GNSSRO operator comparison

[XuanliLi-NOAA]

Document the differences and performances among GNSSRO operators: NBAM, ROPP1D, and ROPP2D.
Related GDASApp issues: Phase 3 test for NBAM 1740
Phase 1 and 2 tests for NBAM 750

[XuanliLi-NOAA]

Comparison of ROPP1D, ROPP2D with NBAM using the same obs error model: NRL and background check QC filters: 3σ

Obs after QC vs. HofX (red: ropp1d black: NBAM)

Obs after QC vs. HofX (red: ropp2d black: NBAM)

HofX NBAM vs. ROPP1D

HofX NBAM vs. ROPP2D

HofX ROPP1D vs. ROPP2D

Difference of HofX (NBAM-ROPP1D) vs. HofX NBAM

Difference of HofX (NBAM-ROPP2D) vs. HofX NBAM

Difference of HofX (ROPP1D-ROPP2D) vs. HofX ROPP1D

(O-B)/B counts counts below 7 km impact height

(O-B)/B bias bias below 7 km impact height

(O-B)/B rms rms below 7 km impact height

(O-B)/B stddev stddev below 7 km impact height