inrows check and doc string update

Author: danineamati

gnss_lib_py/utils/dop.py

@@ -39,6 +39,8 @@ def get_dop(navdata, **which_dop):
         NavData instance containing received GNSS measurements for a
         particular time instance, contains elevation and azimuth angle
         information for an estimated location.
+        Instance of the NavData class which must include at least
+        ``gps_millis``, ``el_sv_deg``, and ``az_sv_deg``
 
     which_dop : dict
         Dictionary of which dop values are needed. Default is HDOP and VDOP.
@@ -68,6 +70,9 @@ def get_dop(navdata, **which_dop):
         Dilution of precision data along with the relevant time stamp.
     """
 
+    # Check that the navdata has the necessary elevation and azimuth data
+    navdata.in_rows(['gps_millis', 'el_sv_deg', 'az_sv_deg'])
+
     # Default which_dop values assume HDOP and VDOP are needed.
     default_which_dop = {'GDOP': False,
                          'HDOP': True,

notebooks/tutorials/utils/dop.ipynb

@@ -48,8 +48,6 @@
    "outputs": [],
    "source": [
     "glp.make_dir(\"../data\")\n",
-    "\n",
-    "# %wget https://raw.githubusercontent.com/Stanford-NavLab/gnss_lib_py/main/data/unit_test/google_decimeter_2022/device_gnss.csv --quiet -nc -O \"../data/device_gnss.csv\"\n",
     "urllib.request.urlretrieve(\"https://raw.githubusercontent.com/Stanford-NavLab/gnss_lib_py/main/data/unit_test/google_decimeter_2022/device_gnss.csv\", \"../data/device_gnss.csv\")\n",
     "\n",
     "navdata = glp.AndroidDerived2022(\"../data/device_gnss.csv\")"

tests/utils/test_dop.py

@@ -388,33 +388,31 @@ def test_singularity_dop(navdata):
     Parameters
     ----------
     navdata : NavData
-        A NavData with only one time entry of a *singular* satellite scenario.
+        A NavData with only one time entry of a **singular** satellite scenario.
 
     """
 
     # Run the DOP calculation
     dop_dict = calculate_dop(navdata)
 
-    print("DOP dict")
-    print(dop_dict)
-
     # Check the DOP output has all the expected keys
     assert dop_dict.keys() == {'dop_matrix',
                             'GDOP', 'HDOP', 'VDOP', 'PDOP', 'TDOP'}
 
     try:
         enut_matrix = _calculate_enut_matrix(navdata)
-        print("ENUT matrix")
-        print(enut_matrix)
-
-        dop_manual = np.linalg.inv(enut_matrix.T @ enut_matrix)
-        print("DOP manual")
-        print(dop_manual)
+        np.linalg.inv(enut_matrix.T @ enut_matrix)
 
         # If we get here, then we did not get a singularity error
         # This is possible due to floating point errors, so we will check
         # that the values are unrealistically large.
+        #
+        # Note: When very poorly conditioned, the DOP matrix can have negative
+        # entries. Then, the square root of the DOP matrix will be nan! So,
+        # we first check for nans, and then for large values (otherwise there
+        # is an issue in comparing nan > number).
         # Note: we use np.any() since we can get small values in the DOP matrix
+        # even if singular (i.e., in the off-diagonal entries).
         for _, val in dop_dict.items():
             assert np.any(np.isnan(val)) or np.any(np.abs(val) > 1e6)