diff --git a/cartographer/cloud/internal/handlers/add_fixed_frame_pose_data_handler.cc b/cartographer/cloud/internal/handlers/add_fixed_frame_pose_data_handler.cc
index c5deef5..585b897 100644
--- a/cartographer/cloud/internal/handlers/add_fixed_frame_pose_data_handler.cc
+++ b/cartographer/cloud/internal/handlers/add_fixed_frame_pose_data_handler.cc
@@ -21,8 +21,8 @@
 #include "cartographer/cloud/internal/sensor/serialization.h"
 #include "cartographer/cloud/proto/map_builder_service.pb.h"
 #include "cartographer/common/make_unique.h"
-#include "cartographer/sensor/dispatchable.h"
 #include "cartographer/sensor/fixed_frame_pose_data.h"
+#include "cartographer/sensor/internal/dispatchable.h"
 #include "google/protobuf/empty.pb.h"
 
 namespace cartographer {
diff --git a/cartographer/cloud/internal/handlers/add_imu_data_handler.cc b/cartographer/cloud/internal/handlers/add_imu_data_handler.cc
index bed063e..ff41e0d 100644
--- a/cartographer/cloud/internal/handlers/add_imu_data_handler.cc
+++ b/cartographer/cloud/internal/handlers/add_imu_data_handler.cc
@@ -21,8 +21,8 @@
 #include "cartographer/cloud/internal/sensor/serialization.h"
 #include "cartographer/cloud/proto/map_builder_service.pb.h"
 #include "cartographer/common/make_unique.h"
-#include "cartographer/sensor/dispatchable.h"
 #include "cartographer/sensor/imu_data.h"
+#include "cartographer/sensor/internal/dispatchable.h"
 #include "google/protobuf/empty.pb.h"
 
 namespace cartographer {
diff --git a/cartographer/cloud/internal/handlers/add_landmark_data_handler.cc b/cartographer/cloud/internal/handlers/add_landmark_data_handler.cc
index dbd4b04..0989d96 100644
--- a/cartographer/cloud/internal/handlers/add_landmark_data_handler.cc
+++ b/cartographer/cloud/internal/handlers/add_landmark_data_handler.cc
@@ -21,7 +21,7 @@
 #include "cartographer/cloud/internal/sensor/serialization.h"
 #include "cartographer/cloud/proto/map_builder_service.pb.h"
 #include "cartographer/common/make_unique.h"
-#include "cartographer/sensor/dispatchable.h"
+#include "cartographer/sensor/internal/dispatchable.h"
 #include "cartographer/sensor/landmark_data.h"
 #include "google/protobuf/empty.pb.h"
 
diff --git a/cartographer/cloud/internal/handlers/add_local_slam_result_data_handler.cc b/cartographer/cloud/internal/handlers/add_local_slam_result_data_handler.cc
index d6dd283..1a2d173 100644
--- a/cartographer/cloud/internal/handlers/add_local_slam_result_data_handler.cc
+++ b/cartographer/cloud/internal/handlers/add_local_slam_result_data_handler.cc
@@ -22,7 +22,7 @@
 #include "cartographer/common/make_unique.h"
 #include "cartographer/mapping/local_slam_result_data.h"
 #include "cartographer/mapping/trajectory_node.h"
-#include "cartographer/sensor/dispatchable.h"
+#include "cartographer/sensor/internal/dispatchable.h"
 #include "google/protobuf/empty.pb.h"
 
 namespace cartographer {
diff --git a/cartographer/cloud/internal/handlers/add_odometry_data_handler.cc b/cartographer/cloud/internal/handlers/add_odometry_data_handler.cc
index 0b709ae..00aa575 100644
--- a/cartographer/cloud/internal/handlers/add_odometry_data_handler.cc
+++ b/cartographer/cloud/internal/handlers/add_odometry_data_handler.cc
@@ -21,7 +21,7 @@
 #include "cartographer/cloud/internal/sensor/serialization.h"
 #include "cartographer/cloud/proto/map_builder_service.pb.h"
 #include "cartographer/common/make_unique.h"
-#include "cartographer/sensor/dispatchable.h"
+#include "cartographer/sensor/internal/dispatchable.h"
 #include "cartographer/sensor/odometry_data.h"
 #include "google/protobuf/empty.pb.h"
 
diff --git a/cartographer/cloud/internal/handlers/add_rangefinder_data_handler.cc b/cartographer/cloud/internal/handlers/add_rangefinder_data_handler.cc
index ac174ca..f809695 100644
--- a/cartographer/cloud/internal/handlers/add_rangefinder_data_handler.cc
+++ b/cartographer/cloud/internal/handlers/add_rangefinder_data_handler.cc
@@ -20,7 +20,7 @@
 #include "cartographer/cloud/internal/map_builder_context_interface.h"
 #include "cartographer/cloud/proto/map_builder_service.pb.h"
 #include "cartographer/common/make_unique.h"
-#include "cartographer/sensor/dispatchable.h"
+#include "cartographer/sensor/internal/dispatchable.h"
 #include "cartographer/sensor/timed_point_cloud_data.h"
 #include "google/protobuf/empty.pb.h"
 
diff --git a/cartographer/cloud/internal/map_builder_server.h b/cartographer/cloud/internal/map_builder_server.h
index 9476202..87d40dd 100644
--- a/cartographer/cloud/internal/map_builder_server.h
+++ b/cartographer/cloud/internal/map_builder_server.h
@@ -28,7 +28,7 @@
 #include "cartographer/mapping/local_slam_result_data.h"
 #include "cartographer/mapping/map_builder.h"
 #include "cartographer/mapping/trajectory_builder_interface.h"
-#include "cartographer/sensor/dispatchable.h"
+#include "cartographer/sensor/internal/dispatchable.h"
 
 namespace cartographer {
 namespace cloud {
diff --git a/cartographer/cloud/internal/testing/test_helpers.h b/cartographer/cloud/internal/testing/test_helpers.h
index 955ca26..cac0a52 100644
--- a/cartographer/cloud/internal/testing/test_helpers.h
+++ b/cartographer/cloud/internal/testing/test_helpers.h
@@ -18,7 +18,7 @@
 #define CARTOGRAPHER_CLOUD_INTERNAL_TESTING_TEST_HELPERS_H
 
 #include "cartographer/cloud/proto/map_builder_service.pb.h"
-#include "cartographer/sensor/dispatchable.h"
+#include "cartographer/sensor/internal/dispatchable.h"
 #include "google/protobuf/util/message_differencer.h"
 
 namespace cartographer {
diff --git a/cartographer/mapping/internal/2d/local_trajectory_builder_2d.h b/cartographer/mapping/internal/2d/local_trajectory_builder_2d.h
index 93b103e..9cd3b6b 100644
--- a/cartographer/mapping/internal/2d/local_trajectory_builder_2d.h
+++ b/cartographer/mapping/internal/2d/local_trajectory_builder_2d.h
@@ -29,9 +29,9 @@
 #include "cartographer/mapping/pose_extrapolator.h"
 #include "cartographer/metrics/family_factory.h"
 #include "cartographer/sensor/imu_data.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 #include "cartographer/sensor/odometry_data.h"
 #include "cartographer/sensor/range_data.h"
-#include "cartographer/sensor/voxel_filter.h"
 #include "cartographer/transform/rigid_transform.h"
 
 namespace cartographer {
diff --git a/cartographer/mapping/internal/2d/local_trajectory_builder_options_2d.cc b/cartographer/mapping/internal/2d/local_trajectory_builder_options_2d.cc
index 438fb3b..5dd596e 100644
--- a/cartographer/mapping/internal/2d/local_trajectory_builder_options_2d.cc
+++ b/cartographer/mapping/internal/2d/local_trajectory_builder_options_2d.cc
@@ -20,7 +20,7 @@
 #include "cartographer/mapping/internal/2d/scan_matching/ceres_scan_matcher_2d.h"
 #include "cartographer/mapping/internal/2d/scan_matching/real_time_correlative_scan_matcher_2d.h"
 #include "cartographer/mapping/internal/motion_filter.h"
-#include "cartographer/sensor/voxel_filter.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 
 namespace cartographer {
 namespace mapping {
diff --git a/cartographer/mapping/internal/2d/pose_graph/constraint_builder_2d.h b/cartographer/mapping/internal/2d/pose_graph/constraint_builder_2d.h
index f2b1150..3e350a0 100644
--- a/cartographer/mapping/internal/2d/pose_graph/constraint_builder_2d.h
+++ b/cartographer/mapping/internal/2d/pose_graph/constraint_builder_2d.h
@@ -36,8 +36,8 @@
 #include "cartographer/mapping/pose_graph/proto/constraint_builder_options.pb.h"
 #include "cartographer/mapping/pose_graph_interface.h"
 #include "cartographer/metrics/family_factory.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 #include "cartographer/sensor/point_cloud.h"
-#include "cartographer/sensor/voxel_filter.h"
 
 namespace cartographer {
 namespace mapping {
diff --git a/cartographer/mapping/internal/2d/pose_graph_2d.cc b/cartographer/mapping/internal/2d/pose_graph_2d.cc
index c910930..5f12521 100644
--- a/cartographer/mapping/internal/2d/pose_graph_2d.cc
+++ b/cartographer/mapping/internal/2d/pose_graph_2d.cc
@@ -33,7 +33,7 @@
 #include "cartographer/common/math.h"
 #include "cartographer/mapping/pose_graph/proto/constraint_builder_options.pb.h"
 #include "cartographer/sensor/compressed_point_cloud.h"
-#include "cartographer/sensor/voxel_filter.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 #include "glog/logging.h"
 
 namespace cartographer {
diff --git a/cartographer/mapping/internal/2d/scan_matching/fast_global_localizer.h b/cartographer/mapping/internal/2d/scan_matching/fast_global_localizer.h
index 13bfb8d..26a9823 100644
--- a/cartographer/mapping/internal/2d/scan_matching/fast_global_localizer.h
+++ b/cartographer/mapping/internal/2d/scan_matching/fast_global_localizer.h
@@ -21,7 +21,7 @@
 
 #include "Eigen/Geometry"
 #include "cartographer/mapping/internal/2d/scan_matching/fast_correlative_scan_matcher_2d.h"
-#include "cartographer/sensor/voxel_filter.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 
 namespace cartographer {
 namespace mapping {
diff --git a/cartographer/mapping/internal/3d/local_trajectory_builder_3d.h b/cartographer/mapping/internal/3d/local_trajectory_builder_3d.h
index 3712f0c..3fc9218 100644
--- a/cartographer/mapping/internal/3d/local_trajectory_builder_3d.h
+++ b/cartographer/mapping/internal/3d/local_trajectory_builder_3d.h
@@ -29,9 +29,9 @@
 #include "cartographer/mapping/pose_extrapolator.h"
 #include "cartographer/metrics/family_factory.h"
 #include "cartographer/sensor/imu_data.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 #include "cartographer/sensor/odometry_data.h"
 #include "cartographer/sensor/range_data.h"
-#include "cartographer/sensor/voxel_filter.h"
 #include "cartographer/transform/rigid_transform.h"
 
 namespace cartographer {
diff --git a/cartographer/mapping/internal/3d/local_trajectory_builder_options_3d.cc b/cartographer/mapping/internal/3d/local_trajectory_builder_options_3d.cc
index 21bd1d1..6774b0a 100644
--- a/cartographer/mapping/internal/3d/local_trajectory_builder_options_3d.cc
+++ b/cartographer/mapping/internal/3d/local_trajectory_builder_options_3d.cc
@@ -20,7 +20,7 @@
 #include "cartographer/mapping/internal/3d/scan_matching/ceres_scan_matcher_3d.h"
 #include "cartographer/mapping/internal/motion_filter.h"
 #include "cartographer/mapping/scan_matching/real_time_correlative_scan_matcher.h"
-#include "cartographer/sensor/voxel_filter.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 #include "glog/logging.h"
 
 namespace cartographer {
diff --git a/cartographer/mapping/internal/3d/pose_graph/constraint_builder_3d.h b/cartographer/mapping/internal/3d/pose_graph/constraint_builder_3d.h
index 82c0d16..815e6bf 100644
--- a/cartographer/mapping/internal/3d/pose_graph/constraint_builder_3d.h
+++ b/cartographer/mapping/internal/3d/pose_graph/constraint_builder_3d.h
@@ -39,8 +39,8 @@
 #include "cartographer/mapping/trajectory_node.h"
 #include "cartographer/metrics/family_factory.h"
 #include "cartographer/sensor/compressed_point_cloud.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 #include "cartographer/sensor/point_cloud.h"
-#include "cartographer/sensor/voxel_filter.h"
 
 namespace cartographer {
 namespace mapping {
diff --git a/cartographer/mapping/internal/3d/pose_graph_3d.cc b/cartographer/mapping/internal/3d/pose_graph_3d.cc
index 3b31aab..e9cc96d 100644
--- a/cartographer/mapping/internal/3d/pose_graph_3d.cc
+++ b/cartographer/mapping/internal/3d/pose_graph_3d.cc
@@ -32,7 +32,7 @@
 #include "cartographer/common/math.h"
 #include "cartographer/mapping/pose_graph/proto/constraint_builder_options.pb.h"
 #include "cartographer/sensor/compressed_point_cloud.h"
-#include "cartographer/sensor/voxel_filter.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 #include "cartographer/transform/transform.h"
 #include "glog/logging.h"
 
diff --git a/cartographer/mapping/internal/collated_trajectory_builder.h b/cartographer/mapping/internal/collated_trajectory_builder.h
index 1612cec..9bee21f 100644
--- a/cartographer/mapping/internal/collated_trajectory_builder.h
+++ b/cartographer/mapping/internal/collated_trajectory_builder.h
@@ -29,7 +29,7 @@
 #include "cartographer/mapping/submaps.h"
 #include "cartographer/mapping/trajectory_builder_interface.h"
 #include "cartographer/sensor/collator_interface.h"
-#include "cartographer/sensor/dispatchable.h"
+#include "cartographer/sensor/internal/dispatchable.h"
 
 namespace cartographer {
 namespace mapping {
diff --git a/cartographer/mapping/internal/pose_graph/constraint_builder.cc b/cartographer/mapping/internal/pose_graph/constraint_builder.cc
index 3753655..52b0c88 100644
--- a/cartographer/mapping/internal/pose_graph/constraint_builder.cc
+++ b/cartographer/mapping/internal/pose_graph/constraint_builder.cc
@@ -20,7 +20,7 @@
 #include "cartographer/mapping/internal/2d/scan_matching/fast_correlative_scan_matcher_2d.h"
 #include "cartographer/mapping/internal/3d/scan_matching/ceres_scan_matcher_3d.h"
 #include "cartographer/mapping/internal/3d/scan_matching/fast_correlative_scan_matcher_3d.h"
-#include "cartographer/sensor/voxel_filter.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 
 namespace cartographer {
 namespace mapping {
diff --git a/cartographer/mapping/map_builder.cc b/cartographer/mapping/map_builder.cc
index c6aac76..08f92af 100644
--- a/cartographer/mapping/map_builder.cc
+++ b/cartographer/mapping/map_builder.cc
@@ -30,10 +30,10 @@
 #include "cartographer/mapping/internal/3d/pose_graph_3d.h"
 #include "cartographer/mapping/internal/collated_trajectory_builder.h"
 #include "cartographer/mapping/internal/global_trajectory_builder.h"
-#include "cartographer/sensor/collator.h"
+#include "cartographer/sensor/internal/collator.h"
+#include "cartographer/sensor/internal/trajectory_collator.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 #include "cartographer/sensor/range_data.h"
-#include "cartographer/sensor/trajectory_collator.h"
-#include "cartographer/sensor/voxel_filter.h"
 #include "cartographer/transform/rigid_transform.h"
 #include "cartographer/transform/transform.h"
 #include "glog/logging.h"
diff --git a/cartographer/sensor/collator.cc b/cartographer/sensor/internal/collator.cc
similarity index 97%
rename from cartographer/sensor/collator.cc
rename to cartographer/sensor/internal/collator.cc
index 2fbcfb2..f303ba5 100644
--- a/cartographer/sensor/collator.cc
+++ b/cartographer/sensor/internal/collator.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/sensor/collator.h"
+#include "cartographer/sensor/internal/collator.h"
 
 namespace cartographer {
 namespace sensor {
diff --git a/cartographer/sensor/collator.h b/cartographer/sensor/internal/collator.h
similarity index 88%
rename from cartographer/sensor/collator.h
rename to cartographer/sensor/internal/collator.h
index c696613..43b7114 100644
--- a/cartographer/sensor/collator.h
+++ b/cartographer/sensor/internal/collator.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_SENSOR_COLLATOR_H_
-#define CARTOGRAPHER_SENSOR_COLLATOR_H_
+#ifndef CARTOGRAPHER_SENSOR_INTERNAL_COLLATOR_H_
+#define CARTOGRAPHER_SENSOR_INTERNAL_COLLATOR_H_
 
 #include <functional>
 #include <memory>
@@ -25,7 +25,7 @@
 
 #include "cartographer/sensor/collator_interface.h"
 #include "cartographer/sensor/data.h"
-#include "cartographer/sensor/ordered_multi_queue.h"
+#include "cartographer/sensor/internal/ordered_multi_queue.h"
 
 namespace cartographer {
 namespace sensor {
@@ -60,4 +60,4 @@ class Collator : public CollatorInterface {
 }  // namespace sensor
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_SENSOR_COLLATOR_H_
+#endif  // CARTOGRAPHER_SENSOR_INTERNAL_COLLATOR_H_
diff --git a/cartographer/sensor/collator_test.cc b/cartographer/sensor/internal/collator_test.cc
similarity index 98%
rename from cartographer/sensor/collator_test.cc
rename to cartographer/sensor/internal/collator_test.cc
index 9662fb3..012b193 100644
--- a/cartographer/sensor/collator_test.cc
+++ b/cartographer/sensor/internal/collator_test.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/sensor/collator.h"
+#include "cartographer/sensor/internal/collator.h"
 
 #include <array>
 #include <memory>
@@ -22,8 +22,8 @@
 #include "cartographer/common/make_unique.h"
 #include "cartographer/common/time.h"
 #include "cartographer/sensor/imu_data.h"
+#include "cartographer/sensor/internal/test_helpers.h"
 #include "cartographer/sensor/odometry_data.h"
-#include "cartographer/sensor/test_helpers.h"
 #include "cartographer/sensor/timed_point_cloud_data.h"
 #include "gtest/gtest.h"
 
diff --git a/cartographer/sensor/dispatchable.h b/cartographer/sensor/internal/dispatchable.h
similarity index 89%
rename from cartographer/sensor/dispatchable.h
rename to cartographer/sensor/internal/dispatchable.h
index 5960512..f694ea5 100644
--- a/cartographer/sensor/dispatchable.h
+++ b/cartographer/sensor/internal/dispatchable.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_SENSOR_MAPPING_DISPATCHABLE_H_
-#define CARTOGRAPHER_SENSOR_MAPPING_DISPATCHABLE_H_
+#ifndef CARTOGRAPHER_SENSOR_INTERNAL_MAPPING_DISPATCHABLE_H_
+#define CARTOGRAPHER_SENSOR_INTERNAL_MAPPING_DISPATCHABLE_H_
 
 #include "cartographer/mapping/trajectory_builder_interface.h"
 #include "cartographer/sensor/data.h"
@@ -49,4 +49,4 @@ std::unique_ptr<Dispatchable<DataType>> MakeDispatchable(
 }  // namespace sensor
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_SENSOR_MAPPING_DISPATCHABLE_H_
+#endif  // CARTOGRAPHER_SENSOR_INTERNAL_MAPPING_DISPATCHABLE_H_
diff --git a/cartographer/sensor/ordered_multi_queue.cc b/cartographer/sensor/internal/ordered_multi_queue.cc
similarity index 98%
rename from cartographer/sensor/ordered_multi_queue.cc
rename to cartographer/sensor/internal/ordered_multi_queue.cc
index e159ae3..39d7833 100644
--- a/cartographer/sensor/ordered_multi_queue.cc
+++ b/cartographer/sensor/internal/ordered_multi_queue.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/sensor/ordered_multi_queue.h"
+#include "cartographer/sensor/internal/ordered_multi_queue.h"
 
 #include <algorithm>
 #include <sstream>
diff --git a/cartographer/sensor/ordered_multi_queue.h b/cartographer/sensor/internal/ordered_multi_queue.h
similarity index 92%
rename from cartographer/sensor/ordered_multi_queue.h
rename to cartographer/sensor/internal/ordered_multi_queue.h
index 6129b3c..f43b933 100644
--- a/cartographer/sensor/ordered_multi_queue.h
+++ b/cartographer/sensor/internal/ordered_multi_queue.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_SENSOR_ORDERED_MULTI_QUEUE_H_
-#define CARTOGRAPHER_SENSOR_ORDERED_MULTI_QUEUE_H_
+#ifndef CARTOGRAPHER_SENSOR_INTERNAL_ORDERED_MULTI_QUEUE_H_
+#define CARTOGRAPHER_SENSOR_INTERNAL_ORDERED_MULTI_QUEUE_H_
 
 #include <functional>
 #include <map>
@@ -26,7 +26,7 @@
 #include "cartographer/common/blocking_queue.h"
 #include "cartographer/common/port.h"
 #include "cartographer/common/time.h"
-#include "cartographer/sensor/dispatchable.h"
+#include "cartographer/sensor/internal/dispatchable.h"
 
 namespace cartographer {
 namespace sensor {
@@ -96,4 +96,4 @@ class OrderedMultiQueue {
 }  // namespace sensor
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_SENSOR_ORDERED_MULTI_QUEUE_H_
+#endif  // CARTOGRAPHER_SENSOR_INTERNAL_ORDERED_MULTI_QUEUE_H_
diff --git a/cartographer/sensor/ordered_multi_queue_test.cc b/cartographer/sensor/internal/ordered_multi_queue_test.cc
similarity index 98%
rename from cartographer/sensor/ordered_multi_queue_test.cc
rename to cartographer/sensor/internal/ordered_multi_queue_test.cc
index 578c8a7..66557a5 100644
--- a/cartographer/sensor/ordered_multi_queue_test.cc
+++ b/cartographer/sensor/internal/ordered_multi_queue_test.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/sensor/ordered_multi_queue.h"
+#include "cartographer/sensor/internal/ordered_multi_queue.h"
 
 #include <vector>
 
diff --git a/cartographer/sensor/test_helpers.h b/cartographer/sensor/internal/test_helpers.h
similarity index 93%
rename from cartographer/sensor/test_helpers.h
rename to cartographer/sensor/internal/test_helpers.h
index 9806371..0d0274d 100644
--- a/cartographer/sensor/test_helpers.h
+++ b/cartographer/sensor/internal/test_helpers.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_SENSOR_TEST_HELPERS_H_
-#define CARTOGRAPHER_SENSOR_TEST_HELPERS_H_
+#ifndef CARTOGRAPHER_SENSOR_INTERNAL_TEST_HELPERS_H_
+#define CARTOGRAPHER_SENSOR_INTERNAL_TEST_HELPERS_H_
 
 #include <string>
 #include <tuple>
@@ -23,8 +23,8 @@
 #include "cartographer/common/make_unique.h"
 #include "cartographer/common/time.h"
 #include "cartographer/sensor/collator_interface.h"
-#include "cartographer/sensor/dispatchable.h"
 #include "cartographer/sensor/imu_data.h"
+#include "cartographer/sensor/internal/dispatchable.h"
 #include "cartographer/sensor/odometry_data.h"
 #include "cartographer/sensor/timed_point_cloud_data.h"
 #include "gmock/gmock.h"
@@ -84,4 +84,4 @@ struct CollatorInput {
 }  // namespace sensor
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_SENSOR_TEST_HELPERS_H_
+#endif  // CARTOGRAPHER_SENSOR_INTERNAL_TEST_HELPERS_H_
diff --git a/cartographer/sensor/trajectory_collator.cc b/cartographer/sensor/internal/trajectory_collator.cc
similarity index 97%
rename from cartographer/sensor/trajectory_collator.cc
rename to cartographer/sensor/internal/trajectory_collator.cc
index 753151c..7d8409d 100644
--- a/cartographer/sensor/trajectory_collator.cc
+++ b/cartographer/sensor/internal/trajectory_collator.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/sensor/trajectory_collator.h"
+#include "cartographer/sensor/internal/trajectory_collator.h"
 
 namespace cartographer {
 namespace sensor {
diff --git a/cartographer/sensor/trajectory_collator.h b/cartographer/sensor/internal/trajectory_collator.h
similarity index 89%
rename from cartographer/sensor/trajectory_collator.h
rename to cartographer/sensor/internal/trajectory_collator.h
index f3ec4e7..1ebfe33 100644
--- a/cartographer/sensor/trajectory_collator.h
+++ b/cartographer/sensor/internal/trajectory_collator.h
@@ -14,15 +14,15 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_SENSOR_TRAJECTORY_COLLATOR_H_
-#define CARTOGRAPHER_SENSOR_TRAJECTORY_COLLATOR_H_
+#ifndef CARTOGRAPHER_SENSOR_INTERNAL_TRAJECTORY_COLLATOR_H_
+#define CARTOGRAPHER_SENSOR_INTERNAL_TRAJECTORY_COLLATOR_H_
 
 #include <memory>
 #include <unordered_map>
 #include <vector>
 
 #include "cartographer/sensor/collator_interface.h"
-#include "cartographer/sensor/ordered_multi_queue.h"
+#include "cartographer/sensor/internal/ordered_multi_queue.h"
 
 namespace cartographer {
 namespace sensor {
@@ -62,4 +62,4 @@ class TrajectoryCollator : public CollatorInterface {
 }  // namespace sensor
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_SENSOR_TRAJECTORY_COLLATOR_H_
+#endif  // CARTOGRAPHER_SENSOR_INTERNAL_TRAJECTORY_COLLATOR_H_
diff --git a/cartographer/sensor/trajectory_collator_test.cc b/cartographer/sensor/internal/trajectory_collator_test.cc
similarity index 97%
rename from cartographer/sensor/trajectory_collator_test.cc
rename to cartographer/sensor/internal/trajectory_collator_test.cc
index 44ebc3f..1699c01 100644
--- a/cartographer/sensor/trajectory_collator_test.cc
+++ b/cartographer/sensor/internal/trajectory_collator_test.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/sensor/trajectory_collator.h"
+#include "cartographer/sensor/internal/trajectory_collator.h"
 
 #include <array>
 #include <memory>
@@ -22,8 +22,8 @@
 #include "cartographer/common/make_unique.h"
 #include "cartographer/common/time.h"
 #include "cartographer/sensor/imu_data.h"
+#include "cartographer/sensor/internal/test_helpers.h"
 #include "cartographer/sensor/odometry_data.h"
-#include "cartographer/sensor/test_helpers.h"
 #include "cartographer/sensor/timed_point_cloud_data.h"
 #include "gtest/gtest.h"
 
diff --git a/cartographer/sensor/voxel_filter.cc b/cartographer/sensor/internal/voxel_filter.cc
similarity index 98%
rename from cartographer/sensor/voxel_filter.cc
rename to cartographer/sensor/internal/voxel_filter.cc
index ad28646..17c9762 100644
--- a/cartographer/sensor/voxel_filter.cc
+++ b/cartographer/sensor/internal/voxel_filter.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/sensor/voxel_filter.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 
 #include <cmath>
 
diff --git a/cartographer/sensor/voxel_filter.h b/cartographer/sensor/internal/voxel_filter.h
similarity index 93%
rename from cartographer/sensor/voxel_filter.h
rename to cartographer/sensor/internal/voxel_filter.h
index ed08f5b..1a24b99 100644
--- a/cartographer/sensor/voxel_filter.h
+++ b/cartographer/sensor/internal/voxel_filter.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_SENSOR_VOXEL_FILTER_H_
-#define CARTOGRAPHER_SENSOR_VOXEL_FILTER_H_
+#ifndef CARTOGRAPHER_SENSOR_INTERNAL_VOXEL_FILTER_H_
+#define CARTOGRAPHER_SENSOR_INTERNAL_VOXEL_FILTER_H_
 
 #include <bitset>
 #include <unordered_set>
@@ -75,4 +75,4 @@ class AdaptiveVoxelFilter {
 }  // namespace sensor
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_SENSOR_VOXEL_FILTER_H_
+#endif  // CARTOGRAPHER_SENSOR_INTERNAL_VOXEL_FILTER_H_
diff --git a/cartographer/sensor/voxel_filter_test.cc b/cartographer/sensor/internal/voxel_filter_test.cc
similarity index 97%
rename from cartographer/sensor/voxel_filter_test.cc
rename to cartographer/sensor/internal/voxel_filter_test.cc
index b0f39c7..da57c40 100644
--- a/cartographer/sensor/voxel_filter_test.cc
+++ b/cartographer/sensor/internal/voxel_filter_test.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/sensor/voxel_filter.h"
+#include "cartographer/sensor/internal/voxel_filter.h"
 
 #include <cmath>
 
diff --git a/cartographer/sensor/landmark_data_test.cc b/cartographer/sensor/landmark_data_test.cc
index 0859ab6..dfd9c16 100644
--- a/cartographer/sensor/landmark_data_test.cc
+++ b/cartographer/sensor/landmark_data_test.cc
@@ -18,7 +18,7 @@
 
 #include <cmath>
 
-#include "cartographer/sensor/test_helpers.h"
+#include "cartographer/sensor/internal/test_helpers.h"
 #include "cartographer/transform/rigid_transform_test_helpers.h"
 #include "cartographer/transform/transform.h"
 #include "gtest/gtest.h"
diff --git a/cartographer/sensor/range_data_test.cc b/cartographer/sensor/range_data_test.cc
index 7c495e3..c91d168 100644
--- a/cartographer/sensor/range_data_test.cc
+++ b/cartographer/sensor/range_data_test.cc
@@ -19,7 +19,7 @@
 #include <tuple>
 #include <vector>
 
-#include "cartographer/sensor/test_helpers.h"
+#include "cartographer/sensor/internal/test_helpers.h"
 #include "gmock/gmock.h"
 
 namespace cartographer {