发明授权
- 专利标题: Position sensing system
- 专利标题(中): 位置传感系统
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申请号: US09475312申请日: 1999-12-30
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公开(公告)号: US06261247B1公开(公告)日: 2001-07-17
- 发明人: Akira Ishikawa , Nabuo Takeda , Suzanne I. Ahn , Samuel S. Ahn , Steven R. Hays , F. Andrew Gaffney
- 申请人: Akira Ishikawa , Nabuo Takeda , Suzanne I. Ahn , Samuel S. Ahn , Steven R. Hays , F. Andrew Gaffney
- 主分类号: A61B5103
- IPC分类号: A61B5103
摘要:
An anatomical position sensing system (100) using one or more substantially spherical transponders for measuring relative positions and distances. Transponders (P) and (S) are capable of receiving and transmitting RF signals, and communicating between themselves and with a separate CPU (112). The CPU (112) is controlled by an operator at an operator control panel (114), interacts with an alarm (120) for providing audible alerts to the operator, and a display for displaying information to the operator. The CPU (112) controls a broadband antenna (118) to transmit, at a frequency f1, a low-frequency RF power signal (122) across a wide field to energize the transponders (P) and (S). Directional components (122a) and (122b) intercept and energize the transponders (P) and (S). Once energized, transponder (P) transmits a range signal in all directions including component (124) at a very high RF frequency f2, extending from transponder (P) to transponder (S). Upon receipt of the range signal (124), transponder (S) emits a data signal at a very high RF frequency f3 in all directions, including component (126), which is directed at the antenna (118). The distance (D) is determined by measuring the attenuation of the range signal (124) as it is received by transponder (S). Transponder (S) then modulates the value of the strength of the incoming range signal (124) onto the data signal. The CPU (112) computes the distance (D) from the incoming data signal (126) from a lookup table derived from a sequence of calibration steps prior to beginning normal operation.