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    "# Tutorial 21: Ground Segment and CCSDS\n",
    "\n",
    "This tutorial explains how to format spacecraft telemetry using the CCSDS (Consultative Committee for Space Data Systems) standard for ground-to-satellite communication.\n",
    "\n",
    "## 1. CCSDS Space Packet\n",
    "Every CCSDS Space Packet consists of a 6-byte Primary Header followed by the Packet Data Field. The header defines the Application Process ID (APID), packet type, sequence flags, and sequence count."
   ]
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   "cell_type": "code",
   "execution_count": 7,
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    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Full Packet (hex): 0123c02a00074121999a41a1999a\n",
      "Header (hex): 0123c02a0007\n",
      "Total Packet Length: 14 bytes\n"
     ]
    }
   ],
   "source": [
    "from opengnc.ground_segment.ccsds import SpacePacket, PacketType, SequenceFlags\n",
    "import numpy as np\n",
    "\n",
    "# 1. Create a Space Packet\n",
    "# APID: 0x123 (291), Sequence Count: 42\n",
    "packet = SpacePacket(\n",
    "    apid=0x123, \n",
    "    packet_type=PacketType.TELEMETRY, \n",
    "    seq_count=42\n",
    ")\n",
    "\n",
    "# 2. Append some payload data (two float32 values)\n",
    "# CCSDS standards use Big-Endian (Network Byte Order)\n",
    "payload = np.array([10.1, 20.2], dtype='>f4').tobytes()\n",
    "packet.data = payload\n",
    "\n",
    "# 3. Pack the full packet to binary\n",
    "raw_bytes = packet.pack()\n",
    "print(f\"Full Packet (hex): {raw_bytes.hex()}\")\n",
    "print(f\"Header (hex): {raw_bytes[:6].hex()}\")\n",
    "print(f\"Total Packet Length: {len(raw_bytes)} bytes\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 2. Telemetry Decommutation\n",
    "The `decom` module handles extracting fields from binary telemetry streams based on a parameter map. We use the `DecomEngine` to convert the raw octets back into engineering units."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Decommutated Telemetry (Big-Endian): {'voltage': 10.100000381469727, 'current': 20.200000762939453}\n",
      "Measured Voltage: 10.10 V\n",
      "Measured Current: 20.20 A\n"
     ]
    }
   ],
   "source": [
    "from opengnc.ground_segment.decom import DecomEngine\n",
    "\n",
    "# Define the structure of the data inside the CCSDS packet data field\n",
    "# 'f' corresponds to a 32-bit float (4 bytes)\n",
    "parameter_config = [\n",
    "    {\"name\": \"voltage\", \"data_type\": \"f\", \"offset\": 0, \"scale\": 1.0},\n",
    "    {\"name\": \"current\", \"data_type\": \"f\", \"offset\": 4, \"scale\": 1.0}\n",
    "]\n",
    "\n",
    "# Initialize the DecomEngine\n",
    "engine = DecomEngine.from_dict(parameter_config)\n",
    "\n",
    "# Extract data from the packed bytes (skipping the 6-byte CCSDS header)\n",
    "data_field = raw_bytes[6:]\n",
    "results = engine.decommutate(data_field)\n",
    "\n",
    "print(f\"Decommutated Telemetry (Big-Endian): {results}\")\n",
    "print(f\"Measured Voltage: {results['voltage']:.2f} V\")\n",
    "print(f\"Measured Current: {results['current']:.2f} A\")"
   ]
  }
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