JP2006074113A - Receiver for mobile body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver for a mobile body capable of continuously view a terrestrial digital broadcast program even when a frequency of a broadcast station of the terrestrial digital broadcast program broadcast for a broadcast area of a moving destination of the mobile body is changed. <P>SOLUTION: A GPS sensor acquires information of a present location when a position of a user is between positions 44 and 46, and acquires information of a broadcast area 41 and a broadcast area 42 going to be moved thereto from now on the basis of broadcast station area information and a searching path. When the user reaches the position 46, two tuners detect an electric field strength of a broadcast wave from a radio wave tower 47 and an electric field strength of a broadcast wave from a radio wave tower 48, and compare them. When the user furthermore moves and the electric field strength of the radio wave from the radio wave tower 47 is stronger than the electric field strength of the radio wave from the radio wave tower 48, a broadcast program of a channel viewable in the broadcast area 42 is outputted to a display monitor and a speaker. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mobile receiver that receives digital terrestrial broadcasting.

Using TV channel information stored in the storage system of the navigation system, it is possible to automatically switch to the channel of the same broadcasting station or affiliated broadcasting station and watch programs continuously without interruption. There has been known a mobile television receiver that can perform the above (Patent Document 1).
Japanese Patent Laid-Open No. 7-284030

  In recent years, it is a transitional period in which terrestrial broadcasting changes from analog broadcasting to digital broadcasting, and the frequency of a broadcasting station that broadcasts terrestrial digital broadcasting may be changed. At this time, the mobile television receiver described in Patent Document 1 uses the television broadcast station channel information stored in the storage device of the navigation system. When the frequency is changed, there is a problem that the broadcast station or the affiliated broadcast station cannot be received and the broadcast cannot be continuously viewed.

(1) According to the first aspect of the present invention, there is provided a mobile receiver for receiving terrestrial digital broadcasting, a current location detection means for detecting the current location of the mobile object, at least first and second tuning means, and a current location of the mobile object. A duplicate broadcast area entry detection means for detecting whether or not a broadcast area including the current location and a broadcast area adjacent to the broadcast area have entered an overlapping broadcast area, and a duplicate broadcast area entry detection means to detect the current location of the moving object. Is detected to have entered the overlapping broadcasting area, the second tuning means different from the first tuning means that is viewing the terrestrial digital broadcast is used to broadcast the broadcasting area adjacent to the broadcasting area including the current location And a viewable channel specifying means for specifying a viewable channel.
(2) According to the invention of claim 2, in the mobile receiver according to claim 1, when a predetermined condition is detected, the first tuning means can be viewed from the channel currently being viewed. It further comprises tuning switching means for switching the channel to one of the channels specified by the channel specifying means.
(3) The third aspect of the present invention is the mobile receiver according to the second aspect, further comprising at least first and second electric field strength detecting means, and a channel currently being viewed by the first tuning means. The second electric field strength detecting means different from the first electric field strength detecting means for detecting the electric field strength of the channel is detected by detecting the electric field strength of the channel specified by the viewable channel specifying means, and a predetermined condition Is characterized in that the electric field strength of the channel specified by the viewable channel specifying means detected by the second electric field strength detection means is stronger than the electric field strength detected by the first electric field strength detection means. And
(4) The invention of claim 4 is the mobile receiver according to claim 3, comprising map data including broadcast area information of digital terrestrial broadcasting, and the current location of the mobile detected by the current location detecting means. The overlapping broadcast area is specified based on the map data.
(5) The invention according to claim 5 is the mobile receiver according to claim 4, further comprising route searching means for the moving body, wherein the current location is included based on the searched route searched by the route searching means. A broadcast area adjacent to the broadcast area is specified.

  According to the present invention, even when the frequency of a terrestrial digital broadcast station that is broadcast in a broadcast area to which the mobile object is moved is changed, viewing of the terrestrial digital broadcast is not interrupted.

  A configuration of a navigation apparatus according to an embodiment of the present invention is shown in FIG. The navigation device 1 in FIG. 1 can receive and display a terrestrial digital broadcast in addition to a normal navigation function such as a map display. The navigation device 1 includes a control circuit 11, a ROM 12, a RAM 13, a current location detection device 14, an image memory 15, a display monitor 16, a speaker 17, an input device 18, a terrestrial digital broadcast receiving unit 19, and a disk drive 110. The disc drive 110 is loaded with a DVD-ROM 111 on which map data is recorded. The map data includes broadcast station area information, map display data, route search data, and the like. The map display data has map data of a plurality of scales from wide areas to details, and the scale of the display map can be changed according to the operator's request.

  The broadcast station area information includes broadcast area information indicating an area to which a broadcast wave from a radio tower transmitting a broadcast wave of digital terrestrial broadcasting reaches. Here, terrestrial digital broadcasting refers to broadcasting in which the contents of broadcasting are digitized and broadcast on terrestrial waves. In terrestrial digital broadcasting, broadcast waves from a plurality of broadcasting stations are transmitted from a single radio tower.

  The control circuit 11 includes a microprocessor and its peripheral circuits, and performs various controls by executing a control program stored in the ROM 12 using the RAM 13 as a work area. When the control circuit 11 performs a predetermined route search process based on the map data stored in the DVD-ROM 111, the processing result is displayed on the display monitor 16 as a recommended route.

  The current position detection device 14 is a device that detects the current position of the vehicle. For example, a vibration gyro 14a that detects the traveling direction of the vehicle, a vehicle speed sensor 14b that detects the vehicle speed, and a GPS signal from a GPS (Global Positioning System) satellite. It consists of a GPS sensor 14c and the like. The navigation device 1 determines a map display range, a route search start point, and the like based on the current location of the vehicle detected by the current location detection device 14, and displays the current location on the map.

  The image memory 15 stores image data to be displayed on the display monitor 16. The image data includes road map drawing data and various graphic data, which are appropriately generated based on map data stored in the DVD-ROM 111 read by the disk drive 110. The navigation device 1 can perform map display and the like by using the image data generated in this way.

  The display monitor 16 provides various information such as a road map near the vehicle position to the operator of the navigation apparatus 1 as a screen display based on various information such as map data. The display monitor 16 displays video information of the terrestrial digital broadcast received by the terrestrial digital broadcast receiver 19. The speaker 17 provides the driver with various information such as a map near the vehicle position based on various information such as map data. The speaker 17 outputs the terrestrial digital broadcast audio information received by the terrestrial digital broadcast receiver 19.

  The input device 18 has an input switch for a driver to set a destination of the vehicle, and this is realized by an operation panel, a remote controller, or the like. The driver selects the destination by setting the destination by operating the input device 18 in accordance with the instruction on the display screen of the display monitor 16 or the instruction of the voice from the speaker 17. In addition, a broadcast station received by the terrestrial digital broadcast receiver 19 can be selected by the input device 18.

  When the destination is set by the operator, the navigation device 1 performs a route calculation from the current location detected by the current location detection means 14 to the destination based on a predetermined algorithm. The route obtained in this way (hereinafter referred to as a searched route) is displayed on the screen separately from other roads by changing the display form, for example, the display color. Thereby, the operator can recognize the search route on the map on the screen. In addition, the navigation device 1 instructs the operator to travel in the direction of the screen or voice so that the vehicle can travel according to the searched route, thereby guiding the vehicle.

  The terrestrial digital broadcast receiver 19 receives the terrestrial digital broadcast and outputs the content of the received broadcast to the display monitor 16 and the speaker 18. The disk drive 110 reads map data for displaying a map on the display monitor 16 from the loaded DVD-ROM 111. The map data may be read from a recording medium other than the DVD-ROM, such as a CD-ROM or a hard disk.

  Next, the terrestrial digital broadcast receiver 19 will be described with reference to FIG. The terrestrial digital broadcast receiving unit 19 includes antennas 21 and 22, tuners 23 and 24, demodulation units 25 and 26, tuner control circuit 27, decoding unit 28, decoding unit RAM 29, NTSC (National Television System Committee) encoding unit 210, audio signal A DA conversion unit 211, a reception unit control circuit 212, a reception unit ROM 213, and a communication unit 214 are included. Here, the part of the broken line 215 is called the front end part 215 and the part of the broken line 216 is called the back end part 216.

  The antennas 21 and 22 have a function of receiving terrestrial digital broadcasting. The tuners 23 and 24 have a function of switching broadcast channels received by the antennas 21 and 22, a function of detecting electric field strength of signals received by the antennas 21 and 22, and a function of converting analog signals into digital signals. The demodulation units 25 and 26 have a function of digitally demodulating the signals converted into digital signals by the tuners 23 and 24.

  The tuner control circuit 27 has a function of setting a channel to be switched by the tuners 23 and 24, a function of synthesizing signals from the two tuners 23 and 24 and outputting them to the decoding unit 28, and only one signal of the tuners 23 and 24. Is output to the decoding unit 28. By combining the signals from the two tuners 23 and 24 and outputting them to the decoding unit 28, the shape of the rectangular wave of the digital signal output to the decoding unit 28 is improved.

  The decoding unit 28 has a function of compressing / decompressing and extracting a digital video signal and a digital audio signal which are MPEG-compressed included in the terrestrial digital wave signal. The decoding unit RAM 29 has a function as a work area for the compression / decompression processing in the decoding unit 28. The NTSC encoding unit 210 has a function of converting the digital video signal extracted by the decoding unit 28 into an NTSC analog output video signal and outputting it to the monitor 16. The audio signal DA conversion circuit 211 has a function of converting the digital audio signal extracted by the decoding unit 28 into an analog audio signal and outputting the analog audio signal to the speaker 17. As for video output, NTSC is used as an example, but RGB (DVI (Digital Video Interface)) used in PAL (Phase Alternation by Line System), PC (Personal Computer), etc., and HDMI (High Video) are used. (Definition Multimedia Interface) may be used.

  The reception unit control circuit 212 has a function of controlling operations of the tuner control circuit 27 and the decoding unit 28. Under the control of the receiving unit control circuit 212, the channel of one of the tuners 23 and 24 set by the tuner control circuit 27 is scanned to detect a receivable channel. The communication unit 214 has a function of inputting an output from the control circuit 11 and outputting the output to the reception unit control circuit 212.

  Next, the contents of the automatic channel switching process in the navigation device 1 according to the embodiment of the present invention will be described with reference to the flowchart of FIG.

  In the start state, the terrestrial digital broadcast is received by the antenna 21 and the terrestrial digital broadcast program is viewed by the tuner 23. A user of the navigation device 1 (hereinafter referred to as a user) is on the moving body and moves on the searched route calculated by the route search.

  In step S301, information on the current location is acquired. Information on the current location is acquired by the current location detection device 14. Next, in step S302, from the broadcast station area information stored in the DVD-ROM 111 and the current location information acquired in step S301, a broadcast area that can receive the terrestrial digital broadcast of the currently viewed channel, that is, the current location. Information of a terrestrial digital broadcast broadcast area (hereinafter referred to as broadcast area A) is acquired.

  In step S303, from the broadcasting station area information stored in the DVD-ROM 111, the current location information acquired in step S301, and the search route, the broadcasting area (hereinafter referred to as the broadcasting area) of the digital terrestrial broadcasting to which the user moves next. B)). That is, the broadcast area through which the search route passes among the broadcast areas adjacent to the broadcast area A is specified as the broadcast area B. In step S304, it is determined from the current location information and the positions and ranges of the broadcast areas A and B whether the user is located in an area where the broadcast area A and the broadcast area B overlap (hereinafter referred to as an overlapping broadcast area). . If the determination is affirmative, the process proceeds to step S305. If a negative determination is made, the process returns to step S301.

  In step S305, a broadcast station that can be viewed by the user in the broadcast area B is specified by another tuner 24 different from the tuner 23 of the two tuners 23 and 24. As a specifying method, the receiver control circuit 212 scans all the channels of the terrestrial digital broadcast of the tuner 24 set by the tuner control circuit 27 and detects the channels that can be received in the broadcast area B. The detected channel is stored in the RAM 13. At this time, since the channels that can be received before entering the overlapping broadcasting area are also detected, the channels that can be received before entering the overlapping broadcasting area are excluded.

  In this way, the channels that can be viewed in the broadcast area B can be specified. That is, the table of channels that can be viewed in the broadcast area B can be acquired before switching to any one of the channels that can be viewed in the broadcast area B.

  In step S306, the tuner 23 detects the electric field strength of the broadcast wave of the channel currently being viewed in the broadcast area A. Then, the channel of the tuner 24 is switched to any one of the channels specified in step S305, and the tuner 24 detects the electric field intensity of the broadcast wave of one of the channels that can be viewed in the broadcast area B. .

  In step S307, the electric field intensity of the broadcast wave detected by the tuner 23 is compared with the electric field intensity of the broadcast wave detected by the tuner 24. If the electric field strength of the channel currently being viewed detected by the tuner 23 is stronger, a negative determination is made and the process returns to step S306. If the electric field strength of the channel that can be viewed in the broadcast area B detected by the tuner 24 is higher, an affirmative determination is made, and the process proceeds to step S308.

  In step S308, the channel that is viewed using the tuner 23 is switched from the currently viewed channel to the channel that can be viewed in the broadcast area B by the receiving unit control circuit 212, and the channel that can be viewed in the broadcast area B is broadcast. It is output to the display monitor 16 and the speaker 17.

With reference to FIG. 4, the relationship of the position of a mobile body and the automatic switching of the channel of the navigation apparatus 1 in embodiment of this invention is demonstrated.
The broadcast area 41 and the broadcast area 42 indicate ranges that can be received from the radio towers 47 and 48 existing in the respective broadcast areas. Broadcast area 41 and broadcast area 42 overlap in overlapping broadcast area 43. First, it is assumed that the position of the moving body is located at a position 44 in the broadcast area 41. Then, the vehicle travels on the search route 45 from the broadcast area 41 toward the broadcast area 42, and enters the overlapping broadcast area 43 at a position 46.

  When the position of the moving body is between the position 44 and the position 46, the broadcast from the radio tower 47 is viewed. Then, the current location information is acquired by the current location detection device 14, the broadcast area 41 is specified from the current location information and the broadcast station area information, and the destination broadcast area 41 to be moved from the broadcast station area information and the searched route. The broadcast area 42 adjacent to the is identified.

  Next, when the position of the moving body reaches the position 46, the two tuners 23 and 24 individually detect and compare the electric field intensity of the broadcast wave from the radio tower 47 and the electric field intensity of the broadcast wave from the radio tower 48.

  When the user further moves, the electric field intensity of the broadcast wave from the radio tower 47 becomes stronger than the electric field intensity of the broadcast wave from the radio tower 48 (for example, A in FIG. 5), and the electric field intensity detected by the tuner 24 is increased. When it becomes stronger than the electric field strength detected by the tuner 23, a broadcast of a channel that can be viewed in the broadcast area 42 is output to the display monitor 16 and the speaker 17.

The navigation device according to the embodiment of the present invention described above has the following operational effects.
(1) In the embodiment of the present invention, a channel that can be received in a broadcast area that moves next is scanned by one of the two tuners. For this reason, even if the channel of the broadcasting station broadcast in the next moving broadcasting area is changed, it is possible to specify and select a channel that can be viewed in the next moving broadcasting area. Even if it changes, you can continue to watch the broadcast.
(2) In the embodiment of the present invention, the broadcasting area where the user moves next is selected in consideration of the traveling direction of the user. For this reason, even if there are a plurality of adjacent broadcast areas, an appropriate broadcast area can be selected.

  In the above embodiment, whether or not a user has entered an overlapping broadcast area of two broadcast areas is determined from the broadcast area information and current location information, but is determined from the electric field strength of the radio wave from the radio tower in each broadcast area. May be. For example, FIG. 5 shows the electric field strength when the user moves along the path 45 in FIG. A change in electric field intensity from the radio tower 47 in the broadcast area 41 when moving from the broadcast area 41 to the broadcast area 42 is defined as an electric field intensity curve 51, and a change in electric field intensity from the radio tower 48 in the broadcast area B is defined as an electric field intensity curve 52. And

  As the user moves along the path 45, the electric field intensity 51 of the broadcast wave from the radio tower 47 decreases, and the electric field intensity of the broadcast wave from the radio tower 48 increases. By the way, the broadcast area is an area where the electric field intensity of the broadcast wave is a required value 53 or more (a limit value that can be viewed, for example, 60 dBμV / m or more). Therefore, if the two electric field strength curves 51 and 52 are both equal to or greater than the required value 53, the user determines that the user is located in the overlapping broadcast area 43 where the two broadcast areas 41 and 42 overlap. Can do. In this case, one tuner out of the two tuners must always detect the electric field strength of the broadcast wave, but since the field strength is actually measured and judged, the entry of the overlapping broadcast area can be more accurately known. There is an advantage.

  In the above embodiment, a program is viewed by one tuner 23 and a channel that can be viewed in the broadcast area B is detected by the other tuner 24. When the mobile body is not located in the overlapping broadcast area, The tuners 23 and 24 may receive the same channel, synthesize the received signals, and output them to the decoding unit 28 to view the program. Compared to the case of reception by one tuner 23, the rectangular wave of the received signal is improved, and dot omission in the image is improved. Further, after detecting a channel that can be viewed in the broadcasting area B by the tuner 24, the program is viewed by the tuner 24, and the tuner 23 is used to detect a channel that can be viewed in the broadcasting area of the next destination. Also good.

  In the above embodiment, the navigation apparatus 1 reads the map data from the storage medium such as the DVD-ROM and acquires the broadcast station area information. However, the present invention is not limited to this content. For example, the present invention can be applied to a communication navigation apparatus that downloads map data from an information distribution center using wireless communication using a mobile phone or the like.

  In the above embodiment, when the broadcast area changes due to movement, the channel to be viewed changes to one of the channels that can be viewed in the destination broadcast area, but using the information of the broadcaster included in the terrestrial digital broadcast, You may make it switch to the channel of the broadcasting station of the same series as the broadcasting station of the broadcast which was watching. In addition, the broadcast program information included in the terrestrial digital broadcast may be used to switch to a channel that broadcasts the same program as the program that was being viewed.

  In the above embodiment, the mobile receiver is a navigation device, but is not limited to a navigation device. For example, the present invention can be applied to a mobile phone having a terrestrial digital broadcast receiving function capable of detecting a current position by communication with GPS or a base station, and a television receiver having a GPS function.

The correspondence between the elements of the claims and the embodiments will be described.
The current location detection means corresponds to the current location detection device 14. The first tuning means corresponds to the tuner 23, and the second tuning means corresponds to the tuner 24. A broadcast area including the current location corresponds to broadcast area A, and a broadcast area adjacent to the broadcast area corresponds to broadcast area B. The viewable channel specifying means corresponds to the receiving unit control circuit 212. The first electric field strength detection means corresponds to the tuner 23, and the second electric field strength detection means corresponds to the tuner 24. The tuning switching unit corresponds to the reception unit control circuit 212.

It is a block diagram which shows the structure of the navigation apparatus in embodiment of this invention. It is a block diagram which shows the structure of a terrestrial digital broadcast receiver. It is a flowchart for demonstrating the channel automatic switching process in the navigation apparatus which is embodiment of this invention. It is a figure for demonstrating the relationship of a user's position and the automatic switching of the channel of the navigation apparatus in embodiment of this invention. It is a figure explaining the relationship between a user's position and the electric field strength detected by a tuner.

Explanation of symbols

1 Navigation device 11 Control circuit 12 ROM
13 RAM
14 current location detection device 15 image memory 16 display monitor 17 speaker 18 input device 19 terrestrial digital broadcast receiving unit 110 disk drive 111 DVD-ROM
21 and 22 Antennas 23 and 24 Tuners 25 and 26 Demodulator 27 Tuner control circuit 28 Decoder 29 Decoder RAM
210 NTSC encoding unit 211 Audio signal DA conversion circuit 212 Reception unit control circuit 213 Reception unit ROM
214 Communication section 41, 42 Broadcast area 43 Duplicate broadcast area 45 Search route 47, 48 Radio tower

Claims (5)

In a mobile receiver for receiving terrestrial digital broadcasting,
Current location detection means for detecting the current location of the moving object;
At least first and second tuning means;
Duplicate broadcast area entry detection means for detecting whether the current location of the mobile body has entered an overlapping broadcast area where a broadcast area including the current location and a broadcast area adjacent to the broadcast area overlap,
When the present location of the mobile body is detected to have entered the overlapping broadcast area by the overlapping broadcast area entry detecting means, another second tuning means different from the first tuning means that is viewing the terrestrial digital broadcast is used. And a viewable channel specifying means for specifying a viewable channel in a broadcast area adjacent to the broadcast area including the current location. The mobile receiver according to claim 1,
When a predetermined condition is detected, the first tuning unit further includes a tuning switching unit that switches a channel from a currently viewed channel to one of the channels specified by the viewable channel specifying unit. A mobile receiver. The mobile receiver according to claim 2,
Further comprising at least first and second electric field strength detection means,
The second tuning means uses the second electric field strength detection means different from the first electric field strength detection means for detecting the electric field strength of the channel currently being viewed by the first tuning means, and the viewable channel identification means. Detect the field strength of the identified channel,
The predetermined condition is that the electric field intensity of the channel specified by the viewable channel specifying means detected by the second electric field intensity detection means is based on the electric field intensity detected by the first electric field intensity detection means. A mobile receiver characterized by being strong. The mobile receiver according to claim 3,
It has map data including information on the broadcasting area of digital terrestrial broadcasting,
A receiving apparatus for a moving body, wherein the overlapping broadcasting area is specified based on the current position of the moving body detected by the current position detecting means and the map data. The mobile receiver according to claim 4, wherein
It further comprises route searching means for the moving body,
A mobile receiving apparatus, wherein a broadcast area adjacent to a broadcast area including the current location is identified based on a searched route searched by the route search means.

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