diff --git a/gtsam/navigation/CombinedImuFactor.cpp b/gtsam/navigation/CombinedImuFactor.cpp
index ba51fa31a..4d2fe14ea 100644
--- a/gtsam/navigation/CombinedImuFactor.cpp
+++ b/gtsam/navigation/CombinedImuFactor.cpp
@@ -143,9 +143,9 @@ void CombinedImuFactor::CombinedPreintegratedMeasurements::integrateMeasurement(
       (measurementCovariance_.block<3,3>(6,6)  +  measurementCovariance_.block<3,3>(18,18) ) *
       (H_angles_biasomega.transpose());
 
-  G_measCov_Gt.block<3,3>(9,9) = deltaT * measurementCovariance_.block<3,3>(9,9);
+  G_measCov_Gt.block<3,3>(9,9) = (1/deltaT) * measurementCovariance_.block<3,3>(9,9);
 
-  G_measCov_Gt.block<3,3>(12,12) = deltaT * measurementCovariance_.block<3,3>(12,12);
+  G_measCov_Gt.block<3,3>(12,12) = (1/deltaT) * measurementCovariance_.block<3,3>(12,12);
 
   // NEW OFF BLOCK DIAGONAL TERMS
   Matrix3 block23 = H_vel_biasacc * measurementCovariance_.block<3,3>(18,15) *  H_angles_biasomega.transpose();
@@ -164,10 +164,10 @@ void CombinedImuFactor::CombinedPreintegratedMeasurements::integrateMeasurement(
     // This is for testing & documentation
     ///< measurementCovariance_ : cov[integrationError measuredAcc measuredOmega biasAccRandomWalk biasOmegaRandomWalk biasAccInit biasOmegaInit] in R^(21 x 21)
     (*G_test) << I_3x3 * deltaT,  Z_3x3,          Z_3x3,              Z_3x3,              Z_3x3,           Z_3x3,              Z_3x3,
-                 Z_3x3,           H_vel_biasacc,  Z_3x3,              Z_3x3,              Z_3x3,           H_vel_biasacc,      Z_3x3,
-                 Z_3x3,           Z_3x3,          H_angles_angles,    Z_3x3,              Z_3x3,           Z_3x3,              H_angles_biasomega,
-                 Z_3x3,           Z_3x3,          Z_3x3,              I_3x3 * deltaT,     Z_3x3,           Z_3x3,              Z_3x3,
-                 Z_3x3,           Z_3x3,          Z_3x3,              Z_3x3,              I_3x3 * deltaT,  Z_3x3,              Z_3x3;
+                 Z_3x3,          -H_vel_biasacc,  Z_3x3,              Z_3x3,              Z_3x3,           H_vel_biasacc,      Z_3x3,
+                 Z_3x3,           Z_3x3,         -H_angles_biasomega, Z_3x3,              Z_3x3,           Z_3x3,              H_angles_biasomega,
+                 Z_3x3,           Z_3x3,          Z_3x3,              I_3x3,              Z_3x3,           Z_3x3,              Z_3x3,
+                 Z_3x3,           Z_3x3,          Z_3x3,              Z_3x3,              I_3x3,           Z_3x3,              Z_3x3;
   }
 }
 
diff --git a/gtsam/navigation/tests/testCombinedImuFactor.cpp b/gtsam/navigation/tests/testCombinedImuFactor.cpp
index c88e054e6..bb6828216 100644
--- a/gtsam/navigation/tests/testCombinedImuFactor.cpp
+++ b/gtsam/navigation/tests/testCombinedImuFactor.cpp
@@ -382,25 +382,36 @@ TEST( CombinedImuFactor, JacobianPreintegratedCovariancePropagation )
 
   Fexpected << df_dpos, df_dvel, df_dangle, df_dbias;
   EXPECT(assert_equal(Fexpected, Factual));
-//
-//  // Compute expected G wrt integration noise
-//  Matrix df_dintNoise(9,3);
-//  df_dintNoise << I_3x3 * newDeltaT, Z_3x3, Z_3x3;
-//
-//  // Compute expected F wrt acc noise
-//  Matrix df_daccNoise =
-//      numericalDerivative11<Vector, Vector3>(boost::bind(&updatePreintegratedMeasurementsTest,
-//          deltaPij_old, deltaVij_old, logDeltaRij_old,
-//          _1, newMeasuredOmega, newDeltaT, use2ndOrderIntegration), newMeasuredAcc);
-//  // Compute expected F wrt gyro noise
-//  Matrix df_domegaNoise =
-//      numericalDerivative11<Vector, Vector3>(boost::bind(&updatePreintegratedMeasurementsTest,
-//          deltaPij_old, deltaVij_old, logDeltaRij_old,
-//          newMeasuredAcc, _1, newDeltaT, use2ndOrderIntegration), newMeasuredOmega);
-//  Matrix Gexpected(9,9);
-//
-//  Gexpected << df_dintNoise, df_daccNoise, df_domegaNoise;
-//  EXPECT(assert_equal(Gexpected, Gactual));
+
+  // Compute expected G wrt integration noise
+  Matrix df_dintNoise(15,3);
+  df_dintNoise << I_3x3 * newDeltaT, Z_3x3, Z_3x3, Z_3x3, Z_3x3;
+
+  // Compute expected F wrt acc noise (15,3)
+  Matrix df_daccNoise =
+      numericalDerivative11<Vector, Vector3>(boost::bind(&updatePreintegratedMeasurementsTest,
+          deltaPij_old, deltaVij_old, logDeltaRij_old, bias_old,
+          _1, newMeasuredOmega, newDeltaT, use2ndOrderIntegration), newMeasuredAcc);
+  // Compute expected F wrt gyro noise (15,3)
+  Matrix df_domegaNoise =
+      numericalDerivative11<Vector, Vector3>(boost::bind(&updatePreintegratedMeasurementsTest,
+          deltaPij_old, deltaVij_old, logDeltaRij_old, bias_old,
+          newMeasuredAcc, _1, newDeltaT, use2ndOrderIntegration), newMeasuredOmega);
+  // Compute expected F wrt bias random walk noise (15,6)
+  Matrix df_rwBias(15,6); // random walk on the bias does not appear in the first 9 entries
+  df_rwBias.setZero();
+  df_rwBias.block<6,6>(9,0) = eye(6);
+
+  // Compute expected F wrt gyro noise (15,3)
+  Matrix df_dinitBias =
+      numericalDerivative11<Vector, imuBias::ConstantBias>(boost::bind(&updatePreintegratedMeasurementsTest,
+          deltaPij_old, deltaVij_old, logDeltaRij_old, _1,
+          newMeasuredAcc, newMeasuredOmega, newDeltaT, use2ndOrderIntegration), bias_old);
+  df_dinitBias.block<6,6>(9,0) = Matrix::Zero(6,6); // only has to influence first 9 rows
+  Matrix Gexpected(15,21);
+  Gexpected << df_dintNoise, df_daccNoise, df_domegaNoise, df_rwBias, df_dinitBias;
+
+  EXPECT(assert_equal(Gexpected, Gactual));
 }
 
 /* ************************************************************************* */