GPS reception apparatus and positional calculation method for the same

摘要

A reception apparatus includes a first determination unit to determine whether a state exists in which timing information and six orbital elements information can be obtained from GPS signals transmitted by only two GPS satellites. When the state exists, a calculation unit calculates a trajectory line having a predetermined width on a surface of the earth, based on the GPS signals transmitted by the two satellites. A second determination unit determines whether the trajectory line traverses a district of use stored by the apparatus. A time correcting unit obtains a current time using the obtained timing information, by correcting the timing information based on a time zone corresponding to the district of use, when the trajectory line traverses the district of use. The time correcting unit does not obtain the current time using the obtained timing information when the trajectory line does not traverse the district of use.

主权项

1. A reception apparatus comprising:
a storage unit configured to store a set district of use of the reception apparatus; a reception unit configured to receive global positioning system signals transmitted by a plurality of satellites; a first determination unit configured to determine whether or not a state of reception by the reception unit is a predetermined reception state in which the reception unit obtains timing information and six orbital elements information from the global positioning system signals transmitted by only two of the satellites; a calculation unit configured to calculate trajectory line having a predetermined width on a surface of the earth, based on the global positioning system signals transmitted by the two satellites when the first determination unit determines that the state of reception by the reception unit is the predetermined reception state; a second determination unit configured to determine whether or not the trajectory line calculated by the calculation unit traverses the district of use stored in the storage unit; and a time correcting unit configured to (i) obtain a current time using the timing information obtained by the reception unit, by correcting the timing information based on a time zone corresponding to the district of use, when the second determination unit determines that the trajectory line traverses the district of use, and (ii) not obtain the current time using the timing information obtained by the reception unit, when the second determination unit determines that the trajectory line does not traverse the district of use.