Method and system for calibrating wireless location system

An antenna and receiver technology, applied in the field of calibration wireless positioning systems and systems, can solve the problems of consuming system capacity, calibration variation, TDOA calibration variation, etc.

Inactive Publication Date: 2007-10-17
HARRIS CORP
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

If a long time elapses between calibration and subsequent TDOA and / or FDOA measurements, the calibration may be degraded by oscillator bias or changes in the receiver due to temperature-induced drift in element parameters
Although reducing the time interval between reference transmissions improves corrections, this further consumes additional system capacity
Another disadvantage is that during the calibration process, i.e. when measuring the TOA / TDOA of a reference transmission, multipath-introduced errors in the time-of-arrival measurement by the receiver degrade the TDOA correction, since it is assumed that the TDOA correction from the reference transmitter to each The receiver is a straight line propagation

Method used

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  • Method and system for calibrating wireless location system
  • Method and system for calibrating wireless location system
  • Method and system for calibrating wireless location system

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[0031] The present invention will be described in more detail below with reference to the accompanying drawings showing preferred embodiments of the invention. However, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The same reference numerals denote the same parts in the drawings.

[0032]The present invention is advantageous and allows the use of one receiver at one receiving location to determine the position of a mobile transmitting unit, eg a transmitting tag for a vehicle or person carrying a tag, a mobile transceiver or other mobile unit. The system uses a proxy receiver (or passive reflector) for time of arrival and / or time difference of arrival calculations. Throughout the text, the term "proxy receiver" is used fo...

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Abstract

This invention relates to a method for calibrating a wireless location system (WLS) to enable the system to make highly accurate differential measurements such as time difference of arrival (TDOA) and frequency difference of arrival (FDOA). Calibration is accomplished by transmitting a signal from an unknown location and measuring at each of two receivers the parameter to be calibrated from that part of the received signal reflected or refracted from an object at a known location in the area. A differential measurement error is determined by comparing the expected difference in the parameter measurements with the actual difference in the parameter measurements. The expected difference is known, a priori, based on the locations of the receivers and the location of the object.

Description

technical field [0001] The present invention relates to a method and system for calibrating a Wireless Location System (WLS) such that the system makes high precision differential measurements such as Time Difference of Arrival (TDOA) and Frequency Difference of Arrival (FDOA). Background technique [0002] Wireless location systems are becoming more and more important. An example is disclosed in US Patent 5,719,584, commonly assigned to Otto, the entire disclosure of which is hereby incorporated by reference. Many Wireless Location Systems use time difference of arrival (TDOA) calculations to determine a set of possible locations for a signal's transmitter. The position is determined arithmetically from the known positions of the two receivers as a two-dimensional hyperbola and a three-dimensional hyperbola, and the measured time-of-arrival (TOA) of the signal at the two receivers is different. These systems use various methods to measure TOA at a receiver. However, all ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01S3/02G01S5/06G01S5/02G01S19/11
CPCG01S5/02G01S5/0252G01S5/021G01S5/0273
Inventor 布赖恩·霍尔特
Owner HARRIS CORP
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