Communications: directive radio wave systems and devices (e.g. – Determining velocity – Combined with determining distance
Patent
1987-07-21
1989-07-25
Tarcza, Thomas H.
Communications: directive radio wave systems and devices (e.g.,
Determining velocity
Combined with determining distance
342125, 342127, G01S 1350, G01S 1384
Patent
active
048518514
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method of measuring the distance and/or the relative velocity between two objects. More specifically, although not exclusively, the invention relates to the measurement of the distance and/or the relative velocity between a first object and a second object, of which the first object incorporates a transmitter-receiver unit and the second object incorporates a transponder. The transmitter-receiver unit is constructed to transmit a signal to the transponder and to receive a signal emanating therefrom.
The invention relates specifically to the measurement of distance and/or velocity by making a phase comparison in the transmitter-receiver unit between the signal transmitted to the transponder and the signal received therefrom.
The concept of the phase difference method in distance measuring processes is well known per se and can be applied with various types of transmitter-receiver apparatus and transponders or reflectors.
When practising the present invention there is preferably used the method and apparatus for creating phase differences described, and illustrated in the Swedish patent specification No. . . . (corresponding to Swedish patent application No. 8505888-1), although it will be understood that the present invention is not at all dependent on the use of this described and illustrated method and apparatus.
Since a phase difference can only be determined within the range 0-2.pi., the greatest unambiguous distance R for a given transmitted frequency F1 is
The present invention particularly recommends the use of microwave frequencies. R.sub.max is only 6 cms when using the frequency 2500 MHz.
Another problem associated with measuring methods that rely on phase-differences resides in the difficulties which occur when the two objects move in relation to one another, since the phase relationships then change with time.
It is often necessary at times, however, to measure distances under dynamic conditions.
It is also desirable, in many contexts, to be able to determine the location of an object, e.g. a motor vehicle, within a restricted area with a high degree of accuracy, inter alia so as to be able to navigate the vehicle within this area. One common method of determining the position of an object in relation to a reference system is to measure the distance between the object and a number of reference points in the system. The position of the object can be readily calculated from these measured distances, with the aid of trigonometrical functions. The accuracy to which the position of the object is determined is directly proportional to the accuracy to which the distance(s) is (are) measured.
These drawbacks and problems are not found with the method according to the invention, which enables distances to be determined very accurately, even under dynamic conditions, and with which both the distance and the prevailing velocity between the objects can be measured.
Thus, the present invention relates to a method for measuring the distance between two objects and/or the speed at which they move relative to one another, said two objects incorporating respectively a transmitter-receiver unit and a transponder or reflector, in which method a phase comparison is made between a signal transmitted by the transmitter-receiver unit and a signal received thereby from the transponder or reflector, the method being characterized by transmitting from the transmitter-receiver unit signals of microwave frequency, preferably a microwave frequency of about 2450 MHz; transmitting a first signal having a first frequency; transmitting a second signal of higher or lower frequency; transmitting a third signal of the same frequency as the frequency of the first signal; and forming the phase differences .phi. between the transmitted signals, these phase differences corresponding to the distance between the transmitter-receiver unit and the transponder.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail with reference to various diagrams shown on the accompanyi
REFERENCES:
patent: 2907999 (1959-10-01), Wadley
patent: 3315257 (1967-04-01), Sauberlich
patent: 3514777 (1970-05-01), Woerrlein
patent: 3659293 (1972-04-01), Gupta
patent: 3697985 (1972-10-01), Faris et al.
patent: 3715753 (1973-02-01), Applebaum et al.
patent: 3750172 (1973-07-01), Tresselt
patent: 3766554 (1973-10-01), Tresselt
patent: 3854133 (1974-12-01), Cabion
patent: 3898655 (1975-08-01), Tresselt
patent: 3913106 (1975-10-01), Sato
patent: 4101888 (1978-07-01), Heller et al.
patent: 4307397 (1981-12-01), Holscher
patent: 4388622 (1983-06-01), Fletcher, Jr.
patent: 4464662 (1984-08-01), Tomasi
patent: 4577150 (1986-03-01), Schreuder
patent: 4646092 (1987-02-01), Schreuder
The above art, copies attached, were cited in the International Search Report mailed on Feb. 10, 1987.
*NOTE: A U.S. Pat. No. 4,577,150 to Jan Schreuder corresponds to EPA No. 0096558.
Hellner Mark
Stiftelsen Institutet for Mikrovagsteknik Vid Tekniska Hogskolan
Tarcza Thomas H.
LandOfFree
Method for measuring the distance and/or the relative velocity b 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 measuring the distance and/or the relative velocity b, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for measuring the distance and/or the relative velocity b will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2361539