bug correction in process_traj_antenna_pattern: region with co-locate…

…d data between ASR and Dole has to be recomputed at each GPS time step

src/pyrad_proc/pyrad/proc/process_traj.py

@@ -681,16 +681,16 @@ def process_traj_antenna_pattern(procstatus, dscfg, radar_list=None,
             # flag regions with colocated usable data in r_radar
             r_ind_invalid = r_radar.gate_altitude['data'] > max_altitude
             r_radar.fields['colocated_gates']['data'][r_ind_invalid] = 0
-
-            if ('colocated_gates' not in radar_sel.fields):
-                # flag regions with colocated usable data in radar_sel
-                gate_coloc_radar_sel = intersection(
-                    radar_sel, r_radar, h_tol=alt_tol, latlon_tol=latlon_tol
-                    vol_d_tol=None, vismin=None, hmin=None, hmax=max_altitude,
-                    rmin=None, rmax=None, elmin=None, elmax=None, azmin=None,
-                    azmax=None, visib_field=None,
-                    intersec_field='colocated_gates')
-                radar_sel.add_field('colocated_gates', gate_coloc_radar_sel)
+            
+            # flag regions with colocated usable data in radar_sel
+            gate_coloc_radar_sel = intersection(
+                radar_sel, r_radar, h_tol=alt_tol, latlon_tol=latlon_tol
+                vol_d_tol=None, vismin=None, hmin=None, hmax=max_altitude,
+                rmin=None, rmax=None, elmin=None, elmax=None, azmin=None,
+                azmax=None, visib_field=None,
+                intersec_field='colocated_gates')
+            radar_sel.add_field('colocated_gates', gate_coloc_radar_sel,
+                                replace_existing=True)
 
             (colgates, r_radar_colg) = colocated_gates(r_radar, radar_sel,
                                                        h_tol=alt_tol,