Positioning device, method of controlling positioning device, and recording medium

Abstract

A positioning device includes an estimated height storage section which stores an estimated height H 1 , a signal reception section which receives a satellite signal which is a signal from a satellite positioning system (SPS) satellite, a two-dimensional height calculation section which calculates a two-dimensional height H 2 c by two-dimensional positioning using the estimated height H 1 , a three-dimensional height calculation section which calculates a three-dimensional height H 2 b by preliminary three-dimensional positioning during two-dimensional positioning, a height selection section which selects the two-dimensional height H 2 b or the three-dimensional height H 2 c in order to update the estimated height H 1 , and an updating section which updates the estimated height H 1 with the two-dimensional height H 2 b or the three-dimensional height H 2 c selected by the height selection section.

1 . A method at a positioning device, comprising:
 calculating a first height by two-dimensional positioning based on a satellite signal and an estimated height indicating a distance from a center of the earth;   calculating a second height by three-dimensional positioning based on the satellite signal; and   updating the estimated height by using the first height or the second height.   
     
     
         2 . The method of  claim 1 , further comprising
 determining a positioning environment, wherein   the updating the estimated height updates the estimated height based on the positing environment.   
     
     
         3 . The method of  claim 1 , wherein
 the updating the estimated height updates the estimated height based on a movement state of the positioning device.   
     
     
         4 . The method of  claim 1 , wherein
 the updating the estimated height updates the estimated height based on reliability of the two-dimensional positioning.   
     
     
         5 . The method of  claim 1 , further comprising
 determining whether or not the estimated height satisfies a predetermined update condition including at least the number of updates of the estimated height, wherein   the updating the estimated height updates the estimated height while increasing weight of the estimated height when a difference between the estimated height and the first or second height is within a predetermined allowable range.   
     
     
         6 . The method of  claim 1 , further comprising
 determining whether or not the estimated height satisfies a predetermined update condition including at least the number of updates the estimated height, wherein   the updating the estimated height updates the estimated height while reducing weight of the estimated height when a difference between the estimated height and the first or second height is not within a predetermined allowable range.   
     
     
         7 . The method of  claim 1 , wherein
 the updating the estimated height updates the estimated height based on a difference between the estimated height and the first or second height, and a degree of positioning reliability.   
     
     
         8 . A positioning device, comprising:
 a first height calculator that calculates a first height by two-dimensional positioning based on a satellite signal and an estimated height indicating a distance from a center of the earth;   a second height calculator that calculates a second height by three-dimensional positioning based on the satellite signal; and   an estimated height updater that updates the estimated height by using the first height or the second height.   
     
     
         9 . The positioning device of  claim 8 , further comprising
 an environment determiner that determined a positioning environment, wherein   the estimated height updater updates the estimated height based on the positioning environment.   
     
     
         10 . The positioning device of  claim 8 , wherein
 the estimated height updater updates the estimated height based on a movement state of the positioning device.   
     
     
         11 . The positioning device of  claim 8 , wherein
 the estimated height updater updates the estimated height based on reliability of the two-dimensional positioning.   
     
     
         12 . The positioning device of  claim 8 , further comprising
 an update condition determiner that determines whether the estimated height satisfies a predetermined update condition including at least the number of updates of the estimated height, wherein   the estimated height updater updates the estimated height while increasing weight of the estimated height when a difference between the estimated height and the first or second height is within a predetermined allowable range.   
     
     
         13 . The positioning device of  claim 8 , further comprising
 an update condition determiner that determines whether the estimated height satisfies a predetermined update condition including at least the number of updates of the estimated height, wherein   the estimated height updater updates the estimated height while reducing weight of the estimated height when a difference between the estimated height and the first or second height is not within a predetermined allowable range.   
     
     
         14 . The positioning device of  claim 12 , further comprising
 a weight table storager that storages a weight table including the weight and a weight counter that designates the weight.   
     
     
         15 . The positioning device of  claim 8 , wherein
 the estimated height updater updates the estimated height based on a difference between the estimated height and the first or second height, and a degree of positioning reliability.   
     
     
         16 . The positioning device of  claim 8 , further comprising
 an estimated height storager that stores the estimated height.