The Effects of the Troposphere on Doppler-Navigated Station Positions.
Abstract
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 (AN/BRN-3 strategy) reduces the errors by 70%. The BRN-3 software was modified to account for the troposphere using Black's analytic form of Hopfield's tropospheric model. Two sets of fixes were done at the APL/JHU 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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1978
- Accession Number
- ADA070184
Entities
People
- A. Eisner
Organizations
- Johns Hopkins University