A global navigation satellite system (GNSS) receiver includes a processor to determine whether a first satellite is in view of GNSS receiver; whether a second satellite is in view of GNSS receiver when first satellite is in view of GNSS receiver; and whether a third satellite is in view of GNSS receiver when first satellite is not in view of GNSS receiver. Second satellite was previously determined more likely to be in view when first satellite is in view based on a first average distance between first satellite and second satellite based on a first orbit of first satellite and a second orbit of second satellite. Third satellite was previously determined more likely to be in view when first satellite is not in view based on a second average distance between first satellite and third satellite based on first orbit of first satellite and a third orbit of third satellite.

The invention, in some embodiments, relates to the field of global navigation satellite systems, and more particularly to the field of methods and devices for identifying whether a satellite in a global navigation satellite system has a line of sight to a specific global navigation satellite system receiver (LOS satellite) or does not have a line of sight to the global navigation satellite system receiver (NLOS satellite).

The invention, in some embodiments, relates to the field of global navigation satellite systems, and more particularly to the field of methods and devices for identifying whether a satellite in a global navigation satellite system has a line of sight to a specific global navigation satellite system receiver (LOS satellite) or does not have a line of sight to the global navigation satellite system receiver (NLOS satellite).

A method for selecting usable satellites from among the satellites of a localization constellation, to determine an instantaneous kinematic state of a train, is provided. The method includes determining a measured value and an estimated value of a Doppler coefficient and/or a pseudo-range, then comparing the measured and estimated values and, in case of divergence, deleting the satellite from the usable satellites. The estimated value results from a dynamic model of the train, which uses only a kinematic state at a past moment to calculate an estimated instantaneous kinematic state and that uses a mapping of the track on which the guided vehicle moves.

A method for selecting usable satellites from among the satellites of a localization constellation, to determine an instantaneous kinematic state of a train, is provided. The method includes determining a measured value and an estimated value of a Doppler coefficient and/or a pseudo-range, then comparing the measured and estimated values and, in case of divergence, deleting the satellite from the usable satellites. The estimated value results from a dynamic model of the train, which uses only a kinematic state at a past moment to calculate an estimated instantaneous kinematic state and that uses a mapping of the track on which the guided vehicle moves.

In one embodiment, a method for selecting a sub-set of satellites from a set of N satellites is provided. The method includes recursively evaluating each sub-set of N−P satellites of a set of N satellites. If only one sub-set satisfies one or more first criterion, then the one sub-set that satisfies the one or more first criterions is selected. If, however, more than one sub-set satisfies the one or more first criterion, then the sub-sets that satisfy the one or more first criterion are evaluated with respect to one or more second criterion and the one sub-set that optimizes the one or more second criterion is selected. Once the selected set of N satellites is equal to the number of satellites from which a receiver is configured to calculate a navigation solution, then that selected set of N satellites is used to calculate a navigation solution.

In one embodiment, a method for selecting a sub-set of satellites from a set of N satellites is provided. The method includes recursively evaluating each sub-set of N−P satellites of a set of N satellites. If only one sub-set satisfies one or more first criterion, then the one sub-set that satisfies the one or more first criterions is selected. If, however, more than one sub-set satisfies the one or more first criterion, then the sub-sets that satisfy the one or more first criterion are evaluated with respect to one or more second criterion and the one sub-set that optimizes the one or more second criterion is selected. Once the selected set of N satellites is equal to the number of satellites from which a receiver is configured to calculate a navigation solution, then that selected set of N satellites is used to calculate a navigation solution.

A relative position calculating system for work machines includes a first dump truck (101) which receives a navigation signal from at least one of a plurality of satellites (120), a second dump truck (111) which receives a navigation signal from at least one of the plurality of satellites (120), and a relative position calculating apparatus (102) which calculates a relative position between the first dump truck (101) and the second dump truck (111) based on the navigation signals which the first dump truck (101) and the second dump truck (111) receive, respectively, from a common satellite of the plurality of satellites (121). Thus, an influence of a positioning error due to a satellite positioning system is reduced, and accuracy of a calculation for the relative position between the two dump trucks (101, 111) can be enhanced.

A relative position calculating system for work machines includes a first dump truck (101) which receives a navigation signal from at least one of a plurality of satellites (120), a second dump truck (111) which receives a navigation signal from at least one of the plurality of satellites (120), and a relative position calculating apparatus (102) which calculates a relative position between the first dump truck (101) and the second dump truck (111) based on the navigation signals which the first dump truck (101) and the second dump truck (111) receive, respectively, from a common satellite of the plurality of satellites (121). Thus, an influence of a positioning error due to a satellite positioning system is reduced, and accuracy of a calculation for the relative position between the two dump trucks (101, 111) can be enhanced.

A method for improving accuracy of a raw GPS positioning of an untargeted pedestrian device wherein the pedestrian device receives from a nearby vehicle device a message containing a calculated offset between a raw GPS location of the vehicle and a corrected location of the vehicle, the message being received as a direct consequence of the pedestrian device and the vehicle device coming into mutual communication range without a need for pairing between the two devices. The calculated offset is applied to the raw GPS positioning of the pedestrian device to obtain a more accurate location of the pedestrian device.