WO2014112442A1 - 中継装置、中継衛星および衛星通信システム - Google Patents
中継装置、中継衛星および衛星通信システム Download PDFInfo
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- WO2014112442A1 WO2014112442A1 PCT/JP2014/050359 JP2014050359W WO2014112442A1 WO 2014112442 A1 WO2014112442 A1 WO 2014112442A1 JP 2014050359 W JP2014050359 W JP 2014050359W WO 2014112442 A1 WO2014112442 A1 WO 2014112442A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18515—Transmission equipment in satellites or space-based relays
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/40—Monitoring; Testing of relay systems
Definitions
- the present invention relates to a relay device, a relay satellite, and a satellite communication system.
- space devices with excellent radiation resistance generally have a lower sampling rate and processing speed than consumer devices used on the ground. There was a problem that it was difficult due to the performance limit of the device.
- one set of processing units processes one wideband signal. For this reason, if any one of the A / D converter, D / A converter, and digital demultiplexer / multiplexer is out of the set of processing units, or an input signal due to unexpected interference wave input, etc. There was a problem that communication would become impossible if the network became saturated.
- the present invention has been made in view of the above, and is capable of relaying a broadband signal even when the performance of the device is limited, and can reduce deterioration in communication quality due to failure or interference.
- An object is to obtain a relay device, a relay satellite, and a satellite communication system.
- the present invention outputs a plurality of reception processing units, a plurality of transmission processing units, and signals processed by the reception processing unit to the transmission processing unit.
- a local generation unit that generates two or more local signals having different frequencies from the connection unit, and supplies the local signals to the reception processing unit; and calculates a phase difference between the local signals, and sends the local signal to the reception processing unit
- a local phase calculation unit that inputs the phase difference
- the reception processing unit includes a reception-side phase correction unit that performs phase correction based on the phase difference
- the transmission processing unit receives from the connection unit A signal is transmitted, and the reception processing unit processes the reception signal by one or more of the reception processing units when a wideband received signal whose bandwidth is wider than a processable bandwidth is input.
- the relay satellite, the relay apparatus, and the satellite communication system according to the present invention can relay a wideband signal even when the device performance is limited, and can reduce deterioration in communication quality due to failure or interference. There is an effect.
- FIG. 1 is a diagram illustrating a configuration example of a relay satellite according to the first embodiment.
- FIG. 2 is a diagram illustrating a configuration example of a receiving unit in the relay satellite illustrated in FIG.
- FIG. 3 is a diagram illustrating a configuration example of a transmission unit in the relay satellite illustrated in FIG.
- FIG. 4 is a diagram illustrating a configuration example of the local generation unit.
- FIG. 5 is a diagram illustrating a configuration example of the local phase difference calculation unit.
- FIG. 6 is a diagram illustrating an outline of a signal relay operation by the relay satellite according to the first embodiment.
- FIG. 7 is a diagram illustrating an example of a signal relay operation procedure by the relay satellite according to the first embodiment.
- FIG. 1 is a diagram illustrating a configuration example of a relay satellite according to the first embodiment.
- FIG. 2 is a diagram illustrating a configuration example of a receiving unit in the relay satellite illustrated in FIG.
- FIG. 3 is a diagram illustrating a configuration example of
- FIG. 8 is a diagram illustrating an example of a spectrum relationship of signals processed by the demultiplexing unit.
- FIG. 9 is a diagram illustrating an example of a signal received at the reception port.
- FIG. 10 is a diagram illustrating an example of the signal relay operation (transmission side).
- FIG. 11 is a diagram illustrating an example of a wideband signal transmitted from the relay satellite to the receiving station.
- FIG. 12 is a diagram illustrating another configuration example of the local generation unit.
- FIG. 13 is a diagram illustrating a flow of frequency conversion processing on the reception side.
- FIG. 14 is a diagram illustrating an example of the phase change of the signal after passing through the limiter.
- FIG. 15 is a diagram showing an example of the flow of frequency conversion on the transmission side.
- FIG. 16 is a diagram illustrating a configuration example of a local phase difference calculation unit according to the second embodiment.
- FIG. 17 is a diagram illustrating a configuration example of a local phase difference calculation unit according to the third embodiment.
- FIG. 18 is a diagram illustrating an example of sampling processing in the third embodiment.
- FIG. 19 is a diagram illustrating a configuration example of a relay satellite according to the fourth embodiment.
- FIG. 20 is a diagram illustrating a configuration example of a relay satellite according to the fourth embodiment.
- FIG. 21 is a diagram illustrating an example of a complex unmodulated signal waveform.
- FIG. 22 is a diagram showing the flow of processing for a complex unmodulated signal for reception side correction.
- FIG. 23 is a diagram illustrating a configuration example of a reception-side phase time difference detection unit according to the fourth embodiment.
- FIG. 24 is a diagram illustrating a waveform example of each non-modulated signal in the fourth embodiment.
- FIG. 25 is a diagram illustrating a flow of processing for the transmission-side correction CW signal according to the fourth embodiment.
- FIG. 26 is a diagram illustrating a configuration example of a transmission-side phase time difference detection unit according to the fourth embodiment.
- FIG. 27 is a diagram showing a state of the same frequency interference when the beam areas are brought close to each other.
- FIG. 28 is a diagram illustrating an example of a reception DBF process according to the fifth embodiment.
- FIG. 29 is a diagram illustrating a configuration example of a relay apparatus having a reception DBF function and a transmission DBF function.
- FIG. 30 is a diagram illustrating a transmission DBF processing example and effects.
- FIG. 31 is a diagram illustrating a configuration example of the relay device according to the sixth embodiment.
- FIG. 1 is a diagram illustrating a configuration example of a relay satellite according to a first embodiment of the present invention.
- the relay satellite 200 of this embodiment includes receiving antennas 21-1 to 21-N (N is an integer of 2 or more), a receiving unit 201, a connecting unit 31, a transmitting unit 202, and a transmitting antenna 40. -1 to 40-N.
- FIG. 1 shows the configuration of a relay device mounted on the relay satellite among the entire configuration of the relay satellite.
- the number of reception antennas and the number of transmission antennas are the same, but the number of reception antennas and the number of transmission antennas may be different.
- the relay satellite performs signal processing to be described later on the signals received by the receiving antennas 21-1 to 21-N, and transmits the signals by transmitting from the transmitting antennas 40-1 to 40-N. Relay.
- a relay satellite and a satellite communication system capable of relaying a broadband signal using a device having a low sampling speed and a processing speed will be described.
- FIG. 2 is a diagram illustrating a configuration example of a receiving unit in the relay satellite 200 illustrated in FIG.
- a connection unit 31 transmission stations 101, 103, 104, and 105 that are transmission source devices of signals to be relayed, and a control station that is a ground station that transmits a command signal to a relay satellite 110 is also described.
- the reception antennas 21-1 to 21-N receive signals from the beam areas of the reception beams.
- FIG. 2 shows an example in which there are two beam areas, a wideband beam area 100 and a narrowband beam area 102.
- the wideband beam area 100 includes a transmission station 101 that transmits a wideband signal
- the narrowband beam area 102 includes transmission stations 103, 104, and 105 that transmit a narrowband signal.
- the broadband signal indicates a signal having a bandwidth exceeding the bandwidth that can be processed by the AD converter, the demultiplexing unit, the multiplexing unit, and the DA converter, as will be described later.
- the reception unit 201 of the relay satellite 200 includes an uplink / downlink frequency conversion unit 10, a reception analog switch matrix (first switch unit) 22, and a bandpass filter (BPF) 23- 1 to 23-N, mixers 24-1 to 24-N, local generator 25, source oscillation 26, bandpass filters 27-1 to 27-N, and AD converter (A / D) 28- 1 to 28-N, reception phase correction units (RPC) 29-1 to 29-N, demultiplexing units 30-1 to 30-N, and connection units (digital switch matrix) 31 are provided.
- a reception analog switch matrix first switch unit 22
- BPF bandpass filter
- the uplink / downlink frequency converter 10 also includes band-pass filters (BPF) 12-1 to 12-N on the input side, mixers 13-1 to 13-N, a local oscillator 11, and a band on the output side. Pass filters (BPF) 14-1 to 14-N.
- BPF band-pass filters
- FIG. 3 is a diagram showing a configuration example of a transmission unit in the relay satellite shown in FIG.
- FIG. 3 also shows the beam areas 400 and 402 and the receiving stations 401 and 403 which are receiving apparatuses for signals to be relayed.
- FIG. 3 shows an example in which the receiving station 401 exists in the beam area 400 and the receiving station 403 exists in the beam area 402.
- the transmission unit 202 of the relay satellite 200 includes multiplexing units 32-1 to 32-N, transmission phase correction units 33-1 to 33-N, and a DA converter (D / A).
- 34-1 to 34-N low-pass filters 35-1 to 35-N, mixers 36-1 to 36-N, a transmission analog switch matrix (second switch unit) 37, and a band-pass filter 38-1 To 38-N.
- the relay satellite transmits four uplink signals transmitted from the transmitting stations in the two beam areas (broadband beam area 100 and narrowband beam area 102) to two beam areas (beam area 400). 402), the number of beams and the number of uplink signals to be relayed are not limited to the examples of FIGS.
- connection unit 31 is, for example, a digital switch matrix, and receives the signals output from the demultiplexing units 30-1 to 30-N as inputs, and inputs the input signals to the subsequent multiplexing units 32-1 to 32-N. Sort out.
- FIG. 4 is a diagram illustrating a configuration example of the local generation unit 25 included in the reception unit 201 of the relay satellite 200 according to the present embodiment.
- the local generation unit 25 of the present embodiment includes frequency synthesizers 501 and 502.
- FIG. 5 is a diagram illustrating a configuration example of the local phase difference calculation unit 41.
- the local phase difference calculation unit 41 of the present embodiment includes a mixer 507, a bandpass filter 508, an AD converter (A / D) 509, a quadrature detection unit 510, and (digital ) A local generation unit 511, a (digital) low-pass filter 512, a limiter 513, selectors 514, 515 and 516, and a clock generator 517.
- FIG. 6 is a diagram showing an outline of the signal relay operation by the relay satellite according to the present embodiment.
- relay satellite 200 simultaneously receives signals A, B, C, and D received from transmitting stations 101, 103, 104, and 105 at the frequency arrangement shown in FIG.
- a signal A that is a broadband signal from the transmitting station 101 in the broadband beam area 100 is transmitted to the receiving station 401 in the beam area 400.
- a signal B that is a narrowband signal from the transmitting station 103 in the narrowband beam area 102 is transmitted to the receiving station 403 in the beam area 402.
- a signal C that is a narrowband signal from the transmitting station 104 in the narrowband beam area 102 is transmitted to the receiving station 401 in the beam area 400.
- a signal D that is a narrowband signal from the transmitting station 105 in the narrowband beam area 102 is transmitted to the receiving station 401 in the beam area 400.
- the uplink frequencies of the signals B, C, and D are the same as the left half of the signal A.
- the upper limit of the signal bandwidth that can be processed by a set of AD converters, demultiplexing units, multiplexing units, and DA converters in the relay satellite 200 is 1.
- the bandwidth of the signal A is 1.5 and each bandwidth of the signals B, C, and D is 0.25
- the bandwidth of the signal A is 1 Since it is larger, the conventional technique cannot digitally demultiplex, multiplex, or switch the signal A.
- the details will be described later, but each of the signals (A, B, C, D) can be relayed.
- FIG. 7 is a diagram illustrating an example of a signal relay operation procedure by the relay satellite according to the present embodiment.
- the specific frequency bandwidth values described in the text are values normalized with the upper limit of the signal bandwidth that can be processed by a set of AD converter, demultiplexer, multiplexer, and DA converter as 1.
- the signal A which is a broadband signal, is received by the receiving antenna 21-1, and is input to the input bandpass filter 12-1 of the uplink / downlink frequency converter 10.
- the signals B, C, and D which are narrowband signals, are received by the receiving antenna 21-2 and input to the input bandpass filter 12-2 of the uplink / downlink frequency converter 10.
- an uplink radio frequency and a downlink radio frequency are different, but the uplink / downlink frequency conversion unit 10 performs frequency conversion from an uplink radio frequency to a downlink radio frequency.
- the input bandpass filter 12-1 performs signal A so that the signal band is not lost and signals of other adjacent communication systems are removed. To extract.
- the mixer 13-1 outputs the frequency A output from the local oscillator 11 to the signal A that has passed through the input bandpass filter 12-1. Multiply the local signal with fr-ft).
- the band pass filter 14-1 removes the component of the unnecessary wave 2fr-ft from the two frequency components ft and 2fr-ft generated by the multiplication in the mixer 13-1.
- the frequency of the narrowband signal ⁇ B, C, D ⁇ is increased by the input bandpass filter 12-2, the mixer 13-2, and the output bandpass filter 14-2.
- the radio frequency fr of the signal is converted to the radio frequency ft of the downlink signal.
- the signal A and the signals B, C, and D are input to the reception analog switch matrix 22.
- the reception analog switch matrix 22 is controlled by a command signal from the ground control station 110.
- the command signal is transmitted from the control station 110 to the relay satellite 200 via a separate line.
- the reception analog switch matrix 22 converts the signal A from the bandpass filter 14-1 into the reception port 15-1 (BPF 23-1) and the reception port 15-2 (BPF 23-2) according to the command signal from the control station 110. And input simultaneously.
- the signal A input to the reception port 15-1 passes through the BPF 23-1, the mixer 24-1, and the BPF 27-1, and is frequency-converted from the radio frequency band to the intermediate frequency band or the baseband band.
- the analog filter (pass bandwidth 1.0) in the BPF 23-1 and the BPF 27-1 causes the signal A to be cut in half of the higher band from the center frequency, as shown in FIG. Bandwidth is reduced from 1.5 to 0.75 + ⁇ .
- a local signal LO 1 (frequency: f 1 ) from the local generator 25 is supplied to the mixer 24-1.
- the signal A input to the reception port 15-2 passes through the BPF 23-2, the mixer 24-2, and the BPF 27-2 in the subsequent stage, so that the frequency is changed from the radio frequency band to the intermediate frequency band or the baseband band. Converted.
- a local signal LO 2 (frequency: f 2 ) is supplied from the local generator 25 to the mixer 24-2.
- the analog filter (pass bandwidth 1.0) in the BPF 27-2 cuts the signal A near half of the lower band from the center frequency, and the bandwidth is 1 Reduced from .5 to 0.75 + ⁇ .
- the analog BPFs 27-1 to 27-N are two analog low-pass filters of I and Q. Changed to
- the signal A is processed by half of the bandwidth.
- the signal A may not be half. Any ratio (for example, 0.9 + ⁇ : 0.6 + ⁇ ) may be used as long as the signal bandwidth input to the AD converters 28-1 and 28-2 at the subsequent stage is 1 or less (up to the upper limit of the processing speed). Absent.
- the signal A is output to two reception ports. However, when the signal bandwidth is two or more, the signal A may be output to three or more reception ports.
- the frequency interval (f 1 -f 2 ) between the local signal LO 1 (frequency f 1 ) input to the mixer 24-1 and the local signal LO 2 (frequency f 2 ) input to the mixer 24-2 is 1. And that is, by setting the frequency interval of the local signals LO 1 and LO 2 to the same value as the upper limit value 1 of the signal bandwidth that can be processed by a set of AD converter, demultiplexer, multiplexer, and DA converter, The relay satellite 200 can implement a relay process for a wideband signal having a maximum bandwidth of 2 by inputting the received signal to both of the reception ports 15-1 and 15-2 shown in FIG.
- the local generation unit 25 When the relay processing of the wideband signal having the maximum bandwidth 2 is realized, the local generation unit 25 has a function of supplying one of the two types of local signals (f 1 , f 2 ) to the mixers 24-1 to 24-N. Prepare. Similarly, when the relay processing of the wideband signal having the maximum bandwidth 3 is realized, the local generation unit 25 uses any one of the three types of local signals (f 1 , f 2 , f 3 ) whose frequency interval is 1 for each mixer. A function of supplying to 24-1 to 24-N is provided. Here, since each local signal generated from the local generation unit 25 is generated based on the original oscillation 26, the frequency relationship of each local signal is stable and no frequency shift occurs.
- the digital switch matrix 31 switches the demultiplexed signal and inputs it to the transmission processing unit.
- the transmission analog switch matrix 37 includes transmission antennas 40-1 to 40-N in which signals output from two or more transmission processing units to which demultiplexed signals corresponding to the same reception signal are input constitute the same transmission beam. To enter. For this reason, it is possible to realize relay processing of a wideband signal having a maximum bandwidth exceeding 1.
- the configuration of the local generation unit 25 will be described later.
- the AD converter 28-1 samples the IF signal.
- the AD converter 28-1 samples the baseband signal with two types of in-phase (I) and quadrature (Q).
- phase of the signal in FIG. 7A sampled by the AD converter 28-1 is corrected by the reception phase correction unit (RPC) 29-1.
- RPC reception phase correction unit
- a correction signal related to phase correction is input from a local phase difference calculation unit 41 described later. The contents of phase correction will also be described later.
- the reception phase correction unit 29-1 performs phase correction while converting the intermediate frequency to the baseband frequency by digital quadrature detection. This conversion process will be described later using equations.
- the output signal of the BPF 27-1 shown in FIG. 7A is sampled by the AD converter 28-1, phase-corrected by the reception phase correction unit 29-1, and then includes signals outside the band.
- the signal is decomposed into four signals by the wave unit 30-1.
- the number of demultiplexing is four, but the number of demultiplexing is not limited to this, and any value may be used as long as it is an integer of 2 or more. .
- each of the four filters used in the demultiplexing unit 30-1 are indicated by dotted lines in FIG.
- the demultiplexing unit 30-1 deletes ⁇ from the signal of the bandwidth 0.75 + ⁇ in FIG. 7A, and the band shown in FIG. 7B.
- the signal (X) having a width of 0.75 is decomposed into three signals (1), (2), and (3) having a bandwidth of 0.25 as shown in FIG.
- the demultiplexing unit 30-1 demultiplexes signals including out-of-band signals.
- the signal (bandwidth 0.75 + ⁇ ) of FIG. 7D sampled by the AD converter 28-2 is subjected to phase correction by the reception phase correction unit 29-2.
- the signal shown in FIG. 7D includes signals out of band as shown in FIG. 7F by the demultiplexing unit 30-2 by the four filter characteristics indicated by the dotted lines in FIG. 7E.
- the demultiplexing unit 30-2 deletes ⁇ from the signal having the bandwidth 0.75 + ⁇ shown in FIG. 7D, and the signal (Y) having the bandwidth 0.75 shown in FIG.
- the signal is decomposed into three signals (4), (5), and (6) having a bandwidth of 0.25.
- FIG. 8 is a diagram illustrating an example of a spectrum relationship of signals processed by the demultiplexing unit.
- FIG. 8 is used to show the relationship between the frequency vs. amplitude characteristics of the demultiplexing units corresponding to different reception ports.
- two reception ports from which one signal (signal A in the example of FIG. 6) is output are designated as reception ports 15-i and 15- (i + 1).
- the four frequency-amplitude characteristics indicated by the solid lines indicate the characteristics of the four filters included in the demultiplexing unit 30-i corresponding to the reception port 15-i, and are indicated by the dotted lines 4
- the two frequency versus amplitude characteristics are the characteristics of the four filters included in the demultiplexing unit 30- (i + 1) corresponding to the reception port 15- (i + 1).
- the characteristics of the filter used in each demultiplexing unit are over-exposed between adjacent filters, including between the reception port 15-i and the reception port 15- (i + 1). It is assumed that the design is a wrapping design, the amplitude at which the characteristics of each filter intersect is 0.5, and the sum of the frequency vs. amplitude characteristics of each filter is 1.
- each filter shown in FIG. 8A is designed to be a straight line without discontinuity, for example, the signal A once becomes signals (1), (2), (3), (4 ), (5), and (6) (see FIGS. 7C and 7F), the signal ( X) and signal (Y) are restored (FIG. 8 (b)), and the original signal A is restored by signal synthesis processing in the transmission analog switch matrix 37 (FIG. 8 (c)).
- the frequency vs. phase characteristic of each filter shown in FIG. 8A is a straight line within the reception port (reception port 15-i, reception port 15- (i + 1)). This is possible because ⁇ 30-N is composed of digital circuits.
- making the frequency vs. phase characteristic of each filter a straight line including between the reception port 15-i and the reception port 15- (i + 1) generally means that each reception local signal is not synchronized to the phase. This is difficult because the phase of the local signal changes dynamically under the influence of phase noise and the like. In the present embodiment, this local phase fluctuation is suppressed by digital processing in the relay satellite. Details of suppression of local phase fluctuation will be described later.
- the uplink / downlink frequency conversion unit 10 converts the frequencies of the signals B, C, and D input from the reception antenna 21-2 into downlink frequencies.
- FIG. 9 is a diagram illustrating an example of a signal received by the reception port 15-3.
- the signals B, C, and D input to the BPF 23-3 are frequency-converted from the radio frequency band to the intermediate frequency band or the baseband band via the mixer 24-3 and the BPF 27-3.
- the analog filters in the BPFs 23-3 and 27-3 extract the signals B, C, and D, and when unnecessary waves exist in adjacent frequency bands, the unnecessary waves are removed (FIG. 9A, FIG. 9). 9 (b)).
- a local signal LO 3 (frequency: f 1 ) from the local generator 25 is supplied to the mixer 24-3.
- the signals B, C, and D in FIG. 9B sampled by the AD converter 28-3 do not share some of these signal components with other reception ports and are independent. . For this reason, it is not necessary to give the phase correction by the reception phase correction unit 29-3, and the demultiplexing unit 30-3 includes the out-of-band signal by the four filter characteristics indicated by the dotted lines in FIG. As shown in FIG. 9D, the signal is decomposed into four signals. In this way, the demultiplexing unit 30-3 decomposes (demultiplexes) the signals B, C, and D shown in FIG. 9C into three signals B, C, and D.
- FIG. 10 is a diagram illustrating an example of the signal relay operation (transmission side).
- the digital switch matrix 31 receives the signals output from the preceding demultiplexing units and distributes the input signals to the subsequent combining units 32-1 to 32-N.
- the signals B, C, and D output from the demultiplexing unit 30-3 are input, and the switch process shown in FIG. 10A is performed.
- the signal (1) is the first to m-th (m is an integer of 1 or more) corresponding to the terminal # 1-1, that is, the transmission port 39-1. It is output to the first terminal among the terminals.
- Signal (2) is at terminal # 1-2 (second terminal corresponding to transmission port 39-1)
- signal (3) is at terminal # 1-3 (third terminal corresponding to transmission port 39-1)
- Signal (4) is output to terminal # 1-4 (fourth terminal corresponding to transmission port 39-1), respectively.
- Signal (5) is at terminal # 2-1 (first terminal corresponding to transmission port 39-2), signal (6) is at terminal # 2-2 (second terminal corresponding to transmission port 39-2), Signal B is at terminal # 3-1 (first terminal corresponding to transmission port 39-3), signal C is at terminal # 2-3 (third terminal corresponding to transmission port 39-2), and signal D is terminal It is output to # 2-4 (fourth terminal corresponding to transmission port 39-2).
- These switch connections are controlled by command signals from the ground control station 110.
- m 4
- four terminals first terminal to fourth terminal
- Each multiplexing unit (multiplexing units 32-1 to 32-N) synthesizes four input signals by arranging them at a frequency interval of 0.25.
- each multiplexing unit has a circuit design in which the frequency-to-phase characteristic of the combined signal is a straight line like the demultiplexing units 30-1 to 30-N.
- the multiplexing unit 32-1 multiplexes the signals (1), (2), (3), and (4) input from the digital switch matrix 31 to generate FIG. ) Is generated.
- the multiplexing unit 32-2 combines the signals (5), (6), C, and D to generate signals (V), C, and D having the frequency arrangement shown in FIG.
- the multiplexing unit 32-3 generates the signal B having the frequency arrangement shown in FIG. 10D by the process of multiplexing the signal B and three empty channels.
- the combined signal (Z) is converted into a radio frequency band by a transmission phase correction unit (TPC) 33-1, a DA converter 34-1, an LPF 35-1, a mixer 36-1, and a BPF 38-1.
- TPC transmission phase correction unit
- the combined signals (V), C, and D are transmitted to the radio frequency band by the transmission phase correction unit 33-2, the DA converter 34-2, the LPF 35-2, the mixer 36-2, and the BPF 38-2.
- the combined signal B is converted into a radio frequency band by the transmission phase correction unit 33-3, the DA converter 34-3, the LPF 35-3, the mixer 36-3, and the BPF 38-3.
- the number of multiplexing is four is shown.
- the number of multiplexing is not limited to this, and any value can be used as long as it is an integer of 2 or more. It doesn't matter.
- each DA converter 34-1 to 34-N may be signals in either the intermediate frequency band or the baseband band.
- each DA converter 34-1 to 34-N and each LPF 35-1 to 35-N are composed of two sets (I, Q).
- the correction signal input to the transmission phase correction unit 33-1 is the same as the correction signal input to the reception phase correction unit 29-1, and is input from the local phase difference calculation unit 41 described later. .
- the correction signal input to the transmission phase correction unit 33-2 is the same as the correction signal input to the reception phase correction unit 29-2, and the correction signal input to the transmission phase correction unit 33-N is The correction signal is the same as the correction signal input to the reception phase correction unit 29-N, and is input from the local phase difference calculation unit 41 described later.
- Each correction signal is a complex number, and each transmission phase correction unit treats this correction signal as a complex conjugate. Details will be described later using equations.
- conversion of each transmission signal into a radio frequency band is realized by supplying each transmission local signal generated by the local generation unit 25 to each of the mixers 36-1 to 36-N.
- the mixer 36-1 has the same local signal LO 1 (frequency f 1 ) as the reception-side mixer 24-1, and the mixer 36-2 has the same local signal as the reception-side mixer 24-2.
- the signal LO 2 (frequency f 2 ) is supplied to the mixer 36-3 with the same local signal LO 3 (frequency f 1 ) as the receiving side mixer 24-3.
- the upstream radio frequency fr is converted into the downstream radio frequency ft in advance, and then the local signal for converting from the radio frequency ft to the intermediate frequency f IF (or baseband frequency) and the intermediate frequency f IF (or base).
- the local signal for converting from the radio frequency ft to the intermediate frequency f IF (or baseband frequency) and the intermediate frequency f IF (or base).
- the phase synchronization between ports on the receiving side is performed by one local generation unit 25 and local phase difference calculation unit 41.
- phase synchronization between ports on the transmission side can also be realized.
- the circuit scale is slightly increased, but the local generation unit 25, the local phase difference calculation unit 41 used on the reception side, the local generation unit 25 used on the transmission side, the local level A similar effect can be obtained by providing the phase difference calculation unit 41 separately.
- the uplink / downlink frequency converter 10 that converts the uplink radio frequency fr to the downlink radio frequency ft is provided between the reception antennas 21-1 to 21-N and the reception analog switch matrix 22.
- this position is not necessarily required, and it may be moved between the transmission unit, that is, the transmission analog switch matrix 37 of FIG. 3 and the transmission antennas 40-1 to 40-N.
- a local signal for converting the uplink radio frequency fr to the intermediate frequency f IF (or baseband frequency) and a local signal for converting the intermediate frequency f IF (or baseband frequency) to the radio frequency fr After performing a series of processes in common, the uplink radio frequency fr is converted to the downlink radio frequency ft.
- the connection of the transmission analog switch matrix 37 is controlled by a command signal from the control station 110 on the ground.
- the signal (Z) from the transmission port 39-1 (BPF 38-1) and the signals (V), C, and D from the transmission port 39-2 (BPF 38-2) are simultaneously transmitted to the antenna 40.
- the signal spectrum output from the antenna 40-1 has a form in which the signal (Z) and the signal (V) partially overlap as shown in FIG.
- the frequency interval of each transmission local signal is 1 and the characteristics of each demultiplexing filter shown in FIG. 7
- the combined signal A ′ combining the signal (Z) and the signal (V) is As shown in (g), the signal spectrum shape is the same as the signal A from the original transmitting station 101 and is transmitted to the receiving station 401 in the beam area 400.
- the transmission analog switch matrix 37 outputs the signal B (FIG. 10 (f)) converted to the radio frequency band output from the transmission port 39-3 (BPF 38-3) to the transmission antenna 40-2, Signal B is transmitted to the receiving station 403 in the beam area 402.
- the ground receiving station 401 After receiving the signals A ', C, and D, the ground receiving station 401 demodulates each.
- the ground receiving station 403 receives the signal B and demodulates it.
- the receiving station 401 receives a wideband signal composed of signals A ′, C, and D having a total bandwidth of 2, but generally, the operation speed of a consumer digital device used on the ground is: Since the operating speed of the space digital device is several times higher, the receiving station 401 can demodulate the signals A ′, C, and D without the upper limit of the performance of the digital device.
- the beam area requiring a wide bandwidth exceeding 1 is described as the beam area 100 for the uplink and the beam area 400 for the downlink.
- a wide bandwidth exceeding 1 is required for the uplink.
- the relay satellite of the present invention can easily cope with the problem by simply changing the connection of the reception analog switch matrix. That is, the beam area 100 within the bandwidth 1 is controlled by connecting the output of the BPF 14-1 only to the reception port 15-1 and connecting the output of the BPF 14-2 to both the reception port 15-2 and the reception port 15-3. , And signals from the beam area 102 exceeding the bandwidth 1 can be processed.
- the output of the BPF 38-1 (transmission port 39-1) is connected only to the transmission antenna 40-1, the output of the BPF 38-2 (transmission port 39-2), and the output of the BPF 38-3 (transmission port 39-3).
- the transmission antenna 40-2 By controlling both of them to the transmission antenna 40-2, it is possible to realize signal transmission to the beam area 400 within the bandwidth 1 and signal transmission to the beam area 402 beyond the bandwidth 1.
- a broadband signal relay service is not required for all beam areas, but the beam area that requires a broadband signal relay service changes with time due to traffic fluctuations.
- the effect that the circuit scale can be reduced is obtained.
- each beam prepares up to two ports in one beam area in preparation for broadband signal relay generation. A total of 4 ports are required.
- port # 1 is shared by two beams, so that it can be realized with three ports.
- realizing a broadband signal relay service using two ports at any time such a configuration using a transmission analog switch matrix or a reception analog switch matrix is unnecessary, and two ports are fixed for each beam.
- the configuration assigned to is sufficient.
- FIG. 11 is a diagram illustrating an example of a wideband signal transmitted from the relay satellite to the receiving station.
- the frequency-to-phase characteristics of the combined signal A ′ output from the transmission antenna 40-1 are Discontinuity occurs at two points ⁇ (R), (T) ⁇ in the downward arrows shown in FIG.
- a downward arrow (R) shown in FIG. 11 indicates a discontinuous position generated between the reception port 15-i and the port 15- (i + 1) (in the example of FIG.
- a downward arrow (T) shown in FIG. 11 indicates a discontinuous position generated between the transmission side port 15-i and the port 15- (i + 1) (the transmission port 39-1 and the transmission port 39-2 in the example of FIG. 10). Is shown.
- the local phase difference calculation unit 41, the reception phase correction units 29-1 to 29-N, the transmission phase correction Control by the units 33-1 to 33-N realizes reception sensitivity characteristics equivalent to the case of receiving the original signal A without deterioration in communication quality.
- the phase discontinuity shown in FIG. 11 is mainly caused by a local phase difference generated by down-converting or up-converting the frequency with different local signals (frequencies f 1 and f 2 ). Therefore, in this embodiment, the local phase difference that changes from moment to moment, which is the dominant factor of phase discontinuity, is detected and corrected by digital processing, so that the local phase difference between each port is canceled by digital processing. , All are synchronized to one local signal.
- the frequency synthesizer 501 In the local generation unit 25, the frequency synthesizer 501 generates the local signal Lf1 having the frequency f 1 based on the original vibration signal output from the original vibration 26. Similarly, the frequency synthesizer 502 generates a local signal Lf2 frequency f 2. The frequency difference (f 2 ⁇ f 1 ) between the two is “1” as described above.
- the local signal Lf1 is referred to as LO 1 and is supplied to the receiving-side mixer 24-1 and the transmitting-side mixer 36-1. Further, the local signal Lf1 is referred to as LO 3 and is supplied to the reception-side mixer 24-3 and the transmission-side mixer 36-3. That is, LO 1 and LO 3 are the same as the local signal Lf1 having the frequency f1.
- the local signal Lf2 is referred to as LO 2 and is supplied to the reception-side mixer 24-2 and the transmission-side mixer 36-2.
- the local generation unit 25 supplies either the local signal Lf1 or the local signal Lf2 to the mixer 24-N on the reception side and the mixer 36-N on the transmission side.
- the local generation unit 25 uses the local signal Lf2 at the frequency f2 when the reception port 15-N and the transmission port 39-N handle the higher frequency band, and the frequency f when the lower port is used. 1 local signal Lf1 is supplied to the mixer 24-N on the reception side and the mixer 36-N on the transmission side.
- FIG. 4 shows the connection when the frequency handled by each port is fixed, but it may be configured to output an arbitrary frequency instead of being fixed.
- a selector is additionally provided for each of LO 1 , LO 2 , LO 3 ,..., And the selector selects either the output of the frequency synthesizer 501 (Lf1) or the output of the frequency synthesizer 502 (Lf2).
- Lf1 the output of the frequency synthesizer 501
- Lf2 the output of the frequency synthesizer 502
- the command signal for switching the frequencies f 1 and f 2 is performed by a command signal transmitted from the control station 110 to the relay satellite 200 via a separate line.
- FIG. 12 is a diagram illustrating another configuration example of the local generation unit 25.
- the local generation unit 25 includes frequency synthesizers 504-1, 504-2,..., 504-N, and selectors 505, 506.
- Each frequency synthesizer 504-1, 504-2,..., 504-N can select and output one of a plurality of local frequencies.
- each frequency synthesizer 504-1, 504-2,..., 504-N can select one of the local signals of frequencies f 1 and f 2 . Therefore, even in this configuration, LO 1 , LO 2 , LO 3 ,...
- the selectors 505 and 506 select and output local signals having different frequencies.
- the selector 505 selects the local signal having the frequency f 1
- the selector 506 selects the local signal having the frequency f 2 and outputs them as Lf 1 and Lf 2 , respectively.
- the command signal for switching the frequencies f 1 and f 2 and the signal for controlling the selector are performed by a command signal transmitted from the control station 110 to the relay satellite 200 via another line.
- Each port of the relay satellite can process a signal in an arbitrary frequency band. For this reason, it is possible to flexibly cope with fluctuations in the use frequency band accompanying changes in traffic in each beam area on the ground.
- Local phase difference calculating section 41 receives as input a local signal Lf1 and the local signal Lf2 from the local generation unit 25, by detecting the phase of the local signal Lf2 local signal Lf1, extracting both of the phase difference signal [Delta] [theta] 21 Based on the extracted phase difference signal, each received signal is corrected and each transmitted signal is inversely corrected.
- processing contents will be described using equations.
- the addition theorem of trigonometric function, sum-product formula, product-sum formula, etc. are used.
- FIG. 13 is a diagram illustrating a flow of frequency conversion processing on the reception side.
- the local signal Lf1 is represented by the following equation (1)
- the local signal Lf2 is represented by the following equation (2).
- ⁇ (t) is a phase fluctuation component caused by phase noise or the like observed with the local signal Lf2 when the local signal Lf1 is used as a reference.
- Lf1 cos (2 ⁇ f 1 t)
- Lf2 cos (2 ⁇ f 2 t + ⁇ (t)) (2)
- the mixer 507 multiplies the local signal Lf1 and the local signal Lf2, to obtain a multiplication result M 21 shown in the following equation (3). As shown in the following equation (3), a frequency component of f 1 + f 2 and a frequency component of f 1 ⁇ f 2 are generated.
- the BPF 508 extracts the frequency component of f 1 -f 2 from the output of the mixer 507.
- Expression (4) is the result of removing the first half term (frequency component of f 1 + f 2 ) of the above expression (3) by the BPF 508.
- f C f 2 ⁇ f 1 and f 2 ⁇ f 1 is converted into f C.
- ⁇ C is a fixed phase difference based on the frequency component f C extracted by the BPF 508 and is determined according to the operation start timing of the local signal C.
- Note clock being supplied to the digital part, because it is generated from the original oscillation 26, the frequency f C of the frequency f C and formula generated by the complex local signal C (4) are frequency synchronization.
- C exp [ ⁇ j (2 ⁇ f C t + ⁇ C )] (5)
- the quadrature detection unit 510 multiplies the output B 21 of the BPF 508 by the quadrature detection complex local signal C.
- cos ⁇ * exp [ ⁇ j ( ⁇ )] can be expanded as in the following equation (6).
- FIG. 14 is a diagram showing an example of a phase change example of the signal after passing through the limiter 513.
- ⁇ 21 exp [j ( ⁇ (t) ⁇ C )] (10)
- the received signal is expressed by an equation.
- the received signal after passing through the BPF 14-1 is an unmodulated carrier (CW) arranged at the boundary frequency f 1 + f IF + 0.5f C between the two ports.
- CW unmodulated carrier
- the frequency relationship between the two must be +0.5 f C and ⁇ 0.5 f C and the initial phase must be aligned. If the initial phases are not aligned, energy loss occurs and deteriorates when up-converting again and combining and transmitting both signals. If the initial phases are aligned, the phases of both signals are aligned again at the time of up-conversion, so that the original signal can be transmitted without energy loss when both signals are combined.
- Equation (11) the received signal R is shown in Equation (11).
- R cos (2 ⁇ (f 1 + f IF + 0.5f C ) t + ⁇ r ) (11)
- the multiplied signal is M n1 and is shown in the following equation (12).
- the BPF 27-1 removes the harmonic component of M n1 shown in the above equation (12). Therefore, the signal B n1 after passing through the BPF 27-1 is expressed by Expression (13). Further, FIG. 13B shows the spectrum of the signal output from the BPF 27-1.
- B n1 (1/2) ⁇ cos (2 ⁇ (f IF + 0.5f C ) t + ⁇ r ) ⁇ (13)
- the signal output from the BPF 27-1 is sampled by the A / D converter 28-1 and input to the reception phase correction unit 29-1.
- the reception phase correction unit 29-1 converts the input signal from the intermediate frequency f IF to the baseband using the internal local signal exp [ ⁇ j (2 ⁇ f IF t)].
- the reception phase correction unit 29-1 digitally generates an input signal B n1 inside the reception phase correction unit 29-1.
- the local signal Lf1 is used as a reference, and the signal of each port is synchronized with Lf1 by digital correction.
- FIG. 13D shows the spectrum of the signal output from the reception phase correction unit 29-1.
- Lf2 cos (2 ⁇ f 2 t + ⁇ (t)
- the BPF 27-2 removes the harmonic component of the signal M n2 represented by the above equation (15). Therefore, the signal B n2 after passing through the BPF 27-2 is expressed by the following equation (16).
- FIG. 13C shows the spectrum of the signal output from the BPF 27-2.
- B n2 (1/2) ⁇ cos (2 ⁇ (f IF ⁇ 0.5f C ) t + ⁇ r ⁇ (t)) ⁇ ... (16)
- the local phase difference calculation unit 41 gives the baseband phase difference signal ⁇ 21 obtained by the above equation (10) for the reception port 15-2 to the reception phase correction unit 29-2.
- the reception phase correction unit 29-2 converts the input signal from the intermediate frequency f IF to the baseband using the internal local signal exp [ ⁇ j (2 ⁇ f IF t)]. Correct the phase difference.
- the signal QL n2 after being converted to the baseband frequency is expressed by the following equation (17).
- the intermediate frequency component f IF may be the same as the intermediate frequency component f IF used in the processing related to the signal input to the reception port 15-1.
- Reception phase correction unit 29-2 multiplies the baseband phase difference signal [Delta] [theta] 21 to the signal QL n2 which is converted from the intermediate frequency signal into a baseband signal, performs phase correction.
- the signal after the phase correction is shown in formula (18) below as S n2.
- ⁇ (t) which is a dynamic phase fluctuation component
- the reception signal R remains at the reception port 15-2 while leaving the phase offset ⁇ r ⁇ C.
- the negative frequency component is converted to -0.5f C.
- the spectrum of the signal output from the reception phase correction unit 29-2 is shown in FIG.
- the reception signal R is converted into a positive frequency component + 0.5f C while leaving the phase offset ⁇ r at the reception port 15-1. Therefore, as shown in FIGS. 13D and 13E, the frequency relationship between the phase-corrected signal of the reception port 15-1 and the signal after the phase correction of the reception port 15-2 is + 0.5f C , ⁇ 0.5 f C.
- ⁇ r in equation (14) and ⁇ r ⁇ C in equation (18) the signal after phase correction of reception port 15-1 and the phase correction of reception port 15-2 There remains a deviation of ⁇ C from the signal.
- the dynamic phase fluctuation component ⁇ (t) is canceled by the series of processes described above. If a phase shift of - ⁇ C remains between the two, the phase shift (- ⁇ C ) is again performed when up-converting and synthesizing both frequencies in the transmission process as shown in the following equation (19). As a result, the amplitude decreases. For this reason, it is desirable to separately correct ⁇ C. Any method may be used to correct the fixed value - ⁇ C. Further, for example, ⁇ C may be automatically canceled by a method described later in the fourth embodiment.
- FIG. 15 is a diagram showing an example of the flow of frequency conversion on the transmission side. If the spectrum of S ′ n1 shown in Expression (20) is expressed in a diagram, FIG. 15 (f) is obtained, and if the spectrum of S ′ n2 shown in Expression (21) is expressed in a diagram, FIG. 15 (g) is obtained. .
- S ′ n1 and S ′ n2 have a frequency relationship of +0.5 f C and ⁇ 0.5 f C and the same initial phase. For this reason, when frequency conversion to an ideal radio frequency having no local phase difference variation is performed at each transmission port and synthesized by the transmission analog switch matrix 37, the center frequency f 1 + f shown in FIG. An unmodulated wave with an amplitude of 1 is output at IF + 0.5f C. Actually, however, local phase difference fluctuations occur between the transmission ports, so that the phase and amplitude of the combined transmission signal will fluctuate unless the following processing is performed.
- the transmission phase correction unit 33-1 converts the input signal S ′ n1 from the baseband to the intermediate frequency f IF using the internal local signal exp [ ⁇ j (2 ⁇ f IF t + ⁇ U )].
- ⁇ U is an initial phase offset. Since the transmission phase correction unit 33-1 is a system using the local signal Lf1, it is not necessary to give phase correction, and in this case, exp [j (0)] is given.
- the input signal U 1 converted to the intermediate frequency f IF by the transmission phase correction unit 33-1 is expressed by the following equation (22).
- Re [x] represents the real part of the complex number x.
- the spectrum of U 1 is shown in FIG.
- U 2 that is the input signal converted to the intermediate frequency f IF is expressed by the following equation (23).
- the spectrum of U 2 at this time is shown in FIG.
- the signal U 1 converted to the intermediate frequency f IF is multiplied by the local signal cos (2 ⁇ f 1 t) expressed by Expression (1) by the mixer 36-1.
- the multiplied signal is represented by the following equation (24), where W 1 is W 1 .
- Equation (1) the multiplied signal is represented by the following equation (24), where W 1 is W 1 .
- the signal U 2 converted to the intermediate frequency f IF is multiplied by the local signal cos (2 ⁇ f 2 t + ⁇ (t)) expressed by the equation (2) by the mixer 36-2.
- Two frequency components are generated as W 2 .
- this ⁇ C may be automatically canceled using, for example, the method of Embodiment 4 described later.
- the band pass filter 508 shown in FIG. 5 is changed to a low pass filter, the frequency component of f 2 + f 1 can be removed in the same manner, and therefore the band pass filter 508 may be changed to a low pass filter.
- a clock for driving the AD converter 509 and the subsequent quadrature detection unit 510, LPF 512, and limiter 513 is supplied from the clock generator 517. This clock is supplied from the source oscillation 26 in the clock generation unit 517. Generated based on the signal.
- a baseband phase difference signal [Delta] [theta] 21 which is obtained by the formula (10) is input to a selector 514, 515, 516 shown in FIG.
- the output of the selector 516 is connected to the reception phase correction unit 29-1 and the transmission phase correction unit 33-1.
- the output of the selector 515 is connected to the reception phase correction unit 29-2 and the transmission phase correction unit 33-2.
- the output of the Nth selector 514 is connected to the reception phase correction unit 29-N and the transmission phase correction unit 33-N.
- the receiving phase compensation section of the destination port of the transmission phase correction unit if the port local signal Lf2 is supplied, the selector selects the baseband phase difference signal [Delta] [theta] 21.
- the third port relays signals within the bandwidth 1 on both the reception side and the transmission side, so that the local port with other ports Phase synchronization is unnecessary, and there is no need to give dynamic control to the reception phase correction unit 29-3 and the transmission phase correction unit 33-3 of the third port.
- the receiving side uses the receiving port 15-1 and the receiving port 15-2.
- a wideband signal is relayed by switching from the combination to the combination of the reception port 15-2 and the reception port 15-3.
- the transmission side uses the combination of the transmission port 39-1 and the transmission port 39-2.
- the broadband signal is relayed by switching to the combination of the transmission port 39-2 and the transmission port 39-3.
- the phase is synchronized with the local signal Lf1 by the digital correction described above.
- the low phase noise characteristic equivalent to that of the local signal Lf1 can be realized. That is, even if the local signals Lf2, Lf3,..., LfN other than the local signal Lf1 are used with low frequency stability, low phase noise characteristics similar to those of the local signal Lf1 with good stability can be realized. Therefore, the cost of the frequency synthesizer used for the local signals Lf2, Lf3,..., LfN can be reduced.
- the clock supplied to the digital unit of the relay apparatus is generated from the original oscillation used by the local signal Lf1 or the local signal Lf1 itself.
- the original oscillation used by the frequency synthesizer used for the local signals Lf2, Lf3,..., LfN may not be shared with the original oscillation of the local signal Lf1.
- the frequency interval of each local signal is not f C and a frequency offset ⁇ f is added.
- the frequency offset amount is not so large, this case
- the signal of each port can be synchronized with the local signal Lf1 with good stability.
- the configuration of the relay device is simplified, and the cost of the frequency synthesizer used for the local signals Lf2, Lf3,..., LfN can be reduced.
- the clock supplied to the digital unit of the relay device of the present embodiment is generated from the original oscillation used by the local signal Lf1 or the local signal Lf1 itself.
- the first port (reception port 15-1, transmission port 39-1) and the third port (reception port 15-3, transmission port 39-3) are connected to the low band side (f 1 )
- the first port (reception port 15-2, transmission port 39-2) has been described as a system that processes the high frequency side (f 2 ), but for each port, the low frequency side (f 1 ), or may be designed to allow selection of either the high frequency side (f 2).
- the local frequency supplied from the local generator 25 to each of the mixers 24-1 to 24-N and 36-1 to 36-N is configured so that f 1 or f 2 can be selected. Good.
- each port can be freely assigned to either the low frequency side (f 1 ) or the high frequency side (f 2 ). It becomes possible to reduce.
- each local signal not only the f 1 and f 2, the frequency f 1, f 2 up to the maximum number m synthesizable, ..., f m may be a selectable configuration.
- the local phase difference calculation unit 41 obtains a phase difference between the ports, and based on this phase difference.
- the phase difference between ports was corrected. For this reason, it is possible to relay a broadband signal even when the device performance is limited, and it is possible to reduce the deterioration of communication quality due to failure or interference.
- the signal relay based on the flow of the reception unit 201 ⁇ the connection unit 31 ⁇ the transmission unit 202 has been described.
- the signal relay is not necessarily specialized for a repeater.
- the signal may be stopped by the flow of the reception unit 201 ⁇ the connection unit 31 ⁇ the multiplexing unit 32, and the combined signal may be demodulated / decoded in the apparatus.
- the multiplexing unit 32 needs to be designed to double the processing speed, but a receiver that realizes demodulation / decoding of a wideband signal that exceeds the upper limit of the sampling rate of space devices such as A / D. Obtainable.
- the observation data obtained in the present apparatus may be encoded and modulated, and then flowed in the order of the demultiplexing unit 30 ⁇ the connection unit 31 ⁇ the transmission unit 202.
- the demultiplexing unit 30 needs to be designed to double the processing speed, but a modulator that realizes encoding / modulation of a wideband signal exceeding the upper limit of the sampling speed of a space device such as D / A Can be obtained.
- FIG. FIG. 16 is a diagram illustrating a configuration example of the local phase difference calculation unit 41a according to the second embodiment of the present invention.
- the configuration of the relay satellite according to the present embodiment is the same as that of the relay satellite according to the first embodiment, except that the local phase difference calculating unit 41 according to the first embodiment is replaced with a local phase difference calculating unit 41a.
- constituent elements having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and redundant description is omitted.
- the local phase difference calculation unit 41a includes mixers (multipliers) 507, 530, and 536, bandpass filters (BPF) 508, 531, and 537, and AD converters (A / D) 509, 532, and so on. 538, quadrature detection units 510, 533, 539, low-pass filters (LPF) 512, 534, 540, limiters 513, 535, 541, and adders 542, 543.
- mixers multipliers
- BPF bandpass filters
- AD converters A / D
- the local generator 25, the frequency f 1, f 2 to the frequency interval between f C, ..., a local signal Lf1, Lf2 corresponding to f K, ..., generates LFK, corresponding to each port BPF23- 1 to 23-N and BPFs 38-1 to 38-N may be designed with frequency characteristics corresponding to the frequencies f 1 , f 2 ,..., F K.
- a K 4 the case of realizing the bandwidth of up to 4 using 1 to 4 th ports, BPF23-1 ⁇ 23-4, respectively frequencies f 1, f 2, ..., either f K Extract different bands corresponding to.
- the local generation unit 25 generates the local signals Lf1, Lf2,..., Lfk.
- the local phase difference calculation unit 41a of the present embodiment extracts phase difference signals between four local signals respectively corresponding to f 1 , f 2 , f 3 , and f 4 .
- Expression (30) is similar to Expression (10), but the expression is changed so that it can be distinguished from other phase difference signals.
- Expression (31) is a phase difference signal when Lf3 is phase-detected with Lf2
- the local generation unit 25 in the present embodiment performs the following addition processing after extracting the phase difference signals shown in the above equations (30) to (32).
- Expression (33) is equivalent to the phase difference signal when Lf3 is phase-detected with the local signal Lf1
- Expression (34) is equivalent to the phase difference signal when Lf4 is phase-detected with the local signal Lf1.
- the phase difference signal ⁇ 21 is extracted from the limiter 513 by the same processing as in the first embodiment.
- the phase difference signal ⁇ 32 is extracted by the mixer 530, the BPF 531, the AD converter 532, the quadrature detection unit 533, the low-pass filter 534, and the limiter 535
- the phase difference signal ⁇ 43 is extracted by the mixer 536, the BPF 537, and the AD converter. 538, quadrature detection unit 539, low-pass filter 540, and limiter 541.
- the adder 542 adds the limiter 513 output and the limiter 535 output, to generate a phase difference signal [Delta] [theta] 31 represented by the formula (33). Further, the adder 543 adds the output of the limiter 541 and the output of the adder 542, and generates a phase difference signal ⁇ 41 represented by Expression (34).
- the local phase difference calculation unit 41a receives / replaces the phase difference signal ⁇ 41 obtained by Expression (34) using the local signal Lf4. Supplied to the phase correction unit.
- the reception phase correction unit / transmission phase correction unit to which the local signal Lf4 is input performs phase correction / inverse correction based on the input local signal Lf4.
- the local phase difference calculation unit 41a of the present embodiment receives the phase difference signal ⁇ 31 obtained by the equation (33) using the local signal Lf3, and a reception phase correction unit for a port that performs down-conversion / up-conversion. / Supply to the transmission phase correction unit.
- the reception phase correction unit / transmission phase correction unit to which the local signal Lf3 is input performs phase correction / inverse correction based on the input local signal Lf3.
- the local phase-difference calculating unit 41a of the present embodiment the phase difference signal [Delta] [theta] 21 obtained by equation (30), receiving the phase correction section of the port to implement the down-converting / up-conversion using a local signal Lf2 / Supply to the transmission phase correction unit.
- the reception phase correction unit / transmission phase correction unit to which the local signal Lf2 is input performs phase correction / inverse correction based on the input local signal Lf2.
- each port can synchronize the phase with the local signal Lf1.
- ⁇ K ⁇ K ⁇ 1 may be generated and supplied to the corresponding reception phase correction unit / transmission phase correction unit.
- a wideband signal is processed by dividing a band by three or more ports. For this reason, it is possible to relay a signal having a wider band than that of the first embodiment without deterioration in communication performance.
- FIG. 17 is a diagram illustrating a configuration example of the local phase difference calculation unit 41b according to the third embodiment of the present invention.
- the configuration of the relay satellite according to the present embodiment is the same as that of the relay satellite according to the first embodiment except that the local phase difference calculating unit 41 according to the first embodiment is replaced with the local phase difference calculating unit 41b.
- constituent elements having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and redundant description is omitted.
- the local phase difference calculation unit 41a of the second embodiment three types of mixers, bandpass filters, and AD converters are required, and the analog circuit scale increases as K increases. For this reason, in this embodiment, a signal obtained by adding the local signals other than Lf1 is changed to a configuration in which the signals are collectively detected by Lf1, and the number of mixers, bandpass filters, and AD converters is reduced.
- the local phase difference calculation unit 41b includes a mixer 507, a BPF 508, an AD converter (A / D) 509, adders 544 and 545, an orthogonal detection unit 546, and the like. 547, 548, low pass filters (LPF) 549, 550, 551, and limiters 552, 553, 554.
- LPF low pass filters
- the local phase difference calculation unit 41b of the present embodiment adds the local signal Lf2, the local signal Lf3, and the local signal Lf4 by the adders 544 and 545.
- This addition result is input to the mixer 507.
- the mixer 507 multiplies the input addition result by the local signal Lf1.
- the BPF 508 removes the high frequency component of the multiplied signal and extracts the low frequency component.
- the BPF 508 may be a low pass filter.
- the frequency components f 2 , f 3 , and f 4 included in the signal obtained by adding the three local signals are frequency shifted to the DC (Direct Current) side by f 1 .
- FIG. 18 is a diagram illustrating an example of sampling processing in the present embodiment.
- FIG. 18A shows an example of a signal spectrum after passing through the BPF 508.
- the frequency of Lf2 frequency of f C, Lf3 frequency of 2f C, Lf4 is converted to 3f C
- one side bandwidth of the signal after passing through BPF508 is 3f C.
- the AD converter 509 samples the signal in FIG. 18A at a sampling rate that is at least twice that of the one-side band 3f C.
- FIG. 18B shows an example of a spectrum when sampling is performed at a sampling speed of 7 f C. Each dotted arrow is a folded component of each signal.
- the quadrature detection unit 546 multiplies Lf2 of the center frequency f C by an internally generated complex local signal exp [ ⁇ j (2 ⁇ f C t)] and extracts a low frequency component, thereby extracting the center frequency f C.
- Lf2 is converted into a signal having a baseband frequency.
- the quadrature detection unit 547 multiplies Lf3 of the center frequency 2f C by the internally generated complex local signal exp [ ⁇ j (2 ⁇ 2f C t)], and extracts the low frequency component, thereby extracting the center frequency.
- 2f C Lf3 is converted into a signal of a baseband frequency.
- the quadrature detection unit 548 multiplies Lf4 of the center frequency 3f C by the internally generated complex local signal exp [ ⁇ j (2 ⁇ 3f C t)], and extracts the low frequency component, thereby Lf4 having a frequency of 3f C is converted into a signal having a baseband frequency.
- the local signals converted into the baseband by the local signal Lf1 are converted into constant amplitudes by the limiters 552, 553, and 554, and then output as phase difference signals ⁇ 21 , ⁇ 31 , and ⁇ 41 .
- the operations of the present embodiment other than those described above are the same as those of the second embodiment.
- the local phase difference calculation unit 41b of the present embodiment needs to set the sampling rate of the AD converter higher than that of the first embodiment, but the mixer, the bandpass filter (BPF), and the AD converter are set to 1. Therefore, the analog circuit scale can be reduced. If an AD converter that can also handle undersampling is used, the sampling speed of the AD converter can be lowered from 7 f C to 3.5 f C as shown in FIG. As shown in FIG. 18C, undersampling may be performed at a frequency such that the folded components of the signals indicated by the dotted arrows do not overlap with the main signal components Lf2, Lf3, and Lf4.
- FIG. 19 and 20 are diagrams showing a configuration example of the relay satellite according to the fourth embodiment of the present invention.
- the relay satellite according to the present embodiment includes delay units 60-1, 60-2, 65-1, 65-2, a reception-side phase time difference detection unit (reception-side phase difference detection unit) 61, an unmodulated signal generation unit (CW Generation units) 62-1 and 62-2, an adder 63 (in the transmission analog switch matrix 37), and a transmission-side phase time difference detection unit (transmission-side phase difference detection unit) 64 are added.
- delay units 60-1, 60-2, 65-1, 65-2 a reception-side phase time difference detection unit (reception-side phase difference detection unit) 61, an unmodulated signal generation unit (CW Generation units) 62-1 and 62-2, an adder 63 (in the transmission analog switch matrix 37), and a transmission-side phase time difference detection unit (transmission-side phase difference detection unit) 64 are added.
- Components having the same functions as those in the first embodiment are denoted by the same reference numerals as
- the configuration for compensating for the dynamic carrier phase fluctuation ⁇ (t) due to phase noise or the like has been described.
- the present embodiment not only the dynamic carrier phase fluctuation due to phase noise and the like, but also the fixed time difference caused by the phase offset ⁇ C shown in the first embodiment, the path length difference between each port, delay characteristics, etc. Automatically corrects up to.
- this fixed time difference may be corrected manually, but it will take time to correct, and once corrected, the phase and time deviation will gradually reappear in units of hours, months, and years due to aging and temperature fluctuations. If it occurs (if it is semi-fixed), it is also possible. Therefore, in this embodiment, after correcting the dynamic phase fluctuation component ⁇ (t) shown in the first embodiment, this phase / time shift is automatically corrected.
- this automatic correction a non-modulation (CW) wave for correction is generated and used in the relay device. Therefore, this automatic correction is performed after the relay signal input / output to the corresponding port is stopped and in the standby state. carry out.
- the relay satellite does not secure only the number of ports necessary for actual operation, and has a plurality of spare ports in preparation for failure. Therefore, when each port is sequentially set to the standby state and correction is performed, the following procedure is performed to avoid a situation where signal relay is temporarily interrupted by this correction.
- a standby port that has already been corrected by the correction processing of the present embodiment described later is started, and the same relay signal as that of the correction target port is also applied to the standby port by switch control of the reception analog switch matrix 22. input.
- the transmission analog switch matrix 37 combines the signal of the correction target port and the signal of the standby port and outputs the resultant signal to the antenna. However, control is performed so that the two signals are not combined by stopping the output of the backup data at some point in the digital unit (for example, the transmission phase correction units 33-1 to 33-N).
- the standby signal is stored at a predetermined timing in any of the digital units (for example, the transmission phase correction units 33-1 to 33-N).
- the data of the system port is output, and the output of the correction target port data is stopped.
- the signal is transferred from the correction target port to the standby port and relayed without any signal disconnection.
- reception analog switch matrix 22 selects only the standby port and switches to a connection that does not input a signal to the correction target port.
- transmission analog switch matrix 37 switches to a connection that selects only the standby port.
- the same relay signal is sent not only to the standby port but also to the correction target port by the switch control of the reception analog switch matrix 22.
- the transmission analog switch matrix 37 is a connection that combines the signal of the correction target port and the signal of the standby system port and outputs the synthesized signal to the antenna, but somewhere in the digital unit (for example, the transmission phase correction unit 33-1).
- step 33-N the output of the corrected port data is stopped so that the two signals are not combined.
- the data of the corrected port is output at a certain timing in the digital (for example, transmission phase correction units 33-1 to 33-N). Then, stop the data of the standby system port. By this digital switching, the signal is transferred from the standby port to the corrected port and relayed without causing a signal disconnection.
- the reception analog switch matrix 22 selects only the corrected port and switches to a connection in which no signal is input to the standby port. Similarly, the transmission analog switch matrix 37 switches to a connection that selects only corrected ports.
- the relay signal is temporarily transferred from the correction target port to the standby port and then returned after correction.
- the correction of the standby port is performed. It can be performed at any time regardless of the above procedure.
- phase difference and time difference between ports occur at the following two locations.
- the phase difference between the reception ports 15-1 and 15-2 (or transmission ports 39-1 and 39-2) shown in FIGS. ⁇ C and time delay differences ⁇ 21 and ⁇ 43 are generated.
- the phase difference and the time delay difference are large, the signal phase difference causes a decrease in S / N (Signal to Noise ratio) when the two signals are combined. .
- phase shift ( ⁇ C ) generated between the receiving-side branching units 30-1 and 30-2 after correcting the dynamic phase fluctuation ⁇ (t), and the receiving analog switch matrix 22
- correction method (A) will be described first, and then the correction method (B) will be described, taking the correction between the first port and the second port as an example.
- the non-modulated signal generation unit 62-2 After the reception ports 15-1 and 15-2 are switched to the standby state in the above-described steps (1) to (3), the non-modulated signal generation unit 62-2 generates a complex non-modulated signal of ⁇ 0.5f C. exp [j (2 ⁇ ( ⁇ 0.5f C ) t)] is generated.
- the complex unmodulated signal of ⁇ 0.5 f C is a burst signal that periodically stops signal output in order to detect a time difference described later.
- FIG. 21 is a diagram showing an example of this complex unmodulated signal waveform.
- the solid line is the real number component (cosine component), and the dotted line is the imaginary number component (sine component).
- the generation of signal harmonics may be suppressed by gradually increasing / decreasing the signal amplitude to some extent when the signal is stopped or generated.
- the complex unmodulated signal waveform is not limited to the example of FIG.
- FIG. 22 is a diagram showing the flow of processing for a complex unmodulated signal for reception side correction.
- the signal spectrum at the input point of the AD converter 28-1 at this time is shown in FIG.
- the other passes the path of BPF 23-2 ⁇ mixer 24-2 ⁇ BPF 27-2 ⁇ AD converter 28-2.
- the signal spectrum at the AD input point at this time is shown in FIG.
- the two unmodulated signals passing through the above two paths are subjected to phase fluctuation correction by the reception phase correction units 29-1 and 29-2, respectively, and then input to the reception-side phase time difference detection unit 61.
- the delay units 60-1 and 60-2 adjust the time delay of the signal that cancels the time difference between the ports based on the time difference ⁇ 21 information obtained by the reception-side phase time difference detection unit 61.
- the phase difference ⁇ C obtained by the reception-side phase time difference detection unit 61 is given to the reception phase correction units 29-1 and 29-2 as a correction value for canceling this. Since the time delay process can be performed by digital signal processing, it can be easily and accurately realized.
- the correction of the time delay can be realized by a digital filter such as an interpolation filter that interpolates sampled data M times or a polyphase filter that further thins out the interpolated data at the original sampling rate.
- FIG. 23 is a diagram illustrating a configuration example of the reception-side phase time difference detection unit 61 according to the present embodiment.
- the reception-side phase time difference detector 61 includes a complex multiplier 601, a low-pass filter 602, a polar coordinate converter (I, Q ⁇ phase ⁇ ) 603, a power converter 604, and a rising difference detector 605. .
- the complex unmodulated signal input from the reception phase correction unit 29-1 (reception port 15-1) to the reception-side phase time difference detection unit 61 is defined as CW (+ 0.5f C ), and RPC 29-2 (reception port 15-
- the complex unmodulated signal input to the receiving-side phase time difference detector 61 from 2) is assumed to be CW ( ⁇ 0.5 f C ).
- FIG. 24 is a diagram illustrating a waveform example of each non-modulated signal in the present embodiment.
- the phase offset ⁇ C on the receiving side shown in the first embodiment corresponds to this ⁇ ′ 21 .
- the reception-side phase time difference detection unit 61 obtains the signal vector angle ⁇ ′ 21 after averaging by the low-pass filter 602, and outputs it to the reception phase correction unit 29-1. Since each unmodulated signal arrives in bursts, the above calculation may be performed when the amplitude of each unmodulated signal is sufficiently large, and an error may occur when there is no signal, so that the above calculation is not performed.
- the reception side phase time difference detection unit 61 obtains the power of each complex unmodulated signal CW (+0.5 f C ) and CW ( ⁇ 0.5 f C ) in bursts, so that there is each power data.
- the power data obtained at the clock sampling period is digitally interpolated to tens of times the clock speed, for example, and the sampling speed is increased, and then the edge detection of the power data is performed to detect the edge. You may raise the precision of time.
- the relay apparatus compensates for the local phase fluctuation described in the first to third embodiments, and has a common non-modulation at the frequency position of the boundary that simultaneously passes through the two ports on the receiving side.
- a wave is input, and the digital unit detects and corrects the phase difference and the time delay difference between the ports on the receiving side. Therefore, automatic correction of the time delay difference between the ports on the receiving side can be realized with accurate and fine phase and time resolution by digital processing while minimizing the addition of analog elements.
- the signal before the input of the delay devices 60-1 and 60-2 is connected to the reception-side phase time difference detection unit 61 to obtain ⁇ 21 , but the outputs of the delay devices 60-1 and 60-2 are used. May be connected to the reception-side phase time difference detection unit 61, and the time difference detected by the reception-side phase time difference detection unit 61 may be gradually corrected by feedback (loop) control. Also in this case, time correction for finally canceling ⁇ 21 is realized.
- FIG. 25 is a diagram showing a flow of processing for the transmission-side correction CW signal in the present embodiment.
- the non-modulated signal generation unit 62-1 After the transmission port 39-1 and the transmission port 39-2 are switched to the standby state in the procedures (1) to (3), the non-modulated signal generation unit 62-1 generates a complex non-modulated signal of + 0.5f C exp [j (2 ⁇ (+ 0.5f C ) t)] is generated.
- FIG. 25 (a) shows the spectrum of this complex unmodulated signal. At this time, no signal is output from the other non-modulated signal generator 62-2.
- the complex unmodulated signal of +0.5 f C is also a burst signal that periodically stops signal output in order to detect a time difference described later.
- This complex unmodulated signal is up-converted by the mixer 36-1 using the local signal Lf1, and is input to the adder 63.
- the signal output from the adder 63 inside the transmission analog switch matrix 37 is used as the input terminal (BPF 14-1 output terminal) of the reception analog switch matrix 22 during correction on the transmission side. To enter.
- the unmodulated signal having the center frequency f 1 + 0.5f C inputted to the input end (BPF 14-1 output end) of the reception analog switch matrix 22 is connected to the BPF 23-1 by the reception analog switch matrix 22. Therefore, this non-modulated signal passes through the path of BPF 23-1 ⁇ mixer 24-1 ⁇ BPF 27-1 ⁇ AD converter 28-1 and is input to the reception phase correction unit 29-1.
- FIG. 25D shows a signal spectrum before input to the AD converter 28-1. As shown in FIG. 25 (d), this signal is a signal having a center frequency of +0.5 f C. Further, the non-modulated signal is input to the transmission side time difference detection unit 64 after the phase fluctuation correction is performed by the reception phase correction unit 29-1.
- the transmission side time difference detection unit 64 generates a complex unmodulated signal (free-running complex unmodulated signal) exp [j (2 ⁇ ( ⁇ ) with a frequency of ⁇ 0.5 f C generated in the transmission side time difference detection unit 64 from the input signal. 0.5f C ) t)] and complex multiplication.
- FIG. 26 is a diagram illustrating a configuration example of the transmission-side phase time difference detection unit 64 according to the present embodiment.
- the transmission-side phase time difference detector 64 of this embodiment includes a complex multiplier 611, a low-pass filter 612, a polar coordinate converter (I, Q ⁇ phase ⁇ ) 613, a power converter 614, a rising difference detector 615, a free-running complex.
- An unmodulated signal generation unit 616 is provided.
- the complex multiplication unit 611 multiplies the signal input from the reception phase correction unit 29-1 by the free-running complex unmodulated signal generated by the free-running complex unmodulated signal generation unit 616.
- the low pass filter 612 averages the signal after the multiplication by the complex multiplier 611.
- the vector angle of the averaged signal is the phase of the free-running complex unmodulated signal and the phase of the unmodulated signal input to the transmission-side phase time difference detector 64 via the transmission port 39-1 ⁇ the reception port 15-1. It corresponds to the difference.
- the polar coordinate conversion unit 613 obtains this vector angle and holds it as phase difference information ⁇ 1 . Since each complex unmodulated signal arrives in bursts, the above calculation is performed when the amplitude of each complex unmodulated signal is sufficiently large, and an error occurs when there is no signal, so that the above calculation is not performed. .
- the power conversion unit 614 performs power conversion on the output signal of the complex multiplication unit 611, and the rising difference detection unit 615 determines the time when the power data exceeds a certain threshold as the rising edge time t. Record as 1 .
- the rising edge difference detection unit 615 also records the time t 0 when the reception of the complex unmodulated signal from the unmodulated signal generation unit 62-1 is started, and obtains the difference (t 1 -t 0 ) between the times. Record the result as ⁇ 1 .
- non-modulation signal generation unit 62-1 stops sending complex unmodulated signal, the other unmodulated signal generator 62-2, -0.5F C complex unmodulated signal exp [j (2 ⁇ ( ⁇ 0.5f C ) t)].
- FIG. 25B shows the spectrum of this signal.
- This complex unmodulated signal is up-converted by the mixer 36-2 using the local signal LF2, and at the output terminal of the adder 63, as shown in FIG. 25 (c), the center frequency f 2 -0.5f C is obtained. Frequency converted.
- the signal spectrum before input to the AD converter 28-1 is the center frequency + 0.5f C as shown in FIG.
- the unmodulated signal is input to the transmission-side phase time difference detection unit 64 after the phase fluctuation is corrected by the RPC 29-1. Transmitting-side phase time difference detector 64, the input signals, complex unmodulated signal frequency -0.5F C generated inside (self complex unmodulated signal) exp [j (2 ⁇ (-0.5f C) t)] and complex multiplication.
- the vector angle of the signal obtained by averaging the multiplication results by the low-pass filter 612 is the phase of the free-running complex unmodulated signal and the transmission-side phase time difference detection unit 64 via the transmission port 39-2 ⁇ the reception port 15-1. This corresponds to the difference from the non-modulated signal phase input to.
- the transmission-side phase time difference detection unit 64 holds this phase difference information as ⁇ 2 . Since each complex unmodulated signal arrives in bursts, the above calculation is performed when the amplitude of each complex unmodulated signal is sufficiently large, and an error occurs when there is no signal, so that the above calculation is not performed. .
- the power conversion unit 614 performs power conversion on the output signal of the complex multiplication unit 611, and the rising difference detection unit 615 determines the time when the power data exceeds a certain threshold as the rising edge time t. Record as 3 .
- the rising difference detector 615 also records the time t 2 when reception of the complex unmodulated signal from the unmodulated signal generator 62-2 is started, obtains the difference (t 3 -t 2 ) between the times, Record the result as ⁇ 2 .
- the phase difference between 39-1 and the transmission port 39-2 can be obtained. That is, the transmission-side phase time difference detection unit 64 can obtain the result of subtracting ⁇ 2 and ⁇ 1 as the phase difference information ⁇ 21 .
- the phase offset ⁇ C on the transmission side shown in the first embodiment corresponds to this ⁇ 21 .
- the transmission-side phase time difference detection unit 64 gives a value that cancels out the phase difference information ⁇ 21 to the transmission phase correction unit 33-2.
- the delay units 65-1 and 65-2 adjust the time delay of the signal that cancels the time difference between the ports based on the time difference information ⁇ 21 obtained by the transmission-side phase time difference detection unit 64. Since the time delay can be performed by digital signal processing, it can be easily and accurately realized.
- the delay units 65-1 and 65-2 are composed of an interpolation filter and a polyphase filter, like the delay units 60-1 and 60-2 described above.
- the local phase fluctuation compensation described in the first to third embodiments is performed, and the frequency located at the boundary that can pass through any of the two ports on the transmission side is An unmodulated wave is alternately input, and the digital section detects and corrects the phase difference and time delay difference between the ports on the transmission side. Therefore, automatic correction of the time delay difference between the ports on the transmission side can be realized with accurate and fine time resolution by digital processing while minimizing the addition of analog elements.
- the phase offset ⁇ C has a different sign on the reception side and transmission side ( ⁇ C , + ⁇ C ), but since the absolute values thereof are the same, the reception side phase time difference detection unit 61 or the transmission side phase time difference detection
- the phase offset may be obtained by any of the units 64, and may be shared between the transmission side and the reception side while inverting only the sign. In this case, the circuit scale for obtaining the phase offset can be reduced.
- the unmodulated signal generation unit 62-1 and the unmodulated signal generation unit 62-2 do not generate signals simultaneously, the unmodulated signal generation unit may be combined into one.
- the unmodulated signal generation unit sets the frequency to +0.5 f C when flowing a complex unmodulated signal to the transmission port 39-1, and sets the frequency to ⁇ when flowing the complex unmodulated signal to the transmission port 39-2. It should be extended to the function to be switched to 0.5f C.
- the frequency is inverted from positive to negative simply by inverting the sign of the orthogonal component of the complex unmodulated signal, this function can be easily expanded.
- the time difference correction on the reception side and the time difference correction on the transmission side have been described for correcting the time delay difference between the first port and the second port.
- Port 15-2, transmission port 39-2) and 3rd port (reception port 15-3, transmission port 39-3), 3rd port and 4th port etc. can do.
- a delay device is required for each port, but the unmodulated signal generation units 62-1 and 62-2 and the reception-side phase time difference detection unit 61 can be used in common.
- a time difference with each port based on a certain port (for example, reception port 15-1) can be obtained. It can also be controlled to zero.
- the example in which the digital unit detects and corrects the phase difference and the time delay difference between the ports on the reception side or the transmission side has been described.
- both the phase difference and the time delay difference are necessarily detected and corrected. If the time delay difference is sufficiently small, it is only necessary to correct the phase. In this case, since the circuit for obtaining the time delay difference and each delay unit can be reduced, the circuit scale can be further reduced.
- Embodiments 1 to 4 the application example to the relay satellite has been described.
- the relay apparatus of the present embodiment is similarly applied to a terrestrial radio relay, a radio base station, and a radio terminal. By doing so, it is possible to realize a wide band of the radio.
- connection unit 31 is described as a digital switch matrix.
- DBF reception digital beam forming
- transmission DBF transmission DBF
- FIG. 27 is a diagram illustrating a state of the same frequency interference when the two beam areas 100 and 102 (broadband beam area 100 and narrowband beam area 102) illustrated in the second embodiment are brought close to each other.
- the wideband signal A from the beam area 100 shown in (a) and the narrowband signal ⁇ B, C, D ⁇ from the beam area 102 shown in (b) use the same frequency band. Therefore, when the distance between the beam area 100 and the beam area 102 is shortened, the antenna 21-1 of the relay satellite 200 has not only the wideband signal A but also the narrow area from the beam area 102 as shown in (c) of FIG. Band signals ⁇ B, C, D ⁇ are also received at a small level.
- Signals 702, 703, and 704 shown in (c) of FIG. 27 are components of the narrowband signal ⁇ B, C, D ⁇ from the beam area 102 received at a small level by the antenna 21-1, respectively. It becomes an interference component with respect to the signal A and brings about deterioration of communication quality.
- the antenna 21-2 of the relay satellite 200 receives a narrowband signal ⁇ B, In addition to C, D ⁇ , the broadband signal A from the beam area 100 is also received at a small level.
- a signal 701 shown in (d) of FIG. 27 is a component of the wideband signal A from the beam area 100 received at a small level by the antenna 21-2, and for the narrowband signal ⁇ B, C, D ⁇ . It becomes an interference component and brings about deterioration of communication quality.
- FIG. 28 is a diagram illustrating an example of the reception DBF process according to the present embodiment.
- the beam number input to the reception DBF function is k ( ⁇ ⁇ 0, 1, 2,..., K ⁇ 1 ⁇ ), and the number of each subchannel signal demultiplexed by each demultiplexing unit is j ( ⁇ ⁇ 0, 1, 2,..., J-1 ⁇ ), the beam number of the output destination is i ( ⁇ ⁇ 0, 1, 2,..., I-1 ⁇ ), and the baseband input signal is D (j, k)
- the reception complex DBF coefficient is r (i, j, k)
- the baseband signal R (i, j) after the reception DBF processing is expressed by the following equation (35).
- the signal after the reception DBF processing is expressed by the following equations (36) and (37).
- R (0,1) D (1,0) ⁇ r (0,1,0) + D (1,1) ⁇ r (0,1,1) (36)
- R (1,1) D (1,0) ⁇ r (1,1,0) + D (1,1) ⁇ r (1,1,1) (37)
- D (1,0) corresponds to the signal (1) ′
- D (1,1) corresponds to the signal B ′
- R (0,1) is the value after DBF processing indicated by 705a in FIG. It corresponds to the signal (1)
- R (1,1) corresponds to the signal B after DBF processing shown by 103a in FIG.
- FIG. 28 shows an example in which the signal 702 that is a small component of the signal B mixed in the signal (1) ′ is canceled using the signal B included in the signal B ′.
- the signal (1) ′ and the signal B ′ are respectively multiplied by the reception DBF coefficients by the complex multipliers 720 and 722, and the multiplied signals are vector-synthesized by the adder 724.
- the signal 702, which is a small component of the signal B is removed from the signal (1) 'as indicated by the signal 705a in FIG.
- the reception DBF coefficient is set so that the signal (1) of 705a has the same amplitude and the same phase as the signal 705 included in the signal 710.
- FIG. 28 shows an example in which the signal 701a which is a small component of the signal (1) mixed in the signal B ′ is canceled using the signal (1) included in the signal (1) ′.
- the received DBF coefficients are multiplied by the complex multipliers 721 and 723 respectively to the signal (1) ′ and the signal B ′, and then the vector synthesis is performed by the adder 725.
- the signal 701a which is a small component of the signal (1), is removed from the signal B as indicated by the signal 103a in FIG.
- the reception DBF coefficient is set so that the signal B of the signal 103a has the same amplitude and phase as the signal 103 included in the signal 711 in the process of removing the interference.
- These received DBF coefficients r (i, j, k) are calculated by the ground control station 110 that knows the position of each ground station and the position of the relay satellite, and are given to the relay satellite 200 via another line. It is also good. At that time, the control station 110 may partially collect input data before DBF processing from the relay satellite 200 via a separate line and use it for calculating the coefficient of the received DBF.
- the relay DB 200 may perform the reception DBF coefficient calculation by itself instead of the control station 110.
- the calculation amount of the relay satellite 200 is increased, real-time (rapid) interference removal can be realized as compared with the case where the control is performed by the ground control station 110.
- FIG. 29 is a diagram illustrating a configuration example of a relay apparatus having a reception DBF function and a transmission DBF function.
- FIG. 29 shows an example of four-beam input and four-beam output, and illustrations other than the reception DBF function, the connection unit 31, and the transmission DBF function are omitted. Configurations other than the reception DBF function, connection unit 31, and transmission DBF function are the same as those in the first embodiment.
- the reception DBF unit 801 performs the processing of the above equation (35).
- the subchannel data after demultiplexing from No. 0 to No. J-1 is time-division multiplexed.
- the number of each input signal D (j, k) becomes one structure for every beam.
- the number of output signals R (j, k) is also one for each beam.
- the subchannel data after demultiplexing does not have to be time-division multiplexed.
- the set of subchannels multiplexed in time-division multiplexing is not limited to the example of FIG.
- Each reception DBF coefficient multiplication section 802, 803, 804, 805 receives the reception DBF coefficient r (i ) in units of the input beam number k ⁇ ⁇ 0, 1, 2, 3 ⁇ with respect to the beam signal D (j, k) . , j, k) is complex multiplied.
- Each of the reception DBF addition units 806, 807, 808, and 809 performs vector addition on all the subchannel signals multiplied by the reception DBF coefficients in units of output beam numbers i ⁇ ⁇ 0, 1, 2, 3 ⁇ .
- the sub-channel signal of each beam from which interference components have been removed by this series of reception DBF processing is distributed to the transmission-side multiplexing unit by the connection unit 31 that performs the same operation as in the first embodiment.
- the transmission side can mitigate the same frequency interference at the ground reception station that occurs when the downlink beam areas (for example, the beam areas 400 and 402) are brought closer by the transmission DBF processing. That is, in the transmission DBF process, the main satellite signal is mixed with the signal from the adjacent beam and transmitted on the relay satellite side in advance so as to cancel the same frequency interference signal from the adjacent beam.
- FIG. 30 is a diagram illustrating a transmission DBF processing example and effects.
- the transmission DBF unit 811 converts the signal 901 for removing interference using the signal B to the transmission spectrum of the transmission antenna 40-1 in FIG. Add to the interference part. Note that when performing interference cancellation of the wideband signal A, a reception DBF coefficient calculated so that the frequency-to-amplitude characteristics and frequency-to-phase characteristics of the wideband signal A after canceling the signal B is not destroyed is set.
- the transmission DBF unit 811 generates a signal 902 for removing interference using a partial band of the signal A with respect to the transmission spectrum of the transmission antenna 40-2 in FIG. Add to the spectrum.
- the signal B from the antenna 40-2 is canceled by the signal 901 from the antenna 40-1, and the broadband signal A that is almost the same as the original signal is received. can do.
- the signal A from the antenna 40-1 is canceled by the signal 902 from the antenna 40-2, and a narrowband signal B that is almost the same as the original signal is not generated. Can be received.
- the beam number input to the transmission DBF unit 811 is k ( ⁇ ⁇ 0, 1, 2,..., K ⁇ 1 ⁇ ), and the number of each subchannel signal is j ( ⁇ ⁇ 0, 1, 2,... J ⁇ 1 ⁇ ), the beam number of the output destination is i ( ⁇ ⁇ 0, 1, 2,..., I ⁇ 1 ⁇ ), the baseband input signal is M (j, k) , and the received complex DBF coefficient is w ( If i, j, k) , the baseband signal T (i, j) after the transmission DBF processing is expressed by the following equation (38).
- FIG. 29 also shows a configuration example of the transmission DBF unit 811 with four inputs and four outputs.
- the transmission DBF unit 811 performs the processing of the above equation (38).
- the subchannel data from No. 0 to J-1 is time-division multiplexed and each data is input from the connection unit 31 in the previous stage.
- the number of each input signal (baseband input signal) M (j, k) becomes one structure for every beam.
- the number of output signals T (j, k) is also one for each beam.
- Each transmission DBF coefficient multiplier 812, 813, 814, 815 is configured to transmit DBF coefficient w (i in units of input beam number k ⁇ ⁇ 0, 1, 2, 3 ⁇ with respect to input signal M (j, k) . , j, k) is complex multiplied. Also, each transmission DBF addition section 816, 817, 818, 819 performs vector addition on all subchannel signals multiplied by the transmission DBF coefficient in units of output beam numbers i ⁇ ⁇ 0, 1, 2, 3 ⁇ .
- These coefficients of transmission DBF w (i, j, k ) is the coefficient r of the receiving DBF (i, j, k) and similar, the position and the respective ground station, the control station on the ground to know the position of the satellite relay A system calculated by 110 and given to the relay satellite 200 via another line may be used.
- each ground station may calculate the transmission DBF coefficient w (i, j, k) and give the calculation result to the relay satellite 200 via another line.
- interference from adjacent beam areas is removed by reception DBF processing and transmission DBF processing. Therefore, in addition to the effect of relaying a broadband signal, it is possible to realize high antenna directivity in which signals of the same frequency do not interfere even when the beam areas are brought close to each other. As a result, the repetition rate of the same frequency is improved, and combined with the effect of relaying a broadband signal, it is possible to realize a further increase in capacity of the satellite system.
- the relay apparatus according to the present embodiment is similarly applied to a radio repeater having a plurality of ground directional antennas, a radio base station, or a radio terminal. By applying it, it is possible to realize high antenna directivity as well as broadening the bandwidth of the radio.
- Embodiment 6 FIG. Next, a relay device according to the sixth embodiment will be described.
- the relay signal input / output to the corresponding port is temporarily stopped and the standby An example of implementation after the state has been shown.
- the adjustment is limited to the adjustment between the ports on the reception side, but the phase offset ⁇ C and the fixed time difference are corrected using CW while the relay signal is being input / output without entering the standby state. This saves the trouble of switching to the standby state and facilitates system operation.
- this embodiment is effective when adjusting the reception-side port, and can be applied to, for example, demodulating a wideband signal on a relay satellite or demodulating a wideband signal on a ground station. it can.
- FIG. 31 is a diagram illustrating a configuration example of the relay device according to the present embodiment.
- the basic configuration of the relay apparatus according to the present embodiment is the same as that of FIG. 19, and a CW replica generation unit 71 and CW removal units 70-1 and 70-2 are added to the configuration example of FIG.
- a CW replica generation unit 71 and CW removal units 70-1 and 70-2 are added to the configuration example of FIG.
- the component concerning a part to add is shown, and illustration of components other than these is abbreviate
- the unmodulated signal generation unit 62-2 generates an unmodulated signal as in the fourth embodiment.
- the reception ports 15-1 and 15-2 are not switched to the standby state but remain in a state in which the relay signal is input / output.
- the unmodulated signal generated by the unmodulated signal generation unit 62-2 is up-converted by 36-2 and input to the reception ports 15-1 and 15-2 via the adder 63.
- the reception-side phase time difference detection unit 61 detects the phase difference and time difference between unmodulated signals (CW waves) input to the two reception ports.
- an unmodulated signal that is input to the reception port 15-1 and input from the RPC 29-1 to the reception-side phase time difference detector 61 is defined as a first unmodulated signal, and is input to the reception port 15-2 and is input to the RPC 29- 2 is a second unmodulated signal input to the receiving-side phase time difference detecting unit 61, the receiving-side phase time difference detecting unit 61 receives the receiving port based on the first unmodulated signal and the second unmodulated signal.
- the phase difference ( ⁇ C ) and time difference between 15-1 and 15-2 are detected. Further, the reception-side phase time difference detection unit 61 calculates a delay correction value ⁇ 21 based on the detected time difference.
- the received signal is also included in each signal input to the reception-side phase time difference detection unit 61.
- the first unmodulated signal and the second unmodulated signal are detected using the characteristics of the component (rise or the like).
- the power (power information) of two CWs is also detected in each detection process.
- the CW replica generation unit (replica generation unit) 71 is 180 degrees out of phase with the CW wave mixed in the reception signal based on the phase difference, power information, and delay correction value ⁇ 21 detected by the reception-side phase time difference detection unit 61. And an equal-power CW replica.
- Each generated CW replica is input to CW removal units (unmodulated signal removal units) 70-1 and 70-2, and a reception baseband in which CW waves output from delay units 60-1 and 60-2 are mixed.
- the signal and vector are added.
- the CW replica generation unit 71 uses the delay correction value ⁇ 21 so that the correction CW mixed in the signal and the timing of the CW replica are aligned, and each CW replica generation unit 71 performs the delay correction by the delay unit. Also adjust the replica timing.
- phase difference between the reception ports 15-1 and 15-2 in which the input signal is branched into two is described.
- 2 can be used similarly to the transmission side in the fourth embodiment, two unmodulated signal generation units 62-1 and 62-2 can be used.
- the correction CW wave is canceled by the CW replica, and only the received signal necessary for the original signal relay is input to the demultiplexing unit. Therefore, it is possible to correct a phase difference (phase offset ⁇ C ) or a fixed time difference using CW while inputting / outputting a relay signal.
- the reception-side phase time difference detection unit 61 needs to detect each CW in a state where the original relay signal is mixed, so that the relay signal may cause an increase in detection error as an interference component. Therefore, if there is a concern about an increase in errors, a narrowband digital filter that extracts only the CW component is provided in the previous stage, and after removing the relay signal component, the time difference and phase difference shown in the fourth embodiment are obtained. Signal processing may be performed.
- the relay device, the relay satellite, and the satellite communication system according to the present invention are useful for a relay system that relays a broadband signal, and are particularly suitable for a satellite relay system.
- uplink / downlink frequency converter 21-1 to 21-N receiving antenna, 22 receiving analog switch matrix, 12-1 to 12-N, 14-1 to 14-N, 23-1 to 23-N, 27-1 to 27-N, 38-1 to 38-N, 508, 531, 537 Band pass filter, 13-1 to 13-N, 36-1 to 36-N, 507, 530, 536 mixer, 25 local Generation unit, 26 original oscillation, 28-1 to 28-N, 509, 532, 538 AD converter, 29-1 to 29-N reception phase correction unit, 30-1 to 30-N demultiplexing unit, 31 connection unit , 32-1 to 32-N multiplexing unit, 33-1 to 33-N transmission phase correction unit, 34-1 to 34-N DA converter, 35-1 to 35-N, 512, 534, 540, 549 , 550, 55 , 602, 612 low-pass filter, 37 transmission analog switch matrix, 40-1 to 40-N transmission antenna, 41, 41a, 41b local phase difference calculation unit, 60-1, 60-2, 65-1, 65-2
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Abstract
Description
図1は、本発明にかかる中継衛星の実施の形態1の構成例を示す図である。図1に示すように、本実施の形態の中継衛星200は、受信アンテナ21-1~21-N(Nは2以上の整数)、受信部201、接続部31、送信部202および送信アンテナ40-1~40-Nを備える。図1では、中継衛星の全体構成のうち、中継衛星に搭載される中継装置の構成を示している。また、本実施の形態では、受信アンテナの数と送信アンテナの数を同じとしているが、受信アンテナの数と送信アンテナの数は異なっていてもよい。
<1>広帯域ビームエリア100内の送信局101からの広帯域信号である信号Aを、ビームエリア400内の受信局401へ送信する。
<2>狭帯域ビームエリア102内の送信局103からの狭帯域信号である信号Bを、ビームエリア402内の受信局403へ送信する。
<3>狭帯域ビームエリア102内の送信局104からの狭帯域信号である信号Cを、ビームエリア400内の受信局401へ送信する。
<4>狭帯域ビームエリア102内の送信局105からの狭帯域信号である信号Dを、ビームエリア400内の受信局401へ送信する。
このように、予め上りの無線周波数frを下りの無線周波数ftに変換後、無線周波数ftから中間周波数fIF(またはベースバンド周波数)に変換するためのローカル信号と、中間周波数fIF(またはベースバンド周波数)から無線周波数ftに変換するためのローカル信号を共通化する(同じものとする)ことで、1つのローカル生成部25、ローカル位相差算出部41で、受信側のポート間位相同期だけでなく、送信側のポート間位相同期も実現することが出来る。
本実施の形態では、1を超える広い帯域幅が必要なビームエリアは、アップリンクはビームエリア100、ダウンリンクはビームエリア400として説明したが、例えば、アップリンクで1を超える広い帯域幅が必要なビームエリアが、ビームエリア100から、ビームエリア102に変化した場合でも、本発明の中継衛星では、受信アナログスイッチマトリックスの接続を変更するだけで、容易に対応できる。即ち、BPF14-1の出力を受信ポート15-1のみ接続し、BPF14-2の出力を受信ポート15-2と受信ポート15-3の両方に接続する制御により、帯域幅1以内のビームエリア100からの各信号と、帯域幅1を超えるビームエリア102からの各信号を処理することができる。
図13は、受信側の周波数変換処理の流れを示す図である。ローカル信号Lf1を以下の式(1)に示し、ローカル信号Lf2を以下の式(2)で示す。ここでθ(t)はローカル信号Lf1を基準とした場合のローカル信号Lf2で観測される、位相雑音等に起因する位相変動成分とする。
Lf1=cos(2πf1t) …(1)
Lf2=cos(2πf2t+θ(t)) …(2)
=(1/2){cos[2π(f1+f2)t+
+cos[2π(f1-f2)t-θ(t)]} …(3)
B21=(1/2){cos[2π(f1-f2)t-θ(t)]}
=(1/2){cos[2π(-fC)t-θ(t)]}
=(1/2){cos[2πfCt+θ(t)]} …(4)
C=exp[-j(2πfCt+θC)] …(5)
cosα*exp[-j(β)]=cosα*(cosβ-jsinβ)
=cosα*cosβ-jcosαsinβ
=(1/2){cos(α+β)+cos(α-β)}
-j((1/2){sin(α+β)+sin(-α+β)})
=(1/2){cos(α+β)+cos(α-β)}
-j((1/2){sin(α+β)-sin(α-β)}
…(6)
Hf=(1/2){cos(α+β)}-j((1/2){sin(α+β)})
=(1/2)exp[-j(α+β)] …(7)
α-βの低域周波数成分Lfは、
Lf=(1/2){cos(α-β)}}-j((1/2){-sin(α-β)})
=(1/2)exp[j(α-β)] …(8)
F21=(1/4){exp[j(2πfCt+θ(t)-(2πfCt+θC))]}
=(1/4){exp[j(2πfCt+θ(t)-2πfCt-θC)]}
=(1/4){exp[j(θ(t)-θC)]} …(9)
Δθ21=exp[j(θ(t)-θC)] …(10)
R=cos(2π(f1+fIF+0.5fC)t+θr) …(11)
Mn1=cos(2π(f1+fIF+0.5fC)t+θr)*cos2π(f1t)
=(1/2){cos(2π(f1+fIF+0.5fC)t+θr)
+cos(2π(fIF+0.5fC)t+θr)} …(12)
Bn1=(1/2){cos(2π(fIF+0.5fC)t+θr)} …(13)
QLn1=(1/4){exp[j(2π(fIF+0.5fC)t
+θr-(2πfIFt))]}
=(1/4){exp[j(2π(0.5fC)t+θr)]}…(14)
Mn2=cos(2π(f1+fIF+0.5fC)t+θr)
*cos2π(2πf2t+θ(t))
=(1/2){cos(2π(f1+fIF+0.5fC)t+θr
+2π(f1+fC)t+θ(t))
+cos(2π(f1+fIF+0.5fC)t+θr
-2π(f1+fC)t-θ(t))}
=(1/2){cos(2π(2f1+fIF+1.5fC)t+θr+θ(t))
+cos(2π(fIF-0.5fC)t+θr-θ(t))}…(15)
Bn2=(1/2){cos(2π(fIF-0.5fC)t+θr-θ(t))}
…(16)
QLn2=(1/4){exp[j(2π(fIF-0.5fC)t
+θr-θ(t)-(2πfIFt))]}
=(1/4){exp[j(2π(-0.5fC)t+θr-θ(t))]}
…(17)
Sn2=(1/4){exp[j(2π(-0.5fC)t+θr-θ(t))]}
*exp[j(θ(t)-θC)]
=(1/4){exp[j(2π(-0.5fC)t+θr-θC)]}
…(18)
=(1/4){exp[j(2π(0.5fC)t+θr)]}
*exp[j(2πf1t)]
+(1/4){exp[j(2π(-0.5fC)t+θr-θC)]}
*exp[j(2π(f1+fC)t)]
=(1/4){exp[j(2π(f1+0.5fC)t+θr)]}
+(1/4){exp[j(2π(f1+0.5fC)t+θr-θC)]}
=(1/2)*cos(-θC/2)*exp[j(2π(f1+0.5fC)t+θr)]
…(19)
次に送信側の処理を式で表現する。送信側では、受信側と逆の処理が行われる。式(20)に送信ポート39-1に対応する合波部32-1から出力される送信信号を示し、式(21)に送信ポート39-2に対応する合波部32-2から出力される送信信号を示す。
S' n1={exp[j(2π(+0.5fC)t)]} …(20)
S' n2={exp[j(2π(-0.5fC)t)]} …(21)
U1=Re[S' n1*exp[j(0)]*exp[j(2πfIFt+θU)]]
=Re[exp[j(2π(+0.5fC)t)]
*exp[j(0)]*exp[j(2πfIFt+θU)]]
=Re[exp[j(2π(fIF+0.5fC)t+θU)]]
=cos(2π(fIF+0.5fC)t+θU) …(22)
U2=Re[S' n2*exp[j((-θ(t)+θC))]
*exp[j(2πfIFt+θU)]]
=Re[exp[j(2π(-0.5fC)t)]
*exp exp[j((-θ(t)+θC))]
*exp[j(2πfIFt+θU)]]
=Re[exp[j(2π(fIF-0.5fC)t-θ(t)+θC+θU)]]
=cos(2π(fIF-0.5fC)t-θ(t)+θC+θU) …(23)
W1=cos(2π(fIF+0.5fC)t+θU)*cos(2πf1t)
=(1/2){cos(2π(f1+fIF+0.5fC)t+θU)
+cos(2π(fIF-f1+0.5fC)t+θU)} …(24)
Y1=(1/2){cos(2π(fIF-f1+0.5fC)t+θU)}…(25)
W2=cos(2π(fIF-0.5fC)t-θ(t)+θC+θU)
*cos(2πf2t+θ(t))
=(1/2){cos(2π(fIF-0.5fC)t-θ(t)+θC+θU
+2πf2t+θ(t))
+cos(2π(2π(fIF-0.5fC)t-θ(t)+θC+θU
-2πf2t-θ(t))}
=(1/2){cos(2π(fIF+f1+0.5fC)t+θC+θU)
+cos(2π(fIF-f1-1.5fC)t+θC+θU-2θ(t))}
…(26)
Y2=(1/2){cos(2π(fIF+f1+0.5fC)t+θC+θU)}
…(27)
T=cos(2π(fIF+f1+0.5fC)t+θr+θU) …(28)
図16は、本発明にかかる実施の形態2のローカル位相差算出部41aの構成例を示す図である。本実施の形態の中継衛星の構成は、実施の形態1のローカル位相差算出部41をローカル位相差算出部41aに替える以外は、実施の形態1の中継衛星と同様である。以下、実施の形態1と同様の機能を有する構成要素は実施の形態1と同一の符号を付して重複する説明を省略する。
Δθ21=exp[j(θ21(t))] …(30)
Δθ32=exp[j(θ32(t))] …(31)
Δθ43=exp[j(θ43(t))] …(32)
Δθ31=Δθ21+Δθ32
=exp[j(θ32(t)+θ21(t))] …(33)
Δθ41=Δθ21+Δθ32+Δθ43
=exp[j(θ32(t)+θ21(t)+θ43(t))] …(34)
図17は、本発明にかかる実施の形態3のローカル位相差算出部41bの構成例を示す図である。本実施の形態の中継衛星の構成は、実施の形態1のローカル位相差算出部41をローカル位相差算出部41bに替える以外は、実施の形態1の中継衛星と同様である。以下、実施の形態1と同様の機能を有する構成要素は実施の形態1と同一の符号を付して重複する説明を省略する。
図19,20は、本発明にかかる中継衛星の実施の形態4の構成例を示す図である。図19では、受信側の補正に関連する部分を抜き出して示している。図20では、送信側の補正に関連する部分を抜き出して示している。本実施の形態の中継衛星は、遅延器60-1,60-2,65-1,65-2、受信側位相時間差検出部(受信側位相差検出部)61、無変調信号生成部(CW生成部)62-1,62-2、加算器63(送信アナログスイッチマトリックス37内)、送信側位相時間差検出部(送信側位相差検出部)64を追加している。実施の形態1と同様の機能を有する構成要素は実施の形態1と同一の符号を付して重複する説明を省略する。
(P1)受信アナログスイッチマトリックス22入力端からAD変換器28-1~28-Nまでの区間
(P2)DA変換器34-1~34-Nから送信アナログスイッチマトリックス37出力端までの区間
上述した(1)~(3)の手順で、受信ポート15-1,15-2をスタンバイ状態に切り替えた後、無変調信号生成部62-2は、-0.5fCの複素無変調信号exp[j(2π(-0.5fC)t)]を生成する。この-0.5fCの複素無変調信号は、後述する時間差を検出するため、周期的に信号出力を停止させるバースト的な信号とする。
図25は、本実施の形態における送信側補正用CW信号に対する処理の流れを示す図である。上記(1)~(3)の手順で、送信ポート39-1と送信ポート39-2をスタンバイ状態に切り替えた後、無変調信号生成部62-1は、+0.5fCの複素無変調信号exp[j(2π(+0.5fC)t)]を生成する。図25(a)は、この複素無変調信号のスペクトラムを示している。この際、もう一方の無変調信号生成部62-2からは信号を出力しない。
次に、実施の形態5の中継装置について説明する。以上の実施の形態では、接続部31がデジタルスイッチマトリックスであるとして説明したが、接続部31の前後に受信デジタルビームフォーミング(DBF:Digital Beam Forming)機能と送信DBF機能を有する構成としても良い。本構成とすることで、広帯域な信号を中継する効果に加え、各ビームエリアを近づけても同一周波数の信号が干渉しない、高いアンテナ指向性も実現することができる。
次に、実施の形態6の中継装置について説明する。実施の形態4では、位相オフセットθCや、各ポート間の経路長差、遅延特性等によって生じる固定的な時間差を補正するために、一旦該当のポートへの中継信号入出力を停止し、スタンバイ状態にした上で実施する例を示した。
Claims (17)
- 複数の受信処理部と、
複数の送信処理部と、
前記受信処理部で処理された信号を、前記送信処理部へ出力する接続部と、
周波数の異なる2つ以上のローカル信号を生成し、前記ローカル信号をそれぞれ前記受信処理部へ供給するローカル生成部と、
前記ローカル信号間の位相差を算出し、前記受信処理部へ前記位相差を入力するローカル位相算出部と、
を備え、
前記受信処理部は前記位相差に基づいて位相補正を行う受信側位相補正部、を備え、
前記送信処理部は、前記接続部からの信号を送信処理し、
前記受信処理部は、処理可能な帯域幅よりも広帯域な広帯域受信信号が入力された場合、受信信号を1つ以上の前記受信処理部で処理することを特徴とする中継装置。 - 複数の受信アンテナと、
複数の送信アンテナと、
前記受信アンテナで受信した受信信号を1つ以上の前記受信処理部に出力し、前記広帯域受信信号が入力された場合、当該広帯域受信信号を2つ以上の受信処理部に出力する第1のスイッチ部と、
同一の受信信号に対応する前記分波信号が入力された1つ以上の前記送信処理部によって送信処理が施された信号を同一の前記送信アンテナに出力する第2のスイッチ部と、
を備え、
前記接続部は、前記受信処理部により分波された分波信号を前記送信処理部へ出力し、
前記受信処理部は、前記広帯域受信信号が入力された場合、前記ローカル信号に基づいて入力信号の一部の帯域を抽出し、抽出した分割信号に対して前記受信処理を行うことを特徴とする請求項1に記載の中継装置。 - 無変調信号を生成する無変調信号生成部と、
前記無変調信号が入力された2つの前記受信処理部を通過した信号に基づいて前記受信処理部間の準固定的な位相差を求める受信側位相差検出部と、
を備え、
前記受信側位相補正部は、前記受信側位相時間差検出部により算出された前記位相差に基づいて位相補正を実施することを特徴とする請求項1または2に記載の中継装置。 - 前記受信側位相時間差検出部は、さらに、前記無変調信号が入力された2つの前記受信処理部を通過した信号に基づいて前記受信処理部間の時間差を求め、
前記受信処理部は、前記時間差に基づいて時間遅延を補正することを特徴とする請求項3に記載の中継装置。 - 前記送信処理部は、前記位相差に基づいて位相補正を行う送信側位相補正部、を備え、
前記送信処理部は、前記広帯域受信信号が分波された分波信号が入力された場合、前記送信処理後の入力信号を前記ローカル信号に基づいて周波数変換することを特徴とする請求項1から4のいずれか1つに記載の中継装置。 - 複数の受信処理部と、
複数の送信処理部と、
前記受信処理部で処理された信号を、前記送信処理部へ出力する接続部と、
周波数の異なる2つ以上のローカル信号を生成し、前記ローカル信号をそれぞれ前記受信処理部へ供給するローカル生成部と、
前記ローカル信号間の位相差を算出し、前記送信処理部へ前記位相差を入力するローカル位相算出部と、
を備え、
前記送信処理部は、前記位相差に基づいて位相補正を行う送信側位相補正部、を備え、
前記送信処理部は、処理可能な帯域幅よりも広帯域な信号送信が求められた場合、送信信号を1つ以上の前記送信処理部で処理後、前記ローカル信号に基づいて周波数変換する送信することを特徴とする中継装置。 - 複数の受信アンテナと、
複数の送信アンテナと、
前記受信アンテナで受信した受信信号を1つ以上の前記受信処理部に出力し、前記受信処理部で処理が可能な帯域幅よりも広帯域の広帯域受信信号が入力された場合、当該広帯域受信信号を2つ以上の受信処理部に出力する第1のスイッチ部と、
同一の受信信号に対応する前記分波信号が入力された1つ以上の前記送信処理部によって送信処理が施された信号を同一の前記送信アンテナに出力する第2のスイッチ部と、
を備え、
前記接続部は、前記受信処理部により分波された分波信号を前記送信処理部へ出力することを特徴とする請求項6に記載の中継装置。 - 第1の無変調信号を生成する第1の無変調信号生成部と、
第2の無変調信号を生成する第2の無変調信号生成部と、
前記第1の無変調信号が入力された前記送信処理部を通過した信号と前記第2の無変調信号が入力された前記送信処理部を通過した信号とが加算された信号が前記受信処理部を通過した信号に基づいて前記送信処理部間の準固定的な位相差を求める送信位相差検出部と、
を備え、
前記送信側位相補正部は、前記送信側位相時間差検出部により算出された前記位相差に基づいて位相補正を実施することを特徴とする請求項5、6または7に記載の中継装置。 - 前記送信側位相時間差検出部は、さらに、前記第1の無変調信号が入力された前記送信処理部を通過した信号と前記第2の無変調信号が入力された前記送信処理部を通過した信号とが加算された信号が前記受信処理部を通過した信号に基づいて前記送信処理部間の時間差を求め、
前記送信処理部は、前記時間差に基づいて時間遅延を補正することを特徴とする請求項8に記載の中継装置。 - 前記受信アンテナは、ビームフォーミングにより受信ビームを形成し、
前記受信アンテナは、ビームフォーミングにより送信ビームを形成し、
前記受信信号を、同一の受信ビームにより受信した受信信号とし、
前記第2のスイッチ部は、同一の受信信号に対応する前記分波信号が入力された1つ以上の前記送信処理部によって送信処理が施された信号を同一の送信ビームを形成する前記送信アンテナに出力することを特徴とする請求項1から9のいずれか1つに記載の中継装置。 - 前記ローカル位相算出部は、周波数の異なる3つ以上の前記ローカル信号を生成し、
前記ローカル位相算出部は、
周波数の隣接する前記ローカル信号間の位相差を隣接位相差として求め、周波数の隣接しない前記ローカル信号間の位相差を前記隣接位相差を加算することにより算出することを特徴とする請求項1から10のいずれか1つに記載の中継装置。 - 前記ローカル位相算出部は、周波数の異なる2つ以上の前記ローカル信号のうちの1つの基準ローカル信号とし、
前記基準ローカル信号以外の前記ローカル信号を加算する加算器と、
前記加算器による加算結果と前記基準ローカル信号とを乗算する乗算器と、
前記乗算器による乗算結果から前記基準ローカル信号以外の前記ローカル信号に対応する帯域の信号をそれぞれ抽出する直交検波部と、
を備えることを特徴とする請求項11に記載の中継装置。 - 複数の前記受信処理部から出力される信号にそれぞれ係数を乗算し、係数乗算後の信号のうちの2つ以上を加算する受信デジタルビームフォーミング部、
をさらに備え、
前記中継部は、前記受信デジタルビームフォーミング部による処理後の信号を前記送信処理部へ出力し、
前記係数は、主信号を受信したビームエリア以外のビームエリアからの信号を打ち消すように設定されることを特徴とする請求項1から12のいずれか1つに記載の中継装置。 - 複数の前記送信処理部へ出力する信号にそれぞれ係数を乗算し、係数乗算後の信号のうちの2つ以上を加算する送信デジタルビームフォーミング部、
をさらに備え、
前記中継部は、入力された信号を、前記送信デジタルビームフォーミング部を介して前記送信処理部へ出力し、
前記係数は、主信号に対応するビーム以外のビームの送信信号が受信局において打ち消されるように設定されることを特徴とする請求項1から13のいずれか1つに記載の中継装置。 - 無変調信号を生成する無変調信号生成部と、
前記受信処理部の1つである第1の受信処理部を通過した前記無変調信号である第1の無変調信号と、前記受信処理部の1つである第2の受信処理部を通過した前記無変調信号である第2の無変調信号とに基づいて、前記第1の無変調信号および前記第2の無変調信号の電力と、前記第1の受信処理部と前記第2の受信処理部との間の位相差および時間差とを求める受信側位相差検出部と、
前記位相差、前記電力および前記時間差に基づいて、前記第1の無変調信号と電力が等しく位相が180度異なる第1のレプリカ信号と、前記第2の無変調信号と電力が等しく位相が180度異なる第2のレプリカ信号とを生成するレプリカ生成部と、
前記第1の受信処理部に入力された受信信号と前記第1のレプリカ信号とに基づいて該受信信号から前記第1の無変調信号を除去する第1の無変調信号除去部と、
前記第2の受信処理部に入力された受信信号と前記第2のレプリカ信号とに基づいて該受信信号から前記第2の無変調信号を除去する第2の無変調信号除去部と、
を備え、
前記受信側位相補正部は、前記受信側位相時間差検出部により算出された前記位相差に基づいて位相補正を実施することを特徴とする請求項1または2に記載の中継装置。 - 請求項1から15のいずれか1つに記載の中継装置を備えることを特徴とする中継衛星。
- 請求項16に記載の中継衛星と、
前記中継衛星で中継された信号を受信する受信局と、
を備えることを特徴とする衛星通信システム。
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