Communications: directive radio wave systems and devices (e.g. – Determining distance – With pulse modulation
Patent
1986-02-25
1988-03-01
Tubbesing, T. H.
Communications: directive radio wave systems and devices (e.g.,
Determining distance
With pulse modulation
342 42, G01S 1374
Patent
active
047289554
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method for determining a mutual position between two objects, and apparatus herefor.
A need for measuring the mutual positions between two objects is to be found in a number of industrial applications and other forms of application, such as the relative positions of a movable and a stationary object. One applicable example is that of a robot adapted to seek automatically an object in order to carry out work thereon. If the position of the robot relative to the object is unknown, it is necessary to use a position meter in order to first determine the position of the robot in relation to the object. Another example is that of determining the position of equipment, such as machines, in relation to the surroundings, for example different ground reference points.
The present invention is particularly suitable for determining the mutual positions of two objects in relation to one another in those cases where a first object is intended to seek a second object. It will be understood, however, that the present invention can be applied on all occasions where there is a need of determining the relative positions of two objects.
The present invention relates to a method for determining a mutual position between two objects, which comprises transmitting a microwave signal from the first object to the second object; causing the second object to receive the signal and to re-transmit a signal which is received by the first object, and which method is characterized in that the first object incorporates a transmitter/receiver which is caused to transmit said signal from a transmitter antenna at a frequency f.sub.o ; in that the second object is caused to re-transmit said signal modulated with a signal f.sub.m ; in that the first object is caused to receive the re-transmitted signal on at least two antennae placed symmetrically on a respective side of the transmitter antenna in an antenna-plane common with said transmitter antenna; and in that the angle between said antenna-plane and said second object in at least one dimension, namely in a first plane passing through the transmitter antenna and the two receiver antennae, is determined by respectively a phase comparison and an amplitude comparison of received signals, depending upon whether the second object is located in the so-called proximity zone of the first object or not, i.e. located at a distance which is shorter, or not, than a distance of the same order of magnitude as the distance d between said two receiver antennae, wherein when the second object is located outside said proximity zone said angle is determined by a phase comparison between the signal received by respective antennae subsequent to being mixed with the transmitter signal f.sub.o, where the phase difference between the signals is determined; and in that said angle is determined with the aid of a computer device associated with the transmitter/receiver unit from the relationship ##EQU1## where c is the speed of light and d is the distance between the two receiver antennae.
The invention also relates to apparatus of the kind set forth in claim 6 and having the fundamental characteristics disclosed therein.
It is possible when using the method and apparatus according to the invention to determine the direction in which a reference point lies in relation to a transmitter/receiver unit, referred to as the S/M-unit. The reference point is a transponder T.
The values are determined in accordance with the invention with the use of microwaves. By using microwaves instead of optical systems, for example, there is obtained a system which will not be influenced by a troublesome environment, such as an environment which incorporates dust, dirt, light-reflections etc. This has an important significance in industrial applications.
A particular problem arises when the transponder lies close to the S/M-unit, or more precisely within the so-called proximity zone of the S/M-unit.
This problem is resolved in that the S/M-unit switches from a mode in which the difference in phase betwee
REFERENCES:
patent: 4151525 (1979-04-01), Strauch et al.
patent: 4333078 (1982-06-01), Henoch et al.
Gregory Bernarr Earl
Stiftelsen Institutet for Mikrovagsteknik vid Tekniska Hogskolan
Tubbesing T. H.
LandOfFree
Method for position-finding and apparatus herefor 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 position-finding and apparatus herefor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for position-finding and apparatus herefor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1001109