diff --git a/frc971/control_loops/python/control_loop.py b/frc971/control_loops/python/control_loop.py
index 9aa00df..e3e00b7 100644
--- a/frc971/control_loops/python/control_loop.py
+++ b/frc971/control_loops/python/control_loop.py
@@ -453,10 +453,17 @@
     if observer_coefficient_type.startswith('StateFeedbackObserver'):
       if hasattr(self, 'KalmanGain'):
         KalmanGain = self.KalmanGain
+        Q = self.Q
+        R = self.R
       else:
         KalmanGain =  numpy.linalg.inv(self.A) * self.L
+        Q = numpy.zeros(self.A.shape)
+        R = numpy.zeros((self.C.shape[0], self.C.shape[0]))
       ans.append(self._DumpMatrix('KalmanGain', KalmanGain, scalar_type))
-      ans.append('  return %s(KalmanGain);\n' % (observer_coefficient_type,))
+      ans.append(self._DumpMatrix('Q', Q, scalar_type))
+      ans.append(self._DumpMatrix('R', R, scalar_type))
+      ans.append('  return %s(KalmanGain, Q, R);\n'
+          % (observer_coefficient_type,))
 
     elif observer_coefficient_type.startswith('HybridKalman'):
       ans.append(self._DumpMatrix('Q_continuous', self.Q_continuous, scalar_type))
diff --git a/frc971/control_loops/python/drivetrain.py b/frc971/control_loops/python/drivetrain.py
index 3f9123f..c59cbab 100644
--- a/frc971/control_loops/python/drivetrain.py
+++ b/frc971/control_loops/python/drivetrain.py
@@ -362,10 +362,15 @@
         self.KalmanGain, self.Q_steady = controls.kalman(
             A=self.A, B=self.B, C=self.C, Q=self.Q, R=self.R)
 
+        # If we don't have an IMU, pad various matrices with zeros so that
+        # we can still have 4 measurement outputs.
         if not self.has_imu:
             self.KalmanGain = numpy.hstack((self.KalmanGain, numpy.matrix(numpy.zeros((7, 1)))))
             self.C = numpy.vstack((self.C, numpy.matrix(numpy.zeros((1, 7)))))
             self.D = numpy.vstack((self.D, numpy.matrix(numpy.zeros((1, 2)))))
+            Rtmp = numpy.zeros((4, 4))
+            Rtmp[0:3, 0:3] = self.R
+            self.R = Rtmp
 
         self.L = self.A * self.KalmanGain