adds ephemeris downloader tutorial

Author: betaBison

docs/source/tutorials/tutorials.rst

@@ -57,5 +57,6 @@ available in the :code:`utils` directory.
    tutorials_visualizations_notebook
    tutorials_coordinates_notebook
    tutorials_utilities_notebook
+   tutorials_ephemeris_downloader_notebook
    tutorials_sv_models_notebook
    tutorials_gnss_models_notebook

docs/source/tutorials/tutorials_ephemeris_downloader_notebook.nblink

@@ -0,0 +1,3 @@
+{
+    "path": "../../../notebooks/tutorials/ephemeris_downloader.ipynb"
+}

notebooks/tutorials/ephemeris_downloader.ipynb

@@ -0,0 +1,134 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "a1126926",
+   "metadata": {},
+   "source": [
+    "# Ephemeris Downloader"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "929486f6",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import numpy as np\n",
+    "import gnss_lib_py as glp\n",
+    "from datetime import datetime, timezone"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "8ea72a0c",
+   "metadata": {},
+   "source": [
+    "The `load_ephemeris` function from the `utils/ephemeris_downloader.py` file can be used to automatically download ephemeris files and check whether the correct ephemeris files have already been downloaded.\n",
+    "\n",
+    "As an example, say we want to find satellite positions for a specific location and time. We will use `load_ephemeris` to download the correct ephemeris files."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "2bbfabff",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "lat, lon, alt = 37.42984154652992, -122.16946303566934, 0.\n",
+    "timestamp_start = datetime(year=2023, month=3, day=14, hour=12, tzinfo=timezone.utc)\n",
+    "timestamp_end = datetime(year=2023, month=3, day=14, hour=13, tzinfo=timezone.utc)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "32390f44",
+   "metadata": {},
+   "source": [
+    "To download ephemeris simply pass in the file type you want to download (either `sp3`, `clk`, or `rinex_nav` and the time at which you want the ephemeris in units of GPS milliseconds. The output of the `load_ephemeris` function is the path to the ephemeris files."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "13e826e6",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "gps_millis = glp.datetime_to_gps_millis(np.array([timestamp_start,timestamp_end]))\n",
+    "sp3_path = glp.load_ephemeris(file_type=\"sp3\", \n",
+    "                              gps_millis=gps_millis,\n",
+    "                              verbose=True)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "fb631ff0",
+   "metadata": {},
+   "source": [
+    "To visualize the data, we can then plot the satellite positions using a skyplot from our receiver's location we input above. For the skyplot we need to parse the sp3 file we downloaded using the `Sp3` class and then create a `NavData` instance to pass in our receiver's position."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "a09816e3",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# load the sp3 file\n",
+    "sp3 = glp.Sp3(sp3_path)\n",
+    "\n",
+    "# create receiver state NavData instance to pass into skyplot function\n",
+    "x_rx_m, y_rx_m, z_rx_m = glp.geodetic_to_ecef(np.array([[lat,lon,alt]]))[0]\n",
+    "receiver_state = glp.NavData()\n",
+    "receiver_state[\"gps_millis\"] = glp.datetime_to_gps_millis(timestamp_start)\n",
+    "receiver_state[\"x_rx_m\"] = x_rx_m\n",
+    "receiver_state[\"y_rx_m\"] = y_rx_m\n",
+    "receiver_state[\"z_rx_m\"] = z_rx_m"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "bcfe81aa",
+   "metadata": {},
+   "source": [
+    "Now we can plot the skyplot from the downloaded data. For readability, we crop the sp3 data to only include satellite positions between the start and end timestamp from above."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "cd23bf03",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "cropped_sp3 = sp3.where(\"gps_millis\",gps_millis[0],\"geq\").where(\"gps_millis\",gps_millis[1],\"leq\")\n",
+    "fig = glp.plot_skyplot(cropped_sp3,receiver_state)"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.8.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}

notebooks/tutorials/sv_models.ipynb

@@ -128,7 +128,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Adding SV states to `NavData` with received measurements using broadcast ephemeris"
+    "# Adding SV states to `NavData` with received measurements using broadcast ephemeris"
    ]
   },
   {
@@ -220,7 +220,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Add SV states for visible satellites given a series of times and positions"
+    "# Add SV states for visible satellites given a series of times and positions"
    ]
   },
   {
@@ -335,7 +335,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Finding PRNs and states for visible SVs for a given position and time"
+    "# Finding PRNs and states for visible SVs for a given position and time"
    ]
   },
   {
@@ -373,7 +373,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Finding SV states at given time and for specific PRNs"
+    "# Finding SV states at given time and for specific PRNs"
    ]
   },
   {
@@ -423,7 +423,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Simulating SV positions given elevation and azimuth"
+    "# Simulating SV positions given elevation and azimuth"
    ]
   },
   {