diff --git a/pygmtsar/pygmtsar/Stack_sbas.py b/pygmtsar/pygmtsar/Stack_sbas.py
index 54a80a16..37b787a7 100644
--- a/pygmtsar/pygmtsar/Stack_sbas.py
+++ b/pygmtsar/pygmtsar/Stack_sbas.py
@@ -943,7 +943,9 @@ def rmse(self, data, solution, weight=None):
             error_pairs.append(error_pair**2)
         # form 3D stack
         error = xr.concat(error_pairs, dim='pair').assign_coords({'pair': pairs.pair})
-        return np.sqrt((weight * error).sum('pair') / weight.sum('pair') / len(pairs))
+        if weight is not None:
+            return np.sqrt((weight * error).sum('pair') / weight.sum('pair') / len(pairs)).rename('rmse')
+        return np.sqrt((error).sum('pair') / len(pairs)).rename('rmse')
 
     def plot_displacement(self, data, caption='Cumulative LOS Displacement, [rad]',
                           quantile=None, vmin=None, vmax=None, symmetrical=False, aspect=None, **kwargs):