diff --git a/src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition.cc b/src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition.cc
index 585b5eacb..79e25061c 100644
--- a/src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition.cc
+++ b/src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition.cc
@@ -88,7 +88,7 @@ GalileoE1PcpsAmbiguousAcquisition::GalileoE1PcpsAmbiguousAcquisition(
     acq_parameters_.dump_filename = dump_filename_;
 
     acq_parameters_.use_automatic_resampler = configuration_->property("GNSS-SDR.use_acquisition_resampler", false);
-    if (acq_parameters_.use_automatic_resampler == true and item_type_.compare("gr_complex") != 0)
+    if (acq_parameters_.use_automatic_resampler == true and item_type_ != "gr_complex")
         {
             LOG(WARNING) << "Galileo E1 acqisition disabled the automatic resampler feature because its item_type is not set to gr_complex";
             acq_parameters_.use_automatic_resampler = false;
diff --git a/src/algorithms/acquisition/adapters/galileo_e5a_pcps_acquisition.cc b/src/algorithms/acquisition/adapters/galileo_e5a_pcps_acquisition.cc
index 466e7c231..4b7abfc8f 100644
--- a/src/algorithms/acquisition/adapters/galileo_e5a_pcps_acquisition.cc
+++ b/src/algorithms/acquisition/adapters/galileo_e5a_pcps_acquisition.cc
@@ -86,7 +86,7 @@ GalileoE5aPcpsAcquisition::GalileoE5aPcpsAcquisition(ConfigurationInterface* con
 
 
     acq_parameters_.use_automatic_resampler = configuration_->property("GNSS-SDR.use_acquisition_resampler", false);
-    if (acq_parameters_.use_automatic_resampler == true and item_type_.compare("gr_complex") != 0)
+    if (acq_parameters_.use_automatic_resampler == true and item_type_ != "gr_complex")
         {
             LOG(WARNING) << "Galileo E5a acquisition disabled the automatic resampler feature because its item_type is not set to gr_complex";
             acq_parameters_.use_automatic_resampler = false;
diff --git a/src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition.cc b/src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition.cc
index 3cdb92ad7..ce0ea4065 100644
--- a/src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition.cc
+++ b/src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition.cc
@@ -87,7 +87,7 @@ GpsL1CaPcpsAcquisition::GpsL1CaPcpsAcquisition(
     acq_parameters_.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
     acq_parameters_.make_2_steps = configuration_->property(role + ".make_two_steps", false);
     acq_parameters_.use_automatic_resampler = configuration_->property("GNSS-SDR.use_acquisition_resampler", false);
-    if (acq_parameters_.use_automatic_resampler == true and item_type_.compare("gr_complex") != 0)
+    if (acq_parameters_.use_automatic_resampler == true and item_type_ != "gr_complex")
         {
             LOG(WARNING) << "GPS L1 CA acquisition disabled the automatic resampler feature because its item_type is not set to gr_complex";
             acq_parameters_.use_automatic_resampler = false;
diff --git a/src/algorithms/acquisition/adapters/gps_l2_m_pcps_acquisition.cc b/src/algorithms/acquisition/adapters/gps_l2_m_pcps_acquisition.cc
index 596221516..dcf663121 100644
--- a/src/algorithms/acquisition/adapters/gps_l2_m_pcps_acquisition.cc
+++ b/src/algorithms/acquisition/adapters/gps_l2_m_pcps_acquisition.cc
@@ -91,7 +91,7 @@ GpsL2MPcpsAcquisition::GpsL2MPcpsAcquisition(
     acq_parameters_.make_2_steps = configuration_->property(role + ".make_two_steps", false);
     acq_parameters_.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
     acq_parameters_.use_automatic_resampler = configuration_->property("GNSS-SDR.use_acquisition_resampler", false);
-    if (acq_parameters_.use_automatic_resampler == true and item_type_.compare("gr_complex") != 0)
+    if (acq_parameters_.use_automatic_resampler == true and item_type_ != "gr_complex")
         {
             LOG(WARNING) << "GPS L2CM acquisition disabled the automatic resampler feature because its item_type is not set to gr_complex";
             acq_parameters_.use_automatic_resampler = false;
diff --git a/src/algorithms/acquisition/adapters/gps_l5i_pcps_acquisition.cc b/src/algorithms/acquisition/adapters/gps_l5i_pcps_acquisition.cc
index 8c3636277..f436da1d4 100644
--- a/src/algorithms/acquisition/adapters/gps_l5i_pcps_acquisition.cc
+++ b/src/algorithms/acquisition/adapters/gps_l5i_pcps_acquisition.cc
@@ -98,7 +98,7 @@ GpsL5iPcpsAcquisition::GpsL5iPcpsAcquisition(
     acq_parameters_.make_2_steps = configuration_->property(role + ".make_two_steps", false);
     acq_parameters_.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
     acq_parameters_.use_automatic_resampler = configuration_->property("GNSS-SDR.use_acquisition_resampler", false);
-    if (acq_parameters_.use_automatic_resampler == true and item_type_.compare("gr_complex") != 0)
+    if (acq_parameters_.use_automatic_resampler == true and item_type_ != "gr_complex")
         {
             LOG(WARNING) << "GPS L5 acquisition disabled the automatic resampler feature because its item_type is not set to gr_complex";
             acq_parameters_.use_automatic_resampler = false;
diff --git a/src/algorithms/channel/adapters/channel.cc b/src/algorithms/channel/adapters/channel.cc
index c39330521..946f17a65 100644
--- a/src/algorithms/channel/adapters/channel.cc
+++ b/src/algorithms/channel/adapters/channel.cc
@@ -146,7 +146,7 @@ void Channel::disconnect(gr::top_block_sptr top_block)
 gr::basic_block_sptr Channel::get_left_block()
 {
     LOG(ERROR) << "Deprecated call to get_left_block() in channel interface";
-    return NULL;
+    return nullptr;
 }
 
 gr::basic_block_sptr Channel::get_left_block_trk()
diff --git a/src/tests/system-tests/position_test.cc b/src/tests/system-tests/position_test.cc
index 01dca3bbb..202f31306 100644
--- a/src/tests/system-tests/position_test.cc
+++ b/src/tests/system-tests/position_test.cc
@@ -33,6 +33,7 @@
  */
 
 #include "MATH_CONSTANTS.h"
+#include "acquisition_msg_rx.h"
 #include "concurrent_map.h"
 #include "concurrent_queue.h"
 #include "control_thread.h"
diff --git a/src/tests/unit-tests/signal-processing-blocks/tracking/tracking_pull-in_test.cc b/src/tests/unit-tests/signal-processing-blocks/tracking/tracking_pull-in_test.cc
index 46cb20827..2d9861d6f 100644
--- a/src/tests/unit-tests/signal-processing-blocks/tracking/tracking_pull-in_test.cc
+++ b/src/tests/unit-tests/signal-processing-blocks/tracking/tracking_pull-in_test.cc
@@ -30,12 +30,12 @@
  * -------------------------------------------------------------------------
  */
 
-
 #include "GPS_L1_CA.h"
 #include "GPS_L2C.h"
 #include "GPS_L5.h"
 #include "Galileo_E1.h"
 #include "Galileo_E5a.h"
+#include "acquisition_msg_rx.h"
 #include "control_message_factory.h"
 #include "galileo_e1_pcps_ambiguous_acquisition.h"
 #include "galileo_e5a_noncoherent_iq_acquisition_caf.h"