JP2005341401A - Mobile unit receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To receive first or second electric waves with superior conditions at all times, regardless of positions of a mobile unit, in a mobile unit receiver for receiving selectively first and second electric waves. <P>SOLUTION: A transmitting station transmits a first electric wave and the first electric wave is relayed by a repeater and transmitted as a second electric wave. The first and second electric waves are received by a directional antenna 11. The position of the repeater is stored in an antenna position memory unit 18, while the position of a mobile unit is detected as a current mobile unit position by a GPS receiver 19. The directional antenna is turned under antenna directivity control of a CPU 17 to a direction of the repeater position as a retrieved result, which is obtained by retrieving the antenna position memory unit, according to the current mobile unit position. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mobile receiver such as an in-vehicle receiver, and more particularly to a mobile receiver that selectively receives a first radio wave and a second radio wave having the same contents as the first radio wave. Is.

  2. Description of the Related Art Conventionally, as a mobile receiver, a receiver that receives a first radio wave such as a satellite broadcast wave and outputs it as sound or the like has been known. Accordingly, since the direction of the satellite as viewed from the moving body changes (that is, the direction of the satellite changes), an omnidirectional antenna is used. However, an omnidirectional antenna has a smaller antenna gain than a directional antenna, which makes it difficult to satisfactorily receive satellite broadcast waves depending on the current location of the mobile object.

  In particular, in urban areas such as large cities, satellite broadcast waves may be blocked by buildings, etc., and there may be situations where satellite broadcast waves cannot be received by mobile receivers. The broadcast wave is reflected, and this reflected wave acts as a disturbing wave, and the satellite broadcast wave may not be received well due to the disturbing wave.

  On the other hand, in order to receive satellite broadcast waves in a mobile receiver, the mobile device is equipped with an antenna that is omnidirectional in the azimuth direction, directional in the elevation direction, and has a variable elevation directional angle. There is one in which the elevation directivity angle is controlled according to the position detection information representing the position of the body. Here, the directivity control data is generated according to the position detection information, and the antenna is connected to the directivity control data. To control the elevation directivity angle (see, for example, Patent Document 1).

JP-A-5-167486 (Pages 2 to 3, FIGS. 1 to 4)

  However, since the conventional mobile receiver is configured as described above, even if the elevation direction angle of the antenna is controlled according to the position detection information indicating the position of the mobile body, When viewed from a mobile object, satellites are often blocked by buildings, etc., so it is difficult to maintain a good reception at all times. There is a problem that satellite broadcast waves cannot be received.

  Furthermore, in conventional mobile receivers, satellite broadcast waves are hardly blocked by buildings in suburbs other than mountainous areas, and satellite broadcast waves can be satisfactorily received even by omnidirectional antennas. Nevertheless, there has been a problem that the elevation angle of the antenna must be controlled in accordance with the position detection information.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a mobile receiver that can always receive broadcast waves in a good state regardless of the position of the mobile. To do.

  A mobile receiver according to the present invention includes a first transmission station that transmits a first radio wave, and a plurality of relay stations that relay the first radio wave and transmit the second radio wave as a second radio wave. Mounted on a mobile body that selectively receives the first and second radio waves, connected to the directional antenna and selectively receives the first and second radio waves, and a relay station The search result obtained by searching the relay station position storage means for storing the position, the mobile body position detection means for detecting the position of the mobile body as the mobile body current position, and the relay station position storage means according to the mobile body current position. Antenna control means for performing antenna direction control in which a directional antenna is directed in the direction of a certain relay station position is provided.

  According to the present invention, since the relay station position storage means is searched according to the current position of the mobile body and the antenna direction control is performed to direct the directional antenna in the direction of the relay station position that is the search result, There is an effect that it is possible to receive broadcast waves in a always good state regardless of the position of the body.

Embodiment 1 FIG.
Referring to FIG. 1, a mobile receiver (shown simply as a receiver) 10 shown in FIG. 1 is mounted on a mobile body (not shown) such as a vehicle, and a satellite (not shown in FIG. 1: transmitting station). ) To receive a satellite broadcast wave (first radio wave) broadcasted from. The satellite broadcast wave is transmitted from, for example, a geostationary satellite or a quasi-zenith satellite. In broadcasting using the quasi-zenith satellite system, the quasi-zenith satellite always passes near the zenith in the service area (broadcast area). Therefore, although the mobile body can receive broadcast waves from the quasi-zenith satellite at a high elevation angle, the satellite broadcast waves may not be received in urban areas due to shadows of buildings.

  For this reason, a repeater station (not shown) such as a repeater that relays satellite broadcast waves is arranged on the ground, and the repeater transmits a broadcast wave having the same content as the satellite broadcast wave (hereinafter referred to as terrestrial wave: second radio wave). (The terrestrial wave transmitted from the repeater is different in the reception frequency and modulation method from the satellite broadcast wave). Even in broadcasting using geostationary satellites, repeaters may be arranged in urban areas because reception of satellite broadcast waves may be blocked.

  In FIG. 1, the illustrated receiving apparatus 10 has first to third antennas 11 to 13, and the first antenna 11 is a directional antenna for terrestrial waves, and will be described later. Direction is controlled. The second and third antennas 12 and 13 are an omnidirectional antenna and a geodetic antenna (for example, a GPS radio wave receiving antenna) for satellite broadcast waves, respectively.

  The directional antenna 11 and the omnidirectional antenna 12 are connected to a vehicle-mounted receiver (reception means) 14, and a reception state detection unit (reception sensitivity detection means) 15 is connected to the vehicle-mounted receiver 14 to receive a reception state. The in-vehicle receiver 14 selects one of the directional antenna 11 and the omnidirectional antenna 12 according to the detection result obtained by the detection unit 15.

  Here, the directional antenna 11, the omnidirectional antenna 12, the in-vehicle receiver 14, and the reception state detection unit 15 constitute a satellite wave / terrestrial wave reception unit 16.

  As shown in the figure, the satellite wave / terrestrial wave receiving unit 16 is connected to a control unit (CPU) 17, which includes an antenna position storage device (relay station position storage unit) 18 and a GPS receiver (mobile body position detection unit). ) 19 is connected. The GPS receiver 19 is connected to the geodetic antenna 13. Further, the CPU 17 is provided with an antenna position detection / selection calculation device 17a, an information storage device (information storage means) 17b, and an antenna directivity control voltage generation device 17c.

  The antenna position detection / selection calculation device 17a and the antenna directivity control voltage generation device 17c function as antenna control means.

  Here, referring to FIG. 2, FIG. 2 is a diagram showing the arrangement of repeaters in an urban area, and as described above, satellite broadcast waves may not be received in the urban area due to the shadow of the building group 21. A plurality of repeaters 22 are arranged on the ground (in the illustrated example, the rooftop of a building), and these repeaters 22 transmit ground waves having the same contents as satellite broadcast waves. Specifically, a satellite broadcast wave is received from the satellite 23 by the earth station 24 arranged on the ground, the satellite broadcast wave is converted into a ground wave, and transmitted by the repeater 22.

  And in order to prevent mutual interference, since the transmission power of each repeater 22 is set small, here, when receiving the terrestrial wave from repeater 22, directional antenna 11 is used.

  Referring to FIG. 1 again, the antenna position storage device 18 stores the position (for example, latitude / longitude and altitude) of the repeater 22 as repeater position information, and the information storage device 17b stores the position as described later. The direction and angle (elevation angle) of the directional antenna 11 are stored as antenna position information.

  The in-vehicle receiver 14 selectively receives satellite broadcast waves received by the omnidirectional antenna 12 and terrestrial waves received by the directional antenna 11 as broadcast waves, demodulates the broadcast waves, for example, broadcast Output as sound representing content. For example, when a vehicle enters an urban area, the user inputs a command for switching from the omnidirectional antenna 12 to the directional antenna 11 to the in-vehicle receiver 14 by an input device (not shown). As a result, the in-vehicle receiver 14 is switched to the ground wave received by the directional antenna 11.

  Further, the reception sensitivity of the terrestrial wave received by the directional antenna 11 is detected by the reception state detection unit 15 and given to the CPU 17 as reception sensitivity information. On the other hand, according to the GPS radio wave received by the geodetic antenna 13, the GPS receiver 19 gives GPS data representing the latitude and longitude of the vehicle to the antenna position detection / selection calculation device 17a. Then, the antenna position detection / selection calculation device 17a refers to a map database (not shown), obtains the vehicle position and traveling direction based on the GPS data, and sets it as the vehicle current location.

  Subsequently, the antenna position detection / selection calculation device 17a obtains the repeater position closest to the vehicle current position as the shortest repeater information according to the repeater position information stored in the antenna position storage device 18, the reception sensitivity information, and the vehicle current position. Then, according to the shortest repeater information, the direction and the elevation angle of the repeater are set as repeater direction information.

  The repeater direction information is stored in the information storage device 17b together with the reception sensitivity information and the vehicle current location, and the repeater direction information is given to the antenna directivity control voltage generation device 17c. The antenna directivity control voltage generator 17c generates an antenna control voltage based on the repeater direction information, applies this antenna control voltage to the directivity antenna 11, and controls the directivity direction to make the directivity antenna 11 the shortest. It will be directed in the direction of the repeater 22.

  Since reception sensitivity information is given to the antenna position detection / selection calculation device 17a in real time, the directional antenna 11 is directed in a direction in which the reception sensitivity information is increased based on the shortest repeater information and the vehicle current location. Become.

Next, the operation will be described.
Referring to FIGS. 1 and 3, it is assumed that a vehicle 31 equipped with the mobile receiver 10 shown in FIG. Here, as shown in FIG. 3, three repeaters 22a to 22c are arranged, the distance between the current location P and the repeater 22a is L1, the distance between the current location P and the repeater 22b is L2, and the distance between the current location P and the repeater 22c. Is represented by L3, and in the state shown in FIG. 3, it is assumed that L1 <L2 <L3. Further, it is assumed that the repeaters 22a and 22c transmit terrestrial waves with directivity, and the repeater 22b transmits terrestrial waves with non-directivity, for example.

  Referring also to FIG. 4, it is assumed that the vehicle 31 enters an urban area and the in-vehicle receiver 14 selects the directional antenna 11 by a command input from the user. The antenna position detection / selection calculation device 17a obtains the position and traveling direction (vehicle current location) of the vehicle according to the GPS data from the GPS receiver 19 (acquisition of own vehicle position / direction: step ST1). Subsequently, the antenna position detection / selection calculation device 17a searches the antenna position storage device 18 to obtain a repeater position located within a predetermined range from the current vehicle position (step ST2). For example, the antenna position detection / selection calculation device 17a searches the antenna position storage device 18 for the position of a repeater within a radius of 5 km from the current vehicle location.

  Assuming that repeaters 22a and 22b are located within a radius of 5 km from the current vehicle position P (in the example shown in FIG. 3, it is assumed that L1 = 1.5 km, L2 = 4.5 km, L3 = 7.5 km). In the position detection / selection calculation device 17a, first, a distance L1 from the current vehicle location P to the repeater 22a is obtained (step ST3), and then a distance L2 from the current vehicle location P to the repeater 22b is obtained (step ST4). Then, the antenna position detection / selection calculation device 17a determines whether or not the distance L1 <the distance L2 (step ST5).

  In the state shown in FIG. 3, since distance L1 <distance L2, the antenna position detection / selection calculation device 17a selects the repeater 22a and sets the position of the repeater 22a as the shortest repeater information. Then, according to the shortest repeater information, the direction of the repeater 22a and its elevation angle are set as repeater direction information, and the antenna directivity control voltage generation device 17c generates a control voltage according to the repeater direction information. The direction is directed to the repeater 22a as indicated by the symbol ANT1 (step ST6). This state is the state shown in FIG.

  When there are three or more repeaters located in the predetermined range, the repeater closest to the current vehicle location is selected, and the directional antenna 11 is directed to the repeater located at the shortest distance from the current vehicle location. It will be.

  There are various methods for directing the directional antenna 11 in the direction of the repeater 22a in accordance with the control voltage. For example, as described in JP-A-4-174384, the directional antenna 11 is used. 11 is rotatably supported in the azimuth direction and the elevation direction, and the directional antenna 11 is rotationally driven by a drive mechanism such as a motor according to the control voltage so that the directional antenna 11 is directed toward the repeater 22a. You can do it.

  Specifically, the antenna directivity control voltage generation device 17c defines a control voltage table that indicates the relationship between the control voltage and the angle between the traveling direction of the vehicle and the repeater position. Since the angle formed by the traveling direction and the repeater is represented, the antenna directivity control voltage generator 17c reads out a control voltage corresponding to the repeater direction information from the control voltage table, and a drive mechanism such as a motor according to the control voltage. Will be driven and controlled.

  For example, as shown in FIG. 5, when the angle formed by the line segment R connecting the repeater 22 a and the vehicle 31 and the traveling direction of the vehicle 31 is −90 ° (here, with respect to the traveling direction of the vehicle 31). -1.0V is read as the control voltage set in the control voltage table. When the control voltage is −1.0 V, a driving mechanism such as a motor directs the directional antenna 11 in the −90 ° direction.

  Then, when the vehicle 31 goes straight north and the angle between the segment R connecting the repeater 22a and the vehicle 31 and the traveling direction of the vehicle 31 is -135 ° as shown in FIG. When 1.5V is read out as the control voltage set to 1 and the control voltage is 1.5V, the drive mechanism such as a motor directs the directional antenna 11 in the -135 ° direction.

  In this way, the control voltage is set according to the angle formed by the repeater (that is, the line segment R connecting the repeater and the vehicle) and the traveling direction of the vehicle, and the directional antenna 11 is rotated according to the control voltage. If it moves, the directional antenna 11 can be directed toward the shortest repeater 22a.

  As described above, in the state shown in FIG. 3, the directional antenna 11 is directed toward the repeater 22 a and the ground wave from the repeater 22 a is received by the in-vehicle receiver 14. In FIG. 3, as the vehicle 31 travels in the direction indicated by the solid arrow, the vehicle 31 moves away from the repeater 22a and gradually approaches the repeater 22b.

  The antenna position detection / selection calculation device 17a repeats the above-described steps ST1 to ST5, and when it passes through an intermediate point (that is, L1 = L2) between the repeaters 22a and 22b shown in FIG. 7, the antenna position detection / selection calculation device In step ST5, 17a determines that distance L1> distance L2, selects repeater 22b, and sets the position of repeater 22b as the shortest repeater information.

  Then, as described above, the antenna directivity control voltage generator 17c generates a control voltage according to the repeater direction information, and directs the directivity antenna 11 toward the repeater 22b (step ST7). This state is the state shown in FIG. That is, the state in which the directional antenna 11 is directed in the direction indicated by the symbol ANT1 (FIG. 3) is switched to the direction indicated by the symbol ANT2 in FIG. 7, and the direction is directed in the direction of the repeater 22b as indicated by the symbol ANT2 shown in FIG. The antenna 11 is directed.

  In this way, the antenna position detection / selection calculation device 17a searches for the shortest repeater from the current vehicle position and always points the directional antenna 11 in the direction of the repeater closest to the vehicle 31 (that is, the shortest repeater). Even when the vehicle 31 is traveling in an urban area such as an urban area, the reception sensitivity is not lowered and the satellite broadcast wave is continuously and satisfactorily improved. It is possible to receive terrestrial broadcasts that broadcast the same content.

  As described above, when the vehicle 31 travels in an urban area, the direction of the directional antenna 11 is changed and controlled (antenna direction control) in accordance with the position of the repeater. In the information storage device 17b, repeater direction information and reception sensitivity information are stored corresponding to the current vehicle location. In other words, repeater azimuth information and reception sensitivity information are accumulated in the information storage device 17b corresponding to the traveling route of the vehicle.

  Here, antenna direction control of the directional antenna 11 when the vehicle 31 moves along a traveling route that has passed in the past will be described. Referring to FIGS. 1 and 9, in FIG. 9, the same steps as those shown in FIG. 4 are denoted by the same reference numerals, and the description thereof will be omitted.

  Assume that the vehicle 31 is traveling between the repeaters 22b and 22c, and repeaters within a radius of 5 km are the repeaters 22b and 22c. As described with reference to FIG. 4, the antenna position detection / selection calculation device 17a obtains the current vehicle position in step ST1, and then in step ST2, the repeater position within a radius of 5 km from the vehicle current position is determined from the antenna position storage device 18. Search to obtain the positions of repeaters 22b and 22c.

  Thereafter, the antenna position detection / selection calculation device 17a obtains a distance L2 from the vehicle current location P to the repeater 22b (step ST8), and then obtains a distance L3 from the vehicle current location P to the repeater 22c (step ST9). Then, the antenna position detection / selection calculation device 17a determines whether or not the distance L2 <the distance L3 (step ST10).

  In step ST10, if the distance L2 <the distance L3, the antenna position detection / selection calculation device 17a searches the information storage device 17b and checks the reception sensitivity information related to the repeater 22b. Then, when it has passed the previous time, it is determined whether or not the reception sensitivity is equal to or higher than a predetermined level (previous reception state OK: step ST11).

  In step ST11, if the previous reception sensitivity is OK, the antenna position detection / selection calculation device 17a points the directional antenna 11 in the direction of the repeater 22b in step ST12 as described in FIG. On the other hand, if the reception sensitivity is not OK in step ST11, the antenna position detection / selection calculation device 17a selects the second repeater (in the example shown, repeater 22c) from the current vehicle position, and in step ST13, the repeater 22c. The directional antenna 11 is directed in the direction of.

  When the vehicle 31 passes an intermediate point between the repeater 22b and the repeater 22c, the antenna position detection / selection calculation device 17a determines that distance L2> distance L3 in step ST10, searches the information storage device 17b, and repeats the repeater 22c. Check the reception sensitivity information related to. Then, when passing the previous time, it is determined whether or not the reception sensitivity is equal to or higher than a predetermined level (previous reception state OK: step ST14).

  In step ST14, if the previous reception sensitivity is OK, the antenna position detection / selection calculation device 17a points the directional antenna 11 in the direction of the repeater 22c in step ST13. On the other hand, if the reception sensitivity is not OK in step ST14, the antenna position detection / selection calculation device 17a selects the second repeater (in the example shown, repeater 22b) from the current vehicle position, and in step ST12, the repeater 22b. The directional antenna 11 is directed in the direction of.

  In the example shown in FIG. 10, the repeater 22 c sends a ground wave in the direction opposite to the traveling direction of the vehicle 31 (the direction indicated by the solid line arrow), and the vehicle 31 passes between the repeater 22 b and the repeater 22 c. Even if the directional antenna 11 is directed toward the repeater 22c, it is difficult to receive a terrestrial wave from the repeater 22c.

  That is, it is difficult to receive a terrestrial wave even if control is performed so that the directional antenna 11 is directed from the vehicle current location P to the repeater 22c. In such a case, in the antenna position detection / selection calculation device 17a, the previous reception sensitivity related to the repeater 22c is less than a predetermined level, so that the second closest repeater (repeater 22b in the illustrated example) The position is retrieved from the antenna position storage device 18. In the illustrated example, since the repeater 22 transmits terrestrial waves in the traveling direction of the vehicle, the previous reception sensitivity is OK. In the antenna position detection / selection calculation device 17a, the directional antenna 11 is directed in the direction of the repeater 22b. (The directional antenna 11 is directed in the direction indicated by the symbol ANT2 from the direction indicated by the symbol ANT3).

  In other words, when the reception sensitivity for the shortest repeater from the current vehicle location is lower than a predetermined level, the repeater that is the second closest to the current vehicle location is selected. Since the wave is transmitted, the reception sensitivity becomes equal to or higher than a predetermined level, and the in-vehicle receiver 14 receives the terrestrial wave from the repeater 22b.

  As described above, the repeater is selected according to the previous reception sensitivity. However, as shown in FIG. 11, the repeater may be selected in consideration of the current reception sensitivity. 11, the same steps as those shown in FIG. 4 are denoted by the same reference numerals.

  In step ST1, the antenna position storage position detection / selection calculation device 17a obtains the current vehicle position, searches the antenna position storage device 18 (step ST15), and determines the position of the repeater closest to the current vehicle position. Obtained as a repeater position (shortest repeater position specification: step ST16).

  Thereafter, it is determined whether or not the shortest repeater position is within a preset range from the current vehicle position (step ST17), and if the shortest repeater position is within the preset range, the antenna position detection / selection calculation device As described above, 17a directs the directional antenna 11 in the direction of the shortest repeater (step ST18), and whether or not the reception sensitivity detected by the reception sensitivity detection unit 15 has a predetermined level or more (reception is possible). Is determined (step ST19). If reception is possible, the antenna position detection / selection calculation device 17a returns to step ST1.

  On the other hand, in step ST17, if the shortest repeater position is outside the preset range, the antenna position detection / selection calculation device 17a notifies the user by displaying that fact on a display device (not shown) or the like.

  If reception is not possible in step ST19, a repeater search is executed in step ST20, and the position of the repeater that is second closest to the current vehicle position is searched from the antenna position storage device 18 to obtain the second repeater position. Thereafter, the antenna position detection / selection calculation device 17a executes Step ST17 to Step ST19.

  If the second repeater cannot be received, the third repeater position is searched in step ST20 and the same processing is performed. That is, repeaters within a preset range are sequentially searched, and repeaters that receive terrestrial waves are determined according to reception sensitivity.

  In the above example, the example in which the directional antenna 11 is directed toward the repeater that transmits the ground wave having the same content as the satellite broadcast wave is described. However, the content is not limited to the satellite broadcast wave but the same content as the ground broadcast wave. This can be applied when the directional antenna 11 is directed in the direction of a relay station that transmits another terrestrial wave. Further, it is possible to store the radio wave condition of a route that has traveled one or more times without position information, and to improve reception performance during traveling.

  As described above, according to the first embodiment, when an omnidirectional antenna that receives satellite broadcast waves and a directional antenna that receives ground waves are provided, the satellite broadcast waves and terrestrial waves are selectively received. Because, when the directional antenna is selected, the antenna direction control for directing the directional antenna in the direction of the repeater position, which is the search result obtained by searching the antenna position storage device according to the vehicle current location, is performed. Even when the vehicle is traveling in an urban area or the like, there is an effect that the broadcast wave can be always received well.

  According to the first embodiment, since the position of the repeater closest to the current vehicle position is obtained as the shortest repeater position, there is an effect that the ground wave can always be received from the repeater closest to the vehicle.

  According to the first embodiment, if the reception sensitivity detected by the reception state detection unit is less than a predetermined level, the antenna position storage device is searched until the reception sensitivity becomes equal to or higher than the predetermined level. Since the antenna direction control is performed, there is an effect that terrestrial waves can be received from the repeater in a always good state.

  According to the first embodiment, since the position of the repeater within a predetermined range from the current position of the moving body is searched from the antenna position storage device, there is an effect that the repeater in the vicinity of the vehicle can be easily searched. .

  According to the first embodiment, the reception sensitivity related to the repeater to which the directional antenna is directed is stored as the previous reception state in association with the vehicle current location, and when the antenna direction control is performed, the previous reception state is determined according to the search result. Since the directional antenna is directed to other repeaters excluding repeaters that are less than a predetermined level, the directional antenna can be quickly directed to repeaters with good reception status based on past reception sensitivity. effective.

It is a block diagram which shows an example of the receiver for mobile bodies by Embodiment 1 of this invention. It is a figure which shows an example of arrangement | positioning of the repeater which receives a satellite broadcast wave and relays as a ground wave. It is a figure which shows an example of the direction of a directional antenna at the time of the vehicle carrying the receiver for mobile bodies shown in FIG. 1 receiving a terrestrial wave. 3 is a flowchart for explaining an example of direction control of a directional antenna in the mobile receiver shown in FIG. It is a figure for demonstrating an example of the relationship between the angle which an repeater and a vehicle make, and an antenna control voltage. It is a figure for demonstrating the other example of the relationship between the angle which an repeater and a vehicle make, and an antenna control voltage. It is a figure which shows an example of the direction of a directional antenna when a vehicle advances from the state shown in FIG. It is a figure which shows an example of the direction of a directional antenna when a vehicle advances from the state shown in FIG. 6 is a flowchart for explaining another example of direction control of a directional antenna in the mobile receiver shown in FIG. 1. It is a figure which shows an example of the direction of a directional antenna when a vehicle advances from the state shown in FIG. 6 is a flowchart for explaining another example of direction control of a directional antenna in the mobile receiver shown in FIG. 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Mobile receiver, 11 Directional antenna, 12 Non-directional antenna, 13 Geodetic antenna, 14 On-vehicle receiver, 15 Reception state detection unit, 16 Satellite wave / ground wave reception unit, 17 Control unit (CPU) , 17a Antenna position detection / selection calculation device, 17b Information storage device, 17c Antenna directivity control voltage generation device, 18 Antenna position storage device, 19 GPS receiver, 21 Building group, 22, 22a-22c Repeater, 23 Satellite, 24 Earth station, 31 vehicles.

Claims (5)

Mounted on a moving body that moves in a transmission system having a first transmission station that transmits a first radio wave and a plurality of relay stations that relay the first radio wave and transmit as a second radio wave, In the mobile receiver that selectively receives the first and second radio waves,
Receiving means connected to a directional antenna for selectively receiving the first and second radio waves;
Relay station position storage means for storing the position of the relay station;
Mobile body position detecting means for detecting the position of the mobile body as a mobile body current location;
Antenna control means for performing antenna direction control for directing the directional antenna in the direction of the relay station position, which is a search result obtained by searching the relay station position storage means according to the mobile current location A receiving apparatus for a moving object.   2. The mobile receiving apparatus according to claim 1, wherein the search result indicates the position of the relay station closest to the mobile current location as the shortest relay station position. Receiving sensitivity detecting means for detecting the receiving sensitivity of the second radio wave received by the receiving means;
The antenna control means searches the relay station position storage means until the reception sensitivity is equal to or higher than the predetermined level when the reception sensitivity detected by the reception sensitivity detection means is less than the predetermined level. 3. The mobile receiver according to claim 1, wherein antenna direction control is performed.   4. The antenna control unit according to claim 1, wherein the antenna control unit searches the relay station position storage unit for the position of the relay station that is within a predetermined range from the current position of the mobile object. A mobile receiver. Reception sensitivity detection means for detecting reception sensitivity of the second radio wave received by the reception means;
Information storage means for storing the reception sensitivity related to the relay station to which the directional antenna is directed at least as a previous reception state in association with the mobile current location;
2. The antenna control unit according to claim 1, wherein when performing antenna direction control, the directional antenna is directed to another relay station excluding the relay station whose previous reception state is less than a predetermined level. The receiving apparatus for mobile bodies as described.

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