Grammar and formatting changes

Author: kanhereashwin

gnss_lib_py/parsers/precise_ephemerides.py

@@ -296,7 +296,7 @@ def parse_clockfile(input_path, constellation = 'gps'):
 
     return clkdata
 
-def extract_sp3_func(sp3data, sidx, ipos = 10, \
+def extract_sp3(sp3data, sidx, ipos = 10, \
                      method = 'CubicSpline', verbose = False):
     """Computing interpolated function over sp3 data for any GNSS
 
@@ -341,7 +341,7 @@ def extract_sp3_func(sp3data, sidx, ipos = 10, \
 
     return func_satpos
 
-def extract_clk_func(clkdata, sidx, ipos = 10, \
+def extract_clk(clkdata, sidx, ipos = 10, \
                      method='CubicSpline', verbose = False):
     """Computing interpolated function over clk data for any GNSS
 
@@ -378,7 +378,7 @@ def extract_clk_func(clkdata, sidx, ipos = 10, \
 
     return func_satbias
 
-def compute_sp3_snapshot(func_satpos, cxtime, hstep = 5e-1, method='CubicSpline'):
+def sp3_snapshot(func_satpos, cxtime, hstep = 5e-1, method='CubicSpline'):
     """Compute satellite 3-D position and velocity from sp3 interpolated function
 
     Parameters
@@ -415,7 +415,7 @@ def compute_sp3_snapshot(func_satpos, cxtime, hstep = 5e-1, method='CubicSpline'
 
     return satpos_sp3, (satvel_sp3 * 1e3)
 
-def compute_clk_snapshot(func_satbias, cxtime, hstep = 5e-1, method='CubicSpline'):
+def clk_snapshot(func_satbias, cxtime, hstep = 5e-1, method='CubicSpline'):
     """Compute satellite clock bias and drift from clk interpolated function
 
     Parameters
@@ -447,7 +447,7 @@ def compute_clk_snapshot(func_satbias, cxtime, hstep = 5e-1, method='CubicSpline
 
     return satbias_clk, (satdrift_clk * 1e3)
 
-def compute_single_gnss_from_precise_eph(navdata, sp3_parsed_file, \
+def single_gnss_from_precise_eph(navdata, sp3_parsed_file, \
                                          clk_parsed_file, verbose = False):
     """Compute satellite information using .sp3 and .clk for any GNSS constellation
 
@@ -546,14 +546,14 @@ def compute_single_gnss_from_precise_eph(navdata, sp3_parsed_file, \
                 # if does not hold, recompute the interpolation function based on current iref
                 if verbose:
                     print('SP3: Computing new interpolation!')
-                func_satpos = extract_sp3_func(sp3_parsed_file[prn], \
+                func_satpos = extract_sp3(sp3_parsed_file[prn], \
                                                sp3_iref, method = interp_method)
                 # Update the relevant interp function and iref values
                 satfunc_xyz_old[prn] = func_satpos
                 sp3_iref_old[prn] = sp3_iref
 
             # Compute satellite position and velocity using interpolated function
-            satpos_sp3, satvel_sp3 = compute_sp3_snapshot(func_satpos, \
+            satpos_sp3, satvel_sp3 = sp3_snapshot(func_satpos, \
                                                           (timestep - navdata_offset), \
                                                           method = interp_method)
 
@@ -572,15 +572,15 @@ def compute_single_gnss_from_precise_eph(navdata, sp3_parsed_file, \
                 # if does not hold, recompute the interpolation function based on current iref
                 if verbose:
                     print('CLK: Computing new interpolation!')
-                func_satbias = extract_clk_func(clk_parsed_file[prn], \
+                func_satbias = extract_clk(clk_parsed_file[prn], \
                                                 clk_iref, method = interp_method)
                 # Update the relevant interp function and iref values
                 satfunc_t_old[prn] = func_satbias
                 clk_iref_old[prn] = clk_iref
 
             # Compute satellite clock bias and drift using interpolated function
             satbias_clk, \
-            satdrift_clk = compute_clk_snapshot(func_satbias, \
+            satdrift_clk = clk_snapshot(func_satbias, \
                                                 (timestep - navdata_offset), \
                                                 method = interp_method)
             if verbose:
@@ -656,7 +656,7 @@ def compute_single_gnss_from_precise_eph(navdata, sp3_parsed_file, \
 
     return navdata
 
-def compute_multi_gnss_from_precise_eph(navdata, sp3_path, clk_path, \
+def multi_gnss_from_precise_eph(navdata, sp3_path, clk_path, \
                                         gnss_consts, verbose = False):
     """Compute satellite information using .sp3 and .clk for multiple GNSS
 
@@ -685,15 +685,15 @@ def compute_multi_gnss_from_precise_eph(navdata, sp3_path, clk_path, \
 
         sp3_parsed_gnss = parse_sp3(sp3_path, constellation = sv)
         clk_parsed_gnss = parse_clockfile(clk_path, constellation = sv)
-        derived_prcs_gnss = compute_single_gnss_from_precise_eph(navdata_prcs_gnss, \
+        derived_prcs_gnss = single_gnss_from_precise_eph(navdata_prcs_gnss, \
                                                                  sp3_parsed_gnss, \
                                                                  clk_parsed_gnss, \
                                                                  verbose = verbose)
         navdata_prcs_merged.concat(navdata_prcs_gnss, inplace=True)
 
     return navdata_prcs_merged
 
-def compute_sv_gps_from_brdcst_eph(navdata, verbose = False):
+def sv_gps_from_brdcst_eph(navdata, verbose = False):
     """Compute satellite information using .n for any GNSS constellation
 
     Parameters

notebooks/tutorials/parsers.ipynb

@@ -556,25 +556,22 @@
    "id": "3c5de62f",
    "metadata": {},
    "source": [
-    "The data required associated with precise ephemerides involves .sp3 and .clk files, which can be downloaded from [CDDIS](https://cddis.nasa.gov/Data_and_Derived_Products/GNSS/gnss_mgex.html) or [CORS](https://geodesy.noaa.gov/UFCORS/).\n",
+    "The data required to calculate with precise ephemerides uses .sp3 and .clk files, which can be downloaded from [CDDIS](https://cddis.nasa.gov/Data_and_Derived_Products/GNSS/gnss_mgex.html) or [CORS](https://geodesy.noaa.gov/UFCORS/).\n",
     "\n",
-    "The .sp3 files provides post-processed, accurate and precise information regarding the 3-D satellite position in Earth-Centered Earth-Fixed (ECEF) frame at intervals of 15mins each.  \n",
+    "The .sp3 files provide post-processed, accurate, and precise information regarding 3-D satellite position in the Earth-Centered Earth-Fixed (ECEF) frame at intervals of 15mins each.  \n",
     "\n",
-    "Similarly, the .clk files provides post-processed, accurate and precise information on satellite clock errors at intervals of 30secs each.  \n",
+    "Similarly, the .clk files provide post-processed, accurate and precise information on satellite clock errors at intervals of 30secs each.  \n",
     "\n",
-    "These .sp3 and .clk files are available for any GNSS constellation, and hence, provides a common processing platform for applications that involve multi-GNSS satellite signals (without requiring to parse the individual broadcast ephemeris in a separate, individual manner). Also, unlike broadcast ephemeris that can suffer from signal-in-space anomalies, the .sp3 and .clk files are guaranteed to provide accurate satellite information. However, note that, these files are only available in a post-processed manner, and not in real-time"
+    "These .sp3 and .clk files are available for any GNSS constellation, and hence, provide a common processing platform for applications that involve multi-GNSS satellite signals (without requiring to parse the broadcast ephemeris from each constellation separately one at a time). Also, unlike broadcast ephemeris that can suffer from signal-in-space anomalies, the .sp3 and .clk files are guaranteed to provide accurate satellite information. However, note that, these files are only available in a post-processed manner, and not in real-time"
    ]
   },
   {
    "cell_type": "markdown",
    "id": "67fc4f2e",
    "metadata": {},
    "source": [
-    "To analyze this precise ephemerides functionality, \n",
-    "1. Load the derived data from AndroidDerived\n",
-    "2. Remove the rows in NavData class that refer to satellite information (3-D satellite position, 3-D satellite velocity, clock bias and clock drift), i.e., SV_KEYS =['x_sv_m', 'y_sv_m', 'z_sv_m', 'vx_sv_mps','vy_sv_mps','vz_sv_mps', 'b_sv_m', 'b_dot_sv_mps']\n",
-    "3. Specify the .sp3 and .clk files, as well as the desired constellations from which one intends to extract satellite information\n",
-    "4. Populate the columns of SV_KEYS with information extracted via precise ephemerides"
+    "We show how to analyze this precise ephemerides functionality for the Android derived dataset in the following cells, \n",
+    "1. Load the derived data from AndroidDerived"
    ]
   },
   {
@@ -584,48 +581,51 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "from gnss_lib_py.parsers.precise_ephemerides import compute_multi_gnss_from_precise_eph\n",
-    "import numpy as np"
+    "from gnss_lib_py.parsers.precise_ephemerides import multi_gnss_from_precise_eph\n",
+    "import numpy as np\n",
+    "\n",
+    "# load Android Google Challenge data\n",
+    "!wget https://raw.githubusercontent.com/Stanford-NavLab/gnss_lib_py/ramya/multiGNSS_sp3/data/unit_test/android_2021/Pixel4_derived_clkdiscnt.csv --quiet -O \"Pixel4_derived_clkdiscnt.csv\"\n",
+    "derived_data = AndroidDerived2021(\"Pixel4_derived_clkdiscnt.csv\", remove_timing_outliers=False)"
    ]
   },
   {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "e62ed8ee",
+   "cell_type": "markdown",
+   "id": "4e4ee7c8",
    "metadata": {},
-   "outputs": [],
    "source": [
-    "# download .sp3 data file\n",
-    "!wget https://raw.githubusercontent.com/Stanford-NavLab/gnss_lib_py/ramya/multiGNSS_sp3/data/unit_test/precise_ephemeris/grg21553_short.sp3 --quiet -O \"grg21553_short.sp3\"\n",
-    "\n",
-    "# Specify .sp3 file path to extract precise ephemerides\n",
-    "sp3_path = \"grg21553_short.sp3\""
+    "2. Specify the paths to the .sp3 and .clk files, as well as the desired constellations from which one intends to extract satellite information"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "50467c3f",
+   "id": "e62ed8ee",
    "metadata": {},
    "outputs": [],
    "source": [
+    "# download .sp3 data file\n",
+    "!wget https://raw.githubusercontent.com/Stanford-NavLab/gnss_lib_py/ramya/multiGNSS_sp3/data/unit_test/precise_ephemeris/grg21553_short.sp3 --quiet -O \"grg21553_short.sp3\"\n",
+    "# Specify .sp3 file path to extract precise ephemerides\n",
+    "sp3_path = \"grg21553_short.sp3\"\n",
+    "\n",
     "# download .clk data file\n",
     "!wget https://raw.githubusercontent.com/Stanford-NavLab/gnss_lib_py/ramya/multiGNSS_sp3/data/unit_test/precise_ephemeris/grg21553_short.clk --quiet -O \"grg21553_short.clk\"\n",
-    "\n",
     "# Specify .clk file path to extract precise ephemerides\n",
-    "clk_path = \"grg21553_short.clk\""
+    "clk_path = \"grg21553_short.clk\"\n",
+    "\n",
+    "# Specify the GNSS constellations for which you want to extract precise ephemeris\n",
+    "gnss_constellations = {'gps', 'glonass'}"
    ]
   },
   {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "cadb1cf1",
+   "cell_type": "markdown",
+   "id": "2567ff0f",
    "metadata": {},
-   "outputs": [],
    "source": [
-    "# load Android Google Challenge data\n",
-    "!wget https://raw.githubusercontent.com/Stanford-NavLab/gnss_lib_py/ramya/multiGNSS_sp3/data/unit_test/android_2021/Pixel4_derived_clkdiscnt.csv --quiet -O \"Pixel4_derived_clkdiscnt.csv\"\n",
-    "derived_data = AndroidDerived2021(\"Pixel4_derived_clkdiscnt.csv\", remove_timing_outliers=False)"
+    "3. Remove the rows in NavData class that refer to satellite information (3-D satellite position, 3-D satellite velocity, clock bias and clock drift), \n",
+    "\n",
+    "    i.e., `SV_KEYS =['x_sv_m', 'y_sv_m', 'z_sv_m', 'vx_sv_mps','vy_sv_mps','vz_sv_mps', 'b_sv_m', 'b_dot_sv_mps']`"
    ]
   },
   {
@@ -641,7 +641,15 @@
     "           'b_sv_m', 'b_dot_sv_mps']\n",
     "\n",
     "for sv in SV_KEYS:\n",
-    "    derived_data[sv] = 0*derived_data[sv]"
+    "    derived_data[sv] = 0"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "458b0a46",
+   "metadata": {},
+   "source": [
+    "4. Populate the columns of SV_KEYS with information extracted via precise ephemerides"
    ]
   },
   {
@@ -651,12 +659,9 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "# Specify the GNSS constellations for which you want to extract precise ephemeris\n",
-    "gnss_consts = {'gps', 'glonass'}\n",
-    "\n",
     "# Update derived_data class with satellite information computed via precise ephemerides\n",
-    "derived_multi_gnss = compute_multi_gnss_from_precise_eph(derived_data, sp3_path, \\\n",
-    "                                                         clk_path, gnss_consts, verbose = False)"
+    "derived_multi_gnss = multi_gnss_from_precise_eph(derived_data, sp3_path, \\\n",
+    "                                                         clk_path, gnss_constellations, verbose = False)"
    ]
   },
   {
@@ -668,13 +673,13 @@
    "source": [
     "# Check that all the desired fields related to satellite information have useful\n",
     "# information, and norm of computed satellite position matches the altitude of GNSS constellation\n",
-    "norm_val = np.linalg.norm(np.transpose([derived_multi_gnss[SV_KEYS[0]][0:2],\n",
+    "sat_alt = np.linalg.norm(np.transpose([derived_multi_gnss[SV_KEYS[0]][0:2],\n",
     "                                        derived_multi_gnss[SV_KEYS[1]][0:2], \n",
     "                                        derived_multi_gnss[SV_KEYS[2]][0:2]]), axis=1)\n",
-    "print(derived_multi_gnss[\"gnss_id\"][0:2], norm_val)\n",
-    "print(\" \")\n",
+    "print('Distance of two satellites from the center of the Earth (expected around 26000000 m):', derived_multi_gnss[\"gnss_id\"][0:2], sat_alt)\n",
+    "print(\"Extracted values for same satellites: \")\n",
     "for sv in SV_KEYS:\n",
-    "    print(sv, derived_multi_gnss[sv][0:2])"
+    "    print(sv, ':', derived_multi_gnss[sv][0:2])"
    ]
   }
  ],