diff --git a/src/core/receiver/gnss_block_factory.cc b/src/core/receiver/gnss_block_factory.cc
index fd8d0f09f..ac0bb8aad 100644
--- a/src/core/receiver/gnss_block_factory.cc
+++ b/src/core/receiver/gnss_block_factory.cc
@@ -182,7 +182,7 @@ GNSSBlockFactory::~GNSSBlockFactory() = default;
 
 
 std::unique_ptr<GNSSBlockInterface> GNSSBlockFactory::GetSignalSource(
-    const std::shared_ptr<ConfigurationInterface>& configuration, gr::msg_queue::sptr queue, int ID)
+    const std::shared_ptr<ConfigurationInterface>& configuration, const gr::msg_queue::sptr& queue, int ID)
 {
     std::string default_implementation = "File_Signal_Source";
     std::string role = "SignalSource";  //backwards compatibility for old conf files
diff --git a/src/core/receiver/gnss_block_factory.h b/src/core/receiver/gnss_block_factory.h
index 8ead87090..e3eb02226 100644
--- a/src/core/receiver/gnss_block_factory.h
+++ b/src/core/receiver/gnss_block_factory.h
@@ -58,7 +58,7 @@ public:
     GNSSBlockFactory();
     virtual ~GNSSBlockFactory();
     std::unique_ptr<GNSSBlockInterface> GetSignalSource(const std::shared_ptr<ConfigurationInterface>& configuration,
-        gr::msg_queue::sptr queue, int ID = -1);
+        const gr::msg_queue::sptr& queue, int ID = -1);
 
     std::unique_ptr<GNSSBlockInterface> GetSignalConditioner(const std::shared_ptr<ConfigurationInterface>& configuration, int ID = -1);