lisainstrument/instrument.py

@@ -543,9 +543,13 @@ class Instrument:
             return InterpolatedUnivariateSpline(times, values, k=5, ext='raise')
 
         def tps_proper_time_deviations(sc):
-            times = orbitf['tcb']['t'][:]
-            values = orbitf[f'tcb/sc_{sc}']['tau']
-            return InterpolatedUnivariateSpline(times, values, k=5, ext='raise')
+            if self.orbit_dataset == 'tcb/ltt':
+                return lambda x: 0
+            if self.orbit_dataset == 'tps/ppr':
+                times = orbitf['tcb']['t'][:]
+                values = orbitf[f'tcb/sc_{sc}']['tau']
+                return InterpolatedUnivariateSpline(times, values, k=5, ext='raise')
+            raise ValueError(f"invalid orbit dataset '{self.orbit_dataset}'")
 
         try:
             logger.debug("Interpolating proper pseudo-ranges")