JPH10197267A - Fm multiplex broadcast receiving system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an FM multiplex broadcast receiver which can receive FM multiplex data included in broadcast waves of different receiving frequencies while switching. SOLUTION: In order to obtain VICS information or DGPS information by receiving an FM multiplex broadcast of desired receiving frequency, an FM multiplex broadcast receiver 1 comprises a front end 12, an intermediate amplifying/FM detecting circuit 14, a filter circuit 16, an LMSK demodulation circuit 18, an error detecting/correcting circuit 22, a CPU 24, and a selection circuit 30. When a DGPS information receiving command is delivered at a specified timing from a navigation unit 2 through an I/O interface section 28, the CPU 24 makes a switching from VICS receiving frequency to DGPS receiving frequency by delivering a command to the selection circuit 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FM multiplex broadcast receiving system for receiving a plurality of FM multiplex broadcast signals having different reception frequencies.

[0002]

2. Description of the Related Art A road traffic information communication system (VICS) for providing various information such as traffic congestion and traffic regulation to vehicles by FM multiplex broadcasting has been put into practical use, and a driver selects a desired program. A desired VICS service screen can be obtained. The VICS-compatible FM multiplex broadcast receiver is often used in combination with a navigation device having a display device.

[0003] Recently, a differential global positioning system (hereinafter referred to as DG) using other FM multiplex broadcasting has been proposed.
There is a plan to transmit data (referred to as PS) and to correct the positioning position by the GPS receiver used in the navigation device. This DGPS is a GPS receiver that receives and measures a GPS satellite radio wave at a location where an accurate position is known, determines an error thereof, and transmits data such as a correction coefficient of the determined error by FM multiplex broadcasting. In the navigation device which received this, GPS
The above-described error correction is added to the positioning position by the receiver.

[0004]

The above-mentioned V
When attempting to receive both the ICS information and the DGPS information, when the receiving frequency of the FM multiplex broadcasting including each information is different, a separate FM multiplex broadcasting receiver is provided. become. Also, when connecting an external FM multiplex broadcast receiver to an in-vehicle navigation device, it is necessary to secure a space for housing the housings of the two FM multiplex broadcast receivers. There are also cases where it is difficult to mount because it cannot be secured.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to provide an FM multiplex broadcast receiving system which can switch and receive FM multiplex data included in broadcast waves of different reception frequencies. Is to provide.

[0006]

In order to solve the above-mentioned problems, an FM multiplex broadcasting receiver included in an FM multiplex broadcasting receiving system according to the present invention is capable of selectively switching between first and second reception frequencies. An FM multiplex broadcast including first information on an error between a position obtained by receiving a radio wave from an artificial satellite and a known position, and an FM multiplex broadcast including second information such as traffic information. Can be received. Therefore, even when two types of information having different reception frequencies are sent to the navigation device, only one FM multiplex broadcast receiver needs to be connected, so that the device scale does not increase and the cost of the entire system is reduced. be able to.

[0007] In particular, the switching of the reception frequency in the FM multiplex broadcast receiver is performed at the timing instructed by the switch timing instructing means of the navigation device to the frequency switching means of the FM multiplex broadcast receiver. As this timing, a case where the reception frequency is switched when accurate vehicle position data is required in the navigation operation can be considered. In this case, accurate map display, map matching, route guidance, and the like can be performed. Further, as another timing, it is conceivable that second information that is not necessary is transmitted at a predetermined time interval or in this case, and in this case, two types of information can be obtained efficiently. As another timing, a case where switching is instructed by the user can be considered, and accurate vehicle position data can be obtained at an arbitrary timing that the user determines to be necessary.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An FM multiplex broadcast receiving system to which the present invention is applied is a system for receiving FM multiplex broadcasts for VICS and FM multiplex broadcasts for DGPS using a DARC (Data Radio Channel) system. It is characterized in that it is received by the device and the switching is performed at a predetermined timing according to an instruction from the navigation device or the like. Hereinafter, an FM multiplex broadcast receiving system according to an embodiment will be described with reference to the drawings.

FIG. 1 shows an FM according to an embodiment of the present invention.
FIG. 1 is a diagram illustrating a configuration of a multiplex broadcast receiving system, showing a configuration of an FM multiplex broadcast receiver connected to a navigation device. The FM multiplex broadcast receiver 1 shown in FIG. 1 demodulates FM multiplex data from an FM broadcast signal received by an antenna 10 and stores the demodulated data.
2. Intermediate frequency amplification / FM detection circuit (IF / DET) 1
4. Filter circuit 16, LMSK (Level controlled M
inimum Shift Keying) demodulation circuit 18, synchronization circuit 20,
The circuit includes an error detection and correction circuit 22, a CPU 24, a memory 26, and a channel selection circuit 30. Also, this FM
The multiplex broadcast receiver 1 includes an input / output interface (IF) unit 28 for performing various data communications with the navigation device 2 connected to the outside.

The front end 12 includes an antenna tuning circuit, a high frequency amplifier circuit, a local oscillator circuit, a mixing circuit, etc., and performs high frequency amplification on an FM broadcast signal input from the antenna 10 and performs predetermined frequency conversion. Do.
For example, when an FM broadcast signal of a desired frequency to be received is input to the front end 12, it is converted to an intermediate frequency signal of 10.7 MHz. The intermediate frequency amplification / FM detection circuit 14 amplifies the intermediate frequency signal output from the front end 12, performs a tuning operation, and performs an FM detection process on the tuning result. The filter circuit 16 is for separating a multiplex signal included in the signal after the FM detection. When FM multiplex broadcasting using the DARC method is considered, as shown in FIG. 3, the signal after FM detection includes a multiplex signal of about 76 kHz.
The filter circuit 16 extracts only this signal component.

The LMSK demodulation circuit 18 includes a filter circuit 1
The delay detection is performed on the LMSK modulation signal output from 6 to reproduce the bit clock and demodulate the bit data sequence. The synchronization circuit 20 detects the block synchronization and the frame synchronization with respect to the bit data string output from the LMSK demodulation circuit 18, and includes an error detection and correction circuit 22.
, CR is applied to this synchronized bit data sequence.
Error detection by C (Cyclic RedundancyCheck) is performed, and if there is an error, the error is corrected. For example, error correction is performed by a product code using a (272, 190) shortened difference set cyclic code in vertical and horizontal doubles, and error correction is performed with high probability.

The CPU 24 controls the FM multiplex broadcast receiver 1
Is set to either VICS or DGPS, and the error detection and correction circuit 22
Edit the data (data packet) output from
Various data of a higher hierarchy are created. Memory 26
Is used as a work area for the CPU 24, and another part is used as a storage area for various data created by the CPU 24.

The tuning circuit 30 is for setting the receiving frequency of the FM multiplex broadcasting receiver 1, and forms a PLL (phase locked loop) together with a local oscillation circuit in the front end 12. For example, it has a frequency dividing circuit composed of a programmable counter, and by changing the frequency dividing ratio according to an instruction from the CPU 24, the front end 1
The reception frequency is switched by changing the oscillation frequency of the local oscillation circuit in 2.

FIG. 2 is a diagram showing a configuration of the navigation device 2 connected to the FM multiplex broadcast receiver 1 described above. The navigation apparatus 2 shown in FIG. 1 includes a CD-ROM 40 in which map data is stored, an operation panel 42 having various operation keys, a vehicle position and an azimuth in order to independently perform a navigation operation such as map display and route guidance. , A GPS receiver 44 for detecting a traveling distance, a direction sensor 46, a distance sensor 48, a navigation controller 50 for performing map display control, map matching processing, and the like, and a display device 70.

The navigation controller 50 includes a map data memory 52 for temporarily storing map data, a CPU 54 for performing various arithmetic processes,
A memory 56 for storing a processing result by U54, a CPU
VRAM for storing the image data created by 54
58, and a video conversion unit 60 that reads out image data stored in the VRAM 58, converts the image data into an analog video signal, and outputs the analog video signal to the display device 70.

The navigation controller 50
Is provided with an input / output interface (IF) unit 62 for receiving data received by the FM multiplex broadcast receiver 1 shown in FIG. 1 and sending a reception frequency switching instruction to the FM multiplex broadcast receiver 1. The navigation device 2 described above displays various types of traffic information based on the VICS information sent from the FM multiplex broadcast receiver 1 or displays positioning information from the GPS receiver 44 based on the DGPS information. It also has a function to make corrections.

CPU 2 of FM multiplex broadcast receiver 1 described above
4 and the tuning circuit 30 correspond to frequency switching means. The CPU 54 of the navigation device 2 corresponds to the switching timing instructing unit and the position correcting unit, and the navigation controller 50 corresponds to the display unit. Also, the DGPS information described above or described below is used as the first information,
When the reception frequency of the DGPS information is set to the first reception frequency, VI
CS information as the second information, VICS information reception frequency as the second reception frequency, DGPS information reception instruction sent from the navigation device 2 to the FM multiplex broadcast receiver 1, reception frequency switching from the navigation device Each corresponds to an instruction.

Next, a part of the hierarchical structure of the FM multiplex broadcasting using the DARC system will be briefly described. F mentioned above
The hierarchical structure of the DARC to be processed by the M multiplex broadcast receiver 1 includes a layer 1 for a transmission path, a layer 2 for error correction, a layer 3 for data packets, and the like. VIC containing traffic information
The S data and the DGPS data including the correction coefficient for the GPS positioning position are basically common.

The layer 1 of the transmission path corresponds to the signal (baseband signal) after the FM detection output from the above-mentioned intermediate frequency amplification / FM detection circuit 14. As shown in FIG. 3, the signal after FM detection has an FM of about 76 kHz.
A multiplexed signal is included, and only this FM multiplexed signal is separated by the filter circuit 16 and the LMSK demodulation circuit 18
Through which the FM corresponding to this FM multiplex broadcast signal
Multiple data is obtained.

The layer 2 for error correction indicates a frame structure for performing error detection and error correction. FIG.
3 is a diagram showing a frame structure corresponding to layer 2. FIG. As shown in the drawing, the FM multiplex broadcast data output from the LMSK demodulation circuit 18 is composed of a total of 272 blocks per frame, of which 190 blocks are blocks containing data packets, and the remaining 82 blocks are parity packets. It is a block containing. These 82 blocks are distributed among blocks including data packets.

The synchronization circuit 20 has a block identification code BIC (Block Identify Cod) included in the head of each block.
Block synchronization and frame synchronization are achieved by detecting e). Further, the error detection and correction circuit 22 detects an error of each bit data constituting the data packet based on a CRC included in each block, and when an error is detected, corrects the error using a parity packet or parity. Do.

The VICS information is transmitted by using a data packet included in 190 blocks in one frame shown in FIG. The DGPS data is transmitted using two data packets in the 190 blocks.

Layer 3 shows the structure of a data packet, the details of which are shown in FIG. As shown in the figure, each data packet has a 32-bit or 16-bit prefix, and the remaining 144 bits or 1-bit.
It is configured to include a data block of 60 bits. The prefix at the beginning is added to identify a data block which is information content, and a service identification SI,
It consists of a decoding identification flag, an information end flag, an update flag, a data group number, and a data packet number.

In the case of VICS information including traffic information,
A plurality of data blocks included in the above-described data packet are collected to form a data group of hierarchy 4 corresponding to each page of the display screen. In the case of DGPS information, as shown in FIG. 6, two data blocks included in the above-described data packet are collected, and a data group of layer 4 including DGPS data necessary for correcting the GPS positioning position is formed. It is formed.

Next, the operation of the FM multiplex broadcast receiving system according to the present embodiment will be described. First, FM multiplex broadcast receiver 1
Will be described when switching between the operation of receiving VICS information and the operation of receiving DGPS information.
The operation of the navigation device 2 that sends a reception frequency switching instruction to the multiplex broadcast receiver 1 will be described.

FIG. 7 is a flowchart showing the operation procedure of the FM multiplex broadcasting receiver, and mainly shows the operation procedure of the CPU 24. The FM multiplex broadcast receiver 1 shown in FIG. 1 normally receives VICS information, and receives the DGPS information from the navigation device 2 when the DGPS information reception instruction is sent.
An information receiving operation is performed.

First, the CPU 24 sends an instruction to the channel selection circuit 30 to set the reception frequency to the frequency of a broadcast wave on which VICS information is multiplexed (for example, 82.5 MHz) (step 100). Thereafter, the CPU 24 checks whether or not a DGPS information reception instruction has been sent from the navigation device 2 (step 101). If this instruction has not been sent, the CPU 24 next checks whether or not there is a data packet including VICS information. Monitoring (Step 102), when a data packet corresponding to the VICS information is output from the error detection and correction circuit 22, the data is edited while temporarily storing the data packet in a work area in the memory 26 (Step 103). . For example, a data group (layer 4) including any of the traffic information of service identifications 4 to 6 is created. When the data editing is completed, the CPU 24
Transmits the edited data to the navigation device 2 via the input / output interface unit 28 (step 104). The reception of the data corresponding to the VICS information and the transmission of the data to the navigation device 2 are repeated until the navigation device 2 sends a DGPS information reception instruction.

When a DGPS information reception instruction is sent from the navigation device 2, the CPU 24 next sends an instruction to the channel selection circuit 30 to change the reception frequency to the frequency of the broadcast wave (for example, 80) where the DGPS information is multiplexed. .0 MHz) (step 105), and the presence or absence of a data packet including DGPS information is monitored (step 106). When a data packet corresponding to the DGPS information is output from the error detection and correction circuit 22, the data packet is stored in the memory 2
6 and temporarily edit the data (step 10).
7). As shown in FIG. 6, 2 corresponding to the DGPS information
One data packet forms one data group, and DGPS data included in this data group is extracted. Next, the CPU 24 sets the D
The GPS data is transmitted to the navigation device 2 via the input / output interface unit 28 (step 10).
8). After the data transmission is completed, the process returns to step 100, the receiving frequency is switched again to receive the VICS information, and the reception of the data corresponding to the VICS information and the transmission of the data to the navigation device 2 are repeated.

As described above, the FM multiplex broadcast receiver 1 of the present embodiment performs the operation of receiving VICS information during normal operation, and changes the reception frequency only when the navigation device 2 instructs to receive DGPS information. Switch to DGP
S information has been received. Therefore, one FM multiplex broadcast receiver 1 can receive both VICS information and DGPS information.

Next, the above-described FM multiplex broadcast receiver 1
The operation of the navigation device 2 that sends a GPS information reception instruction will be described. The timing at which the navigation device 2 sends a DGPS information reception instruction to the FM multiplex broadcast receiver 1 is as follows: (1) When the navigation device 2 is needed,
Send GPS information reception instruction, (2) DGP at predetermined intervals
Sends S information reception instruction, (3) Sends DGPS information reception instruction when it is not necessary to receive VICS information, (4)
It is conceivable to send a DGPS information reception instruction when a predetermined key input is made by a manual operation of the user. It is assumed that which timing is used is set in advance. Hereinafter, each will be described.

(1) Operation when DGPS information reception instruction is sent when navigation device 2 itself determines that it is necessary FIG. 8 is a flowchart showing the operation procedure of the navigation device, and mainly shows the operation procedure of CPU 54. ing. CP
The U54 monitors whether or not a DGPS information reception request has occurred in parallel with the map display processing and the route guidance processing as a normal operation (step 200). This DGPS information reception request is generated at a timing when it is considered preferable to correct the GPS positioning position during the map display processing or the route guidance processing, and a specific example thereof will be described later. When the DGPS information reception request does not occur, the CPU 54 sends the VICS
When the information is sent (step 201), this VIC
The traffic information included in the S information is displayed (step 20).
2).

When a DGPS information reception request is issued, the CPU 54 sends a DGPS information reception instruction to the FM multiplex broadcast receiver 1 via the input / output interface unit 62 (step 203). (Step 204). Thereafter, when DGPS information is transmitted from the FM multiplex broadcast receiver 1, the CPU 54 next uses the correction data included in the transmitted DGPS information (DGPS data shown in FIG. 6) to
The positioning position calculated based on the detection output of the GPS receiver 44 is corrected (step 205). Thereafter, the process returns to step 200 (monitoring the DGPS information reception request) and the process is repeated.

Next, a specific example in which the above-described DGPS information reception request is generated, that is, a specific example in which it is considered preferable to correct the GPS positioning position when performing the map display processing, the route guidance processing, and the like will be described. I do.
FIG. 9 is a flowchart illustrating an example of a normal map display process performed by the navigation device. When the power switch (not shown) of the navigation device 2 is turned on and the power is turned on, the CPU 54 first detects the own vehicle position based on the output of the GPS receiver 44 (step 300), and this detection is performed. Map data around the position of the own vehicle
And stores it in the map data memory 52 (step 301), and draws a map image on a predetermined scale so that the own vehicle position is at the center of the screen to display the map (step 30).
2). Next, the CPU 54 determines whether the vehicle has traveled a predetermined distance (step 303) or whether the traveling route of the vehicle deviates from a road on the map and a map matching process is required (step 304). If the vehicle has traveled a predetermined distance, the process returns to step 301 to read out new map data from the CD-ROM 40, and the process is repeated. If it is determined that map matching is required, the map matching is performed (step 305). ), The process returns to step 302, and the display of the map data centering on the own vehicle position is repeated. When performing hybrid navigation using the GPS receiver 44, the azimuth sensor 46, and the distance sensor 48 in combination, for example, autonomous navigation using the azimuth sensor 46 and the distance sensor 48 is mainly used, and the GPS navigation is used supplementarily.

In such a normal map display operation,
It is preferable to generate a DGPS information reception request at the timing shown below and to correct the GPS positioning position based on the DGPS data.

A. B. Correct the GPS positioning position by DGPS data when detecting the vehicle position in step 300 immediately after turning on the power. During several minutes after the power is turned on, the temperature drift of the gyro built in the direction sensor 46 is large.
B. Correct the S positioning position by DGPS data to obtain an accurate host vehicle position. A step of determining whether the vehicle is stopped is inserted before or after step 302, and the GPS positioning position is corrected only once with the DGPS data when the vehicle is stopped, and otherwise, traffic information based on VICS information is displayed. . D. When the detection result of the autonomous navigation by the azimuth sensor 46 and the distance sensor 48 deviates from the GPS positioning position, correction is performed using DGPS data. If the map matching process of step 305 is performed and there is no road on the candidate map,
Perform correction using PS data. In the case of performing the map matching process in step 305, after extracting and attracting roads on a map as a candidate, the GPS positioning position is corrected based on the DGPS data, thereby confirming whether the extracted road is correct. G. When the map matching process of step 305 is performed and the number of roads on the candidate map is large,
Perform correction using DGPS data. When the map matching process of step 305 is performed by comparing the altitude data included in the map data (or to be included in the future) with the GPS measurement altitude, the DG
Correction by PS data I. When the pre-reading of the link on which the vehicle travels is performed (when the next intersection where the vehicle travels is enlarged and displayed) and the vehicle passes through a road with a small branch angle, the DGP
Correction by S data J. When the map matching process of step 305 is performed and the width of the road on which the vehicle is traveling is narrow, there may be a large number of candidate roads.
Perform correction using PS data. When an elevated toll road and a general road overlap, it is possible to determine which road the vehicle is traveling on, or the accuracy of autonomous navigation is not good due to a large elevation difference such as a mountain road (map data from the sky) This is a plan view as viewed. In the case of a sloping road, the road length on the map data is shorter than the actual road length, so that the position measured by the distance sensor 48 and the road position on the map data are shifted.) Sometimes, GPS measurement altitude is corrected by DGPS data. When the vehicle speed data output from the GPS receiver 44 and the vehicle speed data output from the speed sensor installed in the vehicle are shifted, the correction is performed using the DGPS data.

FIG. 10 is a diagram showing an example of a normal route guidance process performed by the navigation device. Prior to this route guidance operation, various settings such as a destination are input in advance, a route search is performed so as to connect the own vehicle position and the destination under predetermined conditions, and a guidance route is set. It is assumed that this guidance route is stored. When the driver instructs the start of the route guidance process, the CPU 54 performs a predetermined route guidance operation (steps 400 and 401). For example, as in steps 301 and 302 shown in FIG. 9, the map data around the own vehicle position is read from the CD-ROM 40, and a map image is drawn so that the own vehicle position is at the center of the screen to display the map. In addition, a guidance route is displayed while being superimposed on this map, and a guidance instruction is given by voice when approaching an intersection or a branch road. CPU5
No. 4 monitors whether the vehicle position has deviated from the guidance route (step 402), and if it has deviated, searches for the guidance route again (step 403) and continues the route guidance along the new guidance route. I do.

In such a normal route guidance operation,
It is preferable to generate a DGPS information reception request at the timing shown below and to correct the GPS positioning position based on the DGPS data.

M. When monitoring whether the vehicle has deviated from the guidance route in step 402 by comparing a predetermined guidance route with the GPS positioning position, correction is performed using DGPS data. When searching for a new guidance route in step 403, the GPS positioning position is corrected with the DGPS data in order to confirm whether or not the own vehicle position is on the newly set guidance route. In the route guidance in step 401, when approaching the destination, correction is made with DGPS data for confirmation.

(2) Operation when DGPS Information Reception Instruction is Transmitted at Predetermined Intervals FIG. 11 is a flowchart showing the operation procedure of the navigation device when requesting DGPS information at predetermined intervals, and mainly shows the operation of the CPU 54. The procedure is shown. The operation procedure shown in FIG. 11 corresponds to step 200 of the operation procedure shown in FIG.
(Monitoring whether there is a DGPS information reception request)
The difference is that the operation is replaced with the operation of step 500 for monitoring whether or not a fixed time has elapsed after receiving the GPS data. That is, when VICS information is transmitted from the FM multiplex broadcast receiver 1 until a certain time has elapsed (step 201), the CPU 54 displays traffic information included in the VICS information (step 202). Also, C
The PU 54 sets the FM multiplex broadcast receiver 1
A DGPS information reception instruction is sent to the user (step 20).
3) When the DGPS information is received (step 204), the DGPS information is sent.
The positioning position of the GPS receiver 44 is corrected using the correction data included in the information (step 205). Note that the constant interval monitored in step 500 described above is set to, for example, about 5 seconds, 10 seconds, or 15 seconds. Further, if DGPS information is included in the first two blocks in one frame shown in FIG. 4, the transmission of DGPS information is repeated at a predetermined cycle in which this one frame is transmitted. A DGPS information reception instruction may be sent to the FM multiplex broadcast receiver 1 every cycle, and VICS information may be received at other timings.

(3) Operation When Sending DGPS Information Receiving Instruction When It Is Not Necessary to Receive VICS Information FIG. 12 shows the operation procedure of the navigation apparatus when the same unupdated VICS information is sent. It is a flowchart shown. When the VICS information is transmitted from the FM multiplex broadcast receiver 1 (step 600), the CPU 54 transmits the transmitted VICS information to the VIC already transmitted.
It is checked whether it is the same as the S information (step 601),
For example, if any of the program number and the page number is different, it is determined that the information is new VICS information, and the traffic information included in the transmitted VICS information is displayed (step 602). If both the program number and the page number are the same, it is determined that they are the same VICS information,
Next, the CPU 54 sends a DG to the FM multiplex broadcast receiver 1.
A PS information reception instruction is sent (step 603), and DGP
It is in a state of waiting for reception of S information (step 604), and D
When the GPS information is sent, the positioning position of the GPS receiver 44 is corrected using the correction data included in the DGPS information (step 605).

(4) Operation When Sending DGPS Information Receiving Instruction When Predetermined Key Input by Manual Operation of User FIG. 13 shows a case where the user operates predetermined keys provided on operation panel 42. 9 is a flowchart illustrating an operation procedure of the navigation device 1 when manually instructing the switching of the reception frequency.
Step 200 (monitoring whether there is a DGPS information reception request) of the operation procedure shown in FIG. 8 is performed by monitoring whether a predetermined key of the operation panel 42 is pressed and a frequency switching instruction for receiving DGPS information is issued. The difference is that the operation is replaced by the operation of step 700. That is, the CPU 54
Until an instruction to manually switch the receiving frequency is received, when VICS information is transmitted from the FM multiplex broadcasting receiver 1 (step 201), the traffic information included in the VICS information is displayed (step 202). ). Also, C
When the PU 54 is instructed to switch the reception frequency manually, the PU 54 sends a DGPS information reception instruction to the FM multiplex broadcast receiver 1 (step 203), and waits for reception of the DGPS information (step 204). When the DGPS information is sent, the positioning position of the GPS receiver 44 is corrected using the correction data included in the DGPS information (step 205).

The case where the user manually instructs frequency switching for receiving DGPS information means a case where more advanced position information is required. When it is determined that accurate vehicle position detection is not possible with navigation, or when a tire chain is installed to travel on snowy or frozen roads, the diameter of the tire changes, and accurate There may be a case where it is determined that the vehicle position cannot be detected. In these cases, the distance correction data learned so far becomes useless, so it is necessary to reset the learning, and the GPS information is received by the above-described DGPS information reception.
It is preferable to correct the positioning position of the receiver 44. Also, immediately after the navigation device 2 is mounted on the vehicle, the learning reset is applied. Until the vehicle travels a predetermined distance and learns the distance correction, the position detection accuracy of the navigation device 2 is low. Is D
It is preferable to correct the positioning position of the GPS receiver 44 by receiving the GPS information.

As described above, the FM multiplex broadcast receiving system according to the present embodiment uses a single FM multiplex broadcast receiver 1 to switch the receiving frequency to use the VIC.
Since it is possible to receive the FM multiplex broadcast including the S information and the FM multiplex broadcast including the DGPS information, the device scale can be reduced, the occupied space can be reduced, and the cost can be reduced.

In particular, VICS information and DGPS information do not always need to be continuously received, and there is no practical problem even if they are switched at the required timing and received. The switching timing includes (1) when the navigation device 2 determines that it is necessary, (2) at predetermined intervals, and (3) when it is not necessary to receive VICS information.
(4) It is conceivable that there is a manual instruction from the user. The timing (1) is when the navigation device 2 needs an accurate GPS positioning position to perform a predetermined process, and the GPS corrected by the DGPS data.
The use of the measured position enables map matching and route guidance accompanying accurate vehicle position detection. Also,
If the reception frequency of the DGPS information is switched in accordance with the transmission cycle of the DGPS information as the timing of (2), the DGPS information is transmitted only for a short time when the DGPS information is transmitted.
GPS information is received and most of the other time is VI
CS information can be received, and both information can be received efficiently. The timing of (3) is VIC
Although this is for receiving the S information preferentially, it is possible to efficiently receive both pieces of information by utilizing the idle time during which the same data is sent. The timing of (4) includes a case where the detection accuracy of the vehicle position by the autonomous navigation is reduced and a case where it is difficult for the navigation device 2 itself to determine the position. Even in such a case, the DGP
Since an accurate GPS positioning position corrected by the S data can be obtained, map matching and route guidance accompanying accurate vehicle position detection can be performed as in the case of (1).

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, in the above-described embodiment, the navigation device 2 sends a DG
When the PS information receiving instruction is sent, the receiving frequency is switched in the FM multiplex broadcasting receiver 1. However, when the receiving frequency is switched for DGPS information every fixed time, or when the same VICS information is transmitted. When the reception frequency is switched for the DGPS information upon reception, the CPU 24 in the FM multiplex broadcast receiver 1 may determine these switching timings.

In the above-described embodiment, the DGPS data sent from the FM multiplex broadcast receiver 1 is input to the navigation controller 50.
You may make it input into the S receiver 44. That is,
As shown in FIG. 14, the DGPS of the FM multiplex broadcast receiver 1
The output terminal is connected to the DGPS input terminal of the GPS receiver 44. Then, the GPS receiver 44 sends D
When receiving the GPS input instruction, it receives DGPS data from the FM multiplex broadcast receiver 1 and
The PS positioning position is corrected, and the corrected position data is
4 may be sent.

[0047]

As described above, according to the present invention, the first
And a first FM multiplex broadcast including first information about an error between a position obtained by receiving a radio wave from an artificial satellite and a known position, and a second reception frequency that is selectively switchable. Since it is possible to receive the second reception frequency including the traffic information and to send two types of information having different reception frequencies to the navigation device, it is only necessary to connect one FM multiplex broadcast receiver. In addition, the size of the apparatus is not increased, and the cost of the entire system can be reduced.

In particular, the switching of the reception frequency in the FM multiplex broadcasting receiver is performed at the timing instructed by the timing switching instructing means of the navigation device to the frequency switching means of the FM multiplex broadcasting receiver. Vehicle position data can be obtained, or two types of information can be efficiently obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an FM multiplex broadcast receiving system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a navigation device connected to the FM multiplex broadcast receiver shown in FIG.

FIG. 3 is a diagram showing a transmission path signal of layer 1;

FIG. 4 is a diagram showing a frame structure corresponding to layer 2;

FIG. 5 is a diagram showing a structure of a data packet of layer 3;

FIG. 6 is a diagram illustrating a structure of DGPS data included in two data packets.

FIG. 7 is a flowchart showing an operation procedure of the FM multiplex broadcast receiver.

FIG. 8 is a flowchart showing an operation procedure of the navigation device when a DGPS information reception instruction is sent when necessary.

FIG. 9 is a flowchart illustrating an example of a normal map display process performed by the navigation device.

FIG. 10 is a diagram illustrating an example of a normal route guidance process performed by the navigation device.

FIG. 11 is a flowchart showing an operation procedure of the navigation device when requesting DGPS information at predetermined intervals.

FIG. 12 is a flowchart illustrating an operation procedure of the navigation device when the same VICS information that has not been updated is transmitted.

FIG. 13 is a flowchart showing the operation procedure of the navigation device when the user manually instructs the switching of the reception frequency.

FIG. 14 is a diagram showing a configuration of a modification of the present embodiment.

[Explanation of symbols]

 Reference Signs List 1 FM multiplex broadcast receiver 2 Navigation device 12 Front end (F / E) 14 Intermediate frequency amplification / FM detection circuit (IF / DET) 16 Filter circuit 18 LMSK demodulation circuit 20 Synchronization circuit 22 Error detection and correction circuit 24, 54 CPU 26 , 56 memory 28, 62 input / output interface (IF) unit 30 channel selection circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04H 1/00 H04H 1/00 CE

Claims (6)

[Claims] An FM multiplex broadcast receiver for demodulating FM multiplex data from a received FM multiplex broadcast, and a navigation device connected to the FM multiplex broadcast receiver
In the multiplex broadcast receiving system, the FM multiplex broadcast receiver includes a first information including an error between a position obtained by receiving a radio wave from an artificial satellite and a known position as the FM multiplex data. An FM multiplex broadcast having a reception frequency, and an FM multiplex broadcast having a second reception frequency in which second information including traffic information is included as the FM multiplex data by selectively switching and receiving, An FM multiplex broadcast receiving system, wherein a predetermined process is performed based on the first and second information sent from the FM multiplex broadcast receiver. 2. The FM multiplex broadcast receiver according to claim 1, wherein the FM multiplex broadcast receiver switches a reception frequency to a first reception frequency or a second reception frequency according to a reception frequency switching instruction sent from the navigation device. Frequency switching means, wherein the navigation device obtains by receiving a radio wave from an artificial satellite based on the first information, and a switching timing instructing means for instructing a predetermined timing for switching a receiving frequency by the frequency switching means. And a position correcting means for correcting the determined position, and a display means for displaying traffic information or the like based on the second information.
A multiplex broadcast receiving system. 3. The switching timing instructing unit according to claim 2, wherein the switching timing instructing unit instructs the switching timing of the reception frequency by the frequency switching unit when accurate vehicle position data is required in the navigation operation. FM multiplex broadcast receiving system. 4. The FM multiplex broadcast receiving system according to claim 2, wherein the switching timing instructing unit instructs a switching timing of a reception frequency by the frequency switching unit at predetermined time intervals. 5. The switching timing instructing unit according to claim 2, wherein the switching timing instructing unit is configured to switch from the second receiving frequency to the first receiving frequency by the frequency switching unit when the unnecessary second information is transmitted. An FM multiplex broadcast receiving system for instructing a timing of switching to (i). 6. The FM multiplex broadcast reception according to claim 2, wherein the switching timing instructing unit instructs a switching timing of a reception frequency by the frequency switching unit when switching is instructed by a user. system.