TABLE 2

Measurement Error Model and Nominal Bias Error

	Standard deviation model
*σ_gnd,i*	RTCA DO-245A (RTCA, 2004)
*σ_gnd,i*	σ_gnd,i,IF: an inflation factor, is applied
*σ_tropo,i, σ_iono,i*	RTCA DO-245A (RTCA, 2004)
*σ_tropo,i, σ_iono,i*	Standard deviation is computed at an elevation of 5° The distance between the aircraft and the reference point (x_air) and the speed of the aircraft (v_air) are set to 7 km and 0.042 km/s based on the layout of the Chicago O’Hare airport (one of the largest airports) and the maximum speed at the taxiway (RTCA, 1999) σ_{vert.iono gradient} = 0.004 mm/km
*σ_air,i, σ_air,i,IF*	L1/E1: 0.13 + 0.17e^−el/13° (Circiu et al., 2021)
*σ_air,i, σ_air,i,IF*	IF: 0.34 + 0.4e^−el/14° (Circiu et al., 2021)
*σ_air,cp,i,IF*	at el = 5°
*σ_Δtropo,i*	(Walter et al., 2008)
*σ_Δclock,i*	(Walter et al., 2008)
	Differential nominal bias error in pseudorange residual
*β_i*	[0, 0.1, 0.2, 0.3, 0.4, 0.5] m
	Parameters for overbounding the multipath time constant uncertainty
*τ_mp,min*	30-s carrier smoothing: 26 (Appendix A)
*τ_mp,min*	100-s carrier smoothing: 54 (Appendix A)
*τ_mp,max*	30-s smoothing: 2315 (Appendix A)
*τ_mp,max*	100-s smoothing: 2894 (Appendix A)