diff --git a/cartographer/mapping/internal/2d/pose_graph_2d_test.cc b/cartographer/mapping/internal/2d/pose_graph_2d_test.cc
index bceb588..ad009be 100644
--- a/cartographer/mapping/internal/2d/pose_graph_2d_test.cc
+++ b/cartographer/mapping/internal/2d/pose_graph_2d_test.cc
@@ -129,6 +129,7 @@ class PoseGraph2DTest : public ::testing::Test {
               fixed_frame_pose_translation_weight = 1e1,
               fixed_frame_pose_rotation_weight = 1e2,
               log_solver_summary = true,
+              use_online_imu_extrinsics_in_3d = true,
               ceres_solver_options = {
                 use_nonmonotonic_steps = false,
                 max_num_iterations = 200,
diff --git a/cartographer/mapping/internal/optimization/optimization_problem_3d.cc b/cartographer/mapping/internal/optimization/optimization_problem_3d.cc
index ad12f31..0b525b7 100644
--- a/cartographer/mapping/internal/optimization/optimization_problem_3d.cc
+++ b/cartographer/mapping/internal/optimization/optimization_problem_3d.cc
@@ -367,6 +367,10 @@ void OptimizationProblem3D::Solve(
 
       problem.AddParameterBlock(trajectory_data.imu_calibration.data(), 4,
                                 new ceres::QuaternionParameterization());
+      if (!options_.use_online_imu_extrinsics_in_3d()) {
+        problem.SetParameterBlockConstant(
+            trajectory_data.imu_calibration.data());
+      }
       CHECK(imu_data_.HasTrajectory(trajectory_id));
       const auto imu_data = imu_data_.trajectory(trajectory_id);
       CHECK(imu_data.begin() != imu_data.end());
diff --git a/cartographer/mapping/internal/optimization/optimization_problem_3d_test.cc b/cartographer/mapping/internal/optimization/optimization_problem_3d_test.cc
index 68b39bd..1231f1f 100644
--- a/cartographer/mapping/internal/optimization/optimization_problem_3d_test.cc
+++ b/cartographer/mapping/internal/optimization/optimization_problem_3d_test.cc
@@ -49,6 +49,7 @@ class OptimizationProblem3DTest : public ::testing::Test {
           fixed_frame_pose_translation_weight = 1e1,
           fixed_frame_pose_rotation_weight = 1e2,
           log_solver_summary = true,
+          use_online_imu_extrinsics_in_3d = true,
           ceres_solver_options = {
             use_nonmonotonic_steps = false,
             max_num_iterations = 200,
diff --git a/cartographer/mapping/internal/optimization/optimization_problem_options.cc b/cartographer/mapping/internal/optimization/optimization_problem_options.cc
index 360e4be..fb2e443 100644
--- a/cartographer/mapping/internal/optimization/optimization_problem_options.cc
+++ b/cartographer/mapping/internal/optimization/optimization_problem_options.cc
@@ -44,6 +44,8 @@ proto::OptimizationProblemOptions CreateOptimizationProblemOptions(
       parameter_dictionary->GetDouble("fixed_frame_pose_rotation_weight"));
   options.set_log_solver_summary(
       parameter_dictionary->GetBool("log_solver_summary"));
+  options.set_use_online_imu_extrinsics_in_3d(
+      parameter_dictionary->GetBool("use_online_imu_extrinsics_in_3d"));
   *options.mutable_ceres_solver_options() =
       common::CreateCeresSolverOptionsProto(
           parameter_dictionary->GetDictionary("ceres_solver_options").get());
diff --git a/cartographer/mapping/proto/pose_graph/optimization_problem_options.proto b/cartographer/mapping/proto/pose_graph/optimization_problem_options.proto
index 9994adb..6374fb6 100644
--- a/cartographer/mapping/proto/pose_graph/optimization_problem_options.proto
+++ b/cartographer/mapping/proto/pose_graph/optimization_problem_options.proto
@@ -18,7 +18,7 @@ package cartographer.mapping.optimization.proto;
 
 import "cartographer/common/proto/ceres_solver_options.proto";
 
-// NEXT ID: 18
+// NEXT ID: 19
 message OptimizationProblemOptions {
   // Scaling parameter for Huber loss function.
   double huber_scale = 1;
@@ -54,6 +54,9 @@ message OptimizationProblemOptions {
   // 3D only: fix Z.
   bool fix_z_in_3d = 13;
 
+  // 3D only: activate online IMU extrinsics.
+  bool use_online_imu_extrinsics_in_3d = 18;
+
   // If true, the Ceres solver summary will be logged for every optimization.
   bool log_solver_summary = 5;
 
diff --git a/configuration_files/pose_graph.lua b/configuration_files/pose_graph.lua
index 11a073a..eead726 100644
--- a/configuration_files/pose_graph.lua
+++ b/configuration_files/pose_graph.lua
@@ -72,6 +72,7 @@ POSE_GRAPH = {
     fixed_frame_pose_translation_weight = 1e1,
     fixed_frame_pose_rotation_weight = 1e2,
     log_solver_summary = false,
+    use_online_imu_extrinsics_in_3d = true,
     ceres_solver_options = {
       use_nonmonotonic_steps = false,
       max_num_iterations = 50,