JP2843063B2 - Moving object position identification system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a position identification system for a mobile unit, and more specifically, to a mobile unit which receives a signal emitted from a fixed transmitter by a receiver and receives its own signal. The present invention relates to a position identification system for identifying a position.

(Prior Art) As is well known, the following method has been known as a conventional method for determining the current position of a moving object by using signals from a large number of signal transmission points arranged in an array. That is, the plane on which the moving object can move can be divided into a plurality of small-area blocks, and positions representing each position block are determined in advance. When a moving object exists in a position block, the moving object has identified the position of the moving object as being present at a position representing the position block.

Also, as a method of knowing in which position block the moving object is located, for example, there is a method represented by a car phone. In this method, a signal capable of determining the current position of a moving object by receiving a signal is emitted in a form of magnetism, radio waves, or light from each signal transmission point into space with a constant intensity. In this method, the mobile unit receives this signal and determines that the mobile unit is included in a position block represented by the transmission point that transmitted the signal having the highest signal strength. Under ideal environmental conditions, the area where radio waves can be received at a certain intensity or higher from the signal transmission point is circular. If the transmitting points are arranged so that the circular regions are densely arranged without gaps, the shape of the region in which radio waves from adjacent position blocks can be received with a predetermined electrolytic strength or more is hexagonal. One signal transmission point is provided for each of such hexagonal position blocks.

In an actual car telephone system, for example, a car transmits a radio wave as described in "Automobile Phone" supervised by Moruji Kuwahara, published by the Institute of Electronics and Communication Engineers, pp. 197-200 (published February 10, 1985). There is a system in which the fixed station determines the reception strength and the fixed station determines which transmission block is represented by which transmitting point.

As yet another example, there is a personal location identification card system developed by the same application as the present application. This is because individuals have a card-like device that has the function of receiving light and transmitting radio waves, and perform two-way communication with optical transmitters and radio receivers laid on the ceiling, etc. This is a method of obtaining the current position and identification information of the user. In this method, a signal including information representing the position in the form of a code is transmitted from a signal transmission point. On the mobile side, this signal is received, and its current position block is determined from the code obtained thereby. Nikkei Electronics, No. 469 (1989.3.20) No.
See pages 237-240.

(Problems to be Solved by the Invention) However, in each of these methods, a position block serving as a unit for identifying the position of a moving object and a signal transmission point have a one-to-one correspondence. Therefore, in order to perform fine position detection, it is necessary to reduce the area of the position block. Therefore, if the area of the plane space to be detected is the same, the number of signal transmission points must be increased accordingly. Also, if signals of a plurality of position blocks interfere with each other, it may be impossible to decode the position information. In order to prevent interference, it is necessary to increase the interval between transmission points so that signals from a plurality of transmission points are not received at the same time, in other words, so that the effective reception ranges at each transmission point do not overlap.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the disadvantages of the conventional technology and to provide a position identification system capable of accurately identifying the position of a moving object without providing many transmission points within a limited area.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a position identification system for identifying a position of a moving object in a specific area, transmitting a signal including a code uniquely assigned to each of the positions. A plurality of transmitting means, and receiving means for receiving a signal from at least one of the plurality of transmitting means and extracting a code included in the signal, the plurality of transmitting means being located in the mobile body, and the plurality of transmitting means Dispersively and fixedly arranged, whereby the area thereof is divided into a plurality of position blocks in which a range for effectively transmitting signals of a plurality of transmitting means partially overlaps each other, and the code is a plurality of position blocks. In addition to the signal format unique to each of the transmitting means, when the signals from the plurality of transmitting means are overlapped, a code form for forming a unique code for each of the plurality of position blocks is used in a superimposed form. The transmitting means identifies a block in which the moving object exists among the plurality of position blocks based on the extracted code.

According to the present invention, there is also provided a transmitting device and a receiving device applied to such a moving object position identification system.

(Operation) According to the present invention, a plurality of transmitting units transmit signals modulated by codes unique to each of the transmitting units. The receiving means is
A signal from one or a plurality of transmitting units is received, and a code included in the signal is extracted. This code is unique to each of the plurality of transmitting means, and has a code format for forming a unique code for each of the plurality of position blocks in a superimposed form when signals from the plurality of transmitting means overlap. Therefore, the receiving means can identify the position block in which the moving object is currently included based on the code.

(Embodiment) Next, an embodiment of a system for identifying the position of a moving object according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of a position identification system according to the present invention. The position identification system 2 in the present embodiment, basically a plurality of n transmitters A1 to
An, consisting of a synchronization circuit 6 and a receiver 4. For a mobile object such as a person or an object whose position is to be identified, the receiver 4 is connected to the transmitters A1 to A1.
It is mounted so that it can receive signals from any of An.

The transmitters A1 to An are usually fixedly arranged in an array on a target plane which is a moving area of a moving body, for example, indoors such as factories, offices, and hospitals, or outdoors such as urban areas and parks. If it is indoors, it may be arranged, for example, on the ceiling. There may be a plurality of target planes, and a plurality of receivers 4 may be included in the target area.

As shown in FIG. 1, each of the transmitters A1 to An includes a modulation circuit M1 to Mn, and a light emitting element L1 correspondingly connected thereto.
To Ln. A plurality of light emitting elements may be connected to one modulation circuit. In the present embodiment, the light emitting elements L1 to Ln are advantageously light emitting diodes that emit infrared light, and have a signal transmission function of transmitting signals. As shown in FIG. 2, the modulation circuits M1 to Mn repeatedly generate pulse signals having different patterns unique to each other according to the synchronization signal 10, thereby driving the infrared light emitting diodes L1 to Ln.

The modulators M1 to Mn are commonly connected to the synchronization circuit 6 by a connection line 12.
, From which the clock signal 8 and the synchronization signal 10
Is supplied. The synchronization circuit 6 is a timing generation circuit that generates a stable clock signal 8 and outputs a synchronization signal 10 for adjusting the operation timing of each of the modulation circuits M1 to Mn to the signal line 12 from this.

For four transmitters, a transmission signal A1 emitted by light emitting diodes L1 to L4 modulated by modulators M1 to M4.
FIG. 2 shows an example of waveforms A4 to. In the following figures, reference numerals of signals are referred to by reference numerals of associated signal lines, transceivers or regions.

The pulse width and the repetition period of the unique pulse signals A1 to A4 output from the respective light emitting diodes, for example, L1 to L4, are equal to the pulse width and the repetition period of the clock signal 8, respectively, as illustrated. In this embodiment, the transmitter A1
The pulse A1 transmitted from has a pattern consisting of three consecutive rectangular waves synchronized with the synchronization signal 10, and the pulse A2 transmitted from the transmitter A2 has two consecutive waveforms synchronized with the synchronization signal 10. The rectangular wave has a pattern of one rectangular wave following it in one clock pulse period. Similarly, transmit pulse A3
Consists of two consecutive rectangular waves synchronized with the synchronization signal 10 and one rectangular wave following the two clock pulse periods. In this way, the transmission signals A1 to An are encoded according to the position of each transmitter.

The light emission characteristics of the light emitting diodes 1L to Ln are shown in Fig.3.
As exemplified for A1 to A4, there are circular irradiation areas Z1 to Z4 around them. As shown in the drawing, the areas Z1 to Z4 partially overlap each other, and in the overlapping part, signals are synchronously received from two or three different transmitters depending on positions. The transmitters A1 to An are arranged so that a range in which a signal can be effectively transmitted is densely arranged without a gap.

On the other hand, the receiver 4 receives an infrared signal from any one or more of the transmitters A1 to An, and outputs to its output 30 information identifying the position block in which the receiver 4 is currently included from the code included in the infrared signal. It is a device to do. To realize this function, the receiver 4 has a light receiving element 20, a code extraction circuit 14, a code comparison circuit 16, and a map information storage circuit 18. Light receiving element
Reference numeral 20 denotes a light receiving element that receives an infrared signal transmitted from any of the transmitters A1 to An and converts the infrared signal into a corresponding electric signal. For example, a photodiode or a phototransistor is used. The output of the light receiving element 20 is connected to the code extraction circuit 14 via the signal line 22.

The code extraction circuit 14 is a circuit that extracts a code included in the signal received by the light receiving element 20 from the signal. This code is
A code included in a signal transmitted from any of the transmitters A1 to An, or a code in which signals transmitted from two or more of the transmitters A1 to An are superimposed, and the reception blocks B1 to Bm
(FIG. 4 shows B1 to B11 among them.) The receiver 4 functions as an identification display of the block currently included.

For example, when four transmitters A1 to A4 are arranged as shown in FIG. 3, if a receiver 4 is present in any of the reception blocks B1 to B4, the receivers 4 transmit signals. Only the signals transmitted from the devices A1, A2, A3 and A4 are received. If the position block B5 includes the receiver 4, the receiver 4 receives the signals from the transmitters A1 and A2 in a superimposed waveform shown by the reception signal B5 in FIG. Similarly, in position block B7, transmission signals A1, A2 and
A reception signal B7 in which A3 overlaps is obtained.

The code format used in this system is unique to each of the transmitters A1 to An, and when signals from a plurality of transmitters overlap, they are superimposed on each of the position blocks B1 to Bm. It is configured to form a unique code. Therefore, in the present system, the position of the moving object can be identified by recognizing the waveforms of the received signals B5 and B7 as codes representing the position blocks B5 and B7, respectively. From the output 24 of the code extraction circuit 14, the code extracted in this manner is output to the code comparison circuit 16.

The sign comparison circuit 16 stores the data of the position blocks B1 to Bm represented by the sign obtained from the received signal and the map information storage circuit 18
Is compared with the data of the position blocks B1 to Bm stored in the position block B1, and when they match, an identification display of the matched position blocks B1 to Bm, for example, a number is output to the position information output terminal 30. A display device or a recording device (not shown) is connected to the position information output terminal 30, and the current position and behavior of the moving object can be displayed and recorded. The data of the position blocks B1 to Bm from the code extraction circuit 14 may be directly output to the position information unit 30, and the data may be processed by an external conversion device.

The map information storage circuit 18 is a memory that stores data for specifying the position blocks B1 to Bm. For example, a ROM is advantageously applied to this memory. The data stored in the map information storage circuit 18 includes data for specifying the position blocks B1 to Bm, for example, numbers and codes uniquely assigned to the position blocks B1 to Bm. The latter, transmitter A1 ~
Each of the position blocks B1 to Bm is uniquely identified by a code unique to each of An and a code obtained by logically ORing two or three adjacent codes among the oscillators A1 to An. The data of the map information storage circuit 18 is input to the code comparison circuit 16 via the signal line 26.

In the present embodiment, infrared rays are used as transmission means between the transmitters A1 to An and the receiver 4. However, the present invention is not necessarily limited to this, and for example, visible light or ultraviolet light may be used.

Next, the operation of the system of this embodiment will be described with reference to FIGS. 1, 2, and 3. FIG. Position identification system 2
The synchronizing circuit 6 generates a clock signal 8 and a synchronizing signal 10. The synchronizing signal 10 is supplied to each of the modulation circuits M1 to Mn. For example, the modulation circuits M1 to Mn respond in response thereto with their own unique patterns A1 to An (of which A1 to A4 are shown in FIG. 2). The light emitting elements L1 to Ln are respectively driven. Light emitting element
L1 to Ln emit infrared light corresponding to this.

If the receiver 4 is located in any of the position blocks B1 to Bm formed by the transmitters A1 to An, the receiver 4 is a light emitting element
The light signals from L1 to Ln are received by the light receiving element 20. This is converted into an electric signal by the light receiving element 20 and input to the code extraction circuit 14 via the signal line 22. The code extraction circuit 14 extracts the code included in the signal.

For example, if there is a receiver 4 in the position block B11,
Since the transmission signals A3 and A4 are received in a superimposed or added form, a reception signal B11 (FIG. 2) is obtained. When the signal is in the position block B9, the signals of A2, A3 and A4 are overlapped. B9 is obtained. The code extraction circuit 14 extracts a repeated code portion C from these signals, and sends it to the code comparison circuit 16 via the signal line 24. The code comparison circuit 16 reads the data stored in the map information storage circuit 18 and compares the data with the extracted code. The map information storage circuit 18 stores code data representing position blocks (B1 to B11 in FIG. 3). Based on this data, a position block including the transmitter 4 is specified, and data representing the position block, for example, data representing the number of the position block, is output to the position information output terminal 30 via the signal line 28. Here, a characteristic feature is that the position of the receiver 4 is identified by using the overlapped signal as it is in a region where the signal overlaps, for example, B5. Therefore, the positional accuracy has been further improved.

The position accuracy will be described with reference to FIG. 4 and FIG. FIG. 4 shows an example of the arrangement of the position blocks according to the conventional example.
FIG. 5 shows an example of the arrangement of the position blocks according to the above embodiment. The black square in FIG. 4 shows the position of the transmitter 32 of the conventional system, and the black square 40 in FIG. 5 shows the position of the transmitter A- according to the embodiment of the present invention. Both transmitters 32 and 40
Both signals are transmitted in a circular shape. In any of the arrangement examples, the transmitters 32 and 40 are arranged at the vertices of an equilateral triangle having a radius of three units and four sides each for calculation purposes.

In the arrangement example shown in FIG. 4, in the area where the signals overlap, the method of determining the position by selecting the one with the higher signal strength is adopted, so that the identifiable area is the hexagonal hatched portion 34. In this case, the area of the hatched portion is 13.856. On the other hand, the arrangement example according to the present embodiment shown in FIG. 5 employs a method in which a region where a signal overlaps can be identified as an individual region. For this reason, even though the transmitter arrangement is the same as that of the conventional example, the identifiable region takes the shape shown by the shaded portion 34, and the area of each position block is small. For example, the largest area block 36
Is 3.605, the area of the block 38 having the minimum area is 2.028, and the average area is 2.309. As can be seen from the above, in the present system, even if the same transmitter arrangement is used, the position accuracy improved six times as compared with the conventional method is realized.

As described above, in this embodiment, even in a region where signals from the transmitters overlap, the accuracy of position identification of the moving body is improved by using the overlapped signals.

(Effect of the Invention) As described above, according to the present invention, a signal including a code unique to the transmitter is transmitted from the transmitter, the signal is received by the mobile unit, and the code is compared with data specifying the area. The position of the moving object can be identified with high accuracy. In addition, this does not increase the number of transmitters provided in the limited area.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a position identification system according to the present invention, FIG. 2 is a waveform diagram showing signal waveforms transmitted and received in the embodiment shown in FIG. 1, and FIG. FIG. 4 is an explanatory diagram for explaining the position accuracy according to the conventional example, and FIG. 5 is an explanatory diagram for explaining the position accuracy according to the embodiment. is there. Description of Signs of Main Parts 2 Position Identification System 4 Receiver 6 Synchronization Circuit 8 Clock Signal 10 Synchronization Signal 14 Code Extraction Circuit 16 Code Comparison Circuit 18 Map Information Storage Circuit 20 Light receiving elements A1 to An Transmitters B1 to B11 Position blocks L1 to Ln Light emitting elements M1 to Mn Modulation circuits

Continuation of front page (72) Inventor Tomoyuki Kishi 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) References JP-A-63-60630 (JP, A) (58) Investigated Field (Int.Cl. ⁶ , DB name) G01S 5/00-5/02 H04B 7/26

Claims (5)

(57) [Claims] 1. A position identification system for identifying a position of a moving body in a specific area, the system comprising: a plurality of transmitting means for transmitting a signal including a code uniquely assigned to the moving body; Receiving means for receiving a signal from at least one of the plurality of transmitting means and extracting a code included in the signal, wherein the plurality of transmitting means are dispersed and fixedly arranged in the area. Thereby, the area is divided into a plurality of position blocks by partially overlapping a range for effectively transmitting signals of the plurality of transmitting means, and the code is unique to each of the plurality of transmitting means. And when the signals from the plurality of transmitting units overlap, take a code form for forming a unique code for each of the plurality of position blocks in a superimposed form. The position identification system of the moving body, characterized in that identifying the blocks present of the mobile object among the plurality of position blocks based on the extracted code. 2. The system according to claim 1, wherein said receiving means comprises: storage means for storing data specifying each of said plurality of position blocks corresponding to said code; A position identification system comprising: a comparison unit configured to generate an output for identifying a position block including the moving object by comparing the data with data stored in the storage unit. 3. A transmitting apparatus of a position identification system which is fixedly arranged in a specific area where a position of a mobile object is to be identified and transmits a signal including a code, wherein said transmitting apparatus is distributed in said area and comprises a plurality of said transmitting apparatuses. Is arranged, whereby the area is divided into a plurality of position blocks in which a range for effectively transmitting signals of the plurality of transmission devices partially overlaps each other, and the code is assigned to each of the plurality of transmission devices. When the signals from the plurality of transmitting devices overlap each other, the transmitting device takes a code format that forms a unique code for each of the plurality of position blocks. Signal transmitting means for transmitting the signal, a modulating means for driving the signal transmitting means with a code unique to the transmitting apparatus, and a synchronous circuit means for synchronizing the modulating means in common for the plurality of transmitting apparatuses, The mobile unit receives a signal from at least one of the plurality of transmitting devices, extracts a code included in the signal, and, based on the extracted code, of the mobile unit among the plurality of position blocks. A transmitting device of a position identification system, which identifies an existing block. 4. A position identification which is held by a moving body whose position in a specific area is to be identified and receives a signal transmitted from at least one of a plurality of transmitting means fixedly arranged in the area. In the receiving device of the system, the area is provided by a distributed arrangement of the plurality of transmitting units.
The range in which the signal of the transmitting means is effectively transmitted is partially overlapped with each other and divided into a plurality of position blocks, and the transmitting means includes a code uniquely assigned to each of the signals and transmits the signal. The code has a code format that forms a code unique to each of the plurality of position blocks in a superimposed form when signals from the plurality of transmitting units overlap, and the receiving device includes: Receiving means for receiving a signal from at least one of the following; extracting means for extracting a code included in the received signal; and presence of the moving object among the plurality of position blocks based on the extracted code. A receiving device for a position identification system, comprising: identification means for identifying a block. 5. The apparatus according to claim 4, wherein said identification means comprises: storage means for storing data specifying each of said plurality of position blocks corresponding to said code; A receiving unit configured to generate an output for identifying a position block including the moving object by comparing the data with data stored in the storage unit.