Abstract: A method, apparatus and computer program product facilitate corrections to be made to a location determined utilizing a satellite-based positioning technique to reduce the errors introduced by atmospheric delay and/or advance of navigation signals propagating through an atmospheric layer, such as the ionosphere. In the context of a method for enabling a customized request for corrections to be made, the method includes determining a perimeter of a grid within which the corrections are sought and transmitting, toward a service provider, a request that identifies one or more correction points within the perimeter of the grid. In response to the request, the method includes receiving information associated with the corrections. The method also includes determining a position based upon the satellite-based positioning technique in combination with the received information associated with the corrections.

Abstract: A method, apparatus and computer program product monitor the quality of correction data. In a method, first parameter(s) associated with a navigation satellite or propagation of signals transmitted by the navigation satellite are predicted based upon prior data including prior correction data associated with the navigation satellite or the propagation of signals transmitted thereby. The method derives second parameter(s) associated with the navigation satellite or the propagation of signals transmitted thereby based upon second data including second correction data associated with the navigation satellite or the propagation of signals transmitted thereby. The second data including the second correction data is more recent than the prior data including the prior correction data. The method compares the first parameter(s) to the second parameter(s) and, based on the comparing, generates or provides information regarding the quality of the correction data.

Abstract: A method, apparatus and computer program product determine a position of a client computing device. In the context of a method, a parameter, such as an orbit or a clock, associated with a respective navigation satellite are predicted, with the client computing device, based on data associated with the respective navigation satellite. The method also includes providing time information to a correction service identifying the data used as a basis for predicting the parameter associated with the respective navigation satellite. The method further includes receiving, from the correction service, a correction to the parameter that has been predicted for the respective navigation satellite and determining the position of the client computing device based upon the parameter that has been predicted for the respective navigation satellite in combination with the correction thereto.

Abstract: A method, apparatus and computer program product provide one or more of navigation-data parameters or correction-model parameters for one or more navigation satellites. In the context of a method, the method includes receiving (i) navigation data regarding one or more of a position of a respective navigation satellite or a clock offset of a clock of the respective navigation satellite and (ii) correction data regarding corrections to one or more of the position or the clock offset of the respective navigation satellite. The method also includes predicting an orbit and the clock of the respective navigation satellite based on the navigation data and the correction data. The method further includes fitting at least one of the navigation-data parameters or the correction-model parameters to the predicted data and, following the fitting, providing the at least one of the navigation-data parameters or the correction-model parameters to one or more navigation devices.

Abstract: A method, apparatus and computer program product are provided for detecting multipath signals from a navigation satellite. In the context of a method, the method includes obtaining a measurement of a parameter based on signals transmitted by the navigation satellite and received by a navigation device and determining an estimated position of the navigation device upon receiving the signals. Based on navigation data regarding a position of the navigation satellite and correction data regarding a correction to the position of the navigation satellite, the method also includes determining a virtual observation for the parameter. The virtual observation is determined for the navigation device being located at the estimated position. The method further includes determining whether the signals transmitted by the navigation satellite and received by the navigation device include multipath signals based upon the measurement of the parameter and the virtual observation for the parameter.

Abstract: An apparatus receives values of parameters defining an orbit of a satellite of a satellite navigation system for a validity period. The apparatus furthermore determines whether a received value of at least one parameter of a predetermined set of the parameters is saturated. The apparatus then takes into account whether a received value of at least one parameter of the predetermined set of parameters is determined to be saturated in a process of extending the validity period of the received values of parameters.

Abstract: An apparatus receives values of parameters defining an orbit of a satellite of a satellite navigation system for a validity period. The apparatus furthermore determines whether a received value of at least one parameter of a predetermined set of the parameters is saturated. The apparatus then takes into account whether a received value of at least one parameter of the predetermined set of parameters is determined to be saturated in a process of extending the validity period of the received values of parameters.