| 摘要 |
The present invention relates to a method and apparatus for tracking position of an object in a multipath environment (for example, inside a building) using radio signals. In order to provide an accurate Time of Arrival (TOA) estimate in a multipath environment, a wide bandwidth signal (providing a sharp rise time pulse) is required. Only a limited bandwidth is available in the radio spectrum, however. Further, installations for position tracking which generate wide bandwidth signals require expensive and complex radios. In the present invention, a number of narrow bandwidth signals are generated by a transmitter and combined together at a receiver to provide an effective wideband position location signal. Only relatively narrow bandwidth signals have to be transmitted, therefore, but accurate position can still be determined. Further, transmission of narrow bandwidth signals enables the use of relatively inexpensive radio transmitters.
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