro->Acq_doppler_step = 0;
             d_gnss_synchro->Acq_samplestamp_samples = 0;
             d_well_count = 0;
             d_mag = 0.0;
diff --git a/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_kf_tracking_cc.cc b/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_kf_tracking_cc.cc
index cc05dde31..ee6d29e4f 100644
--- a/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_kf_tracking_cc.cc
+++ b/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_kf_tracking_cc.cc
@@ -174,7 +174,7 @@ Gps_L1_Ca_Kf_Tracking_cc::Gps_L1_Ca_Kf_Tracking_cc(
 
     // Kalman filter initialization (receiver initialization)
 
-    double CN_dB_Hz = 40;
+    double CN_dB_Hz = 30;
     double CN_lin = pow(10, CN_dB_Hz / 10.0);
 
     double sigma2_phase_detector_cycles2;
@@ -182,7 +182,7 @@ Gps_L1_Ca_Kf_Tracking_cc::Gps_L1_Ca_Kf_Tracking_cc(
 
     //covariances (static)
     double sigma2_carrier_phase = GPS_TWO_PI / 4;
-    double sigma2_doppler = 250;  ///  !!
+    double sigma2_doppler = 450;
 
     kf_P_x_ini = arma::zeros(2, 2);
     kf_P_x_ini(0, 0) = sigma2_carrier_phase;
@@ -217,6 +217,13 @@ void Gps_L1_Ca_Kf_Tracking_cc::start_tracking()
     d_acq_code_phase_samples = d_acquisition_gnss_synchro->Acq_delay_samples;
     d_acq_carrier_doppler_hz = d_acquisition_gnss_synchro->Acq_doppler_hz;
     d_acq_sample_stamp = d_acquisition_gnss_synchro->Acq_samplestamp_samples;
+    d_acq_carrier_doppler_step_hz = static_cast<double>(d_acquisition_gnss_synchro->Acq_doppler_step);
+
+    // Correct Kalman filter covariance according to acq doppler step size (3 sigma)
+    if (d_acquisition_gnss_synchro->Acq_doppler_step > 0)
+        {
+            kf_P_x_ini(1, 1) = pow(2, d_acq_carrier_doppler_step_hz / 3.0);
+        }
 
     long int acq_trk_diff_samples;
     double acq_trk_diff_seconds;
diff --git a/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_kf_tracking_cc.h b/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_kf_tracking_cc.h
index 3e33491af..0d4ed779d 100644
--- a/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_kf_tracking_cc.h
+++ b/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_kf_tracking_cc.h
@@ -135,6 +135,7 @@ private:
     //Tracking_2nd_PLL_filter d_carrier_loop_filter;
 
     // acquisition
+    double d_acq_carrier_doppler_step_hz;
     double d_acq_code_phase_samples;
     double d_acq_carrier_doppler_hz;
     // correlator
diff --git a/src/core/system_parameters/gnss_synchro.h b/src/core/system_parameters/gnss_synchro.h
index 7d572dffa..90dd378d3 100644
--- a/src/core/system_parameters/gnss_synchro.h
+++ b/src/core/system_parameters/gnss_synchro.h
@@ -49,6 +49,7 @@ public:
     // Acquisition
     double Acq_delay_samples;                   //!< Set by Acquisition processing block
     double Acq_doppler_hz;                      //!< Set by Acquisition processing block
+    unsigned int Acq_doppler_step;              //!< Set by Acquisition processing block
     unsigned long int Acq_samplestamp_samples;  //!< Set by Acquisition processing block
     bool Flag_valid_acquisition;                //!< Set by Acquisition processing block
     //Tracking