diff --git a/gtsam/base/std_optional_serialization.h b/gtsam/base/std_optional_serialization.h
index 5c250eab4..ac0c16c87 100644
--- a/gtsam/base/std_optional_serialization.h
+++ b/gtsam/base/std_optional_serialization.h
@@ -56,6 +56,8 @@ namespace std { template<> struct is_trivially_move_constructible<boost::seriali
 #endif
 
 
+// Only for old boost
+#if BOOST_VERSION < 108000
 // function specializations must be defined in the appropriate
 // namespace - boost::serialization
 namespace boost {
@@ -99,3 +101,4 @@ void serialize(Archive& ar, std::optional<T>& t, const unsigned int version) {
 }  // namespace serialization
 }  // namespace boost
 #endif
+#endif
diff --git a/gtsam/navigation/BarometricFactor.h b/gtsam/navigation/BarometricFactor.h
index 38677ed58..70cae8d36 100644
--- a/gtsam/navigation/BarometricFactor.h
+++ b/gtsam/navigation/BarometricFactor.h
@@ -91,7 +91,7 @@ class GTSAM_EXPORT BarometricFactor : public NoiseModelFactorN<Pose3, double> {
                -0.00649;
     }
 
-    inline double baroOut(const double& meters) {
+    inline double baroOut(const double& meters) const {
         double temp = 15.04 - 0.00649 * meters;
         return 101.29 * std::pow(((temp + 273.1) / 288.08), 5.256);
     }
diff --git a/gtsam/navigation/navigation.i b/gtsam/navigation/navigation.i
index 8e6090e06..92864c18a 100644
--- a/gtsam/navigation/navigation.i
+++ b/gtsam/navigation/navigation.i
@@ -294,7 +294,7 @@ virtual class GPSFactor : gtsam::NonlinearFactor{
   // Testable
   void print(string s = "", const gtsam::KeyFormatter& keyFormatter =
                                 gtsam::DefaultKeyFormatter) const;
-  bool equals(const gtsam::GPSFactor& expected, double tol);
+  bool equals(const gtsam::NonlinearFactor& expected, double tol);
 
   // Standard Interface
   gtsam::Point3 measurementIn() const;
@@ -307,12 +307,29 @@ virtual class GPSFactor2 : gtsam::NonlinearFactor {
   // Testable
   void print(string s = "", const gtsam::KeyFormatter& keyFormatter =
                                 gtsam::DefaultKeyFormatter) const;
-  bool equals(const gtsam::GPSFactor2& expected, double tol);
+  bool equals(const gtsam::NonlinearFactor& expected, double tol);
 
   // Standard Interface
   gtsam::Point3 measurementIn() const;
 };
 
+#include <gtsam/navigation/BarometricFactor.h>
+virtual class BarometricFactor : gtsam::NonlinearFactor {
+  BarometricFactor();
+  BarometricFactor(size_t key, size_t baroKey, const double& baroIn,
+                   const gtsam::noiseModel::Base* model);
+
+  // Testable
+  void print(string s = "", const gtsam::KeyFormatter& keyFormatter =
+                                gtsam::DefaultKeyFormatter) const;
+  bool equals(const gtsam::NonlinearFactor& expected, double tol);
+
+  // Standard Interface
+  const double& measurementIn() const;
+  double heightOut(double n) const;
+  double baroOut(const double& meters) const;
+};
+
 #include <gtsam/navigation/Scenario.h>
 virtual class Scenario {
   gtsam::Pose3 pose(double t) const;