JPH11248815A - Method and system for providing position information and fm transmission station and portable terminal apparatus used in the system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a position both indoors and outdoors and make a terminal compact and consume less power by using a portable terminal for the DGPS to which a means for taking out positional information from signals of a sound band demodulated from received FM modulated signals is added. SOLUTION: This system comprises an FM transmission station which generates positional information by PB signals (push button signals) and transmits the PB signals by FM waves of 10 mW power, and a DGPS terminal in which a function of extracting PB signals from FM demodulated sound signals is added to a CPU 1. An output signal digitized at an AD conversion part 7 is taken out inside the CPU 1 as positional information represented by numerals and symbolic characters. When and AD converter is set outside, the signal digitized by the AD conversion part 7 is taken into the CPU 1 via a bus 2. Accordingly, a position whether it is indoors or outdoors can be detected and the terminal can be made compact and to consume less power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for providing location information to a moving user, and more particularly to a location information providing method and system applicable to a specific place such as a campus, and FM used in the system. The present invention relates to a transmitting station and a portable terminal.

[0002]

2. Description of the Related Art Conventionally, as means for detecting a moving position, a GPS (Global Positioning System) using a satellite is used.
m) there. In general, GPS can detect a position with an accuracy of 100 to several hundred meters by using four or more satellites (for example, Jun Tsuchiya et al. Basics of GPS Survey ”
See pages 5 to 40). In recent years, DGPS (Differential GPS) using FM multiplex broadcasting has appeared.
It has become possible to know the position with an accuracy of several tens of meters (for example, see the above-mentioned documents, pages 109 to 117).

In DGPS, as will be described in detail later, the difference between the position coordinates of the FM broadcasting station detected by GPS and the actual position coordinates of the broadcasting station is obtained, and the difference is transmitted from the broadcasting station by FM multiplexing as correction information. I do. On the terminal side, GP at the terminal
An accurate position coordinate is obtained using the position detection result by S and the correction information from the FM broadcast station.

FIG. 5 shows a circuit configuration of a conventional portable terminal having a position detecting function by DGPS using satellite and FM multiplex broadcasting.

[0005] In GPS, almost the entire earth is covered.
All four GPS satellites have the same carrier frequency (1,575).
MHz, 1,227 MHz).
Each satellite transmits by a spread spectrum communication system using a pseudo noise code. Thus, even if each satellite transmits a signal at the same carrier frequency, the signal can be received without interference.

[0006] Each satellite has an atomic clock inside and transmits signals at accurate timing. The transmitted information includes the satellite orbit and the correction value of the clock. For this reason, the receiving unit can simultaneously receive signals from at least four satellites and determine the distance from each satellite to calculate the three-dimensional coordinates of the receiving position. Since the details are not directly related to the present invention, the description is omitted. The measurement accuracy by the GPS is 100 to several hundred meters as described above.

Next, FIG. 6 shows an arrangement of baseband signals transmitted by FM broadcasting. In the figure, the horizontal axis is frequency. 0 to
A signal (L + R) obtained by adding stereo left and right (L side and R side) sounds to a band of 15 kHz is arranged, and 23 to 5
In the band of 3 kHz, a differential signal (LR) of modulated left and right stereo audio is arranged. The digital data is not used for voice in the frequency arrangement shown in FIG.
LMSK (Level con
Controlled Minimum Shift Keying) is modulated and multiplexed. Thereby, audio broadcasting and data such as characters can be transmitted simultaneously.

[0008] Now, the FM broadcasting station can know its own accurate three-dimensional coordinates in advance. Therefore, the FM broadcast station calculates the difference between the coordinates measured by the GPS and the accurate three-dimensional coordinates, and sends the information by FM multiplexing using the determined difference as an error. On the receiving side, the accuracy of the position coordinates can be improved by correcting the coordinates measured by the GPS using the error information obtained from the FM multiplexing. This method is DGP
S (Differential GPS). Thereby, the accuracy of 10 to several tens m is obtained as described above.

FIG. 5 shows a portion for detecting a position using a satellite on the right side. Radio waves from the satellite 400 are transmitted through the antenna 10
And sent to the GPS receiving circuit 11. The GPS receiving circuit 11 detects various information from the received signal and calculates the current position.

FIG. 5 shows an FM multiplex receiving section 20 for correcting a position error using FM broadcasting. In the receiving unit 20, a radio wave from the FM broadcasting station 300 is received by the antenna 21 and sent to the tuner 22. Tuner 22
Tuning and demodulation of the received FM signal are performed, and a baseband signal having the frequency arrangement shown in FIG. 6 is output. The stereo matrix unit 23 separates and extracts the left and right stereo signals (L and R) that are mixed and sent in the baseband signal. The baseband signal is further sent to an MSK demodulation unit 25 via a band-pass filter 24 that selects only the frequency band of the multiplexed data area. The MSK demodulation unit 25 performs MSK demodulation and error correction, and extracts error correction information sent from the FM broadcast station 300.

The CPU (central processing unit) 1 reads the position coordinate information from the GPS receiving circuit 11 and the error correction information from the MSK demodulation unit 25 via the bus 2 and recalculates the position coordinates. And a ROM in which map information is stored.
3, a map near the corresponding position is read out, the map is displayed on the liquid crystal display 5 via the liquid crystal display control unit 6, and the obtained coordinate position is displayed on the map as the current position. As a result, the display screen becomes, for example, a navigation screen as shown in FIG.

In addition to the above GPS and DGPS, PHS
(Personal Handy System) has also been proposed. Since it is possible to know the wireless base station of the currently communicating PHS, it is possible to know its own position from the position of the base station as long as the wireless base station is within the range of radio waves.
In addition, there is a proposal of a similar position method implemented between a terminal using infrared communication and a wireless base station. Further, there is a position detection method based on a method similar to GPS using several PHS radio base stations.

[0013]

SUMMARY OF THE INVENTION GPS Using Satellite
However, since radio waves in a high-frequency band exceeding 1 GHz are used, there is a problem that radio waves are highly straightforward and cannot be used in places where satellites cannot be seen or indoors due to obstacles. However, it is often necessary to provide location information according to the location in a specific campus. For example, the information may be information on a sales floor or on the premises of a station.

On the other hand, a position detection method using a PHS
Since the wireless base station has a small structure that can be installed on a telephone pole or an attic, it can be used indoors and outdoors. However, the communication range covered by one wireless base station is 100 m
Therefore, it is practically difficult to use the radio base station in places other than downtown and major roads in terms of the cost of installing a radio base station. Infrared rays have basically the same problem.

[0015] Position detection using a combination of GPS and PHS can solve the above-mentioned problem, but the configuration scale of the terminal is increased, and the size, weight, and power consumption are inevitably increased. You.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a position information providing method capable of detecting a position both indoors and outdoors and making a terminal small and low power consumption. Another object of the present invention is to provide an FM transmission station and a portable terminal used for the system.

[0017]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for performing frequency modulation on position information generated so as to have the same band as an audio signal to obtain an FM modulated signal. Providing location information using an FM transmitting station for transmitting the same FM modulated signal and a portable terminal for DGPS added with a means for extracting location information from a signal in a voice band obtained by demodulating the received FM modulated signal. The solution can be effectively solved by configuring the system.

As described later, the FM transmitting station includes, as main circuits, a circuit for generating position information of a voice band;
It is sufficient to provide an FM modulation unit that performs FM modulation on the position information and transmits it with a low-power high-frequency signal. It is easy to make it about the size of a mobile phone, including an antenna, and is an underground shopping mall where satellite radio waves cannot reach It can be provided everywhere in a building, a station yard, a building, or the like. For example, a building can be provided for each room.

As for the terminal, the portion for receiving the FM radio wave and extracting the FM modulated signal can use the FM multiplex receiving section of the DGPS terminal as it is, and the means for extracting the position information is as follows. , As described below, DG
It can be included in the CPU of the PS terminal. Therefore, the terminal of the present invention can be realized without changing the size and power consumption of the existing portable terminal used for DGPS. As described above, by adopting the above-described solution of the present invention, a position information providing method and system capable of detecting a position regardless of indoors and outdoors and capable of reducing the size of a terminal and reducing power consumption, and An FM transmitting station and a portable terminal used in the system can be realized.

The position information can be represented by characters such as numbers and symbols. By generating such position information using a telephone push button signal (hereinafter referred to as a “PB signal”), the band of the position information can be made the same band as the audio signal. Characters such as numbers and symbols are represented by combinations of PB signals. The content of the position information may be, for example, a room number, a corner number of an underground shopping mall, or the like, depending on the purpose of use, in addition to the position coordinates.

[0021]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an FM transmitting station and a portable terminal according to the present invention; I will explain.

An FM transmitting station for generating position information by a PB signal and transmitting the PB signal as an FM wave with a power of 10 mW, and a DGSP for a CPU having a function of extracting a PB signal from an FM demodulated audio signal to a CPU. FIG. 1 shows an embodiment constituted by a terminal. As will be described in detail later, the position information based on the PB signal is composed of characters using numerals and symbols, and is further multiplexed with a voice signal for guiding the inside of the building, so that the terminal can hear the voice of the inside guidance. . The multiplexing was performed by stereo multiplexing in which the audio signal was on the L side and the position information based on the PB signal was on the R side.

In FIG. 1, reference numeral 200 denotes an FM transmitting station, whose radio waves are received by an FM broadcast receiving antenna 21. Position information based on the PB signal is extracted from the R side of the stereo matrix unit 23. Reference numeral 7 denotes an AD conversion unit that converts the PB signal into a digital signal.

In recent years, a CPU incorporating an AD converter has been realized. Therefore, in this embodiment, such a CPU 1 incorporating the AD converter 1 is used. The output signal digitized by the A / D converter 7 is extracted inside the CPU 1 as position information represented by numerals and symbols. In addition,
When an external A / D converter is used, a signal digitized by the A / D converter 7 is taken into the CPU 1 via the bus 2.

FIG. 2 shows a circuit configuration of the FM transmission station 200. Reference numeral 203 denotes a memory for recording voices such as guides in the hall.
The input signal is converted into an analog signal by the control unit 04. 201 is FM
The PB transmitter 202 generates a PB signal, which will be described later, according to the content of the memory that stores the position information of the transmitting station 200 (denoted as “ID” in the figure). Stereo modulation section 205
Generates the signal (L + R) of the frequency array shown in FIG. 6 and the difference signal (LR) using the audio signal from the DA converter 204 as the L-side input and the PB signal from the PB transmitter 202 as the R-side input. I do. The FM modulation unit 206 includes a stereo modulation unit 205
FM modulation of the baseband signal from
And transmits with a small power of 10 mw. These circuits were mounted on a small substrate.

The PB signal is a low-frequency four sine wave (697
Hz, 770Hz, 852Hz, 941Hz) and high-frequency three sine waves (1,209Hz, 1,366Hz, 1,477Hz)
Is generated by selecting and combining one frequency from each of. For example, when the button “1” is pressed, a signal in which two sine waves of 697 Hz and 1,209 Hz are superimposed is output. In this embodiment, the position information is represented by a combination of numbers (0 to 9) and (*, #). As an example,
There is {## 1234 *}.

The portable terminal of this embodiment receives the FM modulated wave of the PB signal generated in this way. By the way, when the portable terminal receives the radio wave of the FM broadcast station, the audio signal of the broadcast is supplied to the AD converter 7. Therefore, the CPU 1 needs to detect and select only the PB signal from the input signals. A known multi-frequency signal receiving method is employed for such detection (for example,
7-6775). In this embodiment, the receiving method is programmed and stored in the ROM 3. The CPU 1 executes a detection process according to the program. FIG. 3 shows the detection procedure.

The signal received by the AD converter 7 is first subjected to a PARCOR analysis in step 301 (for example, see the Symposium of the Acoustical Society of Japan, S77-06, "Study of a Modified Grid Type PARCOR Analysis-Synthesis Method"). A prediction residual is determined. In step 302, a line spectrum is converted from the PARCOR coefficient (for example, Sonic Speech Society of Japan, S75-34).
"Linear spectrum expression of linear prediction coefficient" is performed, and two frequencies of the PB signal are extracted in step 303. However, if the prediction error in step 301 is a signal equal to or more than a certain threshold, the signal is excluded in step 304 because it is not a PB signal. In this way, only the PB signal is extracted from step 304.

The CPU 1 converts the extracted PB signal into characters such as numbers and symbols, and displays the characters on the liquid crystal display 5.
Further, only the L-side sound is output from the speaker 26. Needless to say, the device that outputs the sound is not limited to the speaker 26, but may be an earphone or a headphone.

The above-described FM transmission station 200 has a small transmission power and can be made to be about the size of a portable telephone including an antenna. This was installed every several tens of meters in the corridor of the premises as shown in FIG. Predetermined position information for distinguishing each FM transmission station is provided. The shaded area shown in FIG. 4 is the range covered by the radio waves of each FM transmission station. Thereby, if the user is within the radio wave reception range, the FM
The own location can be known from the location information of the transmitting station 200.

In this embodiment, the position information and the audio signal for guiding the hall are transmitted in stereo multiplex. However, the present invention is not limited to this. It is also possible to transmit the position information and the audio signal alternately and transmit them in monaural. Further, it is also possible to transmit only the position information in monaural.

In either case, the audio signal is rejected in step 304 so that the audio signal is not mistaken for a PB signal. However, it is necessary to control the output of the stereo matrix unit 23 to the speaker 26 so that the PB signal is blocked. When detecting the PB signal indicating the start of the position information (“#” in the above example), the CPU 1 continues to detect the end of the position information (“*” in the above example) until detecting the PB signal indicating the end of the position information. The stereo matrix unit 23 is controlled so as to interrupt the output from the speaker 26.
As a result, when the position information and the audio signal are alternately transmitted in monaural, the user can hear the sound such as guidance without disturbing the noise of the PB signal, and transmit only the position information in monaural. In this case, the speaker 26 can be set to a silent state.

As described above, when the position information and the audio signal are alternately transmitted in monaural, the stereo modulation section 205 becomes unnecessary, and the FM transmitting station 200 can be provided at a lower cost. When the monaural transmission of only the position information is adopted, the memory 203 and the DA converter 204 are further provided.
Is unnecessary, and the FM transmission station 200 can be made more inexpensive.

[0034]

According to the present invention, it is possible to realize a position information providing system capable of detecting a position both indoors and outdoors and capable of reducing the size of a terminal and reducing power consumption. Since the FM transmission station can also be small and inexpensive, it can be easily installed every several tens of meters in the corridor or in each room of the building, and the in-plant guidance service can be realized at low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of a position information method and system according to the present invention, and an FM transmitting station and a portable terminal used in the system.

FIG. 2 is a circuit diagram illustrating an FM transmitting station according to the present invention.

FIG. 3 is a circuit configuration diagram for explaining an example of a procedure for detecting a PB signal.

FIG. 4 is a layout diagram for explaining an application example of the position information providing system of the present invention.

FIG. 5 is a configuration diagram illustrating a conventional portable communication terminal using DGPS.

FIG. 6 is a diagram for explaining a frequency array of FM multiplexing.

FIG. 7 is a view for explaining an example of a screen for providing position information.

[Explanation of symbols]

1 ... CPU, 3 ... ROM, 5 ... Liquid crystal display, 7 ...
AD converter, 10, 21, 207 ... antenna, 11 ... G
PS receiving circuit, 20: FM multiplex receiving section, 23: stereo matrix section, 26: speaker, 200: FM transmitting station,
201: memory for position information, 202: PB transmitter, 20
5 ... Stereo modulator, 206 ... FM modulator, 300 ... F
M broadcasting station, 400 ... GPS satellite.

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[Procedure amendment]

[Submission date] April 8, 1998

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

FIG. 5

FIG. 6

FIG. 7

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04H 5/00 H04B 7/26 106A

Claims (9)

[Claims] On the transmitting side, position information having the same band as an audio signal is generated, and an FM modulation signal generated by performing FM modulation on the position information is transmitted as a low-power radio wave in the frequency band of FM broadcasting. On the receiving side, the radio wave, the first signal from a GPS (Global Positioning System) satellite, and the DGPS (Differ
In the case of receiving the second signal and the first signal and the second signal, the position information is detected and the error of the position coordinate is corrected, so that the map information is transmitted to the display device. A method for providing position information, comprising: when displaying and receiving the radio wave, extracting position information from a signal in an audio band obtained by the reception, and displaying the extracted position information on the display device. 2. The system according to claim 1, wherein the position information is a signal generated using a telephone push button signal.
Location information providing method described in. 3. A circuit for generating position information having the same band as an audio signal, and an FM modulation for transmitting an FM modulated signal generated by performing frequency modulation on the position information as a low-power radio wave in the frequency band of FM broadcasting. Unit for receiving a signal from a GPS (Global Positioning System) satellite and detecting position coordinates, and receiving a DGPS (Differential GPS) signal from an FM broadcast station Means for correcting position coordinate errors, a display device for displaying map information based on the corrected position coordinates, and means for extracting position information from a voice band signal obtained by receiving radio waves from the FM transmitting station And a portable terminal having means for displaying the retrieved position information on the display device. 4. The apparatus according to claim 3, wherein the position information is a signal generated using a push button signal of a telephone.
Location information providing system described in. 5. A circuit for generating position information having the same band as an audio signal, and an FM for transmitting an FM modulated signal generated by performing frequency modulation on the position information as a low-power radio wave in the frequency band of FM broadcasting. An FM transmission station comprising: a modulation unit. 6. The apparatus according to claim 5, wherein the position information is a signal generated by using a telephone push button signal.
FM transmission station described in. 7. A circuit for multiplexing an audio signal and the position information, wherein the FM modulated signal is a signal generated by performing frequency modulation on a multiplexed signal output from the circuit. 7. The FM transmitting station according to claim 6, wherein: 8. Global Positioning System (GPS)
Means for receiving a signal from a satellite for use to detect position coordinates, and DGPS (Differential GP) from an FM broadcast station.
6. A portable terminal comprising: means for receiving a signal for S) to correct an error in position coordinates, and a display device for displaying map information based on the corrected position coordinates, and A means for extracting position information from a signal in a voice band obtained by receiving a radio wave from the FM transmitting station according to any one of claims 1 to 7, and a means for displaying the extracted position information on the display device. A portable terminal characterized by the following. 9. A means for outputting the sound of the sound signal multiplexed with the position information, and a period of time from when the signal indicating the start of the position information is detected to when the signal indicating the end of the position information is detected. 9. The portable terminal according to claim 8, further comprising means for interrupting the supply of the audio signal to the output means.