ntia-core.sigmf-ext.md

The ntia-core SigMF Extension Namespace v2.0.0

This document defines the ntia-core extension namespace for the Signal Metadata Format (SigMF) specification. This extension namespace provides generally-useful metadata fields for NTIA's SigMF namespace extensions.

0 Datatypes

The ntia-core extension provides the following datatypes, which are referenced by this and other NTIA extensions:

name	long-form name	description
Antenna	antenna specification	JSON Antenna object specifying an antenna
enum	enumeration type	Enumeration accepting a defined set of elements represented by a core datatype
HardwareSpec	hardware specification	JSON HardwareSpec object, used to provide hardware details within other objects

0.1 The Antenna Object

Antenna object has the following properties:

name	required	type	unit	description
antenna_spec	true	HardwareSpec	N/A	Metadata to describe antenna.
type	false	string	N/A	Antenna type. E.g. "dipole", "biconical", "monopole", "conical monopole".
frequency_low	false	double	Hz	Low frequency of operational range.
frequency_high	false	double	Hz	High frequency of operational range.
polarization	false	double	string	Antenna polarization. E.g. "vertical", "horizontal", "slant-45", "left-hand circular", "right-hand circular".
cross_polar_discrimination	false	double	N/A	Cross-polarization discrimination.
gain	false	double	dBi	Antenna gain in direction of maximum radiation or reception.
horizontal_gain_pattern	false	double[]	dBi	Antenna gain pattern in horizontal plane from 0 to 359 degrees in 1 degree steps.
vertical_gain_pattern	false	double[]	dBi	Antenna gain pattern in vertical plane from -90 to +90 degrees in 1 degree steps.
horizontal_beamwidth	false	double	degrees	Horizontal 3 dB beamwidth.
vertical_beamwidth	false	double	degrees	Vertical 3 dB beamwidth.
voltage_standing_wave_ratio	false	double	volts	Voltage standing wave ratio.
cable_loss	false	double	dB	Cable loss for cable connecting antenna and preselector.
steerable	false	boolean	N/A	Defines whether the antenna is steerable.
azimuth_angle	false	double	degrees	Angle of main beam in azimuthal plane from North.
elevation_angle	false	double	degrees	Angle of main beam in elevation plane from horizontal.

0.2 The HardwareSpec Object

HardwareSpec object has the following properties:

name	required	type	unit	description
id	true	string	N/A	Unique ID of hardware. E.g., serial number.
model	false	string	N/A	Hardware make and model.
version	false	string	N/A	Hardware version.
description	false	string	N/A	Description of the hardware.
supplemental_information	false	string	N/A	Information about hardware, e.g., url to on-line data sheets.

1 Global

The ntia-core extension adds the following name/value pair to the global SigMF object:

name	required	type	unit	description
classification	true	string	N/A	The classification markings for the acquisition, e.g., UNCLASSIFIED, CONTROLLED//FEDCON, SECRET

2 Captures

The ntia-core extension does not extend the captures SigMF object.

3 Annotations

The ntia-core extension does not extend the annotations SigMF object.

4 Collection

The ntia-core extension does not extend the collection SigMF object.

5 Example

This example snippet shows the ntia-core extension being used to indicate that the corresponding data are unclassified, and how to record the use of ntia-core in the Global core:extensions array. Examples showing the Antenna and HardwareSpec objects may be found in the examples for ntia-sensor and the example for ntia-emitter.

{
  "global": {
    "core:datatype": "rf32_le",
    "core:sample_rate": 2.8E7,
    "core:extensions": [
      {
        "name": "ntia-core",
        "version": "v2.0.0",
        "optional": false
      }
    ],
    "ntia-core:classification": "UNCLASSIFIED"
  },
  ...
  "captures": [
    ...
  ],
  "annotations": [
   ...
  ]
}