JP5959303B2 - Digital broadcast receiving apparatus and digital broadcast receiving method - Google Patents

Description

  The present invention relates to a digital broadcast receiving apparatus and a digital broadcast receiving method.

  When a mobile unit equipped with a digital broadcast receiving apparatus moves from within the receivable area of the physical channel received by the digital broadcast receiving apparatus to outside the receivable area, the physical channel that has been normally received is provided. Broadcast service broadcast signals cannot be received. In this case, conventionally, the user can manually detect a receivable physical channel by causing the digital broadcast receiving apparatus to perform a channel scan by manual operation, and the user selects a physical channel that provides the same broadcast service from the detected physical channel. I was stationing. Here, the physical channel is a channel that defines a specific frequency bandwidth as one unit.

  Further, for example, Patent Document 1 discloses a digital broadcast receiving apparatus having a broadcast signal channel selection function that does not require the manual operation. The digital broadcast receiver disclosed in Patent Document 1 detects a receivable physical channel by viewing a program with the first tuner / demodulator and scanning the physical channel with the second tuner / demodulator. Then, a broadcast area map including a receivable area is created from the current position information and the broadcast service information of the detected physical channel. This digital broadcast receiving apparatus records the vertexes of a polygon indicating a receivable area in the coordinates of an orthogonal coordinate system. The digital broadcast receiving apparatus generates a list of broadcast services that can be received at the current position from the broadcast area map at the time of channel selection, and switches physical channels using this list.

JP 2011-061753 A

  However, since the digital broadcast receiving apparatus described in Patent Document 1 records the vertices of a polygon indicating a receivable area in the coordinates of an orthogonal coordinate system, the position information of at least three points is required to generate a broadcast area map. It is necessary, and three hours of measurement time are required to generate a broadcast area map.

  In addition, the digital broadcast receiving apparatus described in Patent Document 1 may have a large error from the actual broadcast area depending on the position indicated by the position information when the number of position information for generating the broadcast area map is small.

  In view of the above, an object of the present invention is to be able to specify a receivable area quickly and accurately.

A digital broadcast receiving apparatus according to an aspect of the present invention is a digital broadcast receiving apparatus mounted on a moving body that moves on a road , receives a signal of a physical channel, and further detects the reception intensity of the received signal. Detected by a receiving unit, a channel scan control unit that controls the receiving unit to detect a physical channel capable of receiving a broadcast signal by the receiving unit, a current position detecting unit that detects a current position, and a current position detecting unit When the channel scan control unit detects a physical channel capable of receiving a broadcast signal at the current position at a plurality of points on the road, the detected current position is associated with the detected physical channel. and position information indicating a and a radius of a circle centered on the said current position, and area map generator for generating a reception area information including for each of a plurality of points For example, area map generation unit, as detected reception intensity is high, to increase the radius of the circle, the area inside the circle is specified for a plurality of points based on the positional information and radius included in the received area information And a common outer tangent line to a circle adjacent to the specified circle, and a region surrounded by the specified circle and the adjacent circle are generated as receivable area information indicating a receivable area. And
A digital broadcast receiving method according to an aspect of the present invention is a digital broadcast receiving method of a digital broadcast receiving device mounted on a moving body moving on a road, and receives a signal of a physical channel and receives the received signal. Detected in the reception process to further detect the received intensity of the channel, the channel scan control process to detect the physical channel that can receive the broadcast signal in the reception process, the current position detection process to detect the current position, and the current position detection process When the channel scan control process detects a physical channel capable of receiving a broadcast signal in the reception process at the current position at a plurality of points on the road, the detected current position is associated with the detected physical channel. And the receivable area information including the radius of the circle centered on the current position for each of a plurality of points. The area map generation process is specified for each of a plurality of points based on the position information and the radius included in the receivable area information, as the detected reception intensity is stronger, the radius of the circle is increased. The area inside the circle, the common outer tangent line to the circle adjacent to the specified circle, and the area surrounded by the specified circle and the adjacent circle are used as the receivable area information indicating the receivable area. It is characterized by generating.

  According to one embodiment of the present invention, a receivable area can be specified quickly and accurately.

1 is a block diagram schematically showing a configuration of a digital broadcast receiving device according to Embodiments 1 and 2. FIG. 6 is a schematic diagram illustrating an example of broadcast area map information according to Embodiment 1. FIG. FIG. 3 is a schematic diagram showing a receivable area included in broadcast area map information held by the digital broadcast receiving apparatus according to the first embodiment. 6 is a schematic diagram illustrating an example of generated area information according to Embodiment 1. FIG. 4 is a flowchart showing broadcast service list generation processing by a list generation unit of the digital broadcast receiving apparatus according to Embodiment 1; 6 is a flowchart illustrating a determination process for determining whether or not the current position is included in a receivable area in the first embodiment. (A)-(g) is the schematic which shows the division area | region which divided | segmented the receivable area. 7 is a flowchart showing broadcast area map information non-generated area determination processing by the digital broadcast receiving apparatus according to Embodiment 1; 3 is a flowchart showing an operation at the time of channel scanning by the digital broadcast receiving apparatus according to the first embodiment. 6 is a flowchart showing an operation (subroutine) at the time of reliable channel scanning in the first embodiment. 6 is a flowchart showing an operation (subroutine) at the time of high-speed channel scanning in the first embodiment. 6 is a flowchart showing an expansion process of generated area information in the first embodiment. 6 is a schematic diagram illustrating an example of a process for extending generated area information according to Embodiment 1. FIG. 6 is a schematic diagram for explaining the effect of the digital broadcast receiving apparatus according to Embodiment 1. FIG. 10 is a flowchart showing broadcast area map information non-generated area determination processing by the digital broadcast receiving apparatus according to the second embodiment. It is a block diagram which shows roughly the structure of the digital broadcast receiver which concerns on the modification of Embodiment 1 or 2. FIG.

Embodiment 1 FIG.
FIG. 1 is a block diagram schematically showing the configuration of the digital broadcast receiving apparatus 100 according to the first embodiment. The digital broadcast receiving apparatus 100 includes a first antenna 110, a first receiving unit 111, a first demultiplexing unit 112, a decoding unit 113, a graphics superimposing unit 114, a video output unit 115, and an audio output unit 116. And an operation input unit 117 and a channel selection control unit 118. In addition, the digital broadcast receiving apparatus 100 includes a second antenna 120, a second receiving unit 121, a second demultiplexing unit 122, a reception mode switching unit 123, a channel scan control unit 124, and a third antenna 130. The current position detection unit 131, the area map generation unit 132, the area map storage unit 133, the area determination unit 134, and the list generation unit 135 are provided. The first receiving unit 111 and the second receiving unit 121 constitute a receiving unit. Moreover, the code | symbol in the parenthesis of FIG. 1 has shown the structure in Embodiment 2. FIG.

  The first antenna 110 and the first receiving unit 111 constitute a first system broadcast receiving unit. The second antenna 120 and the second receiving unit 121 constitute a second system broadcast receiving unit. The system configured by the first antenna 110 and the first receiving unit 111 and the system configured by the second antenna 120 and the second receiving unit 121 can operate independently of each other. In the digital broadcast receiving apparatus 100, the reception mode switching unit 123 switches between a single tuner mode and a double tuner mode, which are operation modes in the digital broadcast receiving apparatus 100.

  The first antenna 110 generates a signal from radio waves. Then, the first antenna 110 gives the generated signal to the first reception unit 111.

In the single tuner mode, the first reception unit 111 performs channel selection, demodulation, and error correction on the signal provided from the first antenna 110 to generate a reception signal, for example, a TS (Transport Stream). Then, the first receiving unit 111 performs diversity combining of the generated received signal and the received signal received via the second receiving unit 121 and the receiving mode switching unit 123, thereby obtaining one highly stable received signal. Generate. Then, the first reception unit 111 provides the diversity-generated reception signal to the first demultiplexing unit 112. On the other hand, in the double tuner mode, the first reception unit 111 performs channel selection, demodulation, and error correction on the signal given from the first antenna 110 to generate a reception signal. This is given to the demultiplexing unit 112.
Also, the first receiving unit 111 notifies the channel selection control unit 118 of C / N, bit error rate, tuner PLL (Phase Locked Loop) lock information and OFDM (Orthogonal Frequency Division Multiplex) lock information.

The first demultiplexing unit 112 separates video data (for example, video packets) and audio data (for example, audio packets) from the reception signal received from the first reception unit 111. Then, the first demultiplexing unit 112 gives the separated video data and audio data to the decoding unit 113.
Also, the first demultiplexer 112 provides the channel selection controller 118 with notification of section data (for example, PSI (Program Specific Information) / SI (Service Information) information).

The decoding unit 113 decodes the video data and the audio data received from the first demultiplexing unit 112 to generate a video signal and an audio signal. Then, the decoding unit 113 gives the generated video signal to the graphics superimposing unit 114 and gives the generated audio signal to the audio output unit 116.
Further, the decoding unit 113 notifies the channel selection control unit 118 of information on the decoding error rate.

The graphics superimposing unit 114 superimposes video and graphics based on the video signal provided from the decoding unit 113. This graphics is based on, for example, graphics data given from the list generation unit 135.
The video output unit 115 outputs a video based on the video signal output from the graphics superimposing unit 114. For example, the video output unit 115 may be configured by a display or the like, or may be configured by a video output terminal.
The audio output unit 116 outputs audio based on the audio signal given from the decoding unit 113. For example, the audio output unit 116 may be configured by a speaker or the like, or may be configured by an audio output terminal.

  The operation input unit 117 receives an operation input from the user. Then, the operation input unit 117 gives operation information indicating the input operation to the channel selection control unit 118.

  The channel selection control unit 118 comprehensively controls processing in the digital broadcast receiving apparatus 100. In particular, the channel selection control unit 118 controls processing for selecting a physical channel. For example, when the operation input unit 117 receives an input of a channel selection request, the channel selection control unit 118 refers to the area map storage unit 133 to identify a physical channel to be selected, and sends a channel selection request to the first reception unit 111. Give instructions. Further, the channel selection control unit 118 determines whether or not the signal reception state has deteriorated based on the notification from the first reception unit 111, the first demultiplexing unit 112, and the first decoding unit 113. When the channel selection control unit 118 determines that the signal reception state has deteriorated, the channel selection control unit 118 accesses the area map storage unit 133 and is likely to be broadcasting the same program at the current position. Alternatively, a broadcast station with the same broadcast service name broadcast on different physical channels is searched. If there is a broadcast service that broadcasts the same receivable program, the channel selection control unit 118 notifies the first reception unit 111 to perform automatic channel selection switching.

The second antenna 120 generates a signal from radio waves. Then, the second antenna 120 gives the generated signal to the second reception unit 121.
The second receiving unit 121 performs channel selection, demodulation, and error correction on the signal given from the second antenna 120 to generate a received signal. Then, in the single tuner mode, the second reception unit 121 gives the generated reception signal to the first reception unit 111 via the reception mode switching unit 123. On the other hand, the second reception unit 121 provides the generated reception signal to the second demultiplexing unit 122 in the double tuner mode. In addition, the second receiving unit 121 detects the reception strength of the received signal and gives this reception strength to the channel scan control unit 124. As the reception intensity, any one of reception power, C / N ratio (carrier-to-noise ratio) and PER (packet error rate), or a combination of these is used. The larger the received power and the C / N ratio, the stronger the received intensity, and the smaller PER, the stronger the received intensity.
The second demultiplexer 122 separates the section data related to the broadcast content from the received signal received from the second receiver 121. Then, the second demultiplexer 122 provides the separated section data to the channel scan controller 124 and the area map generator 132. Further, the second demultiplexing unit 122 gives the reception strength given from the second receiving unit 121 to the area map generating unit 132.

  The reception mode switching unit 123 performs diversity processing on the double tuner mode in which the reception signals demodulated in the broadcast reception units of each system (here, the first system and the second system) are output, and the reception signals of a plurality of systems As a result, the single tuner mode in which one reception signal having high reception stability is output from the first reception unit 111 is switched. This switching is performed when switching is instructed from the channel scan control unit 124 to the reception mode switching unit 123 by the switching control signal.

  The channel scan control unit 124 controls the second reception unit 121 and the second demultiplexing unit 122 to execute channel scan. In the channel scan, the second receiving unit 121 selects a physical channel, and the channel scan control unit 124 detects a receivable physical channel, in other words, a physical channel that can receive a broadcast signal. The channel scan controlled by the channel scan control unit 124 is executed in a state in which the viewer does not notice in parallel with the channel selection for program viewing by the first receiving unit 111 (executed behind the program viewing). Therefore, it is also called “back channel scan”. In the following, it is referred to as “back channel scan” only when it is necessary to particularly distinguish, and when it is not necessary to distinguish from normal channel scan, both are collectively referred to as “channel scan”.

The third antenna 130 is an antenna for detecting the current position, and is composed of, for example, a GPS antenna.
The current position detection unit 131 detects the current position from the signal from the third antenna 130. The current position detection unit 131 notifies the detected current position to the channel selection control unit 118, the area map generation unit 132, the area determination unit 134, and the list generation unit 135.

The area map generation unit 132 generates broadcast area map information and generated area information based on the section data received from the second demultiplexing unit 122 and the current position notified from the current position detection unit 131, and stores the area map. Stored in the unit 133.
The broadcast area map information includes receivable area information indicating areas in which broadcast signals can be received for each broadcast service. The broadcast area map information is used to specify a physical channel to be selected when the operation input unit 117 receives a channel selection request. Also, the broadcast area map information indicates that the physical channel (other physical channel) of the same broadcast service as the broadcast service when the reception state of the signal of the selected physical channel deteriorates with the movement of the digital broadcast receiving apparatus 100. Used for automatic switching.
The generated area information includes generated area information indicating an area for which receivable area information has been generated. When the channel scan by the channel scan control unit 124 ends, the area map generation unit 132 stores position information indicating the current position where the channel scan has been performed in the generated area information regardless of the presence or absence of a receivable physical channel.

  The area map storage unit 133 stores broadcast area map information and generated area information.

FIG. 2 is a schematic diagram illustrating an example of broadcast area map information. The broadcast area map information 141 shown in FIG. 2 includes a physical channel column 141a, a TS name / ensemble name column 141b, a broadcast service name column 141c, a center coordinate column 141d of a receivable area, and a radius of the receivable area. The table format information includes a column 141e, a relay station channel column 141f, and an affiliated station channel column 141g.
The physical channel column 141a stores physical channel identification information for identifying a physical channel. In the first embodiment, the physical channel identification information is a physical channel number.
The TS name / ensemble name column 141b stores broadcaster identification information for identifying a broadcaster. Here, ISDB-T (Integrated Services Digital Broadcasting-Terrestrial), DVB-T (Digital Video Broadcasting-Terrestrial), DVB-H (Digital Video Broadcasting-Handheld), DTMB (Digital Terrestrial Multimedia Broadcast) and ATSC (Advanced Television Systems In the case of each of the digital broadcast standards (Committee), the TS name is used as broadcaster identification information. In the case of digital broadcasting standards such as DAB (Digital Audio Broadcast), DAB + (Digital Audio Broadcast plus), and DMB (Digital Multimedia Broadcasting), ensemble names are used as broadcaster identification information.
The broadcast service name column 141c stores broadcast service identification information for identifying a broadcast service provided by a broadcaster. In the first embodiment, a broadcast service name (organized channel name) is used as broadcast service identification information.
In addition, the broadcast station providing the broadcast service as a channel selection unit can be identified by the information stored in the TS name / ensemble name column 141b and the broadcast service name column 141c.

The center coordinate column 141d of the receivable area is a physical channel specified by the physical channel column 141a, and in the broadcast service specified by the broadcast service name column 141c by the broadcaster specified by the TS name / ensemble name column 141b. Stores the coordinate value of the position where the broadcast signal can be received. Here, as the coordinates, an orthogonal coordinate system in which longitude (X coordinate position) is the X coordinate axis and latitude (Y coordinate position) is the Y coordinate axis is used.
The radius field 141e of the receivable area stores the value of the radius according to the reception intensity of the broadcast signal at the point (position) specified by the center coordinate column 141d of the receivable area. For example, the radius increases as the reception intensity of the broadcast signal increases. In Embodiment 1, the radius of the circle is specified by the received intensity, but the radius of the circle may be specified by other information.
Here, the center coordinate column 141d of the receivable area and the radius column 141e of the receivable area store the coordinate and the radius value in chronological order, respectively, so that it is possible to specify the radius value at which coordinate. It is like that.
The broadcast specified by the TS name / ensemble name column 141b on the physical channel specified by the physical channel column 141a based on the values stored in the center coordinate column 141d of the receivable area and the radius column 141e of the receivable area. Receivable area information indicating a receivable area in which a broadcast signal in the broadcast service specified by the broadcast service name column 141c by the operator can be received is configured.

The relay station channel column 141f is a physical channel specified by the physical channel column 141a, and the broadcaster specified by the TS name / ensemble name column 141b receives the broadcast signal of the broadcast service specified by the broadcast service name column 141c. Stores relay station information indicating the physical channel of the relay station that is transmitting.
The affiliated station channel column 141g is a physical channel specified by the physical channel column 141a, and stores affiliated station information indicating the physical channel of the affiliated station of the broadcaster specified by the TS name / ensemble name column 141b.

  FIG. 2 shows an example in which one TS or one ensemble exists in each physical channel and one service is included therein, but the present invention is not limited to this example. . One TS or ensemble may have a plurality of services. The broadcaster identification information is not limited to the TS name or ensemble name. Further, the service identification information is not limited to the service name.

  As shown in FIG. 2, the physical channel of the relay station and the physical channel of the affiliated station are acquired from the section data received by the channel scan, and information indicating these physical channels is stored in the broadcast area map information 141. Therefore, when the signal reception state deteriorates, the channel selection control unit 118 can easily grasp an alternative physical channel that is likely to be broadcasting the same program, and can perform automatic operation in a short time. Switching can be realized. Also, since there is a high possibility that physical channels with the same broadcast service name are broadcasting the same program, it is desirable that the broadcast service name is also stored in the broadcast area map information 141. Furthermore, the broadcast area map information 141 may also store other information that can be acquired from the broadcast wave. Since the frequency of the relay station is described in the terrestrial distribution system descriptor (Terrestrial Delivery System Descriptor) included in the network information table (NIT: Network Information Table), the area map generation unit 132 The relay station is specified by this information. In addition, since the series identification is described in the extended broadcast descriptor (Extended Broadcast Descriptor) included in the broadcast information table (BIT: Broadcaster Information Table), the area map generating unit 132 The affiliated station is specified by the information.

FIG. 3 is a schematic diagram showing receivable areas included in the broadcast area map information 141 held by the digital broadcast receiving apparatus 100 according to the first embodiment. In Embodiment 1, the receivable area is defined by an area represented by a plurality of circles and an area surrounded by a common circumscribed line of adjacent circles. Receivable area AR1 shown in FIG. 3, the line segment _A 10 _{-A 11,} an arc _A 11 _{-D 11,} the line segment _{D 11 -E 1 (m-1} ), line _{E 1 (m -1)} -B _1m , arc B _1m -E _1m -A _1m , line segment A _1m -A _{1 (m-1)} , arc A _{1 (m-1)} -C _{1 (m-1)} , the line segment _{C 1 (m-1) -E} 11, the line segment _E 11 _{-B 10,} an inner area of the region specified by an arc _{B 10 -E} 10 _-A 10. Here, the line segment A ₁₀ -A ₁₁ and the line segment B ₁₀ -B ₁₁ are a common circumscribing line between a circle having a radius r ₁₀ centered on the position P10 and a circle having a radius r ₁₁ centered on the position P11. It is. The line segment D ₁₁ -D _{1 (m−1)} and the line segment C ₁₁ C _{1 (m−1)} are a circle having a radius r ₁₁ centered on the position P11 and a radius r centered on the position P1m−1. _It is a common tangent with a circle of _{1 (m−1)} . The line segment B _1m -B _{1 (m-1)} and the line segment A _1m -A _{1 (m-1)} are a circle having a radius r _1m centered on the position P1m and a radius centered on the position P1m-1. It is a common circumscribing line with the circle of r _{1 (m−1)} . Point _{E 11} is a line segment _B 10 _{-B 11,} which is the intersection between the line segment _{C 11 -C 1 (m-1} ). Point _{E 1 (m-1)} is the line segment _{D 11 -D 1 (m-1} ), a line segment _{B 1 (m-1)} is an intersection of the _{-B 1 m.} Note that the radius r ₁₀ , the radius r ₁₁ , the radius r _{1 (m−1),} and the radius r _1m are set according to the received signal strength at the position P10, the position P11, the position P1m−1, and the position P1m, respectively. The In general, when the reception strength is strong, the radius is large, and when the reception strength is weak, the radius is small.

  FIG. 4 is a schematic diagram illustrating an example of the generated area information. The generated area information 142 shown in FIG. 4 includes a generated area name column 142a, an update date column 142b, and a vertex coordinate column 142c of the generated area.

The generated area name column 142a stores area identification information for identifying each area. In the first embodiment, the area name is used as the area identification information.
The update date column 142b stores the date when the vertex coordinate column 142c of the generated area is updated.
The vertex coordinate column 142c of the generated area stores the coordinate value of the position where the channel scan is performed. Here, as the coordinates, an orthogonal coordinate system in which longitude (X coordinate position) is the X coordinate axis and latitude (Y coordinate position) is the Y coordinate axis is used.
Here, it is assumed that the area inside the polygon having the coordinates stored in the vertex coordinate column 142c of the generated area indicates the area where the broadcast area map information 141 has been generated (generated area).
The vertex coordinate column 142c of the generated area stores the coordinates of the vertices constituting the generated area (position information indicating the position where the channel scan has been performed), for example, in the clockwise order.
In addition, each record of the generated area information 142 includes a slope, an intercept, and other vertices of a linear function that forms a polygon whose vertex is a coordinate value stored in the vertex coordinate column 142c of the generated area. It is assumed that an inequality sign indicating the direction in which is present is associated.
The generated area indicated by the polygon indicated by the coordinates stored in the vertex coordinate column 142c of the generated area may be plural instead of one. For example, when the digital broadcast receiving apparatus 100 is turned off and then turned on again, the current position detected by the current position detection unit 131 is the coordinates stored in the vertex coordinate column 142c of the generated area. When it is outside the polygon shown and the distance to the polygon is longer than a predetermined distance threshold, the area map generator 132 does not add the current position to the existing polygon, A new record is added to the generated area information 142 and the coordinates of the current position are stored. The distance from the current position to the polygon is specified by, for example, the distance from the current position to any side or any point constituting the polygon, or the distance from the current position to the center of gravity of the polygon. be able to.

  Returning to the description of FIG. 1, the area determination unit 134 refers to the generated area information 142 stored in the area map storage unit 133, and broadcast area map information 141 corresponding to the current position notified from the current position detection unit 131. It is determined whether or not has been generated. For example, when the current position notified from the current position detection unit 131 is included in the generated area indicated by the generated area information 142 stored in the area map storage unit 133, the area determination unit 134 broadcasts the broadcast area map. It is determined that the information 141 has been generated.

  The list generation unit 135 refers to the broadcast area map information 141 stored in the area map storage unit 133, and broadcast content of the broadcast service provided by the physical channel that can be received at the current position detected by the current position detection unit 131. A list of broadcast services is generated.

FIG. 5 is a flowchart showing broadcast service list generation processing by the list generation unit 135 of the digital broadcast receiving apparatus 100 according to Embodiment 1. For example, the flow of FIG. 5 is started when the change amount of the current position notified from the current position detection unit 131 exceeds a certain threshold.
The list generation unit 135 searches the broadcast area map information 141 stored in the area map storage unit 133 based on the current position notified from the current position detection unit 131 (S10). For example, the list generation unit 135 identifies a record of the broadcast area map information 141 including the current position notified to the receivable area.

Next, the list generation unit 135 generates a broadcast service list including information indicating the broadcast contents of the broadcast service that can be received at the current position from the record specified in step S10, and via the graphics superimposing unit 114, The video signal including the generated broadcast service list is output to the video output unit 115 (S11). Thereby, the video output unit 115 displays the broadcast service list. The broadcast service list is generated based on the broadcast service information stored in the area map storage unit 133.
The user refers to the displayed broadcast service list and selects a broadcast service to be viewed with the operation input unit 117. When the broadcast service channel selection request from the operation input unit 117 is input to the channel selection control unit 118, the channel selection control unit 118 refers to the area map storage unit 133 to grasp the physical channel to be selected, and The receiving unit 111 is instructed to select a channel. Accordingly, the video output unit 115 and the audio output unit 116 output video and audio based on the signals output via the first demultiplexing unit 112 and the decoding unit 113.

  FIG. 6 is a flowchart showing a process for determining whether or not the current position is included in the receivable area, which is necessary in step S10 of FIG.

  First, the area determination unit 134 divides the receivable area specified by the center coordinate column 141d of the receivable area and the radius column 141e of the receivable area of the broadcast area map information 141 into circular and rectangular areas (S20). A specific division example by the area determination unit 134 will be described with reference to FIG.

FIGS. 7A to 7G are schematic diagrams showing divided areas obtained by dividing the receivable area AR1 shown in FIG. Here, the receivable area AR1 shown in FIG. 3 is divided into seven areas.
As shown in FIG. 7 (a), the area judging unit 134, the coverage area AR1 shown in FIG. 3, divides the divided regions DAR11 is a circle of radius _{r 10} around the position P10 To do.
Further, as shown in FIG. 7 (b), the area determination unit 134 calculates a circle centered on the position P10 and a circle centered on the position P11 from the receivable area AR1 shown in FIG. A divided area DAR12 that is a quadrangle formed by connecting the common outer tangent and the contact points A ₁₀ , A ₁₁ , B ₁₁ , B ₁₀ with these two circles is divided. Note that there are six ways of tying the contacts A ₁₀ , A ₁₁ , B ₁₁ , and B ₁₀ , and the area determination unit 134 selects four ways of tying from these tying methods as follows. . Among the straight lines passing through these contacts, the straight line passing through the contact A ₁₀ passes through the straight line passing through the contact A ₁₀ and the contact A ₁₁ , the straight line passing through the contact A ₁₀ and the contact B ₁₀ , and the contact A ₁₀ and the contact B ₁₁ . It is a straight line. Among these straight lines, with respect to the straight lines passing through the contact A ₁₀ and the contact B ₁₁ , the remaining contacts are included in different regions above and below, respectively. In such a case, the line segment A ₁₀ -B ₁₁ is not selected as the line segment (side) constituting the divided area DAR 12. On the other hand, for the straight line passing through the contact point A ₁₀ and the contact point A ₁₁ and the straight line passing through the contact point A ₁₀ and the contact point B ₁₀ , the other contact points are included in one of the upper and lower regions. Are selected as line segments. Hereinafter, by performing the same determination for each contact, the line segment constituting the divided area DAR12 is specified. It should be noted that line segments constituting the divided area DAR14 and the divided area DAR16 are specified by the same determination.
Further, as shown in FIG. 7 (c), the area judging unit 134, divides the divided region DAR13 is a circle of radius _{r 11} around the position P11.
Further, as illustrated in FIG. 7D, the area determination unit 134 includes a common outer tangent of a circle centered on the position P11 and a circle centered on the position P1m-1, and these two circles. The divided region DAR14 which is a quadrangle formed by connecting the contact points C ₁₁ , C _{1 (m−1)} , D _{1 (m−1)} and D ₁₁ is divided.
In addition, as illustrated in FIG. 7E, the area determination unit 134 divides the divided area DAR15 that is a circle having a radius r1 _{(m−1) with} the position P1m−1 as the center.
Further, as illustrated in FIG. 7F, the area determination unit 134 includes a circle that is centered on the position P1m-1 and a common circumscribing line of the circle that is centered on the position P1m, and these two circles. contact _{a 1 (m-1),} a 1m, B 1m, dividing the a is divided regions DAR16 rectangle formed by connecting _{B 1} to _(m-1).
Further, as illustrated in FIG. 7G, the area determination unit 134 divides the divided region DAR17, which is a circle having a radius r _1m with the position P1m as the center.

  Returning to the description of the flowchart of FIG. 6, in step S <b> 21, the area determination unit 134 extracts one region from the divided regions that have not been determined whether or not the current position is included.

Next, the area determination unit 134 determines whether or not the current position is included in the divided area extracted in step S21 (S22).
For example, the area determination unit 134 represents the divided area extracted in step S21 as an inequality, and substitutes the longitude (X coordinate position) and the latitude (Y coordinate position) of the current position for this inequality, and whether or not the inequality is satisfied. It is then determined whether or not the current position is included in the divided area.

により、現在位置が含まれるか否かが判定される。
次に、分割領域ＤＡＲ１３は、

により、現在位置が含まれるか否かが判定される。
次に、分割領域ＤＡＲ１５は、

により、現在位置が含まれるか否かが判定される。
次に、分割領域ＤＡＲ１７は、

により、現在位置が含まれるか否かが判定される。 For example, among the seven regions shown in FIG. 7, for the circular region, it is determined whether or not the current position is included in the divided region by the inequalities expressed by the following equations (1) to (4). To do.
First, the divided area DAR11 is

Thus, it is determined whether or not the current position is included.
Next, the divided area DAR13 is:

Thus, it is determined whether or not the current position is included.
Next, the divided area DAR15 is

Thus, it is determined whether or not the current position is included.
Next, the divided area DAR17 is:

Thus, it is determined whether or not the current position is included.

で表すことができる。
また、線分Ａ_１０−Ｂ_１０を含む直線は、一次関数

で表すことができる。
また、線分Ｂ_１０−Ｂ_１１を含む直線は、一次関数

で表すことができる。
また、線分Ａ_１１−Ｂ_１１を含む直線は、一次関数

で表すことができる。
従って、分割領域ＤＡＲ１２は、以下の（９）〜（１１）式で示される不等式を全て満たす領域になる。

なお、（９）式〜（１２）式の不等号は、その直線に含まれない他の２つの接点の配置により特定すればよい。例えば、（９）式では、右辺で示される直線には含まれない他の２つの接点Ｂ_１０、Ｂ_１１がともに、この直線の下側にあるため、左辺が右辺以下の領域に分割領域ＤＡＲ１２が含まれる。他の式についても、同様にして不等号を特定すればよい。 In addition, for a divided area represented by a rectangle, it is determined whether or not the current position is included as follows.
First, the divided area DAR12 will be described.
The coordinates of the four contact points constituting the divided area DAR12 are contact point A ₁₀ (x _A10 , y _A10 ), contact point A ₁₁ (x _A11 , y _A11 ), contact point B ₁₀ (x _B10 , y _B10 ), contact point B, respectively. ₁₁ (x _B11 , y _B11 ).
Line is a linear function including segment _A 10 _{-A 11}

Can be expressed as
A straight line including the line segment A ₁₀ -B ₁₀ is a linear function.

Can be expressed as
A straight line including the line segment B ₁₀ -B ₁₁ is a linear function.

Can be expressed as
The straight line including the line segment A ₁₁ -B ₁₁ is a linear function.

Can be expressed as
Accordingly, the divided region DAR12 is a region that satisfies all the inequalities expressed by the following equations (9) to (11).

The inequalities in the equations (9) to (12) may be specified by the arrangement of the other two contacts that are not included in the straight line. For example, in the formula (9), since the other two contacts B ₁₀ and B ₁₁ not included in the straight line indicated by the right side are both below this straight line, the divided region DAR12 is divided into a region whose left side is equal to or less than the right side. Is included. For other formulas, the inequality sign may be specified in the same manner.

Similarly divided regions DAR14 each four contact points of coordinates, the contact _{C 11 (x C11, y C11} ), contact _{D 11 (x D11, y D11} ), the contact _{C 1 (m-1) (} x C1 (m _{-1), y C1 (m-} 1)), contact _{D 1 (m-1) (} x D1 (m-1), when the _{y D1 (m-1))} , the following (13) to (16 ) Is a region that satisfies all inequalities in the equation.

Similarly, in the divided area 16, the coordinates of the four contacts are respectively represented as contact A _1m (x _A1m , y _A1m ), contact A _{1 (m−1)} (x _{A1 (m−1)} , y _{A1 (m−1).} ), contact _{B 1m (x B1m, y B1m} ), contact _{B 1 (m-1) (} x B1 (m-1), when the _{y B1 (m-1)),} the following (17) to (20 ) Is a region that satisfies all inequalities in the equation.

  In step S22 of FIG. 6, when the area determination unit 134 determines that the current position is included in the divided region extracted in step S21 (S22: Yes), the process proceeds to step S23, where the current position is If it is determined that it is not included in the divided area extracted in S21 (S22: No), the process proceeds to step S24.

  In step S23, the area determination unit 134 determines that the current position is included in the receivable area, and ends the flow.

  On the other hand, in step S24, the area determination unit 134 confirms whether all the divided areas have been determined. When the area determination unit 134 determines all the divided areas (S24: Yes), the process proceeds to step S25. On the other hand, if the area determination unit 134 has not determined all the divided areas, in other words, if there is a divided area that has not been determined (S24: No), the process proceeds to step S21.

  In step S25, the area determination unit 134 determines that the current position is not included in the receivable area, and ends the flow.

  FIG. 8 is a flowchart showing broadcast area map information non-generated area determination processing by the digital broadcast receiving apparatus 100 according to the first embodiment.

  First, the area determination unit 134 refers to the generated area information 142 stored in the area map storage unit 133 and searches for whether the current position notified from the current position detection unit 131 is included in the generated area. (S30). For example, the area determination unit 134 calculates a primary inequality for each side based on the slope of the linear function associated with each record of the generated area information 142, the inequality sign indicating the direction in which the intercept and other vertices exist. Then, the area determination unit 134 determines whether or not the current position is included in the generated area depending on whether or not the coordinates of the current position satisfy all the calculated primary inequalities for each side.

  When the area determination unit 134 determines that the current position is included in the generated area (S31: Yes), the process proceeds to step S32, and the current position is not included in the generated area. If it is determined (S31: No), the process proceeds to step S33.

  In step S32, the area determination unit 134 notifies the channel scan control unit 124 that it is within the generated area. The channel scan control unit 124 that has received such notification stops the channel scan and starts the single tuner mode operation, for example. In the single tuner mode, video display and audio output of a program are performed based on a broadcast signal that has been subjected to diversity processing with excellent reception stability.

  In step S33, the area determination unit 134 notifies the channel scan control unit 124 that it is outside the generated area. Upon receiving such notification, the channel scan control unit 124 notifies the reception mode switching unit 123 to operate in the double tuner mode, and in parallel with the operation for viewing by the first reception unit 111, the second reception unit 121 starts channel scanning.

  When the area determination unit 134 determines that the current position is within the generated area, the digital broadcast receiving apparatus 100 basically operates in the single tuner mode, but can perform different operations. . The channel scan control unit 124 acquires section data (for example, PSI / SI information) from the first demultiplexing unit 112 while viewing a program, and acquires network configuration information or broadcast service configuration information from the section data. If a change in the network configuration or the broadcast service configuration is detected from these information, the channel scan control unit 124 may use the broadcast area map information 141 because the broadcast service configuration may have changed in other physical channels. In order to update with the latest information, the reception mode switching unit 123 is notified to operate in the double tuner mode. Then, channel scanning is started by the second receiving unit 121 that is a system different from the first receiving unit 111 that performs the operation for viewing the broadcast signal, and the area map storage unit 133 stores the channel scan based on the channel scanning result. The stored broadcast area map information 141 is updated. In addition, as a case where a change in the network configuration or the broadcast service configuration is detected, for example, when the broadcast service is lost or the transmission physical channel is changed, when the network identification value or the broadcast service identification value is changed, There are cases where the network name, TS name, ensemble name or broadcast service name has changed.

  Further, even when the area determination unit 134 determines that the current position is within the generated area, the channel scan control unit 124 notifies the reception mode switching unit 123 to operate in the double tuner mode after a predetermined time has elapsed. And channel scan may be started. By performing such an operation, a channel scan is periodically performed by the second receiving unit 121, which is a separate system from the first receiving unit 111 receiving the program viewing, and the broadcast area map information 141 is displayed. You can monitor for updates. Since the broadcast network or the broadcast service configuration basically does not change frequently, the channel scan control unit 124 does not need to perform this regular monitoring frequently, and the comparison is performed once every few days. It may be performed in a long cycle.

  FIG. 9 is a flowchart showing an operation at the time of channel scanning by the digital broadcast receiving apparatus 100 according to the first embodiment. The flow of FIG. 9 is started when the channel scan control unit 124 determines that the condition for starting the channel scan is met.

  First, the channel scan control unit 124 notifies the reception mode switching unit 123 of an instruction to change to the double tuner mode (S40). Receiving such notification, the reception mode switching unit 123 sets the operation mode of the digital broadcast receiving apparatus 100 to the double tuner mode.

  Next, the channel scan control unit 124 executes the reliable channel scan twice with a predetermined period (S41, S42). This sure channel scan means that all physical channels are scanned. According to the reliable channel scan, a highly reliable channel scan result can be obtained, but the channel scan time becomes longer. Details of the reliable channel scan will be described with reference to FIG.

Next, the channel scan control unit 124 satisfies at least one of the following conditions (1) and (2) in the first certain channel scan in step S41 and the second certain channel scan in step S42. The physical channel is extracted as the next scan candidate physical channel (S43).
(1) A physical channel whose reception state has changed by a predetermined reference level or more in the first and second channel scans.
(2) A physical channel in the vicinity of the unreceivable level (specifically, a physical channel whose power level is within a certain range in the positive direction and the negative direction with a predetermined threshold power level determined to be unreceivable).

  Then, the channel scan control unit 124 performs a high-speed channel scan only on the physical channel that is set as the next scan candidate physical channel (S44). High-speed channel scanning means that only a part of physical channels are scanned. According to the high-speed channel scan, the channel scan time is shortened, but the reliability of the channel scan result is lowered.

  Next, the channel scan control unit 124 determines whether or not there is a physical channel that is a next scan candidate in step S44 (S45). If the channel scan control unit 124 determines that there is a physical channel that is the next scan candidate in step S44 (S45: Yes), the process proceeds to step S44, and the next scan candidate is selected in step S44. Perform high-speed channel scans on physical channels only. On the other hand, if the channel scan control unit 124 determines in step S44 that there is no physical channel that is the next scan candidate (S45: No), the process proceeds to step S46.

  In step S46, the channel scan control unit 124 gives the information stored in the temporary storage unit 124a to the area map generation unit 132, and the area map generation unit 132 updates the broadcast area map information 141 based on the given information. . Further, the area map generation unit 132 generates broadcast service information from the given information and stores the broadcast service information in the area map storage unit 133. The broadcast service information indicates broadcast contents on the physical channel.

  Then, the channel scan control unit 124 notifies the reception mode switching unit 123 to operate in the single tuner mode (S47). Receiving such notification, the reception mode switching unit 123 sets the operation mode of the digital broadcast receiving apparatus 100 to the single tuner mode, and ends the flow.

  FIG. 10 is a flowchart showing an operation (subroutine) at the time of reliable channel scanning shown in FIG.

  First, the channel scan control unit 124 selects one of all physical channels (S50), and causes the second receiving unit 121 to execute tuning of the selected physical channel (S51).

  Then, the channel scan control unit 124 determines whether a broadcast signal exists in the tuned physical channel, for example, from the power level of the received signal (S52). If the channel scan control unit 124 determines that there is a broadcast signal in the tuned physical channel (S52: Yes), it proceeds to step S53 and determines that there is no broadcast signal in the tuned physical channel. In the case (S52: No), the process proceeds to step S57.

  In step S53, the channel scan control unit 124 performs frame lock determination. In frame lock determination, for example, in the case of ISDB-T, the channel scan control unit 124 performs CRC (cyclic redundancy check) error check and periodic synchronization word check in TMCC (Transmission and Multiplexing Configuration and Control) signal. It is determined whether or not it is a desired digital broadcast wave to be received. If the frame is locked (S53: Yes), the channel scan control unit 124 proceeds to step S54. If the frame is not locked (S53: No), the channel scan control unit 124 proceeds to step S57.

  In step S54, the channel scan control unit 124 starts PSI / SI section filtering processing. Then, the channel scan control unit 124 determines whether or not PSI / SI information has been acquired within a predetermined time (S55). If the channel scan control unit 124 can acquire the PSI / SI information within a predetermined time (S55: Yes), the process proceeds to step S56, and the PSI / SI information cannot be acquired within the predetermined time. In the case (S55: No), the process proceeds to step S57.

  In step S56, when the PSI / SI information can be received, the channel scan control unit 124 extracts necessary information from the received PSI / SI information, and uses the physical channel, the power level of the received signal, and the current position as reception information. It is stored in the temporary storage unit 124a together with the extracted information.

  Then, the channel scan control unit 124 determines whether scanning of all physical channels has been completed (S57). When the scan of all the physical channels is completed, the channel scan control unit 124 exits the reliable channel scan subroutine and proceeds to step S42 or S43 in FIG. On the other hand, if the scanning of all physical channels is not completed, in other words, if there is a physical channel that has not been scanned (S57: No), the channel scan control unit 124 advances the process to step S50.

FIG. 11 is a flowchart showing an operation (subroutine) at the time of high-speed channel scanning shown in FIG. In the flowchart of FIG. 11, at the start of the flowchart of FIG. 11, the physical channel already set as the next scan candidate is set as the next scan candidate physical channel # 1, and the physical channel set as the next scan candidate in the flowchart of FIG. Is the next scan candidate physical channel # 2.
At the time of high-speed channel scanning, the channel scan control unit 124 selects one of the physical channels selected as the next scan candidate physical channel # 1 (S60), and the second receiving unit 121 tunes the selected physical channel. This is executed (S61).

  Then, the channel scan control unit 124 determines whether there is a broadcast signal on the tuned physical channel, for example, based on the power level of the received signal (S62). If there is a broadcast signal on the tuned physical channel (S62: Yes), the channel scan control unit 124 proceeds to step S63, and if there is no broadcast signal on the tuned physical channel (S62: No). ), The process proceeds to step S69.

  In step S63, the channel scan control unit 124 refers to the temporary storage unit 124a, and determines whether a broadcast service exists on the same physical channel at the previous scan of the same physical channel. If the broadcast service exists on the same physical channel (S63: Yes), the channel scan control unit 124 determines that there is no change in the reception state, and proceeds to step S71. On the other hand, when there is no broadcast service on the same physical channel (S63: No), the channel scan control unit 124 has detected a new broadcast signal, and thus proceeds to step S64.

  In step S64, the channel scan control unit 124 performs frame lock determination. The channel scan control unit 124 proceeds to step S71 when the frame is not locked (S64: No), and proceeds to step S65 when the frame is locked (S64: Yes).

  In step S65, the channel scan control unit 124 starts the PSI / SI section filtering process. If the channel scan control unit 124 cannot acquire the PSI / SI information within the predetermined time (S66: No), the process proceeds to step S71, and the PSI / SI information is acquired within the predetermined time. If completed (S66: Yes), the process proceeds to step S67.

  In step S67, the channel scan control unit 124 extracts necessary information from the received PSI / SI information, and uses the physical channel, the power level of the received signal, and the current position as reception information together with the extracted information in the temporary storage unit 124a. save. In this case, the broadcast service did not exist in the previous channel scan, but it can be newly detected in the current channel scan. Therefore, the channel scan control unit 124 does not receive the physical channel selected in step S60. It is determined as a stable channel, and this physical channel is extracted as the next scan candidate physical channel # 2 (S68).

  In step S69, the channel scan control unit 124 refers to the temporary storage unit 124a and determines whether a broadcast service exists on the same physical channel at the previous scan of the same physical channel. If the channel scan control unit 124 determines that there is no broadcast service on the same physical channel (S69: No), the process proceeds to step S71, and the broadcast service exists on the same physical channel. (S69: Yes), the process proceeds to step S70.

  In step S70, the channel scan control unit 124 does not include a broadcast signal in the physical channel selected in step S60. Therefore, the channel scan control unit 124 stores the physical channel selected in step S60 stored in the temporary storage unit 124a. Delete the corresponding information. Then, the channel scan control unit 124 determines that the physical channel selected in step S60 is an unstable physical channel in which the broadcast signal is detected in the previous channel scan and the broadcast signal is not detected in the current channel scan. The physical channel is extracted as the next scan candidate physical channel # 2 (S68).

  In step S71, it is determined whether or not scanning of all physical channels extracted as the next scan candidate physical channel # 1 is completed. Then, when the scan of all physical channels extracted as the next scan candidate physical channel # 1 is completed (S71: Yes), the channel scan control unit 124 advances the process to step S45 in FIG. On the other hand, if the scan of all physical channels extracted as the next scan candidate physical channel # 1 is not completed (S71: No), the channel scan control unit 124 extracts the next scan candidate physical channel # 1. If there is a physical channel that is not targeted for scanning, the process proceeds to step S60.

FIG. 12 is a flowchart showing an expansion process for the generated area information 142.
First, the area map generation unit 132 includes a linear function that defines each side of a generated area indicated by a polygon whose coordinates are stored in the vertex coordinate column 142c of the generated area of the generated area information 142, The coordinates of the current position are substituted into a primary inequality obtained from an inequality sign indicating the direction in which other vertices not included in each side are arranged (S80).

  Next, the area map generation unit 132 determines whether the primary inequality is satisfied on all sides as a result of the substitution (S81). If the primary inequality is satisfied on all sides (S81: Yes), the area map generation unit 132 proceeds to step S82, and if the primary inequality is not satisfied on all sides (S81: No). ), In other words, if there is an edge that does not satisfy the primary inequality, the process proceeds to step S83.

  In step S82, the area map generation unit 132 determines that the current position is within the generated area, and ends the flow without performing the process of adding the current position to the generated area information 142.

  On the other hand, in step S83, the area map generation unit 132 determines that the current position is a new vertex outside the generated area. For example, as shown in FIG. 13, when the generated area AR2 is indicated by vertices P1, P2, P3, P4 and P5, the current position NP is obtained from a linear function passing through the vertices P1 and P2. Since the primary inequality is not satisfied, the area map generation unit 132 sets the current position NP as a new vertex.

  Next, the area map generation unit 132 obtains a linear function of a line segment connecting the new vertex and each vertex of the existing generated area AR2 (S84). For example, in FIG. 13, the linear function SD1 connecting the new vertex NP and the vertex P1, the linear function SD2 connecting the new vertex NP and the vertex P2, the linear function SD2 connecting the new vertex NP and the vertex P3 are connected. A linear function of the line segment SD3, a linear function of the line segment SD4 connecting the new vertex NP and the vertex P4, and a linear function of the line segment SD5 connecting the new vertex NP and the vertex P5 are obtained.

  Then, the area map generation unit 132 determines the positional relationship between the straight line obtained by the linear function obtained in step S84 and other vertices constituting the generated area, and all other vertices are indicated by the linear function. A linear function existing on the same side of the straight line (for example, the positive direction or the negative direction of the Y axis) is searched. For example, in FIG. 13, in the linear function of the line segment SD1, all the other vertices P2, P3, P4, and P5 are on the same side. In the linear function of the line segment SD2, all the other vertices P3, P4, P5, and P1 exist on the same side. On the other hand, in the linear function of the line segment SD3, the vertex P2 exists on the left side of FIG. 13, and the vertices P4, P5, and P1 exist on the right side of FIG. In the linear function of the line segment SD4, the vertices P2 and P3 exist on the left side of FIG. 13, and the vertices P5 and P1 exist on the right side of FIG. Further, in the linear function of the line segment SD5, the vertices P2, P3, and P4 exist on the left side of FIG. 13, and the vertex P1 exists on the right side of FIG. Accordingly, the area map generation unit 132 specifies a linear function of the line segments SD1 and SD2. Then, the area map generation unit 132 adds the coordinates of the new vertex NP to the vertex coordinate field 142c of the generated area of the generated area information 142, and associates the new vertex NP with the record to which the new vertex NP has been added, in line segment SD1. In addition, the slope and intercept of the linear function of SD2 and the inequality sign indicating the side on which another vertex exists are stored in the area map storage unit 133. In this way, the area map generator 132 adds an area AR3 composed of the vertices P1, NP, and P2 to the existing generated area AR2, as shown in FIG. At this time, since the line segment constituted by the vertices P1 and P2 is no longer the side constituting the generated area, the area map generation unit 132 deletes information related to the linear function of the line segment from the area map storage unit 133. .

  According to the digital broadcast receiving apparatus 100 according to the first embodiment, the receivable area is expressed as an area surrounded by an adjacent circle and its common circumscribing line in a coordinate system having longitude and latitude as coordinate axes. Just record the center coordinates of the circle and its radius. For this reason, the digital broadcast receiving apparatus 100 can reduce the required memory size compared to the case where data is recorded by dividing the coordinate plane expressed by longitude and latitude into meshes.

Furthermore, according to the digital broadcast receiving apparatus 100 according to Embodiment 1, the actual road area and the receivable area are compared with the case where the receivable area is expressed as a polygonal area in a coordinate system having longitude and latitude as coordinate axes. Since the error from the receivable area assumed by the receiver can be reduced, the accuracy of the area regarded as the receivable area can be increased.
For example, as shown in FIG. 14, the digital broadcast receiving apparatus 100 moves along the curved road 150 from the left to the right, and determines that reception is possible at three points, point A, point B, and point C. In this case, when the receivable area is represented by a polygon formed by receivable portions as in the prior art, the receivable area is a triangle ABC, but this does not coincide with the actual road 150. In contrast, in digital broadcast receiving apparatus 100 according to Embodiment 1, a receivable area can be formed along road 150.

  As described above, according to the digital broadcast receiving apparatus 100 according to the first embodiment, the channel scan is executed when moving in the area where the broadcast area map information 141 is not generated, so that the diversity process is performed. The period during which a program is viewed as a highly stable received signal becomes longer, and high image quality and high sound quality can be achieved by improving reception performance.

  Further, according to the digital broadcast receiving apparatus 100 according to the first embodiment, even when moving within the generated area of the broadcast area map information 141, a change in the network configuration or the broadcast service configuration is detected from the viewing physical channel. Since the channel scan can be executed at a regular period with a relatively long cycle performed every few days, the broadcast area map information 141 can be updated to the latest information.

  Furthermore, according to the digital broadcast receiving apparatus 100 according to the first embodiment, the broadcast area map information 141 of each broadcast service is automatically generated by channel scanning. Therefore, when the area where the broadcast area map information 141 is created is moved, at that point. A receivable broadcast service list can be presented to the user without a channel scan operation by the user. For this reason, the convenience at the time of mounting the digital broadcast receiving apparatus 100 in a mobile body can be improved.

  Also, the digital broadcast receiving apparatus 100 according to Embodiment 1 automatically generates broadcast area map information 141 for each broadcast service by channel scanning, and stores the physical channels of relay stations and affiliated stations, and the name of the broadcast service. ing. For this reason, when moving to the area where the broadcast area map information 141 is created, if the area is moving out of the area of the broadcast service being viewed, and if the reception state becomes unstable, digital broadcast reception The apparatus 100 can automatically switch to a relay station, an affiliated station, or a physical channel that is broadcasting a broadcast service with the same broadcast service name that is likely to be broadcasting the same program. For this reason, the user can continue watching the program without interruption.

  Furthermore, the digital broadcast receiving apparatus 100 according to Embodiment 1 compares the results of the previous and current channel scans in the operation of the channel scan control unit 124, and the physical channel whose reception state has changed beyond a predetermined reference level. The channel scan is performed again only for the physical channel near the threshold reception intensity. This is because the sampling cycle of the reception status is shortened for the physical channel near the coverage area boundary where the reception status is unstable, so the channel scan is performed in a relatively short time, and the coverage area boundary The accuracy of the channel scan result in the vicinity can be improved.

  Furthermore, in the digital broadcast receiving apparatus 100 according to the first embodiment, the broadcast service exists in the previous channel scan in the second channel scan, and the broadcast signal exists from the power level of the received signal also in the current channel scan. If it is determined that the same broadcast service is present, the frame lock determination and the PSI / SI information acquisition determination are not performed. In other words, the digital broadcast receiving apparatus 100 omits the frame lock confirmation and the PSI / SI information acquisition determination, and only needs the time required for the signal existence check. Normally, the signal presence check needs only several hundred milliseconds, while the frame lock determination time is around 1 second, and the PSI / SI information acquisition determination requires several seconds. By omitting the PSI / SI acquisition determination, the channel scan can be significantly speeded up. For this reason, the digital broadcast receiving apparatus 100 can perform a channel scan in a short time, and the opportunity to use signals from all antennas for viewing a program increases, so that reception stability is high and higher sound quality and higher image quality are achieved. Can be received.

  Also, in the digital broadcast receiving apparatus 100 according to Embodiment 1, in the second channel scan, the broadcast service does not exist in the previous channel scan, and the broadcast signal exists from the power level of the received signal in the current channel scan. If it is determined that no broadcast service is present, it is determined that there is no broadcast service, so that channel scanning can be speeded up. For this reason, the digital broadcast receiving apparatus 100 can perform channel scanning in a short time and can use signals from all antennas for viewing, so that reception stability is high and reception of high sound quality and high image quality is possible. Become.

  Furthermore, in the digital broadcast receiving apparatus 100 according to the first embodiment, in the second channel scan, the broadcast service does not exist in the previous channel scan, and the broadcast signal exists from the power level of the received signal in the current channel scan. Even if the frame lock can be performed and the PSI / SI information can be acquired, the physical channel is regarded as an unstable channel, and the next channel scan is selected. The accuracy of channel scanning near the boundary can be increased.

  Furthermore, in the digital broadcast receiving apparatus 100 according to the first embodiment, in the second channel scan, the broadcast service exists in the previous channel scan, and the broadcast signal exists from the power level of the received signal in the current channel scan. If it is determined that the physical channel is not used, the physical channel is set as an unstable channel and a candidate for the next channel scan, so that the accuracy of channel scanning near the area boundary of the unstable channel can be improved.

Embodiment 2. FIG.
As shown in FIG. 1, a digital broadcast receiving apparatus 200 according to Embodiment 2 includes a first antenna 110, a first receiving unit 111, a first demultiplexing unit 112, a decoding unit 113, and a graphics superimposing unit. 114, a video output unit 115, an audio output unit 116, an operation input unit 117, and a channel selection control unit 118. In addition, the digital broadcast receiving apparatus 200 includes a second antenna 120, a second receiving unit 121, a second demultiplexing unit 122, a reception mode switching unit 123, a channel scan control unit 124, and a third antenna 130. The current position detection unit 131, the area map generation unit 232, the area map storage unit 233, the area determination unit 234, and the list generation unit 135 are provided. The digital broadcast receiving apparatus 200 according to Embodiment 2 is related to Embodiment 1 in terms of processing in the area map generation unit 232 and the area determination unit 234 and information stored in the area map storage unit 233. Different from the digital broadcast receiving apparatus 100.

  The area map generation unit 232 generates broadcast area map information 141 based on the section data received from the second demultiplexing unit 122 and the current position notified from the current position detection unit 131 and stores the broadcast area map information 141 in the area map storage unit 133. To do. In the second embodiment, unlike the first embodiment, the area map generation unit 232 does not create the generated area information 142.

  The area map storage unit 233 stores broadcast area map information 141. In the second embodiment, unlike the first embodiment, the generated area information 142 is not stored.

  The area determination unit 234 refers to the broadcast area map information 141 stored in the area map storage unit 133, and whether or not the broadcast area map information 141 corresponding to the current position notified from the current position detection unit 131 has been generated. Judging. For example, when the current position notified from the current position detection unit 131 is included in the receivable area indicated by the broadcast area map information 141 stored in the area map storage unit 133, the area determination unit 134 broadcast area map information. 141 is determined to have been generated.

  FIG. 15 is a flowchart showing broadcast area map information non-generated area determination processing by the digital broadcast receiving apparatus 200 according to Embodiment 2.

  First, the area determination unit 234 refers to the broadcast area map information 141 stored in the area map storage unit 233 and searches whether the current position notified from the current position detection unit 131 is included in the receivable area ( S90). Here, the area determination unit 234 can determine whether or not the current position is included in the receivable area by a flow similar to the flow shown in FIG.

  If the area determination unit 234 determines that the current position is included in the receivable area (S91: Yes), the process proceeds to step S92, and the current position is not included in the receivable area. If it is determined (S91: No), the process proceeds to step S93.

  In step S92, the area determination unit 234 notifies the channel scan control unit 124 that it is within the generated area. The channel scan control unit 124 that has received such notification stops the channel scan and starts the single tuner mode operation, for example. In the single tuner mode, video display and audio output of a program are performed based on a broadcast signal that has been subjected to diversity processing with excellent reception stability.

  In step S93, the area determination unit 234 notifies the channel scan control unit 124 that it is outside the generated area. Upon receiving such notification, the channel scan control unit 124 notifies the reception mode switching unit 123 to operate in the double tuner mode, and in parallel with the operation for viewing by the first reception unit 111, the second reception unit 121 starts channel scanning.

  As described above, when the area determination unit 234 determines that the current position is within the receivable area, the digital broadcast receiving apparatus 200 basically operates in the single tuner mode, but performs different operations. It can also be made.

  Further, even when the area determination unit 234 determines that the current position is within the receivable area, the channel scan control unit 124 notifies the reception mode switching unit 123 to operate in the double tuner mode after a predetermined time has elapsed. And channel scan may be started. By performing such an operation, a channel scan is periodically performed by the second receiving unit 121, which is a separate system from the first receiving unit 111 receiving the program viewing, and the broadcast area map information 141 is displayed. You can monitor for updates. Since the broadcast network or the broadcast service configuration basically does not change frequently, the channel scan control unit 124 does not need to perform this regular monitoring frequently, and the comparison is performed once every few days. It may be performed in a long cycle.

  According to the second embodiment, the digital broadcast receiving apparatus 200 does not need to generate the generated area information 142, and can reduce the storage capacity of the area map storage unit 233. Further, according to the second embodiment, since the receivable area becomes the generated area, the generated area can be specified accurately.

  FIG. 16 is a block diagram schematically showing a configuration of a digital broadcast receiving apparatus 300 according to a modification of the first or second embodiment. The digital broadcast receiving apparatus 300 according to this modified example is shown in FIG. This is different from the digital broadcast receiving apparatuses 100 and 200 that are used. The GPS built-in device 336 includes, for example, a car navigation device, a mobile phone and a tablet terminal equipped with GPS, and a GPS device having only a GPS function.

  100: 200, 300: digital broadcast receiving apparatus, 110: first antenna, 111: first receiving unit, 112: first demultiplexing unit, 113: decoding unit, 114: graphics superimposing unit, 115: video output unit, 116: Audio output unit, 117: Operation input unit, 118: Channel selection control unit, 120: Second antenna, 121: Second reception unit, 122: Second demultiplexing unit, 123: Reception mode switching unit, 124: Channel scan control unit, 130: third antenna, 131: current position detection unit, 132, 232: area map generation unit, 133, 233: area map storage unit, 134, 234: area determination unit, 135: list generation unit, 336: GPS built-in device, 337: current position input unit.

Claims (10)

A digital broadcast receiving device mounted on a moving body moving on a road,
A receiving unit that receives a signal of a physical channel and further detects a reception intensity of the received signal ;
A channel scan control unit for controlling the receiving unit to detect a physical channel capable of receiving a broadcast signal by the receiving unit;
A current position detector for detecting the current position;
When the channel scan control unit detects a physical channel capable of receiving a broadcast signal at the reception unit at the current position at the plurality of points on the road detected by the current position detection unit, the detected physical in association with the channel, and the position information indicating the detected current position and the radius of a circle centered on the said current position, and area map generator for generating a reception area information including for each of said plurality of locations Prepared,
The area map generation unit increases the radius of the circle as the detected reception intensity is stronger, and determines the circle specified for each of the plurality of points based on position information and radius included in the receivable area information. Receivable area information indicating a receivable area for an inner area, a common outer tangent line to a circle adjacent to the specified circle, and a region surrounded by the specified circle and the adjacent circle A digital broadcast receiver characterized by being generated as: Broadcast to identify the physical channel including a pre-SL current position detected by the current location detection unit in the coverage area, listing the broadcast content indicated by the broadcast service information associated with the physical channel that is the specified The digital broadcast receiver according to claim 1, further comprising a list generation unit that generates a service list. The list generation unit includes a secondary inequality indicating an inner region of the circle and four primary inequality indicating an inner region of a quadrangle surrounded by a contact point between the circle and the common circumscribed line. 3. The digital broadcast receiving apparatus according to claim 2, wherein the current position detected by the current position detection unit determines that the current position detected by the current position detection unit is included in the receivable area. Before Symbol further comprising an area determination unit that determines whether or not the detected current position at the current position detection unit is a physical channel including the receivable area,
The channel scan control unit controls the reception unit when the area determination unit determines that the current position detected by the current position detection unit is not included in the receivable area of any physical channel. The digital broadcast receiving apparatus according to claim 1, wherein a physical channel capable of receiving a broadcast signal is detected by the receiving unit. The area determination unit includes a secondary inequality indicating an inner region of the circle and four primary inequality indicating an inner region of a quadrangle surrounded by a contact point between the circle and the common circumscribed line. 5. The digital broadcast receiving apparatus according to claim 4, wherein the current position detected by the current position detection unit determines that the current position detected by the current position detection unit is included in the receivable area. A digital broadcast receiving method of a digital broadcast receiving device mounted on a moving body moving on a road,
Receiving a physical channel signal and further detecting the received strength of the received signal ;
A channel scan control process for detecting a physical channel capable of receiving a broadcast signal in the reception process;
A current position detection process for detecting the current position;
When the channel scan control process detects a physical channel capable of receiving a broadcast signal in the reception process at the current position at the plurality of points on the road detected in the current position detection process, the detected physical in association with the channel, and the position information indicating the detected current position and the radius of a circle centered on the said current position, the area map generating process of generating a reception area information including for each of said plurality of locations Prepared,
The area map generation process increases the radius of the circle as the detected reception intensity is stronger, and determines the circle specified for each of the plurality of points based on position information and radius included in the receivable area information. Receivable area information indicating a receivable area for an inner area, a common outer tangent line to a circle adjacent to the specified circle, and a region surrounded by the specified circle and the adjacent circle A digital broadcast receiving method, characterized in that : Broadcast to identify the physical channel including the current position detected in the previous SL current position detection process in the coverage area, listing the broadcast content indicated by the broadcast service information associated with the physical channel that is the specified The digital broadcast receiving method according to claim 6, further comprising a list generation process of generating a service list. The list generation process includes a second inequality indicating an inner area of the circle and four primary inequality indicating an inner area of a quadrangle surrounded by a contact point between the circle and the common circumscribed line. 8. The digital broadcast receiving method according to claim 7, wherein when the current position detected in step 1 satisfies, the current position detected in the current position detection process is determined to be included in the receivable area. Further comprising an area determination step of pre-Symbol determined whether the detected current position at the current position detection process is a physical channel including the receivable area,
The channel scan control process controls the reception process when the area determination process determines that the current position detected in the current position detection process is not included in the coverage area of any physical channel. The digital broadcast receiving method according to claim 6, further comprising: detecting a physical channel capable of receiving a broadcast signal in the reception process. The area determination process includes a secondary inequality indicating an inner area of the circle and four primary inequality indicating an inner area of a quadrangle surrounded by a contact point between the circle and the common circumscribed line. 10. The digital broadcast receiving method according to claim 9, wherein when the current position detected in step S3 satisfies, the current position detected in the current position detection process is determined to be included in the receivable area.

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