diff --git a/frc971/control_loops/drivetrain/drivetrain.cc b/frc971/control_loops/drivetrain/drivetrain.cc
index 6a2ea76..2af6765 100644
--- a/frc971/control_loops/drivetrain/drivetrain.cc
+++ b/frc971/control_loops/drivetrain/drivetrain.cc
@@ -245,7 +245,8 @@
       LOG_STRUCT(DEBUG, "localizer_control", *localizer_control_fetcher_);
       localizer_->ResetPosition(monotonic_now, localizer_control_fetcher_->x,
                                 localizer_control_fetcher_->y,
-                                localizer_control_fetcher_->theta);
+                                localizer_control_fetcher_->theta,
+                                localizer_control_fetcher_->theta_uncertainty);
     }
     localizer_->Update({last_last_left_voltage_, last_last_right_voltage_},
                        monotonic_now, position->left_encoder,
diff --git a/frc971/control_loops/drivetrain/localizer.h b/frc971/control_loops/drivetrain/localizer.h
index 9866803..bd48315 100644
--- a/frc971/control_loops/drivetrain/localizer.h
+++ b/frc971/control_loops/drivetrain/localizer.h
@@ -50,7 +50,8 @@
                       double gyro_rate, double longitudinal_accelerometer) = 0;
   // Reset the absolute position of the estimator.
   virtual void ResetPosition(::aos::monotonic_clock::time_point t, double x,
-                             double y, double theta) = 0;
+                             double y, double theta,
+                             double theta_uncertainty) = 0;
   // There are several subtly different norms floating around for state
   // matrices. In order to avoid that mess, we jus tprovide direct accessors for
   // the values that most people care about.
@@ -109,7 +110,7 @@
   }
 
   void ResetPosition(::aos::monotonic_clock::time_point t, double x, double y,
-                     double theta) override {
+                     double theta, double /*theta_override*/) override {
     const double left_encoder = ekf_.X_hat(StateIdx::kLeftEncoder);
     const double right_encoder = ekf_.X_hat(StateIdx::kRightEncoder);
     ekf_.ResetInitialState(t, (Ekf::State() << x, y, theta, left_encoder, 0,
diff --git a/frc971/control_loops/drivetrain/localizer.q b/frc971/control_loops/drivetrain/localizer.q
index 1ae0adc..8fef686 100644
--- a/frc971/control_loops/drivetrain/localizer.q
+++ b/frc971/control_loops/drivetrain/localizer.q
@@ -6,6 +6,7 @@
   float x;      // X position, meters
   float y;      // Y position, meters
   float theta;  // heading, radians
+  double theta_uncertainty; // Uncertainty in theta.
 };
 
 queue LocalizerControl localizer_control;