KR100722092B1 - Receiver for navigation apparatus and frequency switching method thereof - Google Patents

Abstract

Receiving apparatus of a car navigation apparatus which enables to automatically select an information broadcasting station which provides the largest amount of information of road traffic information in the vicinity of one's car among information broadcasting stations which can be received at the position of own car For the purpose of providing an information storage device comprising: information storage means for storing information of each mesh area, information size storage means for storing information size, and each information provided from an information broadcasting station received by the reception means. Information storage means for accumulating the information of the mesh area in the information storage means, information size registration means for acquiring the information size of the information stored in the information storage means and registering or updating the information in the information size storage means, and position detecting means of the car. Received each read from the information size storage means of the mesh area to which the own vehicle position belongs, detected by And information size comparison switching means for comparing the information size of the frequencies and switching the detection frequency of the receiving means to the reception frequency having the largest information size.

Description

Receiving device of car navigation system and its frequency switching method {RECEIVER FOR NAVIGATION APPARATUS AND FREQUENCY SWITCHING METHOD THEREOF}

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing the device configuration of a receiving device according to a first embodiment of the present invention.

2 shows a data format of a data frame.

3 shows the data format of the data packet of FIG.

4 illustrates the data format of a data group.

5 is a diagram showing a data structure stored in an SRAM.

6 is a flowchart showing the operation of the data group construction unit.

7 is a flowchart showing a processing operation of an information size updating unit.

8 is a flowchart showing processing operations of an update history processing unit.

Fig. 9 is a diagram showing the configuration of an update information size table.

10 is a flowchart showing an operation of creating an update information size table of an update history processing unit;

Fig. 11 is a flowchart showing the processing operation in which the update information size table of the update history processing unit is reflected in the SRAM.

Fig. 12 is a flowchart showing a processing operation for updating mesh data already existing in the information size table of the update history processing unit.

Fig. 13 is a flowchart showing a processing operation of adding mesh data not included in the SRAM of the update history processing unit.

Fig. 14 is a flowchart showing a processing operation for deleting distant mesh area information of an SRAM of an update history processing unit.

Fig. 15 is a flowchart showing a switching request processing operation of detection frequency by comparing an error rate of an error rate comparison switching unit.

Fig. 16 is a flowchart showing a switching request processing operation of detection frequency by comparing the information sizes of the information size comparison switching unit.

17 is a flowchart showing a switching process of detection frequencies.
(Explanation of symbols of main part of drawing)
1: receiving antenna 2: detection station
3: PLL frequency demodulator 4: DARC decoder
5: DRAM 6: SRAM
7: Data group builder 8: Information size updater
9: update history processor 10: information size read processor
11: information size comparison switch 12: error rate comparison switch
13: switch judgment unit 14: clock
15: information size table updating unit 16: zero clear processing unit
17: GPS antenna 18: GPS receiver
19: magnetic car position detection unit 20: map information storage unit

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a car navigation apparatus, comprising: a reception apparatus for receiving road traffic information from each information broadcasting station of a road traffic information system, wherein among the information broadcasting stations that can be received at the current car position, The present invention relates to a receiving device for automatically tuning an information broadcasting station that provides the most road traffic information around a location, and a frequency switching method thereof.

Recently, operation of a road traffic information system for providing road traffic information of each region to a driving car using FM multicasting or the like has been started, and accordingly, the road traffic information provided is received and congested. BACKGROUND ART An automobile navigation apparatus that performs optimal guidance by displaying information such as information, accident information, construction information, etc. on a map has been researched and developed.

In such a road traffic information system, regions on a map are divided into mesh regions, and information broadcast stations in each region provide information of mesh regions belonging to a service region. Since each information station performs broadcasting by radio waves of different frequencies, in order to receive road traffic information from a moving car, whenever the service area of the information station changes, it is necessary to track by retuning to a new information station. There is. In particular, when traveling at a high speed and traveling near the boundary of the service area of each information broadcasting station, it is inconvenient for the user to perform the tracking frequently, so that the vehicle navigation can automatically execute such tracking. A receiving device of the device is required.

As a conventional receiving apparatus, Japanese Patent Publication No. JP-A-6-274792 discloses "receiving means for receiving information from a predetermined information broadcasting station which is supplied separately for each region of the region within the reception region. A motor vehicle comprising: a vehicle position detecting means for detecting a driving position of a vehicle and a memory means for storing the area information near the driving position detected by the vehicle position detecting means; The information storage device of a motor vehicle "is disclosed.

The information storage device of a motor vehicle disclosed in the above publication is to store information in a mesh area that has once traveled and to use information stored in the past when traveling in the same mesh area again.

However, the above conventional receiving apparatus has a problem that it is not possible to cope with road traffic information that changes at any time, such as the occurrence of heavy traffic and accidents, and that the provided road traffic information cannot be utilized effectively.

Therefore, in order to perform automatic tracking in response to such time-changing road traffic information, an error rate when receiving an information broadcast signal during reception is detected at each time point, and a time when the error rate exceeds a certain threshold is predetermined. If it continues for more than a time, it may be determined that the difference is out of the service area of this information broadcasting station, and may consider automatically tuning to an information broadcasting station having a good reception state.

However, when such automatic tracking is performed, there are the following problems.

(1) When the vehicle is traveling in a place where radio wave reception conditions are poor, such as a shade of a tunnel and a shield while driving, it is incorrectly determined that it has left the service area of the information broadcasting station, and frequency switching of the information broadcasting station is performed. Since road traffic information is provided at a time interval of 1 to 5 minutes, once frequency switching is performed, it takes time to accumulate information and it becomes impossible to effectively use road traffic information that changes in time.

(2) On the contrary, if the frequency switching is not performed unless the error rate continues for more than a predetermined time or more, the reception state is intermittently satisfactory even when the service station is out of the service area of the information broadcasting station. When a situation arises, frequency switching is rarely performed, and information of information broadcasting stations other than the service area is continuously received, so that road traffic information cannot be effectively used.

(3) In urban areas, the service area of each information broadcasting station often crosses, and in such a case, when the information broadcasting station having a good reception state is automatically tuned and used, all searches are appropriate. It takes time and the road traffic information which changes in time cannot be utilized effectively.

(4) In the case of traveling on a bridge hanging on the sea, etc., the reception state of an alternative information broadcasting station across the sea may be satisfactory. In this case, if frequency switching is performed, the service area Since the information of the outside information broadcasting station is received, the road traffic information cannot be effectively used.

(5) In the vicinity of the service area boundary of each information broadcasting station, road traffic information provided by the information broadcasting station located in the forward direction is required. In order to do this, it is necessary to tune into the information broadcasting station located in the forward direction. . However, when the reception state of the information broadcasting station located behind the traveling direction which has been continuously received so far does not deteriorate, the frequency switching is not performed and although the useful road traffic information is provided from the receivable information broadcasting station, the road Traffic information will not be available effectively.

MEANS TO SOLVE THE PROBLEM This invention solves the said conventional subject, Comprising: It is possible to switch the selection of the information broadcasting station according to the broadcast reception state in the position of own vehicle, and, among the information broadcasting stations which can be received in the position of own vehicle, It is an object of the present invention to provide a vehicle navigation apparatus reception apparatus that enables automatic tuning of an information broadcasting station that provides the largest amount of information of nearby road traffic information, thereby enabling effective utilization of road traffic information provided by the information broadcasting station. It is done.

Furthermore, the present invention solves the above-mentioned conventional problems, and among the information broadcast stations that can be switched between the stations of the information broadcast station and the reception of the information broadcast station at the position of the car, Frequency switching of the receiving device of the car navigation apparatus, which makes it possible to automatically tune into an information broadcasting station that provides the most amount of information of road traffic information near the car position, thereby making effective use of the road traffic information provided by the information broadcasting station. It is an object to provide a method.

(Embodiment 1)

The receiving device of the present embodiment is a receiving device mounted in an automobile navigation apparatus that receives and reproduces VICS (Vehicle Information and Communication System) information transmitted from an FM broadcasting station which is an information broadcasting station by FM multicasting. In accordance with the movement of the vehicle, the detection frequency is automatically switched by the frequency switching method of selecting a broadcasting station that transmits the optimal information at the position of the vehicle.

In FM multicasting, the VICS information is transmitted as 1 to a plurality of data groups at intervals of 1 to 5 minutes. The data group is also composed of a plurality of data blocks, and the VICS information is transmitted as an FM full-wave signal in a data packet as a data block. The reception apparatus of the present embodiment reproduces data blocks after performing error correction on the received data packets, and combines the data blocks in a predetermined order, thereby establishing a data group and reproducing VICS information. The optimum FM broadcast station is tuned in accordance with the error rate at the time of reception in case of reception and the amount of information around the own vehicle position included in the received VICS information.

1 is a block diagram showing an apparatus configuration of a receiving apparatus according to a first embodiment of the present invention.

In Fig. 1, 1 is a receiving antenna for receiving FM radio waves, 2 is a detection selecting section for detecting a received FM received signal and executing tuning to output a detected signal, and 3 is a phase-locked signal that is synchronized with the FM received signal. Phase locked loop demodulator (PLL) demodulator outputting the detection frequency signal of the local section 2, 4 decodes the output FM reception signal of the detection channel section 2 and outputs a data packet. At the same time, a DARC (Data Radio Channel) decoder that measures the error rate during decoding and outputs the error rate on demand, 5 is a dynamic random access memory (DRAM) for storing a data group (described later), and 6 is a Static random access memory (SRAM), which stores and maintains the size of the data group corresponding to each frequency, 7 creates a data group from data packets output from the DARC decoder 4 to the DRAM 5. The data group construction unit 8 for updating the data group stored in the memory 5 or the DRAM 5, the error rate Perr outputted by the DARC decoder 4 is accumulated for a predetermined time so that the reception time integration value Serr is equal to or less than a predetermined threshold Smax. In this case, the size of the data group (hereinafter referred to as information size) S0 (fx, My) corresponding to the current frequency fx and mesh area y (mesh code My) stored in the SRAM 6 is outputted. The information size update unit 9 stores the information size S0 (fx, My) and the information size update unit 8 in the information size S0 (fx, My) and the SRAM 6 when the information size update request is inputted from the information size update unit 8. The information size S1 (fx, My) corresponding to the current frequency fx of the current mesh area y is compared and stored in the SRAM 6 when S1 (fx, My) <S0 (fx, My). Update history processor for updating information size S1 (fx, My) to current information size S0 (fx, My), 10 is frequency fx, mesh area y When there is a request for reading the corresponding information size S1 (fx, My), the size S1 (fx, My) of the previous data group stored in the SRAM 6 and the size S2 of the data group of the last day ( an information size reading processing unit for comparing fx, My) and outputting the larger one as the information size S3 (fx, My); and 11, information size S3 of the mesh area y of the current position input from the information size reading processing unit 10; Comparing (fx, My) with information size S3 (fi, My) of the mesh area y of the current position, which is the frequency fi (i ≠ x) of the neighboring stations, S3 (fx, My) <S3 (fi, My) In the case, the information magnitude comparison switching unit for outputting the switching request S2 to the frequency fi, 12 is a case where the error rate Perr output from the DARC decoder 4 continues to be smaller than the threshold value? For a predetermined time T2 (e.g., 6 minutes). Outputs a switching request S1 to the frequency fi (i is a suitable station other than the station x) of the other station including the mesh area y. When the switching request S1 or S2 is inputted from the information magnitude comparison switching unit 11 and the error rate comparison switching unit 12, the error rate comparison switching unit 13 indicates the set frequency of the PLL frequency demodulator 3 from the current frequency fx to the frequency fi. When switching is performed and the frequencies do not match (they cannot be in phase synchronization) or when data packets are not output from the DARC decoder 4, the set frequency of the PLL frequency demodulator 3 is returned to the original frequency fx. 14 is a clock for outputting current date / time data, and 15 is a previous information size S2 'stored in SRAM 6 when the date of date / time data output by clock 14 is changed. an information size table updating unit for updating all the values of (fj, My) to the information size S2 (fj, My) of the last day, and 16 is information size S0 (fx, My) input from the information size updating unit 8; ) Is 0, or the PLL frequency A zero clear processing unit which zero-clears the information size S1 (fx, My) stored in the SRAM 6 when the demodulator 3 cannot track the frequency, and 17 is a GPS (ground positioning system). GPS antenna for receiving navigation radio waves from satellites, 18 is a GPS receiver for positioning and outputting the position of the car by GPS, and 19 is a car receiver based on the position information signal output from the GPS receiver 18 A car position detection unit for detecting the position of the car by positioning the coordinates (longitude, latitude, etc.) of the position of the car, and 20 is a map information storage unit for storing map information constituted by a CD-ROM and a CD-ROM drive.

The PLL frequency demodulator 3 outputs the detection frequency signal of the set predetermined frequency to the detection selector 2. The detection selecting unit 2 detects and outputs an FM radio wave transmitted from the FM broadcast station to the FM multiplex broadcast received by the reception antenna 1. The detection frequency is set at this time in accordance with the detection frequency output from the PLL frequency demodulator 3. The FM received signal received by the detection selecting unit 2 is demodulated by the DARC decoder 4, and the multiple signals are separated and demodulated. Next, the DARC decoder 4 detects block synchronization of the multiple signals, executes error correction using a CRC, a parity code, or the like, and outputs the packet to the data group construction unit 7 as a packet.

The DARC decoder 4 measures block synchronization error, lateral correcting error, and final correcting error when demodulating the FM signal, and outputs them as required. Here, the block synchronization error indicates an error when the DARC decoder 4 cannot detect the head block identification codes BIC1 to BIC4 of each packet. If a block synchronization error occurs, the contents of the packet cannot be reproduced. In addition, the error correction error is an error detected by error detection by the cyclic code (CRC) of each packet, and the error correction error is to use a parity packet for a frame that could not be error corrected due to the error correction error. This error occurs when you try to correct the error again.

The information size updating unit 8, the information size comparison switching unit 11, and the error rate comparison switching unit 12 are each provided with a clock timer.

The GPS antenna 17 and the GPS receiver 18 receive navigation radio waves transmitted to the ground from four GPS satellites, and output them to the vehicle position detecting unit 19. The own vehicle position detecting unit 19 measures the distance from the GPS satellites to the own vehicle from the radio wave transmission time included in the navigation radio wave, the orbit information around the earth, and the time of arrival of the navigation radio wave, and centers each GPS satellite. The magnetic difference position is detected from the intersection coordinates of the spherical surface.

In the present embodiment, the receiving means comprises a receiving antenna 1, a detection selecting unit 2, a PLL frequency demodulator 3, and a DARC decoder 4, and the vehicle difference detecting means comprises a GPS antenna ( 17, the GPS receiver 18, the car position detection unit 19, the map information storage unit 20, the information storage means is composed of the DRAM 5, and the information size storage means is the SRAM (6). Information storage means is composed of a data group construction unit (7), and the information size registration means is composed of an information size updating unit (8) and an update history processing unit (9), and the information size comparison switching is performed. The means is composed of an information size reading processing section 10 and an information size comparison switching section 11, the error rate comparison switching section is composed of an error rate comparison switching section 12, and the switching judging means is a switching judging section 13. The information size table updating means comprises a clock (14), Consists of a size table updating unit 15, the zero clear processing means is configured to zero clear processing unit 16.

Next, the structure of each data processed in the receiving device of the present embodiment will be described.

2 is a diagram illustrating a data format of a data frame.

As shown in FIG. 2, a data frame is composed of a packet for transmitting 190 blocks of data and a parity packet of 82 blocks. The packet for transmitting data is composed of a 16-bit block identification code BIC, a 176-bit data packet, a 14-bit cyclic redundancy check (CRC), and a 82-bit lateral parity code from the head. The block identification code BIC is a code indicating the type of each packet, the data packet is data including information to be transmitted, such as VICS information, the CRC is a code for executing error detection by a circular code, and a transverse parity code. Is lateral parity information in one frame. The parity packet is composed of 16 bits of block identification code BIC and 190 bits of parity from the beginning. The parity packet is arranged distributed in a data frame to prevent burst errors. The parity packet is a packet including longitudinal parity codes of a plurality of data frames. For example, parity packet 1 of FIG. 2 is a data packet and CRC parity information of data packets 1 to 15, and parity packet 2 is a data packet 16 or 17. Data packet and CRC parity information.

3 is a diagram illustrating a data format of a data packet of FIG. 2.

As shown in Fig. 3, a data packet is a 32-bit prefix and a 144-bit data block (in the case of character and figure information data), or a 16-bit prefix and a 160-bit data block (visual information, broadcast station name). Data, etc.). In addition, the prefix consists of service identification, decoding identification, information end flag, update flag, data group number, and data packet number.

4 is a diagram illustrating a data format of a data group.

The data group is recovered data configured by combining the data blocks of the received data frame in a predetermined order, and as shown in Fig. 4, the program number, the content update flag, the page number, the mesh number, and the map coordinate X from the head. The upper 8 bits, the upper 8 bits of the map coordinate Y, and the rest of the message data. The mesh code is composed of two codes of the upper 8 bits of the map coordinate X and the upper 8 bits of the map coordinate Y.

5 is a diagram showing a data structure stored in an SRAM.

In the SRAM 6, the size (information size) of the data group restored from the received data frame is classified and stored for each reception frequency and each mesh code. Specifically, as shown in Fig. 5, a data set of one unit is used as a data set of a mesh code, reception frequency, last information size, last information size and last day information size. A plurality of units are stored as an information size table. As will be described later, when a data frame is received and a data group is obtained, the reception frequency of this data group and the information size of the last day corresponding to the mesh code are updated in the information size table. In addition, when the date of the date and time output by the clock 14 is changed, each reception frequency in the information size table and the previous information size of each mesh code are updated to the information size of the last day.

In the receiving device of the present embodiment configured as described above, the frequency switching method will be described below.

In the frequency switching method of the present embodiment, in the data group construction unit 7, data is reproduced by constructing a data group from data packets output from the DARC decoder 4, and successively stored in the DRAM 5. · Update. In addition, in parallel with this, the size of the data block stored in the DRAM 5 is calculated by the information size updating unit 8 and the update history processing unit 9, and the information size of each frequency and each mesh code is calculated. The table is created and stored and updated in the SRAM 6. On the other hand, in parallel with this, the error rate output from the DARC decoder 4 by the error rate comparison switching unit 12 and the switching determination unit 13 exceeds a predetermined threshold value ε for a predetermined time (for example, 6 minutes). In this case, the detection frequency of the PLL frequency demodulator 3 is switched to the frequency of the FM broadcast station which is tuned at this time and the FM broadcast station having the least error rate among the adjacent FM broadcast stations. In addition, in parallel with this, the information magnitude comparison switching unit 11 and the switching determination unit 13 inform the size of the information of each frequency of the mesh area to which the current position of the magnetic difference stored in the SRAM 6 belongs. Are compared, and the detection frequency of the PLL frequency demodulator 3 is switched to the frequency with the largest information size. In addition, a control clear process for zero clearing the size stored in the SRAM 6, a date change process for successively updating the oldest data among the data stored in the SRAM 6, and the like are also executed when the broadcasting station stops broadcasting.

In the following, a detailed description will be made in order of establishing a data group, storing and updating data in a DRAM, updating data in an SRAM, requesting a switching of a detection frequency by comparing error rates, requesting a switching of a detection frequency by comparing information sizes, and switching a detection frequency. .

First, the construction of the data group and the storage / update to the DRAM will be described. The data group construction and the storage / update in the DRAM are executed in the data group construction unit in FIG.

6 is a flowchart showing the operation of the data group construction unit.

First, when a packet as shown in Figs. 2 and 3 is input from the DARC decoder 4 (S1), the data group building unit 7 constructs a data frame according to the number of each received packet. Subsequently, it is determined whether or not the data frame construction is finished (S2). If the data frame construction is not finished, the process returns to step S1 to wait for the input of the packet again.

In step S2, when the data frame construction is finished, the data group construction unit 7 draws out and combines the data packets included in the data frame to construct the frame data (S3). Further, a data group is constructed by using one data group having the same data group number in the frame data (S4). If the data group end code is included in the constructed data group, and the data group end code indicates the continuation of the data group (S5), the process returns to step S1 again, and construction of the data group is continued.

In step S5, when the data group end code indicates the end of the data group (S5), the data group building unit 7 checks whether or not the data group of the same mesh code is stored in the DRAM 5 ( S6) If a data group of the same mesh code is not stored in the DRAM 5 (S6), the constructed data group is newly stored in the DRAM 5 (S7). In step S6, when a data group of the same mesh code is stored in the DRAM 5, the data group of the same mesh code stored in the DRAM 5 is updated to the constructed data group (S8).

When the above operation ends, the data group building unit 7 returns to the operation of step S1 again, and continues the storage / update process of the data group to the DRAM 5.

As described above, the data group constructing unit 7 constructs a data group from the data frame output from the DARC decoder 4, and stores and updates the DRAM 5 in order to store the latest data group in the DRAM 5. Accumulate continuously.

Next, the data update process of the SRAM will be described. The data update process of the SRAM is executed by the information size update unit 8 in FIG.

7 is a flowchart showing the processing operation of the information size updating unit.

First, the information size updating unit 8 resets the value of the reception time integration value variable Serr stored therein to zero, and resets the time value t1 of the internal timer to zero to start timekeeping. (S10).

Subsequently, the information size updating unit 8 sends an error rate output request to the DARC decoder 4, and acquires an error rate Perr from the DARC decoder 4 (S11). Subsequently, when the error rate Perr is smaller than the predetermined threshold value epsilon 1 (S12), 1 is added to Serr (S13). That is, the reception time integrated value Serr obtains the number of timings in which the reception condition is good (that is, the reception time in which the reception condition is good).

Subsequently, it is determined whether or not the time value t1 of the timer is less than or equal to the predetermined time duration T1. When the time value t1 is less than or equal to the predetermined time duration T1, the process returns to step S11.

In step S14, when the time value t1 is equal to or greater than the predetermined time time T1 (e.g., 2 minutes 30 seconds), the information size updating unit 8 determines whether the reception time integration value Serr is equal to or less than the predetermined threshold value Smax ( S15), when the reception time integrated value Serr is equal to or less than the predetermined threshold Smax, the process returns to step S11.

Accordingly, when the reception sensitivity is poor (when the user inserts the antenna or enters the underground parking lot, etc.), the information of the SRAM 6 is not judged to be sufficiently provided only by the passage of time. No update of the size table is performed. In addition, if reception is possible at any time, sufficient information is provided at any time to perform updating of the information size. Therefore, in step S15, by waiting for the reception time integrated value Serr to be larger than the predetermined value, the data group is waited until it is sufficiently accumulated in the DRAM 5. When the data size table of the SRAM 6 is updated when the data group is not sufficiently stored in the DRAM 5 without executing step S15, the information size of each updated mesh area is broadcast. It may become smaller than the size, and may be automatically tracked to other broadcasting station frequencies by the information size comparison switching section 11, which is not preferable.

In step S15, when the reception time integration value Serr is equal to or larger than the predetermined threshold Smax, the information size updating unit 8 outputs an update request for the information size table of the SRAM 6 to the update history processing unit 9, and thereafter. By the SRAM update history process described, the size of the data group stored in the SRAM 6 is updated to the latest one (S16), and again, the time value t1 of the internal timer is reset to 0 (S17), and the process returns to step S11. do.

Here, it is very suitable to set the predetermined time T1 at 2.5 to 10 minutes. If it is shorter than 2.5 minutes, since the error rate of the DARC decoder 4 cannot be detected with sufficiently good accuracy, there is a tendency to update the information size table of the SRAM 6 by a small information size, and when it is longer than 10 minutes, Since the error rate detection time of the DARC decoder 4 is too long, the information size table of the SRAM 6 is rarely updated, and tuning to the optimum FM broadcast station by the information size comparison switching section 11 described later is executed. This is because there is a tendency not to appear.

Further, even if the threshold value Smax of the reception time integration value Serr is set, it is suitably set to 2.5 to 10 minutes. If it is smaller than 2.5 minutes, since the reception time of the DARC decoder 4 is too short, sufficient information is not accumulated in the DRAM 5, and the optimal FM broadcast station by the information size comparison switching section 11 to be described later is described. In the case where the channel selection is not performed, it tends not to be executed, and if it is larger than 10 minutes or so, since the reception time of the DARC decoder 4 is too long, the SRAM 6 waits while receiving the same information many times. This is because the update of the size table of information tends to be delayed.

Next, the SRAM history update process in step S16 of FIG. 7 will be described. The SRAM history update process is executed in the update history processor 9 of FIG.

Fig. 8 is a flowchart showing the processing operation of the update history processing unit, and Fig. 9 is a diagram showing the configuration of the update information size table.

First, the update history processing unit 9, in the information size update unit 8, obtains each mesh code Mj (j denotes all the meshes in the service area of the broadcast station x) obtained by decoding the multiple signal transmitted as the frequency fx from the broadcast station x. When the information size S0 (fx, Mj) of the data group of the subscript corresponding to the region is input, each mesh code Mj and the information size S0 (fx, as shown in Fig. 9, are stored in a memory provided therein. , Mj) is created, and an update information size table is created (S20). Next, the information size S0 (fx, Mj) of the mesh code Mj of the update information size table is compared with the frequency fx stored in the SRAM 6, and the information size S1 (fx, Mj) of the last day of the mesh code Mj. If S1 (fx, Mj) < S0 (fx, Mj), the information size S1 (fx, Mj) of the last day stored in the SRAM 6 is changed to S0 (fx, Mj) and recorded (S21). As a result, the update information size table stored in the update history processing unit 9 is reflected in the information size table stored in the SRAM 6.

Next, the zero clear processing unit 16 detects whether or not the data block is being output from the DARC decoder 4 (S22), and when the data block is output, terminates the SRAM history update process. If the data block is not output in step S22, the information size table stored in the SRAM 6 for the frequency fx of the broadcasting station x currently tuned into and the mesh code My of the mesh area to which the current own vehicle position belongs. Update “last information size” S2 (fx, My) to “last day information size” S1 (fx, My), update “last day information size” S1 (fx, My) to 0, Date ”as the current date (S23), and the SRAM history update process ends. By the processing of steps S22 and S23, automatic tracking of the frequency is stopped for the loss of broadcasting of the broadcasting station in the data of the information size of the same frequency which is not used for distinguishing the broadcasting stations.

Here, in the process of creating the update information processing table in step S20, the method of registering the mesh code and the information size in the order read from the DRAM 5 or the quick sorting of the mesh code read from the DRAM 5 is performed. The method of registering the mesh code and information size while sorting in the order of mesh codes by (quick sort) or bubble sort (bubble sort) is used.However, due to memory efficiency and access speed, the mesh codes are used as keys for hashing. It is desirable to create a hash table by hashing.

Below, as an example, the creation process of the update information size table by a hash method is shown.

Here, the number n of the columns of the information size table is 1024, and the hash address is 10 bits. In addition, the upper 8 bits of the map coordinate X (X = x7x6x5x4x3x2x1x0) and the upper 8 bits of the map coordinate Y (Y = y7y6y5y4y3y2y1y0) are used as keys of the hash function (hereinafter, (X, Y) is called the key code of the data group, denoted by K). In addition, a hash function is made as Formula (1).

Equation 1; h ₀ (K) = x ₀ x ₁ (x ₂ | y ₀ ) (x ₃ | y ₁ ) (x ₄ | y ₂ ) (x ₅ | y ₃ ) (x ₆ | y ₄ ) (x ₇ | y ₅ ) y ₆ y ₇

In Equation 1, "|" represents bit 0R logic.

Fig. 10 is a flowchart showing an operation of creating an update information size table of an update history processing unit.

First, the update information size table is initialized (S30). Here, the initialization of the update information size table means that all mesh codes registered in the update information size table are invalidated, and the information size of all the mesh codes is zero.

Subsequently, the internal variable i representing the number of data groups read from the DRAM 5 is set to 0 (S31), and it is determined whether i has reached the number of all data groups stored in the DRAM 5 ( S32), when i has not reached the number of all data groups stored in the DRAM 5, the i-th data group is read out from the DRAM 5, and the key code K (i of the i-th read data group) is read. ), The hash address j = h ₀ (K (i)) is calculated using the hash function h ₀ (S33). Subsequently, it is determined whether the column of the j-th update information size table is empty (S34). If the column of the j-th update information size table is empty, the column of the j-th update information size table is determined. Data group read i-th to information size S1 '(j) of column of j-th update information size table with mesh code Ms (j) as mesh code M (i) of i-th read data group The information size S0 (i) is added (S35), i is increased by one (S41), and the process returns to step S32.

In step S34, when the column of the j-th update information size table is not empty, the mesh code Ms (j) of the column of the j-th update information size table and the mesh code M of the i-th read data group Comparing whether (i) matches or not (S36), when Ms (j) = M (i), the i-th mesh code Ms (j) of the column of the j-th update information size table is read for the i-th time. As the mesh code M (i) of the data group, the information size S0 (i) of the i-th read data group is added to the information size S1 '(j) of the column of the j-th update information size table (S35). ), i is increased by one (S41), and the process returns to step S32.

In step S36, when Ms (j) ≠ M (i), it is determined whether j is the last number n of the update information size table (S37), and when j = n, j = 0 (S38) In the case of j ≠ n, j is increased by one (S39).

Then, the are not the same, judges whether j is equal with h ₀ (K (i)) and (S40), j and h ₀ (K (i)) returns to step S34. If j and h ₀ (K (i)) are the same, i is increased by one (S41) and the process returns to step S32.

In addition, in step S32, when i reaches the number of all the data groups stored in the DRAM 5, it is determined that the process has ended for all the data groups stored in the DRAM 5, and the update information is determined. Ends the size table creation process.

By the above operation, an update information size table, which is a table of the mesh code and the sum of the information sizes corresponding to the mesh code, is generated in a memory provided in the update history processing unit 9.

Subsequently, a process of reflecting the update information size table of the update history processing unit in step S21 in the SRAM will be described in more detail.

Fig. 11 is a flowchart showing the processing operation for reflecting the update information size table of the update history processing unit in the SRAM.

In the processing of reflecting the update information size table for update history processing unit in the SRAM, updating the data of each mesh code for the frequency already registered in the information size table (S50) and not registered in the information size table. Adding the data of each mesh code for the frequency is carried out by step S51.

In step S50, the update history processing unit 9 registers the data of each mesh code My registered in the update data group table of fx currently tuned in the information size table stored in the SRAM 6. If it is registered, and if it is registered, the information size S1 (fx, My) registered in the information size table is compared with the information size S1 '(fx, My) registered in the update information size table. When S1 (fx, My) <S1 '(fx, My), the process of updating S1 (fx, My) to S1' (fx, My) is executed. Although the concrete method is based on the format of the information size table and the update information size table, an example where the update information size table is comprised as a hash table which uses said key code K as a key is demonstrated below. do.

12 is a flowchart showing a processing operation for updating mesh data already existing in the information size table of the update history processing unit.

First, the internal variable i representing the number of data groups read from the SRAM 6 is set to 0 (S60), and whether or not i has reached the number of all the columns of the information size table stored in the SRAM 6? If it is determined (S61) that i has not reached the number of all the eggs in the information size table stored in the SRAM 6, then the mesh code M1 (i) and the frequency f1 of the i th column from the SRAM 6 ( i) is read, and the hash address j = h ₀ (K (i)) is calculated by the hash function h ₀ using the key code K (i) of the i-th read mesh code M1 (i) (S62). . Subsequently, it is determined whether the column of the j-th update information size table is empty (the mesh code of the column of the j-th update information size table is invalid) or not (S63). If the egg is empty, i is increased by one (S71) and the process returns to step S61.

In step S63, when data is recorded in the column of the j-th update information size table, the mesh code M1 '(j) of the column of the j-th update information size table is read out, and (1) the mesh code M1. It is determined whether (i) and the mesh code M1 (j) are the same, and the frequency f1 (i) and the frequency fx currently tuned are the same (S64).

In step S64, when the conditions 1 and 2 are satisfied, the &quot; last size information size &quot; S1 (i) of the i th column of the information size table stored in the SRAM 6 is the j th update information size table. It is determined whether or not the information size S1 '(j) is smaller than (S65). If S1 (i) &lt; S1' (j), the &quot; last column &quot; of the i th column of the information size table stored in the SRAM 6 is determined. Information size of day ”S1 (i) is updated to information size S1 ′ (j) of the column of the j th update information size table, and the date of the i th column of the information size table is updated with the current date, The code size M1 '(j) is made invalid and the information size S1' (j) is made 0 (S66).

n인 경우에는 j를 1 증가시킨다(S69).In step S64, if the conditions 1 and 2 are not satisfied, it is determined whether j is the last number n of the update information size table (S67), and if j = n, j = 0 (S68). ), j

In the case of n, j is increased by 1 (S69).

Subsequently, it is not the same, judges whether j is equal with h ₀ (K (i)) and (S70), j and h ₀ (K (i)) returns to step S63. If j and h ₀ (K (i)) are the same, i is increased by 1 (S71) and the process returns to step S61.

Further, in step S61, when i reaches the number of all the eggs of the information size table stored in the SRAM 6, the process for all the eggs of the information size table stored in the SRAM 6 is finished. It judges and complete | finishes the update process of the mesh data which already exists in an information size table.

By the above operation, the update information size table of the update history processing unit 9 is reflected in the data already registered in the information size table of the SRAM 6.

Step S51 is a process of adding frequency and mesh code data not registered in the information size table of the SRAM 6 to the information size table in the update information size table. If the memory size of the SRAM 6 is large enough, there is no problem, but if there is a limitation in the memory size of the SRAM 6, the process of erasing unnecessary data when adding frequency and mesh code data to the information size table It also needs to run at the same time. In this case, it is preferable to erase the data of the mesh area far from the mesh area to which the position of the current magnetic difference belongs. An example of a process of adding mesh data not included in the SRAM will be described below.

13 is a flowchart showing a processing operation of adding mesh data not included in the SRAM of the update history processing unit.

First, the update history processing unit 9 sets the internal variable j indicating the number of eggs examined in the update information size table to 0 (S80), and j is the update information size stored in the update history processing unit 9. It is determined whether the number of all eggs in the table has been reached (S81), and if j does not reach the number of all eggs in the update information size table stored in the update history processing section 9, the update information. The mesh code M1 '(j) and frequency f1' (j) of the j-th column are read from the magnitude table (S82). Subsequently, it is determined whether the column of the j-th update information size table is empty (or the mesh code of the column of the j-th update information size table is invalid) (S83). If the egg is empty, j is incremented by one (S87) and the process returns to step S81.

In step S83, when data is recorded in the column of the j-th update information size table, the mesh code M1 '(j) of the column of the j-th update information size table is read, and then the update history When there is no free area in the memory area of the SRAM 6, the processing unit 9 includes data of the mesh area far from the mesh area to which the current own difference position belongs among data stored in the information size table of the SRAM 6. The erase process is executed (S85). This processing will be described later. Subsequently, the data of the column of the j-th update information size table is added to the free area of the memory of the update history processing unit 9 (S86), j is increased by 1 (S87), and the process returns to step S81.

Further, in step S81, when j reaches the number of all the columns of the update information size table, it is determined that the processing for all the columns of the update information size table stored in the update history processing unit 9 is finished. The process of adding the mesh data which does not exist in the SRAM ends.

Next, a process of deleting the distant mesh area information of the SRAM in step S85 will be described.

As a specific method, when there is no free area in the memory area of the SRAM 6, a method of erasing data of the mesh area farthest from the mesh area to which the current own difference position belongs is included in the information size table stored in the SRAM 6; In the information size table stored in the SRAM 6, a method of erasing a certain ratio of data in the order of the mesh area farthest from the mesh area to which the current own difference position belongs is selected, but the latter method may shorten the overall processing time. It is preferable because it can. In the following description, as an example, when the free area is lost in the memory area of the SRAM 6, 10% of the information area table stored in the SRAM 6 is located in the order of the mesh area farthest from the mesh area to which the current magnetic difference position belongs. A method of erasing data will be described.

14 is a flowchart showing a processing operation for deleting information of a mesh area far away in the SRAM of the update history processing unit.

Here, the update history processing unit 9 has a variable Dn representing the distance to the mesh region closest to the mesh region to which the current vehicle position belongs to the memory region held therein, and the mesh region to which the current vehicle position belongs. A variable Df representing the distance to the farthest mesh area, a variable D representing the distance from the mesh area to which the current car position belongs to the mesh area to which the current car location belongs, and a mesh area closest to the mesh area to which the current car location belongs. Section counter tables C (0) to C (299), which are formed by dividing and arranging the distance from the mesh region to the farthest mesh region to the farthest mesh region in 300 steps. The variable j indicating the number of data read from the SRAM 6 is stored.

First, the update history processing unit 9 acquires the current own vehicle position from the magnetic position detection unit 19, checks the mesh code of the information size table stored in the SRAM 6, and the current own vehicle position belongs. The distance Dn to the mesh area closest to the mesh area and the distance Df to the mesh area farthest from the mesh area to which the current own difference position belongs are obtained (S91). In reality, since the mesh code is displayed as the reference area mesh code of JIS X0410, the distance to each mesh area can be obtained by the mesh code.

Subsequently, the update history processing unit 9 initializes a variable D representing the distance from the mesh area to which the current own vehicle position belongs to each mesh area to 0 (S92), and the interval counters C (1) to C (300). ) Is initialized to 0 (S93). Subsequently, the variable j indicating the number of data read from the SRAM 6 is initialized to 0 (S94). Subsequently, it is determined whether j reaches the total number N of the information size tables stored in the SRAM (S95), and j does not reach the total number N of the information size tables stored in the SRAM. If the mesh code M1 (j) of the j th column of the information size table is obtained, and the mesh code M1 (j) is an invalid value (S96), j is increased by one (S100) and the process returns to step S95. do. In step S96, when the mesh code M1 (j) is a valid value, the distance between both mesh areas is obtained from the mesh code My and the mesh code M1 (j) of the mesh area to which the current own vehicle position belongs, and set to the variable D. do. Subsequently, the variable D checks whether it is between the distance Dn and the distance Df (S98), and if the variable D is between the distance Dn and the distance Df, j = [(D-Dn) × (300-1 ) / (Df-Dn)], and the counter C (j) of the section counter table is increased by one (S100), and the process returns to step S95. In step S98, when the variable D is not between the distance Dn and the distance Df, the counter C (j) of the section counter table is increased by one (S100), and the process returns to step S95.

In step S95, when j reaches the total number N of the information size tables stored in the SRAM, the counter C (j) is added from C (299) in order of increasing index. Total NK = C (299) + C (298) +... + The index when C (k) exceeds (N + 1) × 0.1 (10% of the total number of data) is k (S101), and Nk is (N + 1) × 0.2 (20 of the total number of data) (S102), and if Nk does not exceed (N + 1) × 0.2, the distance D (k) corresponding to the index k from the mesh area to which the current subject difference belongs is determined. The data of the information size table of the distant mesh area is erased from the memory area of the SRAM 6 (S103), and the process of deleting the distant mesh area information of the SRAM is terminated.

In step S102, when Nk exceeds (N + 1) × 0.2, the mesh is farther away than the distance D (k + 1) corresponding to the index k + 1 from the mesh area to which the current own vehicle position belongs. The data of the information size table of the area is erased from the memory area of the SRAM 6 (S104), Dn is set to D (k), and Df is set to D (k + 1), and the process returns to step S93.

By the above operation, data of the frequency and mesh code which are not registered in the information size table of the SRAM 6 among the update information size table are additionally registered in the information size table, and the memory of the update history processing unit 9 If there is no free area, the data of the mesh area far from the mesh area to which the current own difference position belongs is erased.

Next, the switching request processing of the detection frequency by the error rate comparison will be described. The request for switching the detection frequency by the error rate comparison is executed by the error rate comparison switching unit 12 in FIG. In this processing operation, when the time at which the error rate Perr output from the DARC decoder 4 becomes the predetermined threshold value ε or more continues for a predetermined time T2 or more, the error rate comparison switching part 12 is currently tuned in. It is determined that the frequency fx is outside the service area of the broadcasting station, and the request for switching the detection frequency to the frequency fx 'of the broadcasting station adjacent to the broadcasting station of the frequency fx set in the PLL frequency demodulator 3 is output.

Fig. 15 is a flowchart showing the switching request processing operation of the detection frequency by the error rate comparison of the error rate comparison switching unit.

First, the error rate comparison switching unit 12 resets the time value t2 of the timer provided therein to zero (S110), and starts time counting (S111).

ε의 경우에는, 타이머의 계수치 t2가 소정의 시간 T2(예로서, 6분)에 도달했는가 아닌가를 판정하고(S114), t2<T2의 경우에는, 단계 S112에 복귀하고, t2

T2의 경우에는, 자기 차가 현재 선국하고 있는 주파수 fx의 방송국의 서비스 영역의 밖에 있는 것으로 판단하고, 인접하는 방송국의 주파수 fx′로의 검파 주파수 절환 요구 S1을 절환 판단부(13)에 출력한다(S115).Subsequently, the error rate comparison switching unit 12 acquires an error rate Perr from the DARC decoder 4 (S112), determines whether the error rate Perr is smaller than a predetermined threshold (S113), and in the case of Perr <ε, step S110 Return to In step S113, Perr

In the case of ε, it is determined whether or not the count value t2 of the timer has reached a predetermined time T2 (e.g., 6 minutes) (S114), and in the case of t2 < T2, the process returns to step S112 and t2

In the case of T2, it is determined that the difference is outside the service area of the broadcasting station of the frequency fx currently tuned in, and the detection frequency switching request S1 to the frequency fx 'of the adjacent broadcasting station is output to the switching determining unit 13 (S115). ).

Here, the frequencies of the adjacent broadcasting stations are transmitted as short supplementary data from the broadcasting stations as management data of the broadcasting station called additional information or data for D-GPS. This additional information includes an alternative frequency table which is a list of frequency information which the receiver may switch to when the receiving station is unable to receive. By acquiring this information, information on the frequencies of adjacent broadcast stations can be obtained. The error rate comparison switching unit 12 receives each of these frequencies for 10 seconds to select the frequency having the least error rate.

Next, the switching request processing of the detection frequency by the information magnitude comparison will be described. The request for switching the detection frequency by the information size comparison is executed by the information size comparison switching unit 11 in FIG. In this processing operation, the information size comparison switching unit 11 compares the information size stored in the SRAM with respect to all broadcasting stations having the mesh area to which the current own vehicle position belongs as a service area, and has the largest information size. Outputs a request to switch to the frequency of the broadcasting station.

Fig. 16 is a flowchart showing a switching frequency request processing operation by comparing the size of information in the information size comparison switching unit.

First, the information magnitude comparison switching unit 11 resets the time value t3 of the timer provided therein to zero (S120), starts timekeeping (S121), and the time value t3 of the timer is set to a predetermined time T3 (Yes. Wait until 5 minutes) (S122). This relates to a frequency fx in which a data table is accumulated in the DRAM 5 to some extent, and the information size table stored in the SRAM 6 by the information size updating unit 8 and the update history processing unit 9 is currently tuned. To wait for updates.

When the time value t3 of the timer reaches a predetermined time T3 (e.g., 5 minutes), the information magnitude comparison switching unit 11 determines that all frequencies corresponding to the mesh code My of the mesh region to which the current own vehicle position belongs are located. The information size is obtained from the information size table stored in the SRAM 6 by the information size reading processing section 10 (S123). At this time, the information size reading processing section 10 adds, from the information size table of the SRAM 6, each frequency fj of the mesh code My (j is corresponding to each broadcasting station including the mesh code My in the service area). Read the "size of the last day information" S1 (fj, My) and the information size of the last time S2 (fj, My) for the subscript, and the larger of them is the information size S3 ( fj, My) is output to the information size comparison switching unit 11. This means that if the FM radio wave cannot be received temporarily due to the fact that his car is located in a tunnel or in the shade of a building at the time of update of the update history processing unit 9, the &quot; last day information size &quot; This processing is executed to prevent the output of 0 as information size S3 (fj, My) due to such temporary reception failure.

Subsequently, each obtained information size is compared and the frequency fx 'corresponding to the largest information size is obtained (S124). Subsequently, the obtained frequency fx 'is compared with the frequency fx of the currently tuned in station (S125). When the frequency fx and the frequency fx' are different, the set frequency of the PLL frequency demodulator 3 is switched to the frequency fx '. The signal S2 is output to the switching determination unit 13 (S126).

When the above operation ends, it returns to operation of step S123 again.

Next, the switching processing of the detection frequency will be described. The switching process of the detection frequency is executed by the switching determination unit 13 in FIG.

17 is a flowchart showing a switching process of detection frequencies.

First, upon receiving the detection frequency switching request S1 or S2 to the adjacent station fx ', the switching determination unit 13 sets the frequency fx' from the frequency fx currently set in the PLL frequency demodulator 3 (S130). ). Next, it is checked whether or not there is an output from the detection selecting unit 2 (S131).

Here, the inspection whether or not there is an output from the detection selecting unit 2 is based on the hardware standard of the PLL frequency demodulator 3, but, for example, 1) the detection of the lock of the PLL frequency demodulator 3 ( )) (2) Detect SD (Station Detect) signal (signal determined to perform broadcast station detection in FM (Frequency Modulation) broadcasting) from PLL frequency demodulator (3), and (3) IF of PLL frequency demodulator (3). It is executed by the determination of the frequency.

When the output from the detection selecting unit 2 is detected in step S131, the switching determination unit 13 checks whether there is an output of the packet from the DARC decoder 4 (S132).

Here, the inspection of whether or not there is a packet output from the DARC decoder 4 is based on the hardware standard of the DARC decoder 4, but, for example, 1) the output data packet is synchronized, 2) the output data. This is done by checking that the packet is normal data (not parity data).

When the data packet is output from the DARC decoder 4 in step S132, the switching determination unit 13 includes the data group construction unit 7, the information size update unit 8, the information size comparison switching unit 11, The reset signal is output to the error rate comparison switching unit 12 (S133). When the reset signal is input, the data group building unit 7, the information size updating unit 8, the information size comparison switching unit 11, and the error rate comparison switching unit 12 stop and then reset the operation. The processing resumes from the beginning.

When the output from the detection selecting unit 2 is not detected in step S131, or when no data packet is output from the DARC decoder 4 in step S132 (i.e., the new automatic tracking fails). Regarding the tuned frequency fx 'and the mesh code My of the mesh area to which the current self-difference position belongs, the "previous information size" S2 (fx', My) in the information size table stored in the SRAM 6 Is updated to “the size of information of the last day” S1 (fx ′, My), and the value of “date of the information of the last day” S1 (fx ′, My) is updated to 0, so that “date” is the current date (S134). ). Subsequently, the set frequency of the PLL frequency demodulator 3 is returned to fx (S135), and the switching process of the detection frequency is completed.

In addition to the above process, when the date of the date and time output by the clock 14 is changed, the information size table updating unit 15 indicates that the "last time" of all the columns of the information size table of the SRAM 6 is changed. Information size &quot; is updated to &quot; last day information size &quot;. As a result, the information on the size of the old data information is updated at least every day.

As described above, according to the present embodiment,

(1) The data groups of the VICS information generated from the multiple signals by the DARC decoder 4 and the data group constructing unit 7 are sequentially accumulated in the DRAM 5.

(2) The information size update unit 8 outputs a request for updating the information size table to the update history processing unit 9 when data groups are accumulated in the DRAM 5 for a predetermined time or longer, and broadcast station of the currently tuned frequency. Updates the information size of each mesh code sent in the. At this time, if the information size to be updated is smaller than the information size already registered in the information size table, it is not updated. In addition, when the information size to be updated is zero, the information size of the current code in the information size table and the mesh code to which the current own vehicle position belongs is updated to zero.

(3) On the other hand, the error rate comparison switching unit 12 selects the current detection frequency when the time at which the error rate Perr output from the DARC decoder 4 becomes equal to or greater than a predetermined threshold? Continues for a predetermined time or longer time T2. A switching request S1 for switching to the broadcast area of the broadcasting station being used and the detection frequency of another broadcast station adjacent to the broadcast area is output.

(4) In parallel with this, the information size comparison switching unit 11 waits for a predetermined time T3 for the update of the information size table of the SRAM 6 to be executed, and the current magnetism registered in the information size table. The information size of each frequency of the mesh code to which the difference position belongs is compared, and the switching request S2 for switching the detection frequency to the frequency of the largest information size (information amount) is output.

(5) When the switching request S1 or S2 is input, the switching determination unit 13 switches the current detection frequency fx set in the PLL frequency demodulator 3 to the switching request detection frequency fx. Thereafter, if there is an output from the detection selecting unit 2, and there is an output of a data packet from the DARC decoder 4, the data group construction unit 7, the information size update unit 8, and the information size comparison switching unit (11) A reset signal is output to the error rate comparison switching unit 12, and the operation of these units is reset to restart. In addition, when there is no output from the detection selecting unit 2 or when there is no data packet output from the DARC decoder 4, information of the frequency fx 'in the information size table and the mesh code to which the current own vehicle position belongs. The magnitude is updated to zero, and the set frequency of the PLL frequency demodulator 3 is returned to fx. By such a series of operations, among the broadcasting stations broadcasting the receivable VICS information at the current vehicle position, the broadcasting station having the largest amount of information around the current vehicle position can be automatically tracked to obtain VICS information.

As described above, according to the receiver of the automobile navigation apparatus of the present invention, the following advantageous effects are obtained.

According to the first aspect of the present invention, the detection frequency is switched to the broadcasting station having the largest amount of information in the own vehicle position by the information size comparison switching means, and among the information broadcasting stations which can always be received at the own vehicle position, Since the information broadcasting station which provides the largest amount of information of the road traffic information can be tuned automatically, it is possible to provide the receiving device of the car navigation apparatus which can make effective use of the road traffic information provided from the information broadcasting station. have.

According to a second aspect of the present invention,

(1) Road traffic information provided by an information broadcasting station, since other stations can be tuned automatically when the frequency cannot be received in the mesh area where the vehicle is located, such as when the broadcasting station stops broadcasting. It is possible to provide a receiving device of a vehicle navigation apparatus that can effectively utilize the.

(2) When the error rate comparison switching means judges that the vehicle has moved out of the service area of the information broadcasting station, it is possible to set a long determination time for the state in which the error rate is higher than or equal to a predetermined threshold, so that a tunnel, a shield, or the like during driving of the vehicle can be set. It is possible to provide a receiver of an automobile navigation apparatus which prevents the frequency switching of an information broadcasting station from being performed wrongly when driving in a place where a radio wave reception condition of the vehicle is bad, and makes it possible to effectively use the road traffic information provided by the information broadcasting station. Can be.

According to the third aspect of the present invention, when an information broadcasting station tuned in after the switching stops broadcasting, the vehicle navigation is prevented from being tuned in so that the road traffic information provided by the information broadcasting station can be effectively utilized. A receiving device of the device can be provided.

According to the fourth aspect of the present invention, the presence or absence of a shield such as a building prevents the registration or updating of the information size of the information received in a bad reception state in the information size storage means, and the registration or updating of a small information size. By updating, it is possible to prevent the information size comparison switching means from performing frequency switching by mistake, thereby providing the receiving device of the automobile navigation apparatus which enables to effectively utilize the road traffic information provided from the information broadcasting station.

According to a fifth aspect of the present invention, an information broadcasting station temporarily stops broadcasting and registers 0 in the information size of the last day corresponding to this frequency and mesh code in the information size table, or inadvertently receives an area with poor reception. Even if a small value is registered in the information size of the last day corresponding to this frequency and the mesh code because the vehicle has traveled, the information size comparison switching means compares the information size of the last time with the information size of the last day and is the larger of them. Of the car navigation apparatus, which reads out the information size and compares them to perform detection frequency switching of the receiving means, thereby improving the tuning accuracy of the information broadcasting station and making effective use of the road traffic information provided by the information broadcasting station. A receiving device can be provided.

According to the sixth aspect of the present invention, when an information broadcasting station stops broadcasting, by zeroing the information in the information size table, the data size of the broadcasting station is prevented from remaining in the information size table at any time. The means can provide a receiving apparatus of the car navigation apparatus which can prevent the information broadcasting station from continuing to tune in to the broadcasting station by mistake even when the broadcasting station has stopped broadcasting so that the road traffic information provided by the information broadcasting station can be effectively utilized. Can be.

Moreover, according to the receiver frequency switching method of the automobile navigation apparatus of this invention, the following advantageous effects are acquired.

According to the seventh aspect of the present invention, since the detection frequency is switched to the broadcasting station having the largest amount of information in the own vehicle position, the information quantity of the road traffic information near the own vehicle position among the information stations that can be received at the own vehicle position is It is possible to automatically select the information broadcasting station that provides the most, so that the frequency switching method of the receiving device of the vehicle navigation apparatus can effectively utilize the road traffic information provided from the information broadcasting station.

According to the eighth aspect of the present invention,

(1) When this frequency cannot be received in the mesh area where the vehicle is located, such as when the broadcasting station stops broadcasting, other broadcasting stations can be tuned automatically, so that the road traffic information provided by the information broadcasting station is valid. It is possible to provide a frequency switching method of a receiving device of a vehicle navigation apparatus that can be utilized.

(2) When it is judged that the vehicle is out of the service area of the information broadcasting station, it is possible to set a long determination time for the state in which the error rate is higher than or equal to a predetermined threshold, so that the radio wave reception state such as the shade of a tunnel or a shield while the vehicle is traveling can be set. Since the frequency switching of the information broadcasting station is prevented from being executed by mistake when driving in a bad place, a frequency switching method of the receiving device of the vehicle navigation apparatus which enables to effectively utilize the road traffic information provided by the information broadcasting station can be provided. have.

Claims (11)

delete In the receiving apparatus of the automobile navigation apparatus which receives the information from each information broadcasting station of the road traffic information system, Receiving means for receiving said information of each mesh area provided by radio waves from an information broadcasting station, Magnetic vehicle position detecting means for detecting a magnetic vehicle position; Information storage means for storing the information of each mesh area; Information size storage means for storing an information size which is the information size for each mesh area and each reception frequency; Information storing means for storing the information of each mesh area provided by the information broadcasting station by the receiving means in the information storing means and storing the information; Information size registration means for acquiring the information size of the information for each mesh area accumulated in the information storage means and registering or updating the information size storage means with the information size storage means; The information magnitude is detected by comparing the information magnitude of each reception frequency read out from the information magnitude storage means of the mesh area to which the difference is detected by the vehicle difference position detecting means. An information size comparison switching means for switching to the largest reception frequency, When the state in which the error rate at the time of receiving the information of the receiving means becomes higher than or equal to a predetermined threshold is continued for a predetermined time or more, the detection frequency of the receiving means is changed to a frequency of an information broadcasting station other than the information broadcasting station tuned at this point. And an error rate comparison switching means for switching. 3. The method according to claim 2, wherein the error rate comparison switching means or the information magnitude comparison switching means returns the detection frequency of the reception means if the reception means does not receive the information after switching the detection frequency of the reception means. And a switching determining means for returning to the frequency of the vehicle navigation apparatus. In the receiving apparatus of the automobile navigation apparatus which receives the information from each information broadcasting station of the road traffic information system, Receiving means for receiving said information of each mesh area provided by radio waves from an information broadcasting station, Magnetic vehicle position detecting means for detecting a magnetic vehicle position; Information storage means for storing the information of each mesh area; Information size storage means for storing an information size which is the information size for each mesh area and each reception frequency; Information storing means for storing the information of each mesh area provided by the information broadcasting station by the receiving means in the information storing means and storing the information; Information size registration means for acquiring the information size of the information for each mesh area accumulated in the information storage means and registering or updating the information size storage means with the information size storage means; The information magnitude is detected by comparing the information magnitude of each reception frequency read out from the information magnitude storage means of the mesh area to which the difference is detected by the vehicle difference position detecting means. Information size comparison switching means for switching to the largest reception frequency, The information size registration means receives the information in a state where the error rate at the time of reception of the information by the reception means is less than or equal to a predetermined threshold value after the information storage means starts accumulating the information in the information storage means. And when the time reaches a predetermined time, the information size of the information for each mesh area accumulated in the information storage means is acquired and registered or updated in the information size storage means. Receiving device. In the receiving apparatus of the automobile navigation apparatus which receives the information from each information broadcasting station of the road traffic information system, Receiving means for receiving said information of each mesh area provided by radio waves from an information broadcasting station, Magnetic vehicle position detecting means for detecting a magnetic vehicle position; Information storage means for storing the information of each mesh area; Information size storage means for storing an information size which is the information size for each mesh area and each reception frequency; Information storing means for storing the information of each mesh area provided by the information broadcasting station by the receiving means in the information storing means and storing the information; Information size registration means for acquiring the information size of the information for each mesh area accumulated in the information storage means and registering or updating the information size storage means with the information size storage means; The information magnitude is detected by comparing the information magnitude of each reception frequency read out from the information magnitude storage means of the mesh area to which the difference is detected by the vehicle difference position detecting means. An information size comparison switching means for switching to the largest reception frequency,  An information size table stored in said information size storage means, and having a plurality of units of data having a reception frequency, a mesh code of a mesh area, a size of a previous information, and a size of information of a last day as a unit; Information size table updating means for updating each last information size of the information size table to the information size of the last day when a predetermined time elapses, The information size registration means, if the information size of the last day corresponding to the information size is registered in the information size table before registering or updating the information size in the information size table, the information size is the last. Information of the last day corresponding to the information size in the information size table before updating the information size of the last day to the information size and registering the information size in the information size table when it is larger than the information size of the day. If the size is not registered, the information size is newly registered in the information size table as the information size of the last day, The information size comparison switching means compares the information size of the last time with the information size of the last day when reading out the information size from the information size storing means, and reads the larger one as the information size. A receiving device for an automobile navigation device, characterized in that. 6. The information size comparison switching means according to claim 5, wherein the information size comparison switching means performs a reception frequency after the switching of the information size table and at this point in time when the reception means does not receive the information after switching the detection frequency of the reception means. And zero clear processing means for updating the last information size to the last information size and updating the last information size to zero in a unit corresponding to the mesh area to which the own vehicle position belongs. Receiving device of car navigation system. delete Receiving means for receiving said information of each mesh area provided by radio waves from each information broadcasting station of the road traffic information system, a car vehicle position detecting means for detecting a car vehicle position, and said information of each mesh area; A frequency switching method in a receiving apparatus of an automobile navigation apparatus, comprising information storing means for storing and information size storing means for storing an information size which is the information size for each mesh area and each receiving frequency. An information accumulating step of receiving the information of each mesh area provided by an information broadcasting station by the receiving means, storing the information in the information storing means, and storing the information; An information size registration step of acquiring the information size of the information for each mesh area accumulated in the information storage means, and registering or updating the information size storage means with the information size storage means; The vehicle difference position is detected by the vehicle difference position detecting means, and the information magnitude of each reception frequency of the mesh area to which the vehicle difference position belongs is read out from the information magnitude storing means, and the information magnitude of each reception frequency is compared. An information size comparison switching step of switching the detection frequency of the reception means to a reception frequency having the largest information size; Is executed in parallel with the information accumulation step, the information size registration step, and the information size comparison switching step, and when the state in which the error rate at the time of receiving the information of the receiving means becomes more than a predetermined threshold value is continued for a predetermined time or more And an error rate comparison switching step of switching the detection frequency of the receiving means to a frequency of an information broadcasting station other than the information broadcasting station tuned at this time. 6. The information size registration means according to claim 5, wherein the information size registration means, if the receiving means does not receive the information when registering the information size in the information size table, is equal to the reception frequency at this point in time of the information size table. And zero clear processing means for updating the last information size to the information size of the last day and updating the information size of the last day to zero in a unit corresponding to the mesh area to which the own difference position at the time point belongs. A receiving device for an automobile navigation device, characterized in that. In the receiving apparatus of the automobile navigation apparatus which receives the information from each information broadcasting station of the road traffic information system, Receiving means for receiving said information of each mesh area provided by radio waves from an information broadcasting station, Magnetic vehicle position detecting means for detecting a magnetic vehicle position; Information storage means for storing the information of each mesh area; Information size storage means for storing an information size which is the information size for each mesh area and each reception frequency; Information storing means for storing the information of each mesh area provided by the information broadcasting station by the receiving means in the information storing means and storing the information; Information size registration means for acquiring the information size of the information for each mesh area accumulated in the information storage means and registering or updating the information size storage means with the information size storage means; The information magnitude is detected by comparing the information magnitude of each reception frequency read out from the information magnitude storage means of the mesh area to which the difference is detected by the vehicle difference position detecting means. An information size comparison switching means for switching to the largest reception frequency,  When the state in which the error rate at the time of receiving the information of the receiving means becomes higher than or equal to a predetermined threshold is continued for a predetermined time or more, the detection frequency of the receiving means is changed to a frequency of an information broadcasting station other than the information broadcasting station tuned at this point. An error rate comparison switching means for switching, An information size table stored in said information size storage means, and having a plurality of units of data having a reception frequency, a mesh code of a mesh area, a size of a previous information, and a size of information of a last day as a unit; Information size table updating means for updating each last information size of the information size table to the information size of the last day when a predetermined time elapses, The information size registration means, if the information size of the last day corresponding to the information size is registered in the information size table before registering or updating the information size in the information size table, the information size is the last. Information of the last day corresponding to the information size in the information size table before updating the information size of the last day to the information size and registering the information size in the information size table when it is larger than the information size of the day. If the size is not registered, the information size is newly registered in the information size table as the information size of the last day, The information size comparison switching means compares the information size of the last time with the information size of the last day when reading out the information size from the information size storing means, and reads the larger one as the information size. A receiving device for an automobile navigation device, characterized in that. The reception rate comparison switching means according to claim 10, wherein the error rate comparison switching means, when switching the detection frequency of the reception means, does not receive the information, the reception frequency after the switching of the information magnitude table and the self at this time. And a zero clear processing means for updating the last information size to the last information size and updating the last information size to zero in a unit corresponding to the mesh area to which the vehicle position belongs. Receiving device of navigation device.

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