diff --git a/y2022/control_loops/localizer/BUILD b/y2022/control_loops/localizer/BUILD
index 3332c1e..034c779 100644
--- a/y2022/control_loops/localizer/BUILD
+++ b/y2022/control_loops/localizer/BUILD
@@ -66,12 +66,23 @@
         "//frc971/wpilib:imu_batch_fbs",
         "//frc971/wpilib:imu_fbs",
         "//frc971/zeroing:imu_zeroer",
-        "//y2020/control_loops/drivetrain:drivetrain_base",
         "//y2020/vision/sift:sift_fbs",
         "@org_tuxfamily_eigen//:eigen",
     ],
 )
 
+cc_binary(
+    name = "localizer_main",
+    srcs = ["localizer_main.cc"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":localizer",
+        "//aos:init",
+        "//aos/events:shm_event_loop",
+        "//y2022/control_loops/drivetrain:drivetrain_base",
+    ],
+)
+
 cc_test(
     name = "localizer_test",
     srcs = ["localizer_test.cc"],
@@ -103,5 +114,6 @@
         "//aos/events:simulated_event_loop",
         "//aos/events/logging:log_reader",
         "//aos/events/logging:log_writer",
+        "//y2020/control_loops/drivetrain:drivetrain_base",
     ],
 )
diff --git a/y2022/control_loops/localizer/localizer.cc b/y2022/control_loops/localizer/localizer.cc
index dd2e67d..3c68e59 100644
--- a/y2022/control_loops/localizer/localizer.cc
+++ b/y2022/control_loops/localizer/localizer.cc
@@ -23,16 +23,6 @@
   }
   return vector;
 }
-
-#if 0
-Eigen::Matrix<double, 3, 3> AxisToMatrix(const Eigen::Vector3d &vec) {
-  const double rotation_norm = vec.norm();
-  return rotation_norm < 1e-5
-             ? Eigen::Matrix<double, 3, 3>::Identity()
-             : Eigen::AngleAxis<double>(rotation_norm, vec / rotation_norm)
-                   .toRotationMatrix();
-}
-#endif
 }  // namespace
 
 ModelBasedLocalizer::ModelBasedLocalizer(
@@ -43,6 +33,8 @@
               .plant()
               .coefficients()),
       down_estimator_(dt_config) {
+  CHECK_EQ(branches_.capacity(), static_cast<size_t>(std::chrono::seconds(1) /
+                                                 kNominalDt / kBranchPeriod));
   if (dt_config_.is_simulated) {
     down_estimator_.assume_perfect_gravity();
   }
@@ -394,7 +386,11 @@
   }
   new_branch.accumulated_divergence = 0.0;
 
-  branches_.Push(new_branch);
+  ++branch_counter_;
+  if (branch_counter_ % kBranchPeriod == 0) {
+    branches_.Push(new_branch);
+    branch_counter_ = 0;
+  }
 
   last_residual_ = model_divergence;
 
diff --git a/y2022/control_loops/localizer/localizer.h b/y2022/control_loops/localizer/localizer.h
index 3a09b28..bb52a40 100644
--- a/y2022/control_loops/localizer/localizer.h
+++ b/y2022/control_loops/localizer/localizer.h
@@ -89,6 +89,9 @@
   static constexpr size_t kRightVoltage = 1;
   static constexpr size_t kNModelInputs = 2;
 
+  // Branching period, in cycles.
+  static constexpr int kBranchPeriod = 1;
+
   typedef Eigen::Matrix<double, kNModelStates, 1> ModelState;
   typedef Eigen::Matrix<double, kNAccelStates, 1> AccelState;
   typedef Eigen::Matrix<double, kNModelInputs, 1> ModelInput;
@@ -176,7 +179,8 @@
   // impact of any lateral motion).
   // We then integrate up all of these states and observe how much the model and
   // accel based states of each branch compare to one another.
-  aos::RingBuffer<CombinedState, 2000> branches_;
+  aos::RingBuffer<CombinedState, 2000 / kBranchPeriod> branches_;
+  int branch_counter_ = 0;
 
   CombinedState current_state_;
   aos::monotonic_clock::time_point t_ = aos::monotonic_clock::min_time;
diff --git a/y2022/control_loops/localizer/localizer_main.cc b/y2022/control_loops/localizer/localizer_main.cc
new file mode 100644
index 0000000..0cc53bb
--- /dev/null
+++ b/y2022/control_loops/localizer/localizer_main.cc
@@ -0,0 +1,21 @@
+#include "aos/events/shm_event_loop.h"
+#include "aos/init.h"
+#include "y2022/control_loops/localizer/localizer.h"
+#include "y2022/control_loops/drivetrain/drivetrain_base.h"
+
+DEFINE_string(config, "config.json", "Path to the config file to use.");
+
+int main(int argc, char *argv[]) {
+  aos::InitGoogle(&argc, &argv);
+
+  aos::FlatbufferDetachedBuffer<aos::Configuration> config =
+      aos::configuration::ReadConfig(FLAGS_config);
+
+  aos::ShmEventLoop event_loop(&config.message());
+  frc971::controls::EventLoopLocalizer localizer(
+      &event_loop, ::y2022::control_loops::drivetrain::GetDrivetrainConfig());
+
+  event_loop.Run();
+
+  return 0;
+}