JPH0546251A - Position detecting system - Google Patents

Abstract

PURPOSE:To improve the reliability of transmission by flickering two light emitting diodes approximate to the light receiving range, detecting the moving direction in the receiving sequence of a signal, superimposing a part of the light receivable range and detecting the position information. CONSTITUTION:A control circuit 2 reads the position information stored beforehand in a memory circuit 1 and a light emitting diode 7 is flickered by a driving circuit 5. On the other hand, the position information is inverted by an inverter circuit 3 and a light emitting diode 6 is flickered by a driving circuit 4. The space propagating light of light emitting diodes 6 and 7 is received by a light receiving circuit 8 at the moving side, amplified by an amplifying circuit 9, subsequently, the light is detected by a detecting circuit 10, decoded by a decoding circuit 12 at the timing reproduced by a clock reproducing circuit 11, and outputted as the position information data to an output terminal 13. At this time, the directivity and luminance of the light emitting diodes 6 and 7 are set so that a part of the light receivable range by the light receiving circuit 8 of the space propagating light can be overlapped. Thus, the moving direction and the position information can be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting method for a position and a moving direction of a moving body used in a moving body position identifying system.

[0002]

2. Description of the Related Art Conventionally, in this type of position detection system, a fixed type optical transmitter is provided with one or more light emitting diodes AM (amplitude) modulated by a code string containing position information. When the device enters the receivable range, the position information is detected and the position can be recognized on the moving side. The reason why a plurality of light emitting diodes are used is to expand the communication area and change the directivity.

FIG. 3 shows an example of the configuration of a conventional position detecting system. In FIG. 3, 21 is a memory circuit, 22 is a control circuit,
23 is a drive circuit, 24 is a light emitting diode, 25 is a light receiving circuit, 26
Is an amplifier circuit, 27 is a detection circuit, 28 is a clock recovery circuit, 29
Is a decoding circuit, and 30 is an output terminal. 21 to 24 are fixed side devices, and 25 to 30 are moving side devices. Next, the operation of the above conventional example will be described. In FIG. 3, the control circuit 22 reads the position information data previously stored in the memory circuit 21, and causes the light emitting diode 24 to blink via the drive circuit 23 in accordance with the position information data. The spatially propagating light is received by the light receiving circuit 25 on the moving side, and after being amplified by the amplifier circuit 26,
The signal is detected by the detection circuit 27 and decoded by the decoding circuit 29 at the timing reproduced by the clock reproduction circuit 28 and output to the output terminal 30 as position information data. In this way, the position information issued by the fixed device can be reproduced on the mobile device side. FIG. 4 shows an example of transmission data of the conventional example. In FIG. 4, the frame sync signal is "1.
In this example, “1011001” and the position information is “00001010”.

[0004]

However, in the above-mentioned conventional position detection method, since the moving device side can detect only the position information stored in the fixed device, there is a problem that the improvement of the position accuracy leads to the increase of the number of fixed devices. there were. The present invention solves such a conventional problem, and an object of the present invention is to provide an excellent position detection method capable of improving position accuracy without increasing the number of fixing devices.

[0005]

In order to achieve the above object, the present invention provides a fixing device with two light emitting diodes,
The moving device can detect not only the position information but also the moving direction by partially overlapping the light receiving ranges of the respective light emitting diodes and determining the light receiving order of the two light emitting diodes.

[0006]

Therefore, according to the present invention, since the two light emitting diodes which are close to each other in the light receiving range are blinked, the moving direction can be detected in the order of signal reception. Further, since the receivable ranges of the two light emitting diodes are partially overlapped, the position information can be detected.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows the configuration of a position detecting system in an embodiment of the present invention. In FIG. 1, 1 is a storage circuit for storing position information, 2 is a control circuit for generating a clock signal and reading position information, 3 is an inverter circuit, 4 and 5 are drive circuits, 6 and 7 are light emitting diodes, and 8 Is a light receiving circuit, 9 is an amplifying circuit, 10 is a detecting circuit, 11 is a clock reproducing circuit, 12 is a decoding circuit, and 13 is an output terminal. It should be noted that the above 1 to 7 compose a stationary device, and 8 to 13 compose a moving device.

Next, the operation of the above embodiment will be described. In the above embodiment, the control circuit 2 reads the position information stored in the storage circuit 1 in advance, and the drive circuit 5 causes the light emitting diode 7 to blink. On the other hand, the inverter circuit 3 inverts the position information, and the drive circuit 4 causes the light emitting diode 6 to blink. The spatially propagating light from the light emitting diodes 6 and 7 is received by the light receiving circuit 8 on the moving side, amplified by the amplifying circuit 9, detected by the detecting circuit 10, and reproduced by the clock reproducing circuit 11 by the decoding circuit 12. It is decoded and output to the output terminal 13 as position information data.
At this time, if the directivity and the brightness of the light emitting diodes 6 and 7 are set so that the light receiving ranges of the space propagating light by the light receiving circuit 8 partially overlap, three types of light emitting diodes 6 and 7 are provided near the fixed device depending on the location as the mobile device moves. The signal of is detected by the detection circuit 10. The data stored in the memory circuit 1 is detected in the place where only the light emitting diode 7 can receive light, and the inverted sign of the data stored in the memory circuit 1 is detected in the place where only the light emitting diode 6 can receive light, and the light emitting diodes 6 and 7 are detected. Since the outputs of both light emitting diodes are optically added in a place where both can be received, all “1” s are detected. FIG. 2 shows an example of a timing diagram. FIG. 2 shows the conventional example shown in FIG.
Similarly to, the frame synchronization signal is “11011001” and the position information is “00001010”. In FIG. 2, (a) is position data accumulated in the memory circuit 1 of FIG.
(b) is its inverted data, and (c) is the output detected by adding the outputs of (1) and (2) through the light emitting diodes (6) and (7) and the light receiving circuit (8) of FIG. 1, the output at point A, (d) is the detection output when only the light emitting diode 7 of FIG. 1 is receiving light, and (e) is the detection output when only the light emitting diode 6 of FIG. 1 is receiving light. Is. Thus, the light emitting diode 6
By providing a range where there is no sign change in the middle of which the and 7 can receive light, the outputs of the light emitting diodes 6 and 7 can be detected with good isolation, and not only the position but also the moving direction can be recognized. In the above embodiment, the case of two light emitting diodes is described, but it is of course possible to use a light emitting diode group of two systems.

[0009]

The present invention has the following effects, as is apparent from the above-mentioned embodiments. (1) Two light-emitting diodes that are close to each other in the light-receiving range are blinked by two types of signals, so that the moving direction can be recognized in the signal reception order. (2) Since the outputs of the two light emitting diodes are optically added and the guard band is generated locally, the transmission reliability is high. (3) When two groups of diodes are used, since a plurality of light emitting diodes are used, the light receiving range and directivity can be set arbitrarily.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a position detection method according to an embodiment of the present invention.

FIG. 2 is an example of a timing diagram of a position detection method according to an embodiment of the present invention.

FIG. 3 is a schematic block diagram of a conventional position detection method.

FIG. 4 is an example of transmission data of a position detection method in a conventional example.

[Explanation of symbols]

1, 21 ... Memory circuit, 2, 22 ... Control circuit, 3 ... Inverter circuit, 4, 5, 23 ... Driving circuit, 6, 7, 24 ... Light emitting diode, 8, 25 ... Light receiving circuit, 9, 26 ... Amplifying circuit , 10, 27 ... Detection circuit, 11, 28 ... Clock recovery device, 12, 29 ... Decoding circuit, 13, 30 ... Output terminal.

Claims (2)

[Claims] 1. Complementary NRZ (non return to zer)
o) Position detection consisting of a fixed optical transmitter equipped with two light emitting diodes that are amplitude (AM) modulated by a code string and a mobile optical receiver equipped with a light receiving / detecting / clock reproducing / decoding circuit method. 2. A fixed type optical transmitter equipped with two groups of light emitting diodes which are AM-modulated by mutually complementary NRZ code strings, and a mobile type optical receiver equipped with a light receiving / detecting / clock recovering / decoding circuit. Position detection method composed by.