Effects of atmospheric delays Effects of the atmospheric delay can be approximately assessed using a simple wls model of the form y=lsin(e)m(e)△H △ZHD Simulated data y(e.g. error in mapping function) can be used to see effects on clock estimate(Aclk), Height (△h), and atmospheric delay(△atm) If m(e) is removed from partials, then effects in zenith delay error on height can be estimated 0409/03 12540Lec15 Effects of atmospheric delay If atmospheric zenith delay not estimated, then when data is used to 10 degree elevation angle, error height is -2. 5 times zenith atmospheric delay error (see Herring, T A, Precision of vertical position estimates from very-long-baseline interferometry, J Geophys. Res, 91 9177-9182.1986 A simple matlab program can reproduce these results Herring Kalman filter paper also discusses effects of process noise value in height estimate uncertainty 04903 12540Lec1504/09/03 12.540 Lec 15 21 Effects of atmospheric delays • Effects of the atmospheric delay can be approximately assessed using a simple WLS model of the form: • Simulated data y (e.g. error in mapping function) can be used to see effects on clock estimate (D (Dh), and atmospheric delay (Datm) • If m(e) is removed from partials, then effects in zenith delay error on height can be estimated. y = [1 sin(e) m(e)] Dclk DH DZHD È Î Í Í Í ˘ ˚ ˙ ˙ ˙ clk), Height Effects of atmospheric delay • If atmospheric zenith delay not estimated, then when data is used to 10 degree elevation angle, error in height is ~2.5 times zenith atmospheric delay error (see Herring, T. A., Precision of vertical position estimates from very–long–baseline interferometry, J. Geophys. Res., 91, 9177–9182, 1986.
• A simple matlab program can reproduce these results • Herring Kalman filter paper also discusses effects of process noise value in height estimate uncertainty. 04/09/03 12.540 Lec 15 22 11