diff --git a/sensor_msgs/include/sensor_msgs/distortion_models.hpp b/sensor_msgs/include/sensor_msgs/distortion_models.hpp
index 243787d1..06a43073 100644
--- a/sensor_msgs/include/sensor_msgs/distortion_models.hpp
+++ b/sensor_msgs/include/sensor_msgs/distortion_models.hpp
@@ -43,6 +43,7 @@ namespace distortion_models
 {
 const char PLUMB_BOB[] = "plumb_bob";
 const char RATIONAL_POLYNOMIAL[] = "rational_polynomial";
+const char EQUIDISTANT[] = "equidistant";
 }
 }