diff --git a/gtsam/navigation/navigation.i b/gtsam/navigation/navigation.i
index ceeab3b35..7300f87ba 100644
--- a/gtsam/navigation/navigation.i
+++ b/gtsam/navigation/navigation.i
@@ -329,7 +329,8 @@ virtual class Pose3AttitudeFactor : gtsam::NoiseModelFactor {
 #include <gtsam/navigation/GPSFactor.h>
 virtual class GPSFactor : gtsam::NonlinearFactor{
   GPSFactor(size_t key, const gtsam::Point3& gpsIn,
-            const gtsam::noiseModel::Base* model);
+            const gtsam::noiseModel::Base* model,
+            const gtsam::Point3& leverArm);
 
   // Testable
   void print(string s = "", const gtsam::KeyFormatter& keyFormatter =
@@ -338,6 +339,7 @@ virtual class GPSFactor : gtsam::NonlinearFactor{
 
   // Standard Interface
   gtsam::Point3 measurementIn() const;
+  gtsam::Point3 leverArm() const;
 
   // enable serialization functionality
   void serialize() const;
@@ -345,7 +347,8 @@ virtual class GPSFactor : gtsam::NonlinearFactor{
 
 virtual class GPSFactor2 : gtsam::NonlinearFactor {
   GPSFactor2(size_t key, const gtsam::Point3& gpsIn,
-            const gtsam::noiseModel::Base* model);
+            const gtsam::noiseModel::Base* model,
+            const gtsam::Point3& leverArm);
 
   // Testable
   void print(string s = "", const gtsam::KeyFormatter& keyFormatter =
@@ -354,6 +357,7 @@ virtual class GPSFactor2 : gtsam::NonlinearFactor {
 
   // Standard Interface
   gtsam::Point3 measurementIn() const;
+  gtsam::Point3 leverArm() const;
 
   // enable serialization functionality
   void serialize() const;