ska-csp-delaymodel

CSP delaymodel 2.2

Example JSON

{
    "interface": "https://schema.skao.int/ska-csp-delaymodel/2.2",
    "epoch": 12345678.123456,
    "validity_period": 10.0,
    "delay_details": [{
        "receptor": "SKA001",
        "poly_info": [{
            "polarization": "X",
            "coeffs": [1.01, 1.02, 1.03, 1.04, 1.05, 1.06]
        }, {
            "polarization": "Y",
            "coeffs": [1.1, 1.2, 1.3, 1.4, 1.5, 1.6]
        }]
    }, {
        "receptor": "SKA100",
        "poly_info": [{
            "polarization": "X",
            "coeffs": [1.101, 1.102, 1.103, 1.104, 1.105, 1.106]
        }, {
            "polarization": "Y",
            "coeffs": [1.11, 1.12, 1.13, 1.14, 1.15, 1.16]
        }]
    }]
}

https://schema.skao.int/ska-csp-delaymodel/2.2

type

object

properties

  • interface

URI of JSON schema applicable to this JSON payload.

type

string

  • epoch

Time when delay model becomes valid (when Mid.CBF shall apply the new model) specified as 32bit UTC time code containing a count of seconds in float since the 1999-12-31T23:59:28Z UTC (SKA epoch).

Range: 32-bit number

type

number

  • validity_period

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

Range: positive number

type

number

  • delay_details

type

array

items

delay details 2.2

additionalProperties

False

delay details 2.2

type

object

properties

  • receptor

ICD DISH to CSP defines DISH ID as 16 bit field. The receptorID specified in the delay model should be the same as the one inserted in the data stream received from the receptor.

Valid receptor IDs include: SKA dishes: “SKAnnn”, where nnn is a zero padded integer in the range of 001 to 133. MeerKAT dishes: “MKTnnn”, where nnn is a zero padded integer in the range of 000 to 063.

Range: any string

type

string

pattern

^(SKA(00[1-9]|0[1-9][0-9]|1[0-2][0-9]|13[0-3]))|

(MKT(0[0-5][0-9]|06[0-3]))$

  • poly_info

type

array

items

poly info 2.2

additionalProperties

False

poly info 2.2

type

object

properties

  • polarization

Polarization of the delay model entry

Range: X or Y

type

string

  • coeffs

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

Range for coefficients: 64 bit number

type

array

items

type

number

additionalProperties

False