SPOS-DD-2026237 · SabahPOS Daily Datum QA/QC

Anchored ITRF2020 double-difference network solution tied to the Sabah Geocentric Datum 2020 (SGD2020), observation epoch 2026.6461.

1 Reference frame & methodology

Engine: Bernese GNSS Software 5.4, RNX2SNX ambiguity-fixed double-difference network, 30 s sampling.
Fiducials: 8 IGS Reference Network (IGS20/ITRF2020) stations held fixed. A-priori coordinates propagated from the IGS20 realisation (reference epoch 2015.0) with station velocities and the ITRF2020 post-seismic deformation (PSD) model to the observation epoch.
Antenna: Absolute IGS ANTEX phase-centre models; antenna reference-point (ARP) eccentricities applied for every station.
Loading: Ocean-tide loading from station-specific coefficients (SPOTL / TPXO7.2).
Products: CODE multi-GNSS final orbits, clocks, Earth-rotation and code biases; CODE global ionosphere maps.
Datum tie: Robust 3-parameter (translation-only) transformation ITRF2020(t)→SGD2020 estimated against the published permanent-CORS control. Translation T = (+143.4, +11.3, +65.4) mm.

2 Quality & external accuracy

Tie RMS 8.9 mm is the scatter of the 15 retained CORS about the fitted SGD2020 control (internal consistency). Kept-station residuals: median 7.5 mm, maximum 14.4 mm.

No check anchors were withheld this session, so no independent external-accuracy figure is reported. Run with check anchors to obtain one (diagnostic only — it never gates the solution).

4 Station disposition & QC

Automatic gates: cycle-slip (>1% loss-of-lock), thin data (<80% of the day), robust residual reject (>40 mm, MAD-based), anchor leave-one-out, and an a-priori gross-error gate.

Sabah CORS — estimated control

CORS	Status	Latitude	Longitude	Residual / note
KP18	rejected >40mm	5.57213	115.59949	48.0 mm
BL08	kept (control)	5.89443	117.56020	6.5 mm
KB03	kept (control)	6.35118	116.43182	13.1 mm
KD05	kept (control)	6.88165	116.85333	7.5 mm
KG13	kept (control)	5.34215	116.15901	10.4 mm
KK01	kept (control)	5.95923	116.07029	14.4 mm
KM22	kept (control)	6.49988	116.77246	4.0 mm
KN09	kept (control)	5.58762	117.84713	9.0 mm
PT23	kept (control)	6.70681	117.02979	5.0 mm
RN06	kept (control)	5.95565	116.67012	7.6 mm
SE12	kept (control)	4.47876	118.61271	4.4 mm
SK07	kept (control)	5.87749	118.05401	13.9 mm
SP19	kept (control)	5.08000	115.55102	6.0 mm
TB14	kept (control)	5.66757	116.36249	11.0 mm
TL27	kept (control)	5.62983	117.12914	7.1 mm
TW10	kept (control)	4.24668	117.88027	4.0 mm

IGS fiducials

Anchor	Status	Latitude	Longitude	Residual / note
CIBG	anchor (fixed)	-6.49037	106.84918	—
CMUM	anchor (fixed)	18.76088	98.93238	—
CUSV	anchor (fixed)	13.73591	100.53392	—
DARW	anchor (fixed)	-12.84369	131.13275	—
GUAM	anchor (fixed)	13.58933	144.86836	—
JOG2	anchor (fixed)	-7.76382	110.37247	—
PIMO	anchor (fixed)	14.63572	121.07773	—
PTGG	anchor (fixed)	14.53540	121.04126	—

6 Caveats

Research & development output. Coordinates are provisional and not sanctioned for cadastral or legal survey use.
Tie RMS measures internal consistency of the CORS→SGD2020 fit, not absolute accuracy; the external check anchors (§2) provide an independent measure when run.
This SGD2020 realisation is tied from the permanent CORS network and may differ from JUPEM primary control at the few-millimetre level.

Daily Datum Realisation — QA/QC Report