diff --git a/include/gnss/processor/processor_gnss_fix.h b/include/gnss/processor/processor_gnss_fix.h
index 07d00f30a156022a028a96c72da7b9cf2bbc4879..4bd3dfe2eb36aa62ab097a9fc092db62f76b3131 100644
--- a/include/gnss/processor/processor_gnss_fix.h
+++ b/include/gnss/processor/processor_gnss_fix.h
@@ -92,7 +92,7 @@ class ProcessorGnssFix : public ProcessorBase
         virtual bool voteForKeyFrame() override;
 
     private:
-        FactorBasePtr emplaceFactor(FeatureBasePtr& ftr_ptr);
+        FactorBasePtr emplaceFactor(FeatureBasePtr _ftr_ptr);
         bool rejectOutlier(FactorBasePtr ctr_ptr);
 
     public:
diff --git a/include/gnss/processor/processor_gnss_single_diff.h b/include/gnss/processor/processor_gnss_single_diff.h
index b4a215d791d7453bb8446f19e4cec080a0538045..b425b162d642e89328b5d2f58bb2f6f3d97e7af7 100644
--- a/include/gnss/processor/processor_gnss_single_diff.h
+++ b/include/gnss/processor/processor_gnss_single_diff.h
@@ -94,7 +94,7 @@ class ProcessorGnssSingleDiff : public ProcessorBase
 
 
     private:
-        FactorBasePtr emplaceFactor(FeatureBasePtr& ftr);
+        FactorBasePtr emplaceFactor(FeatureBasePtr _ftr);
 
     public:
         static ProcessorBasePtr create(const std::string& _unique_name, const ProcessorParamsBasePtr _params, const SensorBasePtr sensor);
diff --git a/src/processor/processor_gnss_fix.cpp b/src/processor/processor_gnss_fix.cpp
index 578e0203ceed53593ae5f6c5c5fe85ce109f8ce5..f11be23a5373ee138d7ebff11a54d802258ae91b 100644
--- a/src/processor/processor_gnss_fix.cpp
+++ b/src/processor/processor_gnss_fix.cpp
@@ -98,16 +98,16 @@ void ProcessorGnssFix::processCapture(CaptureBasePtr _capture)
     }
 }
 
-FactorBasePtr ProcessorGnssFix::emplaceFactor(FeatureBasePtr& ftr)
+FactorBasePtr ProcessorGnssFix::emplaceFactor(FeatureBasePtr _ftr)
 {
     // CREATE CONSTRAINT --------------------
     //WOLF_DEBUG("creating the factor...");
     // 2D
     if (getProblem()->getDim() == 2)
-        return FactorBase::emplace<FactorGnssFix2D>(ftr, ftr, sensor_gnss_, shared_from_this(), false, FAC_ACTIVE);
+        return FactorBase::emplace<FactorGnssFix2D>(_ftr, _ftr, sensor_gnss_, shared_from_this(), false, FAC_ACTIVE);
     // 3D
     else
-        return FactorBase::emplace<FactorGnssFix3D>(ftr, ftr, sensor_gnss_, shared_from_this(), false, FAC_ACTIVE);
+        return FactorBase::emplace<FactorGnssFix3D>(_ftr, _ftr, sensor_gnss_, shared_from_this(), false, FAC_ACTIVE);
 }
 
 bool ProcessorGnssFix::rejectOutlier(FactorBasePtr fac)
diff --git a/src/processor/processor_gnss_single_diff.cpp b/src/processor/processor_gnss_single_diff.cpp
index c2bb47b995d6b07205dc51d984b89d0bd279c141..3bc0a79c7b93175b8a56cbef27861f1204d61cca 100644
--- a/src/processor/processor_gnss_single_diff.cpp
+++ b/src/processor/processor_gnss_single_diff.cpp
@@ -88,12 +88,12 @@ void ProcessorGnssSingleDiff::processCapture(CaptureBasePtr _capture)
     }
 }
 
-FactorBasePtr ProcessorGnssSingleDiff::emplaceFactor(FeatureBasePtr& ftr)
+FactorBasePtr ProcessorGnssSingleDiff::emplaceFactor(FeatureBasePtr _ftr)
 {
     //WOLF_DEBUG("creating the factor...");
     // 2D
     if (getProblem()->getDim() == 2)
-        return FactorBase::emplace<FactorGnssSingleDiff2D>(ftr, ftr, incoming_capture_->getOriginFrame(), sensor_gnss_, shared_from_this());
+        return FactorBase::emplace<FactorGnssSingleDiff2D>(_ftr, _ftr, incoming_capture_->getOriginFrame(), sensor_gnss_, shared_from_this());
     // 3D TODO
     else
         std::runtime_error("Single Differences in 3D not implemented yet.");