diff --git a/cartographer/sensor/CMakeLists.txt b/cartographer/sensor/CMakeLists.txt
index 9320efa..cc380ed 100644
--- a/cartographer/sensor/CMakeLists.txt
+++ b/cartographer/sensor/CMakeLists.txt
@@ -15,13 +15,11 @@
 add_subdirectory("proto")
 
 google_library(sensor_collator
-  USES_EIGEN
-  USES_GLOG
+  SRCS
+    collator.cc
   HDRS
     collator.h
   DEPENDS
-    common_make_unique
-    common_time
     sensor_data
     sensor_ordered_multi_queue
 )
diff --git a/cartographer/sensor/collator.cc b/cartographer/sensor/collator.cc
new file mode 100644
index 0000000..d8b9e3c
--- /dev/null
+++ b/cartographer/sensor/collator.cc
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2016 The Cartographer Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "cartographer/sensor/collator.h"
+
+namespace cartographer {
+namespace sensor {
+
+void Collator::AddTrajectory(
+    const int trajectory_id,
+    const std::unordered_set<string>& expected_sensor_ids,
+    const Callback callback) {
+  for (const auto& sensor_id : expected_sensor_ids) {
+    const auto queue_key = QueueKey{trajectory_id, sensor_id};
+    queue_.AddQueue(queue_key,
+                    [callback, sensor_id](std::unique_ptr<Data> data) {
+                      callback(sensor_id, std::move(data));
+                    });
+    queue_keys_[trajectory_id].push_back(queue_key);
+  }
+}
+
+void Collator::FinishTrajectory(const int trajectory_id) {
+  for (const auto& queue_key : queue_keys_[trajectory_id]) {
+    queue_.MarkQueueAsFinished(queue_key);
+  }
+}
+
+void Collator::AddSensorData(const int trajectory_id, const string& sensor_id,
+                   std::unique_ptr<Data> data) {
+  queue_.Add(QueueKey{trajectory_id, sensor_id}, std::move(data));
+}
+
+void Collator::Flush() { queue_.Flush(); }
+
+}  // namespace sensor
+}  // namespace cartographer
diff --git a/cartographer/sensor/collator.h b/cartographer/sensor/collator.h
index d28e898..627aaef 100644
--- a/cartographer/sensor/collator.h
+++ b/cartographer/sensor/collator.h
@@ -21,15 +21,10 @@
 #include <memory>
 #include <unordered_map>
 #include <unordered_set>
-#include <utility>
+#include <vector>
 
-#include "Eigen/Core"
-#include "Eigen/Geometry"
-#include "cartographer/common/make_unique.h"
-#include "cartographer/common/time.h"
 #include "cartographer/sensor/data.h"
 #include "cartographer/sensor/ordered_multi_queue.h"
-#include "glog/logging.h"
 
 namespace cartographer {
 namespace sensor {
@@ -45,37 +40,22 @@ class Collator {
 
   // Adds a trajectory to produce sorted sensor output for. Calls 'callback'
   // for each collated sensor data.
-  void AddTrajectory(const int trajectory_id,
+  void AddTrajectory(int trajectory_id,
                      const std::unordered_set<string>& expected_sensor_ids,
-                     const Callback callback) {
-    for (const auto& sensor_id : expected_sensor_ids) {
-      const auto queue_key = QueueKey{trajectory_id, sensor_id};
-      queue_.AddQueue(queue_key,
-                      [callback, sensor_id](std::unique_ptr<Data> data) {
-                        callback(sensor_id, std::move(data));
-                      });
-      queue_keys_[trajectory_id].push_back(queue_key);
-    }
-  }
+                     Callback callback);
 
   // Marks 'trajectory_id' as finished.
-  void FinishTrajectory(const int trajectory_id) {
-    for (const auto& queue_key : queue_keys_[trajectory_id]) {
-      queue_.MarkQueueAsFinished(queue_key);
-    }
-  }
+  void FinishTrajectory(int trajectory_id);
 
   // Adds 'data' for 'trajectory_id' to be collated. 'data' must contain valid
   // sensor data. Sensor packets with matching 'sensor_id' must be added in time
   // order.
-  void AddSensorData(const int trajectory_id, const string& sensor_id,
-                     std::unique_ptr<Data> data) {
-    queue_.Add(QueueKey{trajectory_id, sensor_id}, std::move(data));
-  }
+  void AddSensorData(int trajectory_id, const string& sensor_id,
+                     std::unique_ptr<Data> data);
 
   // Dispatches all queued sensor packets. May only be called once.
   // AddSensorData may not be called after Flush.
-  void Flush() { queue_.Flush(); }
+  void Flush();
 
  private:
   // Queue keys are a pair of trajectory ID and sensor identifier.