diff --git a/include/apriltag/processor/processor_tracker_landmark_apriltag.h b/include/apriltag/processor/processor_tracker_landmark_apriltag.h
index 703f092572f1d45bd7f116f8ab0bc59fd1d3b873..7f9b00e01ff79efeb7147cbc0f77002ae69752a2 100644
--- a/include/apriltag/processor/processor_tracker_landmark_apriltag.h
+++ b/include/apriltag/processor/processor_tracker_landmark_apriltag.h
@@ -182,8 +182,10 @@ class ProcessorTrackerLandmarkApriltag : public ProcessorTrackerLandmark
     public:
         double getTagWidth(int _id) const;
         std::string getTagFamily() const;
-        FeatureBasePtrList getIncomingDetections() const;
-        FeatureBasePtrList getLastDetections() const;
+        FeatureBaseConstPtrList getIncomingDetections() const;
+        FeatureBasePtrList getIncomingDetections();
+        FeatureBaseConstPtrList getLastDetections() const;
+        FeatureBasePtrList getLastDetections();
         void ippePoseEstimation(apriltag_detection_t *_det,
                                 cv::Mat_<double> _K,
                                 double _tag_width,
diff --git a/src/processor/processor_tracker_landmark_apriltag.cpp b/src/processor/processor_tracker_landmark_apriltag.cpp
index 275af0028ab3611cc974486490db9e5981ccf64c..86d97395a43ac42a398ffe0c8b99ee91bc94222c 100644
--- a/src/processor/processor_tracker_landmark_apriltag.cpp
+++ b/src/processor/processor_tracker_landmark_apriltag.cpp
@@ -485,12 +485,28 @@ void ProcessorTrackerLandmarkApriltag::pinholeHomogeneous(Eigen::Matrix3d const
     J_h_R = -K * R * p_hat;
 }
 
-FeatureBasePtrList ProcessorTrackerLandmarkApriltag::getIncomingDetections() const
+FeatureBaseConstPtrList ProcessorTrackerLandmarkApriltag::getIncomingDetections() const
+{
+    FeatureBaseConstPtrList list_const;
+    for (auto && obj : detections_incoming_)
+        list_const.push_back(obj);
+    return list_const;
+}
+
+FeatureBasePtrList ProcessorTrackerLandmarkApriltag::getIncomingDetections()
 {
     return detections_incoming_;
 }
 
-FeatureBasePtrList ProcessorTrackerLandmarkApriltag::getLastDetections() const
+FeatureBaseConstPtrList ProcessorTrackerLandmarkApriltag::getLastDetections() const
+{
+    FeatureBaseConstPtrList list_const;
+    for (auto && obj : detections_last_)
+        list_const.push_back(obj);
+    return list_const;
+}
+
+FeatureBasePtrList ProcessorTrackerLandmarkApriltag::getLastDetections()
 {
     return detections_last_;
 }