Communications: directive radio wave systems and devices (e.g. – Determining distance
Reexamination Certificate
2003-06-26
2004-11-09
Sotomayor, John B. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Determining distance
C346S127000, C346S135100
Reexamination Certificate
active
06816108
ABSTRACT:
PRIOR ART
Some technical measuring tasks yield several phase measurement values; the quantity to be measured, e.g. an angle or a distance to a target, must be determined from among these phase measurement values.
Examples of this include:
Distance measurement with RADAR or with modulated laser light. N measurements are carried out with different frequencies f
1
. . . f
N
. At the reception point, the signals reflected by the target at a distance of x have the following phase shifts (c=the speed of light):
α
i
=
2
·
π
·
f
i
·
2
·
x
c
The phase shifts are thus proportional to the quantity to be measured and to the frequency used. However, the actual measurement values of the phases always lie in the range from 0 to 2&pgr;, i.e. they are always determined only up to integral multiples of 2&pgr;.
Optical angle transmitter: scanning of N optical ruled gratings. N traces are placed on a disk or a cylinder with optical ruled gratings. In one rotation, there are therefore n
i
periods or marks. If the phase positions of the traces are measured with the aid of optoelectronic detectors in relation to a fixed measurement window, then this yields the phase positions:
&agr;=
n
i
·&phgr;
The phases are thus proportional to the torsion angle &phgr; and the periodicities n
i
. Here, too, the actual measurement values always lie in the range from 0 to 2&pgr;.
The following methods are known for evaluating these signals, i.e. for determining x and &phgr;:
Classic Vernier Method:
The difference between 2 measurement angles is calculated; if it is less than 0, then 2&pgr; is added. This method has serious limitations: measurement errors in the angles have a significant impact on the end result; in addition, the method only works if the two periodicities being considered differ by precisely 1.
Modified Vernier Method (See DE P 19506938):
From 2 measurement angles, the value of the quantity to be measured is determined through weighted addition and the further addition of an angular range-dependent constant. The advantage therein is that measurement errors in the angles are reduced by a factor of <1.
Cascaded, Modified Vernier Method:
The modified vernier method is used multiply for a number of traces in a hierarchical arrangement.
OBJECT OF THE INVENTION
The object of the invention is to obtain an optimal, unambiguous phase measurement value from N multivalued, distorted phase signals &agr;
i
, wherein the disadvantages of the known methods are circumvented.
Possible uses include tasks in which a high-precision, robust measurement value must be determined from among a number of phase signals, e.g.:
multi-frequency distance measurement
angle measurement
combined angle- and torque measurement
using RADAR, laser, optical, magnetic, or other sensor principles.
ADVANTAGES OF THE INVENTION
The invention permits direct, optimal, non-hierarchical evaluation of N phase signals.
In contrast with the known methods, virtually any periodicity n
i
can be used. Measurement errors in the individual phase signals are clearly reduced. The inclusion of a number of phase traces can achieve a distinctly increased tolerance with regard to measurement errors.
In particular, the invention is suited to optimally evaluating the signals of an optical TAS (torque angle sensor).
REFERENCES:
patent: 5198822 (1993-03-01), Brown
patent: 5237333 (1993-08-01), Guard
patent: 6489917 (2002-12-01), Geisheimer et al.
patent: 6665335 (2003-12-01), Rajagopal et al.
patent: 2002/0097180 (2002-07-01), Geisheimer et al.
patent: 2004/0007663 (2004-01-01), Steinlechner et al.
patent: 2004/0010928 (2004-01-01), Steinlechner et al.
patent: 2004/0080451 (2004-04-01), Steinlechner et al.
patent: 195 06 938 (1996-08-01), None
patent: 0 693 693 (1996-01-01), None
“Block-coded PSK modulation using two-level group codes over dihedral groups”, Bali, J.;Rajan, B.S.;Information Theory, IEEE Transactions on, vol.: 44, Issue: 4, Jul. 1998 Ps: 1620-1631.
Steinlechner Siegbert
Wenzler Axel
Robert & Bosch GmbH
Sotomayor John B.
Striker Michael J.
LandOfFree
Method for determining a rotational angle or a distance by... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for determining a rotational angle or a distance by..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for determining a rotational angle or a distance by... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3317188