Where were you
Bern Grush · Traffic Technology International · 2006
The benefits of global navigation satellite systems (GNSS) over dedicated short range communications (DSRC) for the implementation of congestion charging and road pricing are discussed. Assessing a fee for a vehicle's use of a roadway depends on the measurement of the vehicle's location, the measurement time and duration of the journey, market-related information that may be fixed or variable, and the assessment of a charge whether on-board or in a data centre. Determination of the position of a vehicle using GNSS depends on the management of sources of error in the originating satellite signal, signal propagation delays, errors in the computed user position due to receiver noise and perturbation of the satellite signals due to the user environment. The improvement in accuracy that can be expected when Galileo signals are available is discussed. Ways of error mitigation at the receiver are considered with reference to receiver-autonomous multipath mitigation.