THE LAGOS 11.4 KM BASELINE
Authors: Egberongbe, F. O. A.; Fadahunsi, O.; Fajemirokun, F. A.; Parm, T.
Source: Survey Review, Volume 28, Number 222, October 1986 , pp. 389-398(10)
Publisher: Maney Publishing
Abstract:An 11.4 km baseline has been established for calibration of electronic distance-measuring instruments in Lagos, as well as for research work and for calibration of the triangulation network tied to the African Doppler satellite programme currently in progress. This line is part of the proposed 44 km on the same site on the boundary of Lagos and Ogun States. The baseline was measured with an Aga Geodimeter model 8 using a laser as carrier.
Because of higher frequency stability, only the U1 frequency is made functional, while the remaining three frequencies (U2–U4) have been disconnected. In addition, a microwave instrument, Sial MD-60, was employed to produce the coarse measurement. The standard error attained for the baseline was better than 1 ppm.
The difference in ground elevation does not exceed 70 m, while towers of 30–40 m high are placed at the terminals of the line. The measuring beam runs well above the treetops, which average 10 min height. Two 40 m meteorological towers were built beside the line to enhance direct meteorological observations in measuring the beam.
Document Type: Research Article
Publication date: 1986-10-01
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