diff --git a/.github/workflows/build-python.yml b/.github/workflows/build-python.yml
index d8dfce0ee7..520e94c09b 100644
--- a/.github/workflows/build-python.yml
+++ b/.github/workflows/build-python.yml
@@ -29,7 +29,7 @@ jobs:
         name:
           [
             ubuntu-20.04-gcc-9,
-            ubuntu-22.04-gcc-9-tbb,
+            ubuntu-20.04-gcc-9-tbb,
             ubuntu-20.04-clang-9,
             macOS-11-xcode-13.4.1,
             windows-2019-msbuild,
@@ -43,8 +43,8 @@ jobs:
             compiler: gcc
             version: "9"
 
-          - name: ubuntu-22.04-gcc-9-tbb
-            os: ubuntu-22.04
+          - name: ubuntu-20.04-gcc-9-tbb
+            os: ubuntu-20.04
             compiler: gcc
             version: "9"
             flag: tbb
@@ -145,6 +145,12 @@ jobs:
           echo "GTSAM_WITH_TBB=ON" >> $GITHUB_ENV
           echo "GTSAM Uses TBB"
 
+      - name: Set Swap Space (Linux)
+        if: runner.os == 'Linux'
+        uses: pierotofy/set-swap-space@master
+        with:
+          swap-size-gb: 6
+
       - name: Install System Dependencies (Linux, macOS)
         if: runner.os != 'Windows'
         run: |
diff --git a/gtsam/base/std_optional_serialization.h b/gtsam/base/std_optional_serialization.h
index 0ab778761f..444c317033 100644
--- a/gtsam/base/std_optional_serialization.h
+++ b/gtsam/base/std_optional_serialization.h
@@ -57,7 +57,14 @@ namespace std { template<> struct is_trivially_move_constructible<boost::seriali
 #endif
 #endif
 
-
+/*
+ * PR https://github.com/boostorg/serialization/pull/163 was merged
+ * on September 3rd 2023,
+ * and so the below code is now a part of Boost 1.84.
+ * We include it for posterity, hence the check for BOOST_VERSION being less
+ * than 1.84.
+ */
+#if BOOST_VERSION < 108400
 // function specializations must be defined in the appropriate
 // namespace - boost::serialization
 namespace boost {
diff --git a/gtsam/navigation/BarometricFactor.h b/gtsam/navigation/BarometricFactor.h
index 38677ed589..70cae8d367 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 8e6090e06a..92864c18a0 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;