Component Definition Files

Sensor metadata and information is primarily written to the sensor definition file, a JSON file which resides in the configs/ directory. This page describes the sensor definition file and provides a real-world example of one as a reference.

Sensor Definition File

The sensor definition file contains information about the sensor and the components being used. It is used to generate SigMF metadata identifying the hardware used for the measurement. In general, this file conforms to the SigMF-NS-NTIA Sensor Object format. The one exception to this is that the sensor definition file additionally supports a location field, to record a static sensor location.

While SCOS Sensor will run using the provided default sensor definition file, it is recommended to populate this file as completely as possible prior to deployment of a sensor. This will ensure that correct metadata and system information is available when running tasks.

Example sensor_definition.json

Here is a real-world example of a sensor definition file used by a sensor deployed for monitoring the Citizens Broadband Radio Service (CBRS) band as part of the NASCTN CBRS Sharing Ecosystem Assessment (SEA) project. The sensor uses a Tektronix RSA 507A signal analyzer with a custom preselector. The preselector includes a calibration source, which allows for in-field calibrations. The RF path additionally includes a low-noise amplifier and a bandpass filter.

{
  "location": {
    "x": -105.27452,
    "y": 39.9918,
    "z": 1783.4,
    "description": "Green Mountain Mesa test site in Boulder, CO"
  },
  "sensor_spec": {
    "id": "seadog07",
    "model": "NASCTN SEA Sensor",
    "version": "Sensor Rev. 1",
    "supplemental_information": "SEA System ID 11"
  },
  "antenna": {
    "antenna_spec": {
      "id": "KP Performance KP-3SX4-90",
      "model": "KP Performance KP-3SX4-90",
      "description": "17 dBi, slant-polarized 90 degree sector antenna",
      "supplemental_information": "Using antenna port 4. Datasheet https://kpperformance.com/Content/Images/Downloadables/Datasheets/KP-3SX4-90_datasheets_US.pdf"
    },
    "frequency_low": 3550000000,
    "frequency_high": 3800000000,
    "polarization": "slant (+45)",
    "gain": 17,
    "horizontal_beamwidth": 90,
    "vertical_beamwidth": 6,
    "voltage_standing_wave_ratio": 1.5,
    "steerable": false
  },
  "preselector": {
    "preselector_spec": {
      "id": "Rev. 1 - 02",
      "model": "NASCTN SEA Preselector",
      "version": "Sensor Rev. 1"
    },
    "cal_sources": [
      {
        "cal_source_spec": {
          "id": "SG61410011",
          "model": "Keysight 346B-100",
          "description": "Broadband noise source with VSWR < 1.15:1 from 0.03 to 5.0 GHz",
          "supplemental_information": "Operating and service manual: https://www.keysight.com/us/en/assets/9018-01420/user-manuals/9018-01420.pdf"
        },
        "type": "calibrated noise source",
        "enr": 14.75
      }
    ],
    "amplifiers": [
      {
        "amplifier_spec": {
          "id": "Li-Conn LNA02004000A",
          "model": "Li-Conn LNA02004000A",
          "description": "0.2 GHz to 4.0 GHz wide band low noise amplifier",
          "supplemental_information": "Datasheet https://www.liconn.com/products/LNA02004000A.pdf"
        },
        "gain": 29,
        "noise_figure": 1.3,
        "max_power": 10
      }
    ],
    "filters": [
      {
        "filter_spec": {
          "id": "23-06",
          "model": "Reactel 8C7-3610-X180S11",
          "description": "Custom bandpass filter with 3610 MHz center frequency and 150 MHz bandwidth",
          "supplemental_information": "Datasheet obtained by NASCTN but not available online"
        },
        "frequency_low_passband": 3535000000,
        "frequency_high_passband": 3685000000
      }
    ],
    "rf_paths": [
      {
        "name": "antenna",
        "cal_source_id": "SG61410011",
        "filter_id": "K&L Microwave 12FV40-3625/U150-O/O",
        "amplifier_id": "Li-Conn LNA02004000A"
      },
      {
        "name": "noise_diode",
        "cal_source_id": "SG61410011",
        "filter_id": "K&L Microwave 12FV40-3625/U150-O/O",
        "amplifier_id": "Li-Conn LNA02004000A"
      }
    ]
  },
  "signal_analyzer": {
    "sigan_spec": {
      "id": "B022224",
      "model": "Tektronix RSA507A",
      "description": "Real-time USB spectrum analyzer",
      "supplemental_information": "https://download.tek.com/datasheet/RSA500A-Datasheet-EN-US-37W-60380-16.pdf"
    },
    "frequency_low": 9000,
    "frequency_high": 7500000000,
    "max_power": 20,
    "a2d_bits": 14
  },
  "computer_spec": {
    "id": "7AJ000N9",
    "model": "Intel NUC12TZi7",
    "description": "Intel NUC with i7, 32GB RAM, 1TB SSD",
    "supplemental_information": "https://simplynuc.com/wp-content/uploads/2022/07/Topaz2_TechProdSpec_04.docx.pdf"
  },
  "mobile": false
}