Patent ID: 11953325
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 4:
5. The direction calculation apparatus according to claim 4, wherein
the first instructed force sensation vector is defined as fdc=|fdc|[cos θd, sin θd]T, and θd is an angle formed by a vector [1, 0]T and the first instructed force sensation vector,
the calculating the second instructed force sensation vector further comprises calculating, from the bias and the first azimuth angle θb′, an azimuth angle θb, wherein the azimuth angle θb indicates an azimuth of the force sensation presentation device, and the azimuth takes into account an influence of geomagnetic distortion in the reference coordinate system at the current position, and
the calculating the second instructed force sensation vector further comprises calculating the second instructed force sensation vector fd,b′ by Math. 10:

fd′b′=|fdc|[cos(θd′−θb′), sin(θd′−θb′)]T 

θd′=θd+(θb′−θb)  [Math. 10]