Patent Document ID: 20140139371
Application ID: 14125375
Patent Flag: 0

Claim One:
1. A method for improving a positioning quality of a global navigation satellite system navigation receiver operating in a differential navigation mode, wherein for each epoch in a plurality of epochs, the global navigation satellite system receiver transmits primary estimates of coordinates and an accuracy estimate, the method comprising the steps of: at the first epoch in the plurality of epochs: receiving the first-epoch primary estimates of coordinates; receiving the first-epoch accuracy estimate; generating first-epoch smoothed estimates of coordinates equal to the first-epoch primary estimates of coordinates; and generating a first-epoch value of threshold accuracy equal to the first-epoch accuracy estimate; and for each current epoch after the first epoch in the plurality of epochs: receiving smoothed estimates of coordinates calculated at the epoch before the current epoch; receiving a value of threshold accuracy calculated at the epoch before the current epoch; receiving the current-epoch primary estimates of coordinates; receiving the current-epoch accuracy estimate; calculating, based at least in part on carrier phases of satellite signals received by the global navigation satellite system navigation receiver, coordinate increments between coordinates at the current epoch and coordinates at the epoch before the current epoch; generating current-epoch extended estimates of coordinates based on a sum of the smoothed estimates of coordinates calculated at the epoch before the current epoch and the coordinate increments; generating a current-epoch value of threshold accuracy equal to the value of threshold accuracy calculated at the epoch before the current epoch; comparing the current-epoch accuracy estimate to the current-epoch value of threshold accuracy; upon determining that the current-epoch accuracy estimate is greater than or equal to the current-epoch value of threshold accuracy: generating current-epoch smoothed estimates of coordinates equal to the current-epoch extended estimates of coordinates; and generating an updated value of threshold accuracy based on a sum of the current-epoch value of threshold accuracy and a product of a degradation rate multiplied by an epoch duration; and upon determining that the current-epoch accuracy estimate is less than the current-epoch value of threshold accuracy: generating an error signal based on a difference between the current-epoch primary estimates of coordinates and the current-epoch extended estimates of coordinates; functionally transforming the error signal into a correction signal; generating current-epoch smoothed coordinates based on a sum of the current-epoch extended estimates of coordinates and the correction signal; and generating an updated value of threshold accuracy equal to the current-epoch accuracy estimate.