Positioning system
AssigneeAlps Alpine Co., Ltd.
InventorsTaiki Igarashi, Daisuke Takai
Life of this patent
Estimating the term…
Abstract
A positioning system includes an elevation angle calculator that determines, as a second elevation angle, an inverse cosine of a first value, upon occurrence of a condition in which an absolute value of a first elevation angle is greater than or equal to a second predetermined angle, the second predetermined angle being greater than a first predetermined angle, the first value being obtained by dividing a second value that is obtained by correcting, with a correction value, an altitude measured by an altitude measurement unit, by a distance measured by a distance measurement unit. The elevation angle calculator selects any one of the first elevation angle and the second elevation angle, based on a value of the first elevation angle.
Claims7
A positioning system comprising:
- a first communication unit;
- an aircraft movable with respect to the first communication unit;
- a second communication unit provided on the aircraft and configured to communicate with the first communication unit;
- an altitude measurement unit provided on the aircraft and configured to measure an altitude of the aircraft with respect to the first communication unit;
- a distance measurement unit configured to measure a distance between the first communication unit and the aircraft, based on a propagation time or a phase of at least one signal that is communicated between the first communication unit and the second communication unit;
- an elevation angle calculator configured to determine a first elevation angle of the aircraft with respect to the first communication unit, based on phases that are obtained in a case where signals communicated between the first communication unit and the second communication unit are received by multiple antenna elements of either the first communication unit or the second communication unit;
- and
- a correction calculator configured to determine, as a correction value, a difference between the altitude measured by the altitude measurement unit and the distance measured by the distance measurement unit, upon occurrence of a condition in which an absolute value of the first elevation angle is a first predetermined angle or smaller,
- wherein after the correction calculator determines the correction value,
- the elevation angle calculator is configured to
- determine, as a second elevation angle, an inverse cosine of a first value, upon occurrence of a condition in which the absolute value of the first elevation angle is greater than or equal to a second predetermined angle, the second predetermined angle being greater than the first predetermined angle, the first value being obtained by dividing a second value that is obtained by correcting, with the correction value, the altitude measured by the altitude measurement unit, by the distance measured by the distance measurement unit, and
- select any one of the first elevation angle and the second elevation angle, based on a value of the first elevation angle.
Dependencies are inferred from the claim text.