The Effects of the Troposphere on Doppler-Navigated Station Positions.
JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
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Ignoring the effect of the troposphere on Doppler data introduces 35 to 40 m errors in the navigated longitude of the Transit system user. Eliminating low elevation data ANBRN-3 strategy reduces the errors by 70. The BRN-3 software was modified to account for the troposphere using Blacks analytic form of Hopfields tropospheric model. Two sets of fixes were done at the APLJHU site. In the first set 39 passes, it was demonstrated that the neglected tropospheric effect had masked a 9 m error in station radius. For the non-troposphere-corrected case, the second set 115 passes resulted in navigated longitudes for passes east and west of the station clustered on opposite sides of the true longitude. The 29 m separation between the east and west clusters was reduced to 6.7 m by correcting the data for the effects of the troposphere. For the BRN-3 navigator at sea this represents, on the average, an 11 m reduction in longitude error. The implied consequences to the fixed site BRN-3 surveyor are a 2.2 m shift in mean latitude, a 0.7 m shift in the mean navigated longitude , a 0.7 m shift in the mean navigated longitude, and a 4.7 m reduction in the scatter of the mean navigated longitude. Author
- Atmospheric Physics