Richard B. Langley

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There is some uncertainty, however, in the receiver’s measurements, and so the location of the range circles will be inexact and result in an error in the computed position. This error depends on the geometry relating the receiver and the transmitters. In Figure 1a, the transmitters are far apart, giving a relatively small region in which the receiver must(More)
World featuring discussions on recent advances in GPS technology and its applications as well as on the fundamentals of GPS positioning. This month we look at some of the mathematics involved in determining a position using GPS pseudorange measurements. We also examine some of the ways of gauging the accuracy of GPS positions. This column is coordinated by(More)
In post-processing dual frequency GPS carrier phase data, the residual tropospheric delay can easily be the largest remaining error source. This error can contribute a bias in height of several centimetres even if simultaneously recorded meteorological data are used. This shortcoming is primarily due to the poor representation of the water vapour profile in(More)
In order to attain high precision positioning and navigation results with GPS, cycle slips must be correctly repaired at the data preprocessing stage. Over the past decade a number of methods have been developed to detect and repair cycle slips. These methods invariably require user intervention for problematic cycle slips in portions of data, tuning of(More)
Continuous portable 24-hour tape recorded monitoring of the electrocardiogram in 189 healthy adults was used to provide data about dysrhythmia during normal daily activity. The age of the subjects ranged from 20 to 70 years and the mean age was 44. One hundred and forty-eight were less than 50 years of age. Dysrhythmia, mainly asymptomatic, occurred in 71(More)
Several hybrid neutral atmosphere delay models have been developed at the University of New Brunswick. In this paper we are presenting UNB3m_pack, a package with subroutines in FORTRAN and corresponding functions in MatLab which provides neutral atmospheric information estimated using the UNB3m model. The main goal of UNB3m is to provide reliable predicted(More)