NEUTRAL_DELAY_MODEL

Below is an example of the NEUTRAL_DELAY_MODEL block:

[NEUTRAL_DELAY_MODEL]
HYDRO_ZENITH_NEUTRAL_DELAY_STD = 0.002
WET_ZENITH_NEUTRAL_DELAY_STD = 0.01
UNCORRECTED_TROPO_DELAY_STD = 10.0
UNCORRECTED_TROPO_DELAY_MEAN = 0
SURFACE_PRESSURE_PA = 99797
SURFACE_TEMPERATURE_K = 298
RELATIVE_HUMIDITY_PCT = 58

UNCORRECTED_TROPO_DELAY_MEAN

Default: 0.0
Parameter Class: Tunable
Impact of Change: Low
Technical Info: Fallback tropospheric delay correction, in meters, used when troposphere correction is enabled but the neutral delay model has not yet been initialized. This mainly occurs briefly at startup before the receiver has a valid position estimate.
Practical Tuning Info: Leave at the default for almost all cases. This is mainly a bootstrap fallback; once PpRx has a valid navigation solution, the full neutral delay model is used instead.

UNCORRECTED_TROPO_DELAY_STD

Default: 10.0
Parameter Class: Tunable
Impact of Change: Low
Technical Info: Assumed standard deviation, in meters, of the fallback tropospheric delay estimate used before the neutral delay model is initialized.
Practical Tuning Info: Leave at the default for almost all cases. This parameter does not affect the receiver once position is known.

HYDRO_ZENITH_NEUTRAL_DELAY_STD

Default: 0.002
Parameter Class: Tunable
Impact of Change: Low
Technical Info: Assumed standard deviation, in meters, of the hydrostatic zenith neutral delay.
Practical Tuning Info: Leave at the default when SURFACE_PRESSURE_PA is representative of local receiver pressure. Increase if surface pressure is unknown, or the receiver altitude/weather conditions may make the hydrostatic correction less reliable. If SURFACE_PRESSURE_PA is left at the default across varying receiver altitudes, a value of 0.1 or larger may better represent hydrostatic uncertainty.

WET_ZENITH_NEUTRAL_DELAY_STD

Default: 0.010
Parameter Class: Tunable
Impact of Change: Low
Technical Info: Assumed standard deviation, in meters, of the modeled wet zenith neutral-atmosphere delay caused by water vapor.
Practical Tuning Info: Leave at the default for most cases. Increase this value when local humidity or temperature is unknown, rapidly changing, or poorly represented by the configured SURFACE_TEMPERATURE_K and RELATIVE_HUMIDITY_PCT values. If SURFACE_TEMPERATURE_K and RELATIVE_HUMIDITY_PCT are left at their defaults, a value of 0.1 would be more accurate.

SURFACE_PRESSURE_PA

Default: 101325
Parameter Class: Tunable
Impact of Change: Low
Technical Info: Surface pressure, in Pascals, used by the Saastamoinen neutral-atmosphere model to compute the hydrostatic, or dry-air, zenith delay. Higher pressure increases the modeled tropospheric delay.
Practical Tuning Info: Leave at the default only for near-sea-level operation when local weather pressure data is available. For use cases not near sea level, ensure surface pressure is approximately correct for local use.

SURFACE_TEMPERATURE_K

Default: 294.26
Parameter Class: Tunable
Impact of Change: Low
Technical Info: Surface temperature, in Kelvin, used with relative humidity to estimate water vapor pressure for the Saastamoinen wet-delay model.
Practical Tuning Info: Leave at the default unless local temperature data is available. Note that temperature should be in Kelvin (K = C + 273.15). SURFACE_TEMPERATURE_K being far from its actual value influences vertical position error roughly at the decimeter scale and horizontal position error roughly at the centimeter scale.

RELATIVE_HUMIDITY_PCT

Default: 60
Parameter Class: Tunable
Impact of Change: Low
Technical Info: Relative humidity, in percent, used with surface temperature to estimate water vapor pressure for the Saastamoinen wet-delay model.
Practical Tuning Info: Leave at the default unless local humidity data is available. RELATIVE_HUMIDITY_PCT being far from its actual value influences vertical position error roughly at the decimeter scale and horizontal position error roughly at the centimeter scale.