Differential satellite positioning system ground station with integrity monitoring

Claim 2

A differential satellite positioning system ground station for determining GPS differential correction information with integrity monitoring, said differential satellite positioning system ground station comprising: a plurality of GPS signal receivers, each at a known geocentric position, each operative for receiving a satellite-specific information signal transmitted from each of selected ones of a plurality of satellite vehicles, and each operative for deriving, from each of said received satellite-specific information signals from said satellite vehicles, receiver-satellite-specific GPS signal information; first differential correction processing means for deriving receiver-satellite-specific GPS differential correction information associated with each of said satellite-specific information signals, where said receiver-satellite specific differential correction information is a function of said receiver-satellite-specific GPS signal information determined by a specific one of said GPS signal receivers and said known position of said GPS signal receivers for the same one of said GPS signal receivers; second differential correction processing means operative for determining satellite-specific GPS differential correction information, associated with each of said satellite-specific information signals, as a function of said receiver-satellite-specific GPS differential correction information determined by more than one of said plurality of GPS signal receivers and associated with the same one of said satellite-specific information signals; ground station integrity monitoring means for determining satellite-specific integrity information associated with each of said satellite-specific information signals, as a function of said receiver-satellite-specific GPS differential correction information and said satellite-specific GPS differential correction information, where said satellite-specific integrity information is descriptive of the integrity of said satellite-specific GPS differential correction information.

Claim 3

The differential satellite positioning system ground station of claim 1 wherein: said first differential correction processing means is operative for determining a receiver-satellite-specific GPS differential correction value, associated with each of said satellite-specific information signals and each of said plurality GPS signal receivers, as a function of said receiver-satellite-specific GPS signal information, and said known position of the corresponding one of said plurality of GPS signal receivers; said second differential correction processing means includes means for providing a satellite-specific statistical GPS differential correction value, associated with each of said received satellite-specific information signals, as an average of said receiver-satellite-specific differential correction values associated with the same satellite information signal and derived from said receiver-satellite-specific GPS signal information from more than one of said plurality of GPS signal receivers; and said ground station integrity monitoring means includes, discriminator means operative for determining, for each of said receiver-satellite-specific GPS differential correction values, a receiver-satellite-specific integrity discriminant value as a selected function of corresponding ones of said satellite-specific statistical GPS differential correction values and said receiver-satellite-specific differential correction values associated with the same satellite-specific information signal and corresponding one of said plurality of GPS signal receivers, a statistical value processing means operative for determining a receiver-satellite-specific statistical value associated with each of said receiver-satellite-specific integrity discriminant values, as a function of corresponding ones of said receiver-satellite-specific integrity discriminant values, and which is descriptive of the behavior of said receiver-satellite-specific integrity discriminant values sampled over a selected time period.

Claim 4

The differential satellite positioning system ground station of claim 2 wherein said ground station integrity monitoring means determines said satellite-specific integrity information as a function of said receiver-satellite-specific statistical integrity discriminant values associated with more than one of said plurality of GPS signal receivers and associated with the same one of said satellite-specific information signals.

Claim 5

The differential satellite positioning system ground station of claim 2 wherein said integrity monitoring means further includes deselecting means for identifying those of said receiver-satellite-specific integrity discriminant values which exceed a selected detection threshold.

Claim 6

The differential satellite positioning system ground station of claim 4 wherein said deselecting monitoring means includes: means for determining a detection threshold value as a function of said receiver-satellite-specific statistical integrity discriminate values; and comparator means for comparing each of said integrity discriminate values with said detection threshold value, and providing an identification of which receive-satellite-specific ones of said receiver-satellite-specific discriminant values exceeds said detection threshold value.

Claim 7

The differential satellite positioning system ground station of claim 1 further comprising means for communicating said satellite-specific differential correction information and corresponding satellite-specific integrity information to a remote differential satellite positioning system user.

Claim 8

The differential satellite positioning system ground station of claim 1 wherein said differential correction processing means includes means for determining said receiver-satellite-specific differential correction values synchronized to a common measurement time and with receiver-specific clock bias removed.

Claim 9

The differential satellite positioning system ground station of claim 5 wherein each of said satellite-specific differential correction values is a function of said receiver-satellite-specific differential correction values excluding those receiver-satellite-specific ones having corresponding receiver-satellite-specific discriminant values which were identified by said comparator means.

Claim 10

A differential satellite positioning system comprising: ground station for determining GPS differential correction information, with integrity monitoring including, a plurality of GPS signal receivers, each at a known geocentric position, each operative for receiving a satellite-specific information signal transmitted from each of selected ones of a plurality of satellite vehicles, and each operative for deriving, from each of said received satellite-specific information signals from said satellite vehicles, receiver-satellite-specific GPS signal information; first differential correction processing means for deriving receiver-satellite-specific GPS differential correction information associated with each of said satellite-specific information signals, where said receiver-satellite specific differential correction information is a function of said receiver-satellite-specific GPS signal information determined by a specific one of said GPS signal receivers and said known position of said GPS signal receivers for the same one of said GPS signal receivers; second differential correction processing means operative for determining satellite-specific GPS differential correction information, associated with each of said satellite-specific information signals, as a function of said receiver-satellite-specific GPS differential correction information determined by more than one of said plurality of GPS signal receivers and associated with the same one of said satellite-specific information signals; ground station integrity monitoring means for determining satellite-specific integrity information associated with each of said satellite-specific information signals, as a function of said receiver-satellite-specific GPS differential correction information and said satellite-specific GPS differential correction information, where said satellite-specific integrity information is descriptive of the integrity of said satellite-specific GPS differential correction information means for transmitting said satellite-specific differential correction information and said satellite-specific integrity information to a remote differential satellite positioning system; and a remote differential satellite positioning system including, means for receiving said satellite-specific differential correction information and said satellite-specific integrity information, GPS signal receiver operative for (i) receiving a satellite-specific information signal transmitted from each of selected ones of a plurality of satellite vehicles, and operative for deriving from each of said satellite-specific information signals from said satellite vehicles user-satellite-specific GPS signal information,(ii) deriving the user-position of said remote GPS signal receiver as a function of said user-satellite-specific GPS signal information corrected by said satellite-specific GPS differential correction information, and (iii) determining a position solution matrix representative of the line of sight vectors between the derived user-position and each of said satellite vehicles, and integrity monitoring means for determining the integrity of said user position as a function of said position solution matrix and said satellite-specific integrity information.

Claim 11

A differential satellite positioning system comprising: ground station for determining GPS differential correction information, with integrity monitoring including, a plurality of GPS signal receivers, each at a known geocentric position, each operative for receiving a satellite-specific information signal transmitted from each of selected ones of a plurality of satellite vehicles, and each operative for deriving, from each of said received satellite-specific information signals from said satellite vehicles, receiver-satellite-specific GPS signal information; first differential correction processing means for deriving receiver-satellite-specific GPS differential correction information associated with each of said satellite-specific information signals, where said receiver-satellite specific differential correction information is a function of said receiver-satellite-specific GPS signal information determined by a specific one of said GPS signal receivers and said known position of said GPS signal receivers for the same one of said GPS signal receivers; second differential correction processing means operative for determining satellite-specific GPS differential correction information, associated with each of said satellite-specific information signals, as a function of said receiver-satellite-specific GPS differential correction information determined by more than one of said plurality of GPS signal receivers and associated with the same one of said satellite-specific information signals; ground station integrity monitoring means for determining satellite-specific integrity information associated with each of said satellite-specific information signals, as a function of said receiver-satellite-specific GPS differential correction information and said satellite-specific GPS differential correction information, where said satellite-specific integrity information is descriptive of the integrity of said satellite-specific GPS differential correction information means for transmitting said satellite-specific differential correction information and said satellite-specific integrity information to a remote differential satellite positioning system; and a remote differential satellite positioning system including, means for receiving said satellite-specific differential correction information and said satellite-specific integrity information, GPS signal receiver operative for (i) receiving a satellite-specific information signal transmitted from each of selected ones of a plurality of satellite vehicles, and operative for deriving from each of said satellite-specific information signals from said satellite vehicles user-satellite-specific GPS signal information,(ii) deriving the user-position of said remote GPS signal receiver as a function of said user-satellite-specific GPS signal information corrected by said satellite-specific GPS differential correction information, and (iii) determining a position solution matrix representative of the line of sight vectors between the derived user-position and each of said satellite vehicles, and integrity monitoring means for determining the integrity of said user position as a function of said position solution matrix and said satellite-specific integrity information.

Claim 12

A differential satellite positioning system ground station for determining satellite-specific GPS differential correction information with corresponding satellite-specific integrity information, said differential satellite positioning system ground station comprising: a plurality of GPS signal receivers, each at a known geocentric position, each operative for receiving a satellite-specific information signal transmitted from each of selected ones of a plurality of satellite vehicles, and each operative for deriving, from each of said received satellite-specific information signals from said satellite vehicles, receiver-satellite-specific GPS signal information; differential correction processing means for separately deriving a receiver-satellite-specific GPS differential correction value for each GPS signal receiver, and associated with each of said satellite-specific information signals, as a function of said receiver-satellite-specific GPS signal information determined by each of said plurality of GPS signal receivers; means for determining a satellite-specific GPS differential correction value, associated with each of said satellite-specific information signals, as an averaging function of said receiver-satellite-specific GPS differential correction values determined by more than one of said plurality of GPS signal receivers and associated with the same one of said satellite-specific information signals; discriminator means for determining a receiver-satellite-specific discriminant value associated with each satellite-specific information signal and specific one of said GPS signal receivers, where each receiver-satellite-specific discriminant value is a function of the difference between corresponding ones of said receiver-satellite-specific GPS differential correction value and said satellite-specific GPS differential correction value associated with the same one of said satellite-specific information signals and specific one of said GPS signal receivers statistical value processing means for determining a receiver-satellite-specific statistical value descriptive of the corresponding behavior of each of said receiver-satellite-specific discriminant values detection threshold processing means operative for calculating at least a satellite-specific detection threshold value as a function of a selected false detection probability and corresponding receiver-satellite-specific statistical value; and ground station integrity monitoring means for determining satellite-specific integrity information, associated with each of said satellite-specific information signals and corresponding satellite-specific GPS differential correction values, as a function of said receiver-satellite-specific statistical value, said satellite-specific detection threshold value, and the number of operating GPS signal receivers.

Claim 13

A differential satellite positioning system ground station for determining satellite-specific GPS differential correction information with corresponding satellite-specific integrity information, said differential satellite positioning system ground station comprising: a plurality of GPS signal receivers, each at a known geocentric position, each operative for receiving a satellite-specific information signal transmitted from each of selected ones of a plurality of satellite vehicles, and each operative for deriving, from each of said received satellite-specific information signals from said satellite vehicles, receiver-satellite-specific GPS signal information; differential correction processing means for separately deriving a receiver-satellite-specific GPS differential correction value for each GPS signal receiver, and associated with each of said satellite-specific information signals, as a function of said receiver-satellite-specific GPS signal information determined by each of said plurality of GPS signal receivers; means for determining a satellite-specific GPS differential correction value, associated with each of said satellite-specific information signals, as an averaging function of said receiver-satellite-specific GPS differential correction values determined by more than one of said plurality of GPS signal receivers and associated with the same one of said satellite-specific information signals; discriminator means for determining a receiver-satellite-specific discriminant value associated with each satellite-specific information signal and specific one of said GPS signal receivers, where each receiver-satellite-specific discriminant value is a function of the difference between corresponding ones of said receiver-satellite-specific GPS differential correction value and said satellite-specific GPS differential correction value associated with the same one of said satellite-specific information signals and specific one of said GPS signal receivers statistical value processing means for determining a receiver-satellite-specific statistical value descriptive of the corresponding behavior of each of said receiver-satellite-specific discriminant values detection threshold processing means operative for calculating at least a satellite-specific detection threshold value as a function of a selected false detection probability and corresponding receiver-satellite-specific statistical value; and ground station integrity monitoring means for determining satellite-specific integrity information, associated with each of said satellite-specific information signals and corresponding satellite-specific GPS differential correction values, as a function of said receiver-satellite-specific statistical value, said satellite-specific detection threshold value, and the number of operating GPS signal receivers.

Claim 14

The differential satellite positioning system ground station of claim 10 where said receiver-satellite-specific statistical value is descriptive of the behavior of said receiver-satellite-specific integrity discriminant values sampled over a selected time period.

Claim 15

A differential satellite positioning system ground station for determining GPS differential correction information with integrity monitoring, said differential satellite positioning system ground station comprising: a plurality of GPS signal receivers, each at a known geocentric position, each operative for receiving a satellite-specific information signal transmitted from each of selected ones of a plurality of satellite vehicles, and each operative for deriving from each of said received satellite-specific information signals from said satellite vehicles receiver-satellite-specific GPS signal information; differential correction processing means for determining a receiver-satellite-specific differential correction value associated with each of said selected satellite information signals; averaging means for determining a satellite-specific average value of said receiver-satellite-specific differential correction values associated with a mutually exclusive one of said satellite information signals; discriminator means responsive to receiver-satellite-specific differential correction values and said satellite-specific differential correction average values for determining a receiver-satellite-specific discriminant value; means for determining a statistical value representative of the behavior of said discriminant values; and integrity monitoring means responsive to said discriminant values and said statistical values for deriving selected integrity information as one or more selected functions thereof.

Claim 16

A differential satellite positioning system ground station for determining GPS differential correction information with integrity monitoring, said differential satellite positioning system ground station comprising: a plurality of GPS signal receivers, each at a known geocentric position, each operative for receiving a satellite-specific information signal transmitted from each of selected ones of a plurality of satellite vehicles, and each operative for deriving from each of said received satellite-specific information signals from said satellite vehicles receiver-satellite-specific GPS signal information; differential correction processing means for determining a receiver-satellite-specific differential correction value associated with each of said selected satellite information signals; averaging means for determining a satellite-specific average value of said receiver-satellite-specific differential correction values associated with a mutually exclusive one of said satellite information signals; discriminator means responsive to receiver-satellite-specific differential correction values and said satellite-specific differential correction average values for determining a receiver-satellite-specific discriminant value; means for determining a statistical value representative of the behavior of said discriminant values; and integrity monitoring means responsive to said discriminant values and said statistical values for deriving selected integrity information as one or more selected functions thereof.