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   "source": [
    "# EE123 Lab2 - Real-Time Flight Radar App\n",
    "\n",
    "### Written by Miki Lustig and Frank Ong"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
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   "source": [
    "from __future__ import division\n",
    "import numpy as np\n",
    "from numpy import *\n",
    "from numpy.fft import *\n",
    "\n",
    "\n",
    "from rtadsb import rt_flight_radar"
   ]
  },
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   "source": [
    "## Task III: Play with the Real-Time Flight Radar\n",
    "\n",
    "The function rt_flight_radar() in rtadsb.py creates a real-time flight position plot using your preamble detection function and an ADS-B decoder. \n",
    "\n",
    "Decoding the packets is beyond the scope of this lab, but at a high level, the decoding is done by first identifying the useful packets containing location information. For our lab, we are only interested in long squitters with Downlink Format (DF) = 17, which can be identified by the first 5 bits. Once we have identified a DF-17 packet, we can identify the airplane type (ICAO address) from Bytes 2 to 4. The rest of the packet will contain the altitude, latitude and longitude information, which look like this:\n",
    "\n",
    "`[TC-]     [-Altitude-] T F [----Latitude---] [---Longitude--]`\n",
    "\n",
    "`01011 000 000011111111 0 0 10110011110111111 01001101110100110`\n",
    "\n",
    "The latitude and longitude are tricky to decode as there are not enough bits to encode all locations. Each ADS-B packet is further divided into even and odd packets and there is a  complicated equation to combine one even and one odd packet to get the exact location...\n",
    "\n",
    "If you are interested in more detail, you can take a look at these links:\n",
    "* http://www.lll.lu/~edward/edward/adsb/DecodingADSBposition.html. There's a nice explanation how to decode position. \n",
    "* http://sdrsharp.com/index.php/a-simple-and-cheap-ads-b-receiver-using-rtl-sdr is a windows software to decode ads-b using rtl-sdr\n",
    "* http://www.blackcatsystems.com/software/cocoa1090.html is an OSX software to decode ads-b using rtl-sdr\n",
    "* https://github.com/antirez/dump1090 is a *nix software (linux/osx) to decode ads-b using rtl-sdr. It also has a feature that you can display planes positions on google maps. \n",
    "\n",
    "Our ADS-B decoder heavily follows the dump1090 software for mode S decoding."
   ]
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   "source": [
    "Copy and paste your `detectPreamble` function to the code cell below. Scroll down to the bottom and you should be able to run rt_flight_radar()! To receive the ads-b packets from planes, it is recommended you are outside during daytime. It is also recommended to use Chrome to view the map. **Sometimes, some parts of the map become blank, but you can fix it by resizing your browser or refresh the page**.\n",
    "\n",
    "**Information obtained from the flight radar will be printed on the command line.** If a plane with position information is detected, it will be shown as a blue blob on the map. If a flight number is decoded, it will be shown next with the blue blob. It might take some time to detect a plane, but be patient. However, it might not be on the map because its position information is not received. \n",
    "\n",
    "* Run the flight radar until you see at least a plane on the map. You can check whether the plane is real by googling its flight number (if available)."
   ]
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  {
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   "execution_count": null,
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   "outputs": [],
   "source": [
    "# Your detectPreamble and data2bit functions below:\n",
    "\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
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   "source": [
    "fs = 2000000; # 2MHz sampling frequency\n",
    "center_freq = 1090e6 # 1090 MHz center frequency\n",
    "gain = 49.6 # gain\n",
    "N_samples = 2048000 # number of sdr samples for each chunk of data\n",
    "\n",
    "pos_ref = [37.875219, -122.257939] # Berkeley's latitude, longitude for initializing the map\n",
    "\n",
    "functions = (detectPreamble, data2bit)\n",
    "\n",
    "# Run flight radar\n",
    "stop_flag = rt_flight_radar( fs, center_freq, gain, N_samples, pos_ref, functions )\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
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   "source": [
    "# Run this to stop\n",
    "\n",
    "stop_flag.set()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "\n",
    "# I hope you enjoyed the lab!"
   ]
  }
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