CSP delay model 1.1

JSON schema and example for CSP Low delay model

CSP low delaymodel 1.1

Example JSON

{
    "interface": "https://schema.skao.int/ska-low-csp-delaymodel/1.1",
    "start_validity_sec": 748656000.0,
    "cadence_sec": 10.0,
    "validity_period_sec": 600.0,
    "config_id": "sbi-mvp02-20200325-00001-science_A",
    "subarray": 2,
    "station_beam_delays": [{
        "station_id": 512,
        "substation_id": 3,
        "xypol_coeffs_ns": [750.0, 0.0046, -2e-06, -4.1e-12, 9e-16, -1.9e-19],
        "ypol_offset_ns": -0.1
    }, {
        "station_id": 1,
        "substation_id": 0,
        "xypol_coeffs_ns": [750.0, 0.0046, -2e-06, -4.1e-12, 9e-16, -1.9e-19],
        "ypol_offset_ns": 0.5
    }]
}

https://schema.skao.int/ska-low-csp-delaymodel/1.1

type

object

properties

  • interface

URI of JSON schema applicable to this JSON payload. Type: str

type

string

  • start_validity_sec

Time when delay model becomes valid Start point of polynomial validity no sensible default. It indicates an epoch, which could be anytime.

Type: float

type

number

  • cadence_sec

The time in seconds between updates/publications of the

delay polynomials.

Type: float

Range: Non-zero positive number

type

number

  • validity_period_sec

Validity period of the delay model (starting at epoch) [s]

Type: float

Range: Non-zero positive number

type

number

  • config_id

A string, should be the same as the equivalent value in the last “configure” JSON. If not it indicates that these are not yet valid polys for the current configuration.

Type: str

type

string

  • subarray

The subarray for which the delay polynomials apply to.

Type: int

Range: Integer from 1-16 inclusive

type

integer

  • station_beam_delays

type

array

items

station_beam_delays_1.1

additionalProperties

True

station_beam_delays_1.1

type

object

properties

  • station_id

The station ids for which the delay polynomials apply to.

Type: int Range: Integer from 1-512 inclusive

type

integer

  • substation_id

The substation ids for which the delay polynomials apply to.

Type: int

type

integer

  • xypol_coeffs_ns

X coefficient set Delay Model is specified as coefficients for a 5th order polynomial. Coefficients of the polynomial are specified as an array. The delay at time t, where t is measured with respect the beginning of the validity interval is calculated as:

d(t) = c0 + c1*t + c2*t^2 + c3*t^3 + c4*t^4 + c5*t^5

Units for coefficients c0,c1,..c5: ns/s^k where k=0,1,..5

Type: float

Range for coefficients: 64 bit number

type

array

items

type

number

  • ypol_offset_ns

Offset for the Y polarisation

Type: float

type

number

additionalProperties

True