The invention concerns a real-time navigation method for locating a rover using three-carrier radio signals of three different frequencies to determine the position of a user, transmitted by satellites. The method comprises a first step for determining
"extra-wide lane" carrier phase ambiguity, a second step for estimating "wide-lane" phase ambiguity, and a third step for resolving the phase ambiguity of one of the frequencies. An additional step consists in the application of real-time ionospheric
corrections during the third step, these ionospheric corrections being based on a continuously updated ionospheric model of said ionospheric layer calculated by a fixed ground reference station combined with geodetic data calculated by a so-called master fixed ground reference station. The invention also concerns a system for implementing the method.
Thanks to the use of the three-carrier system and the ionospheric estimation, this technology provides a precise navigation service (only a few centimeters of error). Also it requires less ground stations, since they can be separated hundreds of kilometers instead of tens of kilometers. The reduced amount of ground stations required also implies a lowering of the costs . Instead, more ground stations can be placed to cover the same area at the same cost as previous systems, but in this case there is an important increase of the accuracy of the system.
An ad-hoc assessment for each specific application can qualify the limitations.
Air, sea and ground transport and people location for both position control and guidance services. It can also be used as a tool for making ground measures subsequently used for geographical or construction studies. It may also be used in meteorology and ionospheric sounding (thanks to the ionosphere estimation). Thanks to the precision, it may also be used in road applications such as lane keeping, automatic parking fee collection by location and automatic guidance of vehicles among others, but these road applications need further development of this invention and of the cartography (road maps actualization and improvement in precision).
Veronica La Regina
