doc update for altimetry

smrt/inputs/altimeter_list.py

@@ -74,7 +74,16 @@ def cryosat2_lrm():
 
     Parameters from https://earth.esa.int/web/eoportal/satellite-missions/c-missions/cryosat-2
     Altitude from https://doi.org/10.1016/j.asr.2018.04.014
+
     Beam width is 1.08 along track and 1.2 across track
+
+    Note::
+
+        nominal_gate parameter governs timing of leading edge
+
+    Example::
+
+        sensor = altimeter_list.cryosat2_lrm()
     
     """    
 
@@ -93,7 +102,19 @@ def cryosat2_sin():
 
     Parameters from https://earth.esa.int/web/eoportal/satellite-missions/c-missions/cryosat-2
     Altitude from https://doi.org/10.1016/j.asr.2018.04.014
+    
     Beam width is 1.08 along track and 1.2 across track
+
+    
+    Note::
+
+        nominal_gate parameter governs timing of leading edge
+
+        Use this sensor for pseudo-low resolution mode of CryoSat2 operating in SIN mode
+
+    Example::
+
+        sensor = altimeter_list.cryosat2_sin()
     
     """    
 
@@ -111,8 +132,17 @@ def asiras_lam(altitude=None):
     """ Return an altimeter instance for ASIRAS in Low Altitude Mode
 
     Parameters from https://earth.esa.int/web/eoportal/airborne-sensors/asiras
+    
     Beam width is 2.2 x 9.8 deg
-    """    
+
+    :param altitude: aircraft altitude in m
+
+    Example::
+
+        sensor = altimeter_list.asiras_lam(altitude=500)
+
+    """
+
     if altitude is None:
         raise SMRTError('Aircraft altitude must be defined')
     else:

smrt/rtsolver/nadir_lrm_altimetry.py

@@ -5,10 +5,8 @@
 
 Approximation in the medium:
  - Backscatter is computed assuming only first order scattering. The propagation is then simply given by extinction
- - Small angle approximation: to compute delay, the paths in the snow are along the z-axis. We neglect the off-nadir delay.
- This error is likely to be small (except for very deep penetration).
- - At this stage, we consider that the backscatter of layers does not depend on theta (Geometrical optics or other, not AIEM). 
- This is the isotropic assumption which is only valid for rough surfaces
+ - Small angle approximation: to compute delay, the paths in the snow are along the z-axis. We neglect the off-nadir delay. This error is likely to be small (except for very deep penetration).
+ - At this stage, we consider that the backscatter of layers does not depend on theta (Geometrical optics or other, not AIEM). This is the isotropic assumption which is only valid for rough surfaces
  
 Example::