JP4674184B2 - GPS signal transmission system - Google Patents

Description

  The present invention relates to a GPS signal transmission system that retransmits a GPS signal received outside a radio wave interrupter in a radio wave interrupter that is difficult for radio waves to arrive.

  An example of the system described above is disclosed in Patent Document 1. In the technique disclosed in this document 1, a GPS signal received by one GPS receiving antenna is transmitted via a transmission path, and retransmitted from a retransmission antenna at a terminal on the transmission path.

JP 2005-244625 A

  Using the technology disclosed in Patent Document 1, for example, if a GPS receiving antenna is installed on the roof of a building and a retransmission antenna is installed inside the building, GPS signals can be transmitted even in buildings where radio waves are difficult to arrive. Can be received. Therefore, by receiving the GPS signal retransmitted using the GPS receiver in the building, the user of the GPS receiver can know the position of the building. However, this system uses only one GPS receiving antenna. Therefore, no matter where in the building the user of the GPS receiver is, only the position where the GPS receiving antenna is installed can be determined as the position. In this case, for example, when a fire or the like occurs to evacuate, the GPS receiver cannot know its exact position. Such a problem also occurs when the technique of Patent Document 1 is adopted not only in buildings but also in places where radio waves are difficult to reach, such as subways, underground malls, and tunnels.

  An object of the present invention is to provide a GPS signal transmission system in which the position can be known in detail by a GPS receiver even inside a radio wave blocking body in which radio waves are difficult to reach.

  In the GPS signal transmission system according to one aspect of the present invention, a plurality of GPS receiving antennas are provided at different positions outside a radio wave blocking body, for example, a building, a subway, an underground mall, a tunnel, or the like, in which radio waves are difficult to reach inside. Yes. The GPS signals received by these GPS receiving antennas have the same frequency. A plurality of GPS retransmission antennas are installed at positions corresponding to the respective GPS reception antennas inside the radio wave blocking body. Each GPS receiving antenna is provided with first frequency conversion means. Each first frequency conversion means converts the GPS signal received by the corresponding GPS receiving antenna into frequency converted GPS signals having different frequencies. Each frequency-converted GPS signal from the first frequency converter is transmitted through a transmission line disposed inside the radio wave interrupter. Each GPS retransmission antenna is provided with second frequency conversion means. Each frequency conversion GPS signal transmitted through the transmission path is all transmitted to each second frequency conversion means. Each of the second frequency conversion means has a position corresponding to the GPS retransmission antenna provided with the second frequency conversion means among the frequency conversion GPS signals, that is, the GPS reception corresponding to the GPS retransmission antenna. A frequency-converted GPS signal received by the antenna is selected, re-frequency converted to the same frequency as the original GPS signal, and supplied to the GPS retransmission antenna provided with the second frequency converting means.

  In the GPS signal transmission system configured as described above, the GPS signal received by each GPS receiving antenna is transmitted from the GPS retransmission antenna at the corresponding position in the radio wave blocking body. Therefore, even within the radio wave blocking body, the position of the receiver can be known in detail by using the GPS receiver. Therefore, in the case of emergency evacuation, the owner of the GPS receiver can accurately know his / her position and can evacuate quickly. By the way, since each GPS signal is a signal of the same frequency, if each GPS signal is transmitted as it is through the transmission path, it becomes impossible to supply a GPS signal corresponding to these to the GPS retransmission antenna. In addition, if each GPS receiving antenna and the corresponding GPS retransmission antenna are connected one-to-one via a transmission line, the installation of the transmission line becomes very troublesome. Therefore, each GPS receiving antenna is provided with a first frequency conversion means to convert each GPS signal into a frequency conversion GPS signal having a different frequency, and these are transmitted to each second frequency conversion means via one transmission path. . Each second frequency conversion means selects a frequency conversion GPS signal corresponding to the GPS retransmission antenna to which it is connected, re-converts this to the original GPS signal, and retransmits it. Therefore, each GPS receiver can receive a GPS signal under the same conditions as when a GPS signal is received by a GPS receiving antenna provided outside, even in a radio wave blocking body, without using many transmission paths. .

  The radio wave blocking body may be a building having a plurality of floors. In this case, each GPS retransmission antenna and each second frequency conversion means are provided on each floor of the building. If comprised in this way, the position of a GPS receiver can be known in detail using the GPS receiver in each floor of a building.

  Further, the transmission path can be a transmission path of a television joint reception system. If comprised in this way, it is not necessary to lay an exclusive transmission line for transmission of a frequency conversion GPS signal. The frequency converted GPS signal has a frequency in a frequency band different from the frequency band used for transmission of the television broadcast signal in the television joint reception system.

  The frequency of each frequency conversion GPS signal can be approximated. In this case, the reference signal from one first frequency converting means is transmitted to the other first frequency converting means, and each first frequency converting means transmits a local oscillation signal for frequency conversion based on the reference signal. Generate.

  When the frequency of each frequency conversion GPS signal is brought close, if the reference signal of the local oscillation signal used for frequency conversion in each first frequency conversion means is shifted, the frequency of the local oscillation signal of the first frequency conversion means is There is a possibility that the frequency of the generated frequency converted GPS signal overlaps in part and overlaps in part. Therefore, using the common reference signal, the local oscillation signal of each first frequency conversion means is generated, the frequency of the local oscillation signal of each first frequency conversion means is surely varied, and each frequency conversion GPS generated is generated. Avoid overlapping signal frequencies.

  Further, the reference signal may be supplied to each second frequency conversion unit via the transmission line, and the second frequency conversion unit may generate a local oscillation signal for frequency conversion based on the received reference signal. If comprised in this way, the frequency of the local oscillation signal of each 2nd frequency conversion means can also be made the same as the local oscillation signal of each corresponding 1st frequency conversion means, and each 2nd frequency conversion means is originally converted. The frequency conversion GPS signal to be performed can be accurately converted to the original GPS signal.

  Further, at least a part of the transmission line can be an optical transmission line. In this case, on the first frequency conversion means side of the optical transmission line, each frequency conversion GPS signal is converted into an optical signal by the electro-optical conversion means and supplied to the optical transmission line. The optical signal is converted into each frequency converted GPS signal by the optical-electrical conversion means on the second frequency conversion means side of the optical transmission line. If a broadcast signal is included, it is also converted to an optical signal. As described above, when at least a part of the transmission path is an optical transmission path, the reliability is improved.

  As described above, according to the present invention, the reception position can be accurately known by the GPS receiver even in a radio wave blocking body in which radio waves are difficult to reach inside, and evacuation or the like can be performed quickly.

  As shown in FIGS. 1A to 1C, the GPS signal transmission system according to the first embodiment of the present invention is a radio wave blocking body that is difficult to receive radio waves directly inside, for example, the outside of a building 2, such as a rooftop. A plurality of, for example, eight GPS receiving antennas 4a to 4h are arranged in 2R. These GPS receiving antennas 4a to 4h are arranged at different positions. GPS retransmission antennas 6a to 6h are arranged on the ceiling of each floor in the building 2, respectively. These GPS retransmission antennas 6a to 6 are arranged at positions corresponding to the GPS reception antennas 4a to 4h, respectively. That is, each GPS retransmission antenna 6a is arranged at a position in the vicinity of the same latitude and longitude as the GPS receiving antenna 4a, and each GPS retransmission antenna 6b is arranged at a position in the vicinity of the same latitude and longitude of the GPS receiving antenna 6b. Has been. The same applies to the other GPS retransmission antennas 6c to 6h.

  When the GPS signals received by the GPS receiving antennas 4a to 4h are transmitted from the corresponding GPS retransmission antennas 6a to 6h, for example, the GPS signals received by the GPS receiving antenna 4a are transmitted from the GPS retransmission antennas 6a,. -When the GPS signal received by the GPS antenna 4h is retransmitted from each GPS retransmission antenna 6h, the GPS receiver (not shown) carrying person at each floor of the building 2 can select one of the GPS retransmission antennas 6a to 6h. Depending on whether the GPS signal being retransmitted is received, it is possible to know in which position of the building 2 the carrier is located.

  However, the GPS signals received by the GPS receiving antennas 4a to 4h have the same frequency, for example, 1.57542 GHz, as shown in FIG. Therefore, even if the GPS signals received by the GPS receiving antennas 4a to 4h are simply transmitted to the GPS retransmission antennas 6a to 6h and retransmitted from the retransmission antennas 6a to 6h, You cannot know the location. If each GPS receiving antenna 4a to 4h and each GPS retransmission antenna 6a to 6h are connected by individual transmission paths, the received signal of the GPS receiving antenna 4a is sent from the GPS retransmission antenna 6a to the GPS receiving antenna 4h. Since the received signal is reliably retransmitted from the GPS retransmission antenna 6h, the above problem is solved. However, the work of laying eight transmission lines separately on each floor is very troublesome.

  Therefore, each GPS signal received by each of the GPS receiving antennas 4a to 4h is converted into a frequency-converted GPS signal having a different frequency, for example, a GPS-converted signal as shown in FIG. It transmits through the transmission line. Each of the GPS retransmission antennas 6a to 6h selects a GPS conversion signal corresponding to itself, re-frequency converts this to the same frequency as the original GPS signal, and retransmits it.

  Therefore, in the head device shown in FIG. 3, each of the GPS receiving antennas 4a to 4h is provided with first frequency conversion means, for example, down converters 8a to 8h, and the GPS signals received by the corresponding GPS receiving antennas are converted into GPS converted signals. Frequency conversion. The respective GPS conversion signals from the down converters 8a to 8h are synthesized by a synthesizing means, for example, a synthesizer 10, and transmitted to one transmission line 12 constituted by, for example, a coaxial cable.

  As the transmission line 12, a transmission line used in the television joint reception system is used. This eliminates the need to install a transmission line separately from the transmission line for the television joint reception system. Accordingly, the broadcast signal, for example, the UHF television broadcast signal received by the UHF television broadcast receiving antenna 14, the VHF television broadcast signal received by the VHF television broadcast receiving antenna 16, and the BS satellite broadcast receiving antenna 18 is received. The satellite broadcast intermediate frequency signal that has been frequency-converted is mixed by the mixer 20 and further amplified by the amplifier 22 is also mixed by the mixer 24 into the transmission line 12.

  Since the transmission path 12 of the joint reception system is used in this way, the frequency band of the GPS conversion signal is a frequency band that can be transmitted through the transmission path 12 of the joint reception system, for example, UHF television as shown in FIG. A vacant frequency band between the broadcast frequency band and the satellite broadcast intermediate frequency band is used. Moreover, since such a vacant frequency band is utilized, the frequency of each GPS conversion signal is comparatively close.

  As shown in FIG. 4, each broadcast signal and GPS conversion signal transmitted through the transmission path 12 are branched at each floor by a branching unit, for example, one branching unit 26, and retransmitted by a distributing unit, for example, eight distributing unit 28. The signals are distributed so as to correspond to the antennas 6a to 6h and supplied to second frequency conversion means, for example, up-converters 30a to 30h, corresponding to the GPS retransmission antennas 6a to 6h, respectively. The up-converter 30a corresponds to the retransmission antenna 6a, and the up-converter 30h corresponds to the retransmission antenna 6h. The up-converters 30a to 30 correspond to corresponding ones of the supplied GPS converted signals, for example, the amplifier converter 30a is a GPS corresponding to the GPS signal received by the GPS receiving antenna 4a among the supplied GPS converted signals. Select the converted signal and reconvert back to the original GPS signal. This reconverted GPS signal is referred to as a reconverted GPS signal. In addition, each up-converter 30a thru | or 30 lets each broadcast signal pass through.

  The reconverted GPS signals and broadcast signals from each of the up-converters 30a to 30h are amplified by boosters 32a to 32h, respectively, and the reconverted GPS signals are retransmitted from the corresponding GPS retransmission antenna. For example, the reconverted GPS signal from the up-converter 30a is amplified by the booster 30a and then retransmitted from the retransmission antenna 6a. Each broadcast signal is output from the booster 32 and supplied to receiving means, for example, a television receiver or a BS tuner.

  In each of the down converters 8a to 8h, as shown in FIGS. 5 and 6, the GPS signal input from the input terminal 32 is amplified by, for example, three-stage amplifiers 34a to 34c. Filters that extract GPS signals, for example, SAW filters 36a and 36b, are inserted between the amplifiers 34a to 34c, and unnecessary signals are removed. The output signal of the final stage amplifier 34 c is supplied to the mixer 38. A local oscillation signal is also supplied to the mixer 38. The mixer 38 frequency-converts the input GPS signal into a predetermined GPS conversion signal by using a local oscillation signal, and after unnecessary signals are removed by a filter, for example, a band pass filter 40, the level adjuster 42 is turned on. Amplified by amplifiers 44 and 46 provided between them and output from an output terminal 48.

  In order to perform frequency conversion in the mixer 38, a local oscillation signal is required. In order to generate the local oscillation signal, a so-called PLL oscillation circuit is used as the local oscillation means. That is, a voltage-controlled oscillator 50 that generates a local oscillation signal, a frequency divider 52 that divides the local oscillation signal by 1 / n, and a frequency-divided signal from the frequency divider 52 is divided by a frequency divider 54. A PLL circuit 56 for controlling the oscillation frequency of the voltage controlled oscillator 50 so as to match the signal is provided. The frequency divider 54 divides the reference signal by 1 / N. When the frequency division number n of the frequency divider 52 is appropriately selected, the voltage-controlled oscillator 50 generates a required local oscillation signal.

  By the way, in the PLL oscillation circuit, a reference signal is required as a frequency reference for generating a local oscillation signal. However, if a reference signal generated individually by each of the down converters 8a to 8h is used, the down converters 8a to 8h There is a possibility that deviation occurs in each reference signal. Since the frequencies of the GPS conversion signals of the down converters 8a to 8h are close to each other, in the worst case, the frequencies of these GPS conversion signals may partially overlap. In order to avoid this, all the down converters 8a to 8h need to use a common reference signal.

  Therefore, in this embodiment, as shown in FIG. 5, a reference oscillator 58 for generating a reference signal is provided only in the down converter 8a, and the reference signal is passed through a filter that passes only the reference signal, for example, the bandpass filter 60, After amplification by the amplifier 62, the signal is combined with the GPS conversion signal by a combining means, for example, a combiner 64, and supplied to the output terminal 48.

  The reference signal and the GPS conversion signal are supplied to the combiner 10 as shown in FIG. The synthesizer 10 has a two-distributor 64, and one distribution signal of the synthesizer 10 is input to the branch terminal of one branching device 66 and is supplied to the bidirectional distributor 68 via this branching device 66. It is supplied to the converters 8b to 8h.

  In each of the down converters 8b to 8h, as shown in FIG. 6, the reference signal supplied from the distributor 68 to the output terminal 48 is supplied to the amplifier 72 via the branch side of the one branching device 70, and is amplified. For example, only the reference signal is extracted by the band pass filter 74 and supplied to the frequency divider 54. Therefore, the down converters 8a to 8h commonly use the reference signal of the reference oscillator 58 of the down converter 8a. Therefore, the frequencies of the GPS conversion signals from the respective down converters 8a to 8h do not overlap and maintain a predetermined frequency relationship.

  The GPS conversion signals from the respective down converters 8b to 8h are supplied to the combiner 76 via the main line of the distributor 68 and the branching unit 66 shown in FIG. Are combined with the GPS conversion signal and the reference signal from, and supplied to the synthesizer 24. That is, the reference signal is transmitted to the transmission path 12 together with the GPS conversion signals of the down converters 8a to 8h. Therefore, in this embodiment, the reference signal is selected to have a frequency lower than the VHF television broadcast frequency band, for example, as shown in FIG.

  As shown in FIG. 8, in each of the up-converters 30 a to 30 h, each GPS conversion signal, reference signal, and each broadcast signal are supplied to the input terminal 78, and these are supplied to the 2-distributor 80.

  One distribution output of the two distributor 80 is supplied to the one branching device 82, and the output is supplied to a filter, for example, a bandpass filter 84, that extracts a corresponding one-wave GPS conversion signal among the GPS conversion signals. The For example, the up-converter 30a extracts a GPS conversion signal obtained by frequency-converting the GPS signal received by the GPS receiving antenna 4a by the down-converter 8a. The one-wave GPS conversion signal extracted from the bandpass filter 84 is supplied to the amplifier 88 via the level adjuster 86, amplified there, and supplied to the mixer 90.

  On the other hand, the branch output of the single branching device 82 is supplied to a filter for extracting a reference signal, for example, a bandpass filter 92. The reference signal extracted by the band pass filter 92 is amplified by the amplifier 94, supplied to the frequency divider 96 of the local oscillating means, and divided by 1 / N. This frequency-divided signal is supplied to the PLL circuit 98, and the PLL circuit 98 controls the oscillation frequency of the voltage controlled oscillator 100 that generates the local oscillation signal. This control is performed so that the frequency-divided signal of the frequency divider 102 that divides the local oscillation signal by 1 / n1 matches the frequency-divided signal of the frequency divider 96. By appropriately selecting the frequency division number n1 of the frequency divider 102, the local oscillation signal is converted to a frequency required to re-frequency-convert the GPS conversion signal supplied to the mixer 90 to the same frequency as the original GPS signal. Frequency can be maintained. Moreover, in each of the up-converters 30a to 30h, since the reference signal generated by the down-converter 8a and used by the other down-converters 8b to 8h is used, the frequency of each re-frequency converted GPS signal is It becomes completely the same as the original GPS signal.

  The reconverted GPS signal output from the mixer 90 is amplified by an amplifier 108 having filters for removing unnecessary signals, for example, SAW filters 104 and 106 on the input side and the output side. The output signal of the SAW filter 106 at the subsequent stage is branched by the one branching device 110, the branch output is supplied to the detection circuit 112, the level is detected, and the level adjuster 86 outputs the level so that this level becomes a predetermined value. The level is adjusted. That is, automatic gain control is performed.

  On the other hand, the other distribution output of the distributor 80 is supplied to a filter that extracts each broadcast signal, for example, the bandpass filter 114. Each broadcast signal from the bandpass filter 114 is amplified by the amplifier 116, and then synthesized by the synthesizer 118 with the output of the one branching unit 110 (reconverted GPS signal), supplied to the output terminal 120, and boosters 32a to 32h. Are supplied to the corresponding ones.

  The output signals of the up-converters 30a to 30h, that is, the reconverted GPS signals and the broadcast signals are supplied to the input terminals 122 of the boosters 32a to 32h and are divided into two by the two distributors 124, as shown in FIG. . One distribution output of the two distributor 124 is supplied to a filter that extracts each broadcast signal, for example, a band-pass filter 126. Each broadcast signal output from the band pass filter 126 is amplified by a plurality of stages, for example, three stages of amplifiers 128a to 128c, and supplied from the output terminal 130 to a receiving means such as a BS tuner or a television receiver via a coaxial cable. Is done. Since the broadcast signals are amplified by the amplifiers 128a to 128c in this way, even if the broadcast signals are attenuated during transmission, the broadcast signals are supplied to the BS tuner and the television receiver at appropriate levels. .

  The other distribution output of the two distributor 124 is supplied to a filter that extracts a reconverted GPS signal, for example, a bandpass filter 132. The reconverted GPS signal extracted by the bandpass filter 132 is supplied to the input side of the three-stage amplifiers 136a, 136b, and 136c having a level adjuster 134 on the way and amplified. A part of the output of the intermediate-stage amplifier 136b among the three-stage amplifiers 136a to 136c is branched by the one-branch unit 138, and the branch output is supplied to the detector 140. In the detector 140, the level of the branch output is detected, and the level adjuster 134 is adjusted by the output signal of the detector 140 so that this level becomes a predetermined level. That is, automatic gain control is performed. The output signal of the final stage amplifier 136c is supplied to the corresponding one of the retransmission antennas 6a to 6h via the output terminal 142.

  The booster 32a to 32h and the up-converter 30a to 30h thus perform automatic level adjustment of the reconverted GPS signal because the transmission output from the GPS retransmission antennas 6a to 6h is determined by the Radio Law Enforcement Rules. This is because it can be used as a weak radio wave below the output power without a license.

  A second embodiment of the present invention is shown in FIG. In this embodiment, the trunk line of the transmission line is the optical transmission line 12a. Therefore, the broadcast signals, the GPS conversion signals, and the reference signals from the head device 142 including the down converters 8a to 8h, the combiner 10, the mixers 20, 24, and the amplifier 22 shown in FIG. For example, it is converted into an optical signal by the optical transmitter 144 and transmitted to the optical transmission line 12a. The optical signal is branched by the optical branching units 26a, 26a,... At the positions corresponding to the respective floors of the optical transmission line 12a. The branched optical signal is converted into an electrical signal, that is, each broadcast signal, each GPS converted signal, and a reference signal by an optical-electric conversion means, for example, an optical receiver 146, 146.・ ・ Supplied to Hereinafter, the same processing as in the first embodiment is performed.

  In this way, each broadcast signal, each GPS conversion signal, and reference signal are converted into optical signals, and these optical signals are transmitted to each floor via the optical transmission path 12a, so that long-distance transmission in high-rise buildings and the like is possible. , Improve reliability.

  A third embodiment of the present invention is shown in FIG. In this embodiment, the configuration until the GPS conversion signal and each broadcast signal are transmitted to the transmission path 12 is the same as that of the first embodiment. Each broadcast signal and GPS conversion signal transmitted through the transmission path 12 are amplified by an amplifying means, for example, a broadband amplifier 27, provided at the front end side of the transmission path 12. The broadband amplifier 27 can amplify all broadcast signals and GPS conversion signals. Each broadcast signal and GPS conversion signal transmitted through the transmission path 12 are branched at each floor by branching means, for example, one branching unit 26. This branch signal is further branched by a branching unit, for example, one branching unit 29. The branch signal from the 1 branching device 29 is distributed by the 8 distributor 28 so as to correspond to the respective retransmission antennas 6a to 6h, and is supplied to the up converters 31a to 31h corresponding to the respective GPS retransmission antennas 6a to 6h. The original GPS signal is converted again and supplied to the corresponding retransmission antennas 6a to 6h.

  Although not shown, the up-converters 31a to 31h remove the two distributor 80, the bandpass filter 114, the amplifier 116, and the synthesizer 118 from the amplifier converters 30a to 30h shown in FIG. Each broadcast signal and GPS converted signal are directly supplied to the one branching device 82, and the output signal of the one branching device 110 is directly supplied to the output terminal 120.

  Further, the output signal of the one branching device 29 is distributed by a distributing means, for example, a four distributing device, and supplied to a BS tuner or a television receiver.

  The broadband amplifier 27 is provided only at the front end side of the transmission line 12, but may be provided at predetermined intervals in the middle of the transmission line 12.

  In each of the above-described embodiments, the number of GPS receiving antennas and GPS retransmitting antennas is eight, but can be arbitrarily changed as long as the number is two or more. In that case, the number of down-converters and up-converters is also increased or decreased according to the number of both antennas. In each of the above-described embodiments, the frequency band of each GPS conversion signal is set between the UHF band and the frequency band of the satellite broadcast intermediate frequency signal. It can be a belt. In each of the above embodiments, the transmission path of the television joint reception system is used as a transmission path for the GPS conversion signal. However, the present invention is not limited to this, and for example, a transmission path dedicated to the GPS signal conversion signal is installed. It is also possible. In the first and second embodiments, the boosters 32a to 32h are provided, but in some cases, these can be removed. It is also possible to amplify each distribution output from the distributor 28 with a booster, and then reconvert the converted GPS signal into a GPS signal with an upconverter. In this case, the booster amplifies and outputs each broadcast signal in the same manner as the boosters 32a to 32, and selects and outputs a desired one of the converted GPS sides. The selected converted GPS signal from this booster is converted to the original GPS signal by the up-converter. At this time, the up-converter is provided with automatic gain control means, and the output GPS signal is set to a predetermined level. In each of the above embodiments, a building is used as a radio wave blocking body. However, the building is not limited to this. For example, any area may be used as long as it is difficult to directly receive radio waves such as a subway premises, an underground mall, and a tunnel. Can be used as a radio wave blocking body. In each of the above embodiments, the satellite broadcast intermediate frequency signal is included in the broadcast signal. Instead of or in addition to this, the satellite communication signal is received by the satellite communication reception antenna and converted into the satellite communication intermediate frequency signal. Can be used, and the independent broadcast signal in the joint reception system can also be included in the broadcast signal.

It is a figure which shows arrangement | positioning of the GPS receiving antenna and GPS retransmission antenna of the GPS signal transmission system of the 1st Embodiment of this invention. It is a figure which shows the frequency of each signal used with the GPS signal transmission system of FIG. It is a block diagram of the head apparatus of the GPS signal transmission system of FIG. It is a block diagram of each terminal of the GPS signal transmission system of FIG. It is a block diagram of the down converter 8a shown in FIG. FIG. 4 is a block diagram of down converters 8b to 8h shown in FIG. It is a block diagram of the combiner | synthesizer 10 shown in FIG. It is a block diagram of the down converters 30a thru | or 30h shown in FIG. It is a block diagram of the boosters 32a thru | or 32h shown in FIG. It is a block diagram of the frequency signal transmission system of the GPS signal of the 2nd Embodiment of this invention. It is a block diagram of each terminal of the GPS signal transmission system of the 3rd Embodiment of this invention.

Explanation of symbols

2 Building (Radio wave blocking body)
4a to 4h GPS receiving antenna 6a to 6h GPS retransmission antenna 8a to 8h Down converter (first frequency converting means)
12 Transmission path 30a thru | or 30h Up converter (2nd frequency conversion means)

Claims (6)

A plurality of GPS receiving antennas provided at different positions outside the radio wave blocking body;
A plurality of GPS retransmission antennas provided at positions corresponding to the respective GPS reception antennas inside the radio wave blocking body;
A plurality of first frequency conversion means provided on each of the GPS receiving antennas, for frequency-converting GPS signals received by the corresponding GPS receiving antennas into frequency-converted GPS signals having different frequencies;
A transmission path for transmitting the frequency-converted GPS signals from the first frequency conversion means to the inside of the radio wave blocking body;
Of the frequency converted GPS signals that are provided in the GPS retransmission antennas and transmitted through the transmission path, the frequency corresponding to the GPS retransmission antenna that is provided is the same frequency as the original GPS signal. A plurality of second frequency conversion means for re-frequency-converting and supplying to the GPS retransmission antenna provided,
GPS signal transmission system provided.   2. The GPS signal transmission system according to claim 1, wherein the radio wave blocking body is a building composed of a plurality of floors, and each GPS retransmission antenna and each second frequency conversion means are provided on each floor of the building. GPS signal transmission system.   3. The GPS signal transmission system according to claim 1 or 2, wherein the transmission path is a transmission path of a television joint reception system.   4. The GPS signal transmission system according to claim 1, wherein the frequencies of the frequency conversion GPS signals are close to each other, and a reference signal from one first frequency conversion unit is sent to another first frequency conversion unit. A GPS signal transmission system in which each first frequency conversion means generates a local oscillation signal for frequency conversion based on the reference signal.   5. The GPS signal transmission system according to claim 4, wherein the reference signal is supplied to each second frequency conversion means via the transmission path, and the second frequency conversion means is a local part for frequency conversion based on the received reference signal. A GPS signal transmission system that generates an oscillation signal.   6. The GPS signal transmission system according to claim 1, wherein at least a part of the transmission path is an optical transmission path, and each of the frequency converted GPS signals is provided on the first frequency conversion means side of the optical transmission path. It is converted into an optical signal by an electro-optical converting means and supplied to the optical transmission line, and the optical signal is converted into each frequency converted GPS signal on the second frequency converting means side of the optical transmission line. GPS signal transmission system converted by.

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