Communications: electrical – Continuously variable indicating – With meter reading
Reexamination Certificate
1999-08-02
2004-03-23
Horabik, Michael (Department: 2635)
Communications: electrical
Continuously variable indicating
With meter reading
C340S010200
Reexamination Certificate
active
06710719
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a detection system for determining information concerning the orientation of objects. The invention can be applied to people and animals as well as inanimate objects such as furniture, machines, vehicles, equipment and the like, and in this connection object is intended to include any movable entity.
BACKGROUND OF THE INVENTION
Location systems are known which allow the presence or absence of an object in a specified environment (such as a room) to be confirmed or denied, and relative to one or more reference points, to identify where in the environment the object is located.
EP 0485879 describes a system for locating articles in automatic guidance transport systems. Ultrasound is employed as a distance measuring medium whilst an infra-red link allows connection between vehicles.
WO 95/14241 describes a tracking system which enables a spotlight to follow a person on a stage carrying a transponder. Again infra-red signals are used to instigate ultrasonic transmissions to determine the position of the transponder and therefore the person. The spotlight is moved accordingly.
EP 0591899 describes another spotlight controlling system for tracking a moving target (actor on stage) carrying a transponder. Here the radio transmissions establish the communication link and ultrasound transmissions are employed to determine distance and position.
These systems do not allow the orientation of detected objects to be quickly or easily determined. Furthermore, it may not always be necessary to ascertain the precise positions of an object in an environment, if all that is required is to know which direction one face or part of the object is facing relative to the environment.
It is an object of the present invention to determine the orientation of objects.
THE INVENTION
A system embodying the invention enables the orientation of a device in a specified environment to be determined in relation to a plurality of sensing receivers positioned at known points in or around the specified environment, wherein a directional transmission from a directional transmission means which forms part of a known face of the device is initiated by a trigger signal from a timing transmitter located so as to cause transmitted bursts of energy to enter the said environment, said directional transmission means having associated therewith a timing receiver adapted to respond to any such trigger signals to thereby initiate said directional transmission, and wherein at the beginning of a timeslot the sensing receivers are reset and the trigger signal is transmitted, to render them ready to receive the directional transmission, and a control system polls the sensing receivers at the end of the timeslot to determine those on which the directional transmission has been incident within the timeslot.
The position of the receivers is preferably fixed.
The directional transmission may be a radio wave, UV, IR, visible light or a sound wave, typically above the range of normal hearing (ie ultrasound), and appropriate directional transmitters and sensing receivers are used depending on the nature of the transmission to be sent and received, and is preferably an ultrasound signal.
The timing transmission is preferably a high speed of propagation signal, such as a radio transmission.
Where the sensing receivers can be connected directly to the timing transmitter, the timing transmission may be made by way of an electrical current signal along a conductive path. Alternatively they may be triggered by a trigger signal transmission by radio.
By using a slowly propagating energy wave such as a soundwave, typically ultrasound, as the directional transmission, the time periods latched by the sensing receivers can be related to the distances between the directional transmission means and the receivers, and in accordance with a preferred feature of the invention, the sensing receivers may latch the time period between reset, and receipt of the directional transmissions, and at the end of the timeslot, the control system may also poll the time values latched by the sensing receivers, and supply the time values to a computing means which computes from the time values the line of site distances from the directional transmission means and the respective receivers, and in manner known per se determine therefrom the position of the transmission means relative to the known positions of the receiver.
For a given device, there is a region in space relative to the direction of transmission in which sensing receivers will receive a good signal therefrom. The region is determined both by the directional radiation pattern of the device, and the attenuation of the signal with distance. The size and shape of this “region of transmission” can be modified by the presence of objects in the environment.
The pattern of the receivers which have received a good signal can be considered to be the intersection of the “region of transmission”, and the network of receivers, in space. If the relationship of the “region of transmission” to the position and orientation of the transmitter is known, then constraints can be inferred between the position and the orientation of the device from observations of the intersection of that region and the receiver network.
In particular, if the location of the device is known, then the pattern can give information about the orientation of the device, as only some orientations could have resulted in the pattern of reception that is observed.
Information about the location of a device can be obtained from various sources including a knowledge of any constraints upon its motion, or an estimation of its distance from the receivers from the times of flight of the transmitted signal to the receivers on which it is incident. That estimation can be made by finding the point in space whose predicted distance from each receiver most closely match the measured distance. One method of determining the closeness of the match is to minimise the sum of squares of any differences between each measured and predicted distance.
If the orientation of the device is known, then information can be inferred about the position of the device from the pattern of good signal receiver locations. For instance, a device with a narrow beam angle may be mounted facing upwards, and it can be inferred that the object must therefore occupy the region just below the receivers that pick up its signal.
If the device is mounted on an object in a known manner, the orientation of the object can be inferred from the direction and position of the region of transmission.
If the region of transmission is modified by the presence of objects in the environment, then this may alter the pattern of receivers where a good signal is received. Given knowledge about the possible position and orientation of the device, the pattern can be used to deduce information about the positions and possibly other properties of objects that are modifying the region of transmission. For instance, a significant change in the receive pattern linked to a device on an object which is known to be static indicates that changes are occurring in the environment, perhaps due to the movement of that or other objects.
Where differentially propagating wave energies are used, a system embodying the invention enables the orientation of a device in a specified environment to be determined in relation to a plurality of sensing receivers positioned at known fixed points in or around the specified environment, by means of a directional transmission of slowly propagating energy from transducer means which form part of or are mounted on a known face of the device, and which is initiated by a trigger signal from a timing transmitter located so as to cause transmitted energy to enter the said environment, said transducer means having associated therewith a timing receiver adapted to respond to any such transmitted timing signals, to thereby initiate said directional transmission, (the combination of receiver and transmitting transducer means comprising a transponder) and
Jones Alan Henry
Ward Andrew Martin Robert
AT&T Corp.
Horabik Michael
Nguyen Nam
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