Data processing: measuring – calibrating – or testing – Measurement system – Dimensional determination
Reexamination Certificate
1999-03-26
2002-09-03
Hoff, Marc S. (Department: 2852)
Data processing: measuring, calibrating, or testing
Measurement system
Dimensional determination
C342S378000, C455S561000
Reexamination Certificate
active
06446025
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a multiple propagation wave parameter measuring method and apparatus for measuring various parameters of a multiple propagation wave, and a machine-readable recording medium recording a multiple propagation wave parameter measuring program and, more particularly, to a multiple propagation wave parameter measuring method and apparatus for measuring as parameters an arrival direction of a transmission wave radiated from a transmitting means and a change in delay time of the transmission wave from the transmitting means to a receiving means, and a machine-readable recording medium recording a multiple propagation wave parameter measuring program.
FIG. 10
shows the arrangement of a conventional multiple propagation wave parameter measuring apparatus. The multiple propagation wave parameter measuring apparatus shown in
FIG. 10
comprises a transmitting device
101
for radiating transmission waves
104
in air and a receiving device
102
for receiving the transmission waves
104
and measuring various parameters.
When the transmission waves
104
are radiated from the transmitting device
101
, the receiving device
102
directly receives some of the transmission waves
104
. Reflecting members
103
(e.g., buildings) having the function of reflecting an electric wave reflect some of the transmission waves
104
, and the receiving device
102
receives the reflected transmission waves. As described above, the transmission waves
104
arrive at the receiving device
102
via various routes. Therefore, the receiving device
102
receives them as a multiple propagation wave.
The receiving device
102
measures the arrival directions of the transmission waves
104
and their delay times from the transmitting device
101
to the receiving device
102
as follows.
An evaluation function is generated to estimate the arrival directions and delay times. This evaluation function is a function of an angle (arrival direction) and time (delay time).
The angular range of 0 to &THgr; and the time range of 0 to t in the evaluation function are calculated at intervals of &Dgr;&THgr; and &Dgr;t, respectively. The peaks of the calculation values are found to estimate the arrival directions and delay times.
The delay times of two signals received at different timings are estimated by the above method, and the difference between the delay times is calculated to obtain a change in delay time.
To measure the change in delay time with high precision, a sync signal free from an influence of noise or the like must be used. For this purpose, in the multiple propagation wave parameter measuring apparatus shown in
FIG. 10
, to supply a sync signal from the transmitting device
101
to the receiving device
102
via a cable
105
, the cable
105
connects the transmitting and receiving devices
101
and
102
.
In the conventional multiple propagation wave parameter measuring apparatus shown in
FIG. 10
, a two-dimensional search is performed to estimate the two parameters, i.e., “arrival direction” and “change in delay time”. This method, however, is time-consuming in signal processing, and a measurement result cannot be immediately obtained.
In the conventional multiple propagation wave parameter measuring apparatus, the cable
105
connects the transmitting and receiving devices
101
and
102
. For this reason, the conventional multiple propagation wave parameter measuring apparatus is not suitable for measuring a change in delay time by moving the transmitting device
101
outdoors.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the conventional problems described above, and has as its object to shorten the measurement time for two parameters, i.e., “arrival direction” and “change in delay time”.
It is another object of the present invention to allow measuring a change in delay time by moving at least one of transmitting and receiving sides.
In order to achieve the above objects of the present invention, there is provided a multiple propagation wave parameter measuring method comprising the steps of radiating transmission waves from transmitting means into an outer space, receiving the transmission waves by receiving means as a multiple propagation wave, measuring arrival directions of the transmission waves on the basis of reception signals output from the receiving means, defining the transmission wave arriving from one direction of the measured arrival directions as a desired wave and the transmission waves arriving from remaining directions as unnecessary waves, calculating a weight with which a reception power ratio of the desired wave to the unnecessary waves becomes maximum, and multiplying the reception signals with the weight to extract the reception signal in which the unnecessary waves are suppressed, and measuring a change in delay time of the desired wave from the transmitting means to the receiving means on the basis of the reception signal in which the unnecessary waves are suppressed.
REFERENCES:
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patent: 3983559 (1976-09-01), Honore et al.
patent: 4028703 (1977-06-01), Honore et al.
patent: 4750147 (1988-06-01), Roy, III et al.
patent: 5343404 (1994-08-01), Girgis
patent: 5381444 (1995-01-01), Tajima
patent: 5694474 (1997-12-01), Ngo et al.
patent: 6006110 (1999-12-01), Raleigh
patent: 6043235 (1994-02-01), None
Fukawa Kazuhiko
Kuwahara Yoshihiko
Matsumoto Tadashi
Nakamura Yuki
Charioui Mohamed
Dickstein Shapiro Morin & Oshinsky LLP.
Hoff Marc S.
NEC Corporation
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