Abstract: To automatically determine geographic positions of signal sources statically disposed along a path in a geographic area with limited satellite coverage, a system generates an initial estimate of the geographic positions of the signal sources. To this end, the system receives signal data collected by a receiver moving along the path, the signal data being indicative of changes, over a period of time, in strength of respective signals emitted by the signal sources and detected by the receiver and, and generates an initial estimate of the geographic positions of the signal sources using the signal data and an average speed at which the receiver moves along the path. The system then revises the initial estimate of the geographic positions of the plurality of signal sources by determining, for a signal source associated with a segment of the path, a segment-specific average speed of the receiver.

Abstract: To automatically determine geographic positions of signal sources in areas with limited satellite coverage, a system receives signal data collected by a receiver moving along a path through a geographic area with limited satellite coverage, the signal data being indicative of changes, over a period of time, in strength of respective signals detected by the moving receiver and emitted by multiple signal sources statically disposed along the path. The system determines a time it takes for a length of a vehicle to pass by the signal source at the determined speed. The system then calculates static positions of the signal sources using the signal data and the determined time, including associating the location of each signal source with a time when the signal source was directly over the roof of the vehicle in which the moving receiver is travelling.

Abstract: To automatically determine geographic positions of signal sources in areas with limited satellite coverage, a system receives signal data collected by a receiver moving along a path through a geographic area with limited satellite coverage, the signal data being indicative of changes, over a period of time, in strength of respective signals detected by the moving receiver and emitted by multiple signal sources statically disposed along the path. The system determines a time it takes for a length of a vehicle to pass by the signal source at the determined speed. The system then calculates static positions of the signal sources using the signal data and the determined time, including associating the location of each signal source with a time when the signal source was directly over the roof of the vehicle in which the moving receiver is travelling.

Abstract: In a geographic area with limited satellite coverage, multiple signal sources are statically disposed along a path through the geographic area. To automatically determine geographic positions of the signal sources, signal data collected by a receiver moving along the path is received, where the signal data indicates changes, over a period of time, in strength of respective signals emitted by the signal sources. Indications of a first position of the receiver at a first time prior to entering the geographic area and a second position of the receiver at a second time subsequent to leaving the geographic area are received, and positions for the signal sources are determined using the received signal data and the received indications of the positions and the times. The determined positions for the signal sources are used to geoposition a device moving along the path.

Abstract: In a geographic area with limited satellite coverage, multiple signal sources are statically disposed along a path through the geographic area. To automatically determine geographic positions of the signal sources, signal data collected by a receiver moving along the path is received, where the signal data indicates changes, over a period of time, in strength of respective signals emitted by the signal sources. Indications of a first position of the receiver at a first time prior to entering the geographic area and a second position of the receiver at a second time subsequent to leaving the geographic area are received, and positions for the signal sources are determined using the received signal data and the received indications of the positions and the times. The determined positions for the signal sources are used to geoposition a device moving along the path.