JPS62174674A - Wherebouts detection system - Google Patents

Abstract

PURPOSE:To eliminate radio interference with other transmitters and to prevent a battery from being wasted by allowing a transmitter to sends a radio wave only when the position of a moving body needs to be detected. CONSTITUTION:The transmitter 1 consists of an oscillation circuit 14, a modulating circuit 15, a power amplifying circuit 16, etc. Those circuits are supplied with electric power from the battery 12 through a switching circuit 13. When an operation time is set with a key 11, a microcomputer muC10 operates as a timer to turn on the circuit 13 from the start time of operation to the end time and also outputs the code of the transmitter to the circuit 15, which imposes FM modulation upon the radio wave outputted from the circuit 14. When this system is used at an airport, a receiver is installed in the control tower and the transmitter is handed to passengers. The transmitter is so set as to begin to transmit a radio wave, for example, 10min before the departure of the aircraft that the passenger boards. The control tower puts the receiver in operation when the departure time of the aircraft approaches to detect whether there is a transmitter sending a radio wave in the airport or not. Thus, the transmitter sends the radio wave only when required, so there is no radio interference with other transmitters and the detection accuracy is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field This invention relates to a location detection system that detects the location of a moving object by receiving radio waves transmitted from a transmitter attached to the moving object.

(b) Summary of the Invention In the location detection system according to the present invention, a transmitter is attached to a moving object, and the receiver side detects the presence or absence or location of the moving object based on whether or not radio waves transmitted by the transmitter are received. In this system, the radio wave transmission time of the transmitter is set by a transmission time setting means, and the radio wave is transmitted for only this time by a switching means. This reduces consumption of the power supply built into the transmitter and eliminates interference with other transmitters caused by transmitting radio waves at unnecessary times.

(C) Background of the invention Remotely detecting the location of a moving object, especially a person moving within a certain area, for example, detecting where in an airport a checked-in passenger who has not yet boarded the aircraft is located. It is currently being attempted to use frugal devices to detect and locate lost children in amusement parks.

For this reason, the present applicant has already proposed in Utility Model Application No. 59-11546 a method of attaching a transmitter to a detected object (a moving object) and detecting the radio waves emitted by this transmitter to detect the position of the detected object. We have proposed a location detection device that does this.

In this device, since the transmitter starts emitting radio waves from the moment it is attached to the detected object, when multiple transmitters are attached to many detected objects, the transmitters that emit radio waves at the same frequency can May be used more than once. In this case, when a plurality of transmitters emitting radio waves of the same frequency are simultaneously within the receivable range of the receiver, interference occurs and the position of both cannot be detected. Furthermore, since the transmitter continues to emit radio waves from the beginning when it is attached to the object to be detected, the battery is consumed quickly, and there is a risk that the battery may have already been used up by the time position detection is required. Ta.

(d1 Purpose of the Invention In view of the above-mentioned drawbacks, this invention eliminates interference with other transmitters by making the transmitter emit radio waves only when it is necessary to detect the location of a moving object, and also eliminates battery waste. The purpose is to provide a location detection system that can eliminate unnecessary consumption.

(e) Structure and effect of the invention This invention comprises a transmitter attached to a moving body and a receiver that receives radio waves from the transmitter, and the radio waves transmitted by the transmitter are determined depending on whether or not the receiver receives the radio waves. , in the location detection system for detecting the presence or absence or location of the moving object, the transmitter includes a transmission time setting means for setting a time at which radio waves should be transmitted; A switching means for enabling the operation of the transmitter is provided.

By configuring as described above, according to the present invention, when a transmitter is attached to a moving object, the radio wave transmission time can be set in advance to a time when the location of the moving object needs to be detected. By doing this, even if there are many transmitters that emit radio waves at the same frequency, interference can be prevented by staggering the time at which they transmit radio waves, and the transmitter's power supply (as it is a moving transmitter, the power supply is, of course, a battery.

) can prevent wear and tear. For example, a transmitter given to a passenger checking in at an airport is set to emit radio waves from 10 minutes before departure to the departure time of the flight the passenger is boarding. This can prevent the radio waves emitted by the transmitters of passengers who have plenty of time before boarding from interfering with the radio waves emitted by the transmitters of other passengers who are about to depart, thereby interfering with detection.

(f) Embodiment FIG. 1 is a schematic block diagram of a transmitter used in a location detection system according to an embodiment of the present invention. This system is used to detect the presence of people, such as detecting the presence of passengers who have checked in at an airport, and this transmitter can also be carried in a pocket or the like. The transmitter body has an oscillation circuit 14. Modulation circuit 15. Power amplifier circuit 16
An antenna 17 is connected to the power amplification circuit 16. Power from the battery 12 is supplied to these circuits via a switching circuit 13. This switching circuit 13 is opened and closed by the microcomputer IO via an interface 18. The microcomputer 10 is connected to the switching circuit 13 via an interface 18, as well as to a modulation circuit 15 and an input key 11. The key 11 is a key for setting the operating time of this transmitter 1. When the operating time is set by operating this key 11, the microcomputer 1O operates a timer and sets the operation start time and operation end time. To measure time. Between the operation start time and the operation end time, the microcomputer 10 operates the switching circuit 1.
3 is turned on, and the code of this transmitter is output to the modulation circuit 15 to modulate the radio waves output from the oscillation circuit 14. The modulation format is usually FM.

FIG. 2 is a schematic block diagram of the receiver 2 used in the location detection system. This receiver 2 is installed in a boarding control room or the like. This receiver has four antennas 242 to 24d and is connected to an antenna switch 25. By this antenna switching device 25, the antenna 24a
24d is connected to the amplifier circuit 26. The amplifier circuit 26 includes a tuning circuit, and is controlled to tune and receive the frequency of radio waves oscillated by a necessary transmitter. The high frequency signal amplified by the amplifier circuit 26 is input to the detection circuit 27. The code signal is separated from the high frequency signal by the detection circuit 27 and inputted to the microcomputer 20 via the interface 21. This interface 21 includes the antenna switching circuit 2 in addition to the detection circuit 27.
5 and an amplifier circuit 26 are connected. The microcomputer 20 controls switching of the antenna switching circuit 25;
A display 22 and a keyboard 23 are also connected to the microcomputer 20, which switches the receiving frequency of the amplifier circuit 26.

When the above system is used at an airport, the receiver 2 is installed in the boarding control room, and the transmitter 1 is handed to passengers who have checked in. This transmitter 1 is set to start transmitting 10 minutes before the departure of the flight on which this passenger is boarding. Passengers who have checked in are free to wait inside the airport for the boarding light to be turned on, but when the departure of the flight approaches, the control room activates receiver 2 and transmitter 1, which transmits radio waves within the airport, is activated. Detect whether it exists or not. If there is, prompt boarding is encouraged, and if there is none, boarding is completed and the flight is notified that preparations for departure are complete. The transmitter 1 carried by the passenger will be collected at the boarding gate.

Figures 3 and 4 show the antenna 24 of the location detection system.
It is a figure which shows the installation example of a-24d. FIG. 3 shows an example in which antennas are installed in each area, that is, in each room. In the above example of an airport, the system is installed in a domestic lobby, an international lobby, a store area, a coffee room, etc., and detects whether there are passengers in each area.

On the other hand, FIG. 4 shows a case where the antenna is used in a place with good radio wave propagation conditions, and two narrow directional antennas are used, and the angle of the two antennas when receiving the radio wave from the transmitter is θ9.
This system detects the position of the transmitter (mobile object) from θ2.

This system can be effectively used, for example, to investigate lost children in amusement parks.

The fifth part is a flowchart showing the operation of the control section of the transmitter 1. In step nl (hereinafter, step ni is simply referred to as ni), the key 11 is pressed by the staff member,
When the operation start time and operation end time of the transmitter body are set, a soft timer that operates within the CPU is started (n2).

When it is determined in 03 that it is time to start operating the transmitter, the switching circuit 13 is turned on to operate the transmitter main body such as the oscillation circuit 14 (n4), and a radio wave with the code of this transmitter is transmitted. do. If it is determined in n5 that the operating time has ended, the switching circuit 13 is turned off to stop the transmitter and n6) the operation is completed.

FIG. 8 (8) is a flowchart showing the operation of the receiver 2. When it becomes necessary to detect the location of a moving object (passenger, child, etc.), an attendant inputs the code of the transmitter l carried by the moving object. When this code is entered (n
10) Set the receiver to conditions that allow it to receive radio waves from the transmitter (n11), and sequentially switch the antennas 243 to 24d to detect whether radio waves containing the code are received (n12). If a radio wave is received, the presence of the moving object and its location etc. are displayed (nl3), and if not detected, an absence is displayed (n14), and this operation is repeated until the end of the detection operation is determined in n15. If it is determined that the detection operation has ended, the operation ends.

nl corresponds to the transmission time setting means of the present invention, and the switching circuit 13 and n3.nl correspond to the transmission time setting means of the present invention. n5 corresponds to the switching means of the present invention.

In this way, according to this location detection system, the transmitter given to passengers etc. can be configured to transmit radio waves only when necessary. This eliminates interference with other transmitters that emit radio waves of the same frequency, making it possible to improve detection accuracy.

Furthermore, since the transmitter body does not operate when it is not needed, there is no unnecessary battery consumption and the device can operate for a long time.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a transmitter used in a location detection system according to an embodiment of the present invention, FIG. 2 is a block diagram showing a schematic configuration of a receiver used in the location detection system, Figure 3. FIG. 4 is a diagram showing the installation method of the antenna of the receiver, a fifth device is a flowchart showing the operation of the control section of the transmitter, and FIG. 5(B) is a flowchart showing the operation of the control section of the receiver. It is. 1 - transmitter, 2 - receiver, 11 - key, 13 - switching circuit.

Claims (1)

[Claims] (1) Consisting of a transmitter attached to a mobile object and a receiver that receives radio waves from the transmitter, whether or not the mobile object is present or not can be determined depending on whether or not the receiver receives the radio waves emitted by the transmitter. In a location detection system that detects a position, the transmitter includes a transmission time setting means for setting a time at which radio waves should be transmitted, and a switching device that enables the operation of the transmitter only for the time set in the transmission time setting means. A location detection system comprising: means.