WO2019167833A1

WO2019167833A1 - Communication system, space-side transmission station device, terrestrial-side reception station device, and program

Info

Publication number: WO2019167833A1
Application number: PCT/JP2019/006798
Authority: WO
Inventors: 友也深見
Original assignee: 国立大学法人東京大学
Priority date: 2018-02-28
Filing date: 2019-02-22
Publication date: 2019-09-06
Also published as: JP2019149782A; JP7060232B2

Abstract

A communication system 1 includes a space-side transmission station device 10 that receives data which is to be transmitted, divides such data into a plurality of partial data items, encodes the same so that each partial data item obtained by division includes unique partial data item identification information, attaches prescribed encoded data identification information to each of the encoded partial data items respectively and mutually links such encoded partial data items, and transmits the same as a single carrier signal.

Description

Communication system, space side transmitting station apparatus, ground side receiving station apparatus, and program

The present invention relates to a communication system, a space-side transmitting station device, a ground-side receiving station device, and a program used for communication between an artificial satellite and the like and a ground station.

In recent years, many systems have been developed for observing ground conditions using artificial satellites and transmitting the observed data to ground stations. Here, depending on the orbit of the artificial satellite, there is a case where the communicable time with the ground station is limited.

In addition, in data communication from an artificial satellite to a ground station, a method of performing relatively high-speed data communication using a single modulated wave (single carrier method) and a plurality of modulated waves, There is a method (multi-carrier method) for performing relatively low-speed data communication.

Here, in multi-carrier data communication, in order to avoid interference between signals modulated with each modulation wave, a frequency band (a guard band) with no signal between the occupied frequency bands of the signal modulated with each modulation wave. ). For this reason, when the multicarrier method is adopted, the frequency utilization efficiency is lower than when the single carrier method is adopted.

As described above, communication from an artificial satellite or the like to a ground station is preferably performed by a single carrier method from the aspect of frequency utilization efficiency. Since no processing is performed, the signal transmitted by the modulated wave must be demodulated at high speed, and the data included in the signal must be decoded at high speed, which significantly increases the cost of the receiver. .

Note that Non-Patent Document 1 discloses a technique for transmitting signals to a plurality of ground stations in a time division manner by a single carrier method.

The present invention has been made in view of the above circumstances, and includes a communication system, a space-side transmitting station apparatus, a ground-side receiving station apparatus, and a program that can realize communication by a single carrier method while using a relatively inexpensive receiver. One of its purposes is to provide it.

The present invention that solves the problems of the above conventional example is a space-side transmitting station device that transmits a single carrier signal to one ground-side receiving station device, and transmits data to be transmitted to one ground-side receiving station device. Including an accepting means for receiving, a dividing means for dividing the data to be transmitted into a plurality of partial data having a smaller size than the data, and partial data identification information unique to each partial data obtained by the division Encoding means for encoding, and transmission means for attaching each of the encoded partial data with predetermined encoded data identification information, connecting them to each other, and transmitting them as a single carrier signal. is there.

By dividing the data in this way, signals corresponding to each partial data can be processed in a time division manner using different receivers on the ground station side, and a relatively inexpensive receiver. Communication using a single carrier method can be realized.

It is the schematic showing the example of the communication system which concerns on embodiment of this invention. It is a block diagram showing an example of a space-side transmitting station apparatus according to an embodiment of the present invention. It is a structure block diagram showing the example of the ground side receiving station apparatus which concerns on embodiment of this invention. It is a functional block diagram showing the example of the space side transmission station apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of the division | segmentation aspect of the transmission object data in the space side transmission station apparatus which concerns on embodiment of this invention. It is explanatory drawing showing an example of the signal which the space side transmission station apparatus which concerns on embodiment of this invention sends out. It is a flowchart figure showing the example of operation of the space side transmitting station apparatus concerning an embodiment of the invention. It is explanatory drawing showing another example of the signal which the space side transmission station apparatus which concerns on embodiment of this invention sends out.

Embodiments of the present invention will be described with reference to the drawings. As illustrated in FIG. 1, a communication system 1 according to an embodiment of the present invention includes a space-side transmitting station device 10 mounted on an artificial satellite 2 and a ground-side receiving station device disposed in a ground-side facility 3. 20.

The artificial satellite 2 has, for example, at least one sensor that observes ground conditions and the like, and transmits data detected by the sensor to one ground-side receiving station device 20. Further, the artificial satellite 2 sends status information indicating the state of the artificial satellite such as the attitude to the ground-side receiving station device 20 together with the data detected by the sensor.

As illustrated in FIG. 2, the space-side transmitting station apparatus 10 includes a control unit 11, a storage unit 12, a data input unit 13, and a radio unit 14. Further, as illustrated in FIG. 3, the ground-side receiving station device 20 includes a radio receiving unit 21, a distributor 22, a plurality of receivers 23 a, b,... N and an output unit 24. Yes.

Here, the control unit 11 of the space-side transmitting station apparatus 10 is a program control device such as a CPU, and executes a program stored in the storage unit 12. In the present embodiment, the control unit 11 performs processing for transmitting a single carrier signal to one ground side receiving station device 20.

The control unit 11 accepts data to be transmitted to one terrestrial receiving station apparatus, and divides the accepted data to be transmitted into a plurality of partial data having a smaller size than the data. Then, the control unit 11 encodes each partial data obtained by the division including unique partial data identification information, attaches predetermined encoded data identification information to each of the encoded partial data, and connects them to each other. Then, it is transmitted as a single carrier signal via the radio unit 14. The operation of the control unit 11 will be described in detail later.

The storage unit 12 includes a disk device, a memory device, and the like, and stores a program executed by the control unit 11. The storage unit 12 also operates as a work memory for the control unit 11.

The data input unit 13 accepts input of data to be transmitted to one ground side receiving station device. In an example of the present embodiment, the data input unit 13 accepts the outputs and status information of various sensors mounted on the artificial satellite 2 and outputs them to the control unit 11. In an example of the present embodiment, the sensor is an optical camera, a radar, or the like, and each sensor outputs observation data.

The radio unit 14 modulates the encoded data output from the control unit 11 with a single carrier wave, and transmits the modulated data to the ground-side receiving station device 20 as a single carrier signal.

Here, the operation of the control unit 11 of the space-side transmitting station apparatus 10 will be specifically described. As illustrated in FIG. 4, the control unit 11 executes the program stored in the storage unit 12, thereby allowing the receiving unit 31, the dividing unit 32, the encoding unit 33, and the communication control unit 34. Implement the configuration including.

The accepting unit 31 accepts data to be transmitted to one ground side receiving station device from a sensor or the like. Here, the data to be transmitted may include a plurality of types of data (data output from a plurality of sensors, status information, etc.).

The receiving unit 31 outputs the transmission target data to the dividing unit 32 as integrated data (for example, combined with the integrated data by a widely known archiver).

The dividing unit 32 divides the input data to be transmitted into a plurality of pieces of partial data having a smaller size than the data to be transmitted. Specifically, as illustrated in FIG. 5, the dividing unit 32 has a length determined by the performance of the receiving side in order from the head side of the data to be transmitted (specifically, the receiver 23 described later is The data is divided into acceptable data lengths (for example, a length corresponding to the size of one packet of the DVB-S2X standard), and each of them is defined as partial data Pd1, Pd2,. Since this length is affected by the coding rate of the coding unit 33, it becomes a unit of data that the coding unit 33 accepts at a time. In general, since the coding rate is dynamically set based on the distance information between the artificial satellite 2 and the receiving station on the ground side, the unit of data that the coding unit 33 accepts at a time changes with time. Therefore, the size of the partial data here is not always constant (fixed length).

The encoding unit 33 includes unique partial data identification information in each of the partial data obtained by the division. Here, the partial data identification information is information for specifying the combination order of the divided partial data and reconstructing the transmission target data. As an example, this partial data identification information may be a serial number that indicates what partial data each partial data corresponds to from the beginning of the data to be transmitted (original data before division). In the example of FIG. 5, the partial data identification information for the partial data Pd1 corresponding to the first part of the data to be transmitted is “1”, the partial data identification information for the next partial data Pd2 is “2”. Go. This partial data identification information can be extracted separately from the partial data obtained by division. As an example, this partial data identification information is represented by a predetermined number of bits, and is padded with “0” if necessary. Further, the partial data identification information is included in a predetermined portion of the partial data (for example, as a header at the front or as a trailer at the rear).

The encoding unit 33 further encodes each of the partial data including the unique partial data identification information by a predetermined encoding method. As an example, the coding here is coding that adds an error correction code.

The communication control unit 34 adds predetermined encoded data identification information to each encoded partial data. Here, the encoded data identification information is information (demodulation / decoding) indicating which receiver 23 is responsible for decoding among n (n is an integer of 2 or more) receivers 23 provided in the ground-side receiving station device 20. (Information for allocating the receivers 23). As an example of the encoded data identification information, the serial number of the partial data identification information included in the encoded partial data is divided by the number n of the receivers 23 included in the ground-side receiving station device 20 to obtain “1”. It is the added value. In this way, serial numbers from “1” to “n” are repeated and set as encoded data identification information.

It should be noted that this encoded data identification information can also be extracted and distinguished from the main part of the encoded partial data. As an example, this encoded data identification information is represented by a predetermined number of bits, and padded with “0” if necessary. The encoded data identification information is included in a predetermined portion of the encoded partial data (for example, as a header at the front or as a trailer at the rear).

The communication control unit 34 wirelessly transmits the encoded partial data so as to form a series of single carrier signals (in a state where signals corresponding to the encoded partial data are connected to each other). The unit 14 is controlled. As an example, the communication control unit 34 concatenates the encoded partial data to each other and then outputs the data to the radio unit 14. The data after the concatenation by the radio unit 14 is modulated at a radio frequency and transmitted. Alternatively, the communication control unit 34 sequentially outputs the encoded partial data to the radio unit 14, causes the radio unit 14 to modulate the data corresponding to each encoded partial data at a radio frequency, and outputs the modulated signal. Continue to transmit (as a connected state).

FIG. 6 shows an outline of the content of the signal transmitted by the wireless unit 14 by this processing. As illustrated in FIG. 6, the single carrier signal transmitted by the space-side transmitting station apparatus 10 includes the encoded data identification information (H) and the encoded partial data (B) repeatedly.

The radio receiving unit 21 of the ground side receiving station apparatus 20 receives the single carrier signal transmitted from the space side transmitting station apparatus 10 and outputs it to the distributor 22. At this time, the radio reception unit 21 may convert the single carrier signal into an intermediate frequency signal and output the signal to the distributor 22. The distributor 22 duplicates the single carrier signal output from the wireless reception unit 21 and outputs it to each receiver 23.

In an example of the present embodiment, it is assumed that each receiver 23 has predetermined encoded data identification information. The receiver 23 decodes the encoded partial data to which the assigned encoded data identification information is assigned, and outputs partial data including the partial data identification information obtained by decoding.

Specifically, the receiver 23 refers to a portion in which the encoded data identification information is included in the single carrier signal output from the distributor 22, and a predetermined code that is assigned to the referenced portion by the receiver 23. If it is determined that the encoded data identification information is included, the body part of the encoded partial data is demodulated (assuming that the encoded data identification information is transmitted prior to the encoded partial data body). The encoded partial data obtained by demodulation is decoded.

At the time of demodulation and decoding, each receiver 23 performs demodulation and decoding by relatively slow processing over a period until the next encoded data identification information determined to be handled by the receiver 23 arrives. And there is no need to use expensive high speed receivers.

As a result of this decoding, each receiver 23 decodes and outputs the partial data (including the partial data identification information) associated with the encoded data identification information that it is responsible for.

In addition, such an operation of examining the coincidence with the encoded data identification information and demodulating the subsequent portion can be realized by adopting a widely known method using a sliding correlator and a delay line. Detailed explanation here is omitted.

The output unit 24 receives partial data output from at least a part of the plurality of receivers 23, determines a combining method with reference to partial data identification information included in the received partial data, and uses the determined method to The partial data from which the data identification information has been deleted is combined to reproduce and output the data. At this time, the output unit 24 deletes and combines the partial data identification information. The output unit 24 can be realized by a computer device including a program control device such as a CPU or a DSP (Digital Signal Processor) and a storage unit for storing the program.

As an example, the output unit 24 receives the partial data output from each receiver 23, refers to the partial data identification information included in each partial data, and converts the partial data into the original data (space side transmitting station before division). Data to be transmitted by the device 10) are combined in order to reproduce. Specifically, when the partial data identification information is a serial number indicating the order in which the original data is included, the output unit 24 combines the partial data output by the receiver 23 in the order of the serial number. Play and output data.

[Operation]
This embodiment has the above-described configuration and operates as follows. In the following example, the artificial satellite 2 includes status information indicating the state of the artificial satellite such as the attitude, optical observation data obtained by optically imaging the ground, and radar observation data observed by the radar as one ground station. Shall be sent to the side.

The space-side transmitting station device 10 mounted on the artificial satellite 2 accepts data to be transmitted to the one ground-side receiving station device as illustrated in FIG. Then, the space-side transmitting station apparatus 10 divides the received data into partial data for each predetermined length in order from the head side, and obtains a plurality of partial data Pd1, Pd2,... (S1).

The space-side transmitting station apparatus 10 includes unique partial data identification information in each partial data obtained by division (S2). In this example, it is assumed that the partial data identification information is a serial number that indicates what number of partial data from the beginning of the data to be transmitted (original data before division) is.

That is, the space-side transmitting station apparatus 10 sets “1” as the partial data identification information for the partial data Pd1 corresponding to the head portion of the data to be transmitted, “2” as the partial data identification information for the next partial data Pd2. Included in the header of the partial data.

The space-side transmitting station apparatus 10 further performs error correction coding on each of the partial data Pdi (i = 1, 2,...) Including the unique partial data identification information and performs the encoded data Ci (i = 1, 1). 2, ...) is generated (S3). The space-side transmitting station apparatus 10 adds predetermined encoded data identification information to each partial data (data after encoding) Ci that has been subjected to error correction encoding (S4). In this example, the receiver on the ground side receiving station apparatus 20 includes serial numbers i (i = 1, 2,...) Of partial data identification information included in the partial data before encoding of the encoded data. A value obtained by dividing by the number n of 23 and adding “1” to the remainder is used as encoded data identification information. In other words, for example, if n = 10, the encoded data Ci corresponding to the partial data Pdi corresponding to the i-th portion of the data to be transmitted includes “(i mod n) as encoded data identification information. +1 ”is set. Here, i mod n means a remainder obtained by dividing i by n. The space-side transmitting station apparatus 10 includes the encoded data identification information as a header of the encoded data.

The space-side transmitting station device 10 modulates the encoded data at a predetermined radio frequency after concatenating the encoded data in the order of the partial data identification information included in the partial data before encoding, and transmits the data to the ground station side ( S5). As a result of this processing, the signal transmitted from the space-side transmitting station apparatus 10 includes the encoded data identification information (H) and the encoded partial data (B) repeatedly as illustrated in FIG. . Here, of the n receivers 23 included in the ground-side receiving station device 20, encoded data identification information, which is information indicating which receiver 23 is responsible for decoding, is included in the partial data before encoding. The partial data identification information i to be determined is determined based on the remainder when n is divided by n. Since the encoded data corresponding to the order of the partial data identification information is concatenated, each receiver 23 of the ground side receiving station apparatus 20 accepts the signal that it is responsible for only once every n times. Become. Therefore, it is sufficient that each receiver 23 of the ground side receiving station apparatus 20 operates at a bit rate n times slower than the bit rate r of data transmitted from the space side transmitting station apparatus 10. That is, each receiver 23 is not limited as long as it operates at a speed higher than the bit rate r / n, and is an extremely expensive receiver operating at a high speed (currently, the above bit rate r / n). Compared to the receiver (which is more expensive than n receivers), the ground-side receiving station device 20 can be realized by a relatively inexpensive receiver.

The ground-side receiving station apparatus 20 receives the single carrier signal transmitted from the space-side transmitting station apparatus 10, duplicates the received single carrier signal by the number n of the receivers 23, and outputs the signal to each receiver 23. . The terrestrial receiving station device 20 may convert the received single carrier signal into an intermediate frequency signal, copy it, and output it to each receiver 23.

The receiver 23 confirms that the portion of the signal including the encoded data identification information included in the duplicated input single carrier signal includes the encoded data identification information determined in advance by the receiver 23. It is checked with a sliding correlator or the like whether or not the signal is represented.

Then, when each receiver 23 detects from the single carrier signal the encoded data identification information that is determined in advance as one that it is responsible for, each receiver 23 takes in a signal for a predetermined time from the time of detection and demodulates it. Further, the data (corresponding to the encoded data) obtained by demodulation is decoded, and the partial data (including the partial data identification information) is reproduced and output.

Here, the receiver 23a demodulates and decodes the signal corresponding to the encoded data whose encoded data identification information is “1”, and the receiver 23b encodes the encoded data identification information “2”. It is assumed that a signal corresponding to post-data is demodulated / decoded. In this case, the receiver 23a outputs partial data Pd1 obtained by decoding the encoded data C1, the receiver 23b outputs partial data Pd2 obtained by decoding the encoded data C2, and so on. Thus, each receiver 23 outputs partial data one after another.

In addition, the receiver 23a receives the time when the encoded data whose encoded data identification information is “1” is input again (the time nt obtained by multiplying the time t for one encoded data by the number n of the receivers 23). After that, the signal corresponding to the post-encoding data Cn + 1 (for example, the post-encoding data C11 if n = 10) is demodulated and decoded, and the partial data Pdn + 1 is output.

Similarly, the receiver 23b also receives the time when encoded data whose encoded data identification information is “2” is input again (time obtained by multiplying the time t for one encoded data by the number n of the receiver 23). The signal corresponding to the post-encoding data Cn + 2 (for example, the post-encoding data C12 if n = 10) is demodulated and decoded again, and the partial data Pdn + 2 is output.

The ground-side receiving station device 20 refers to the partial data identification information included in the partial data Pdi (i = 1, 2,...) Output from each of the plurality of receivers 23 included in the ground side receiving station device 20, and the partial data identification information is small. Join in order. At this time, the ground side receiving station apparatus 20 deletes the partial data identification information. The ground side receiving station apparatus 20 combines the partial data in this way, thereby reproducing and outputting the original data that is the transmission target in the space side transmitting station apparatus 10.

[Example of setting receiver assignment for each data type]
In the description so far, the partial data obtained by the division is sequentially assigned to the plurality of receivers 23 of the ground-side receiving station apparatus 20 to perform demodulation and decoding. It is not limited to examples.

For example, the receiver 23 (or the set of receivers 23) of the ground-side receiving station device 20 that performs signal demodulation and data decoding may be different for each type of original data.

As an example, when the artificial satellite 2 transmits status information indicating the situation such as its own attitude, optical observation data obtained by optically imaging the ground, and radar observation data observed by a radar to one ground station side. The status information may be assigned to a specific receiver 23x.

In this case, the space-side transmitting station apparatus 10 concatenates data other than the status information (hereinafter referred to as observation data) into a series of data, and then divides and encodes the series of data into partial data. The encoded data corresponding to each partial data is obtained. Also, the space-side transmitting station apparatus 10 sets encoded data identification information for each of the encoded data so that the receivers 23 other than the receiver 23x are in charge. As an example, the serial number i (i = 1, 2,...) Of the partial data identification information included in the corresponding partial data before encoding is calculated from the number of receivers 23 included in the ground side receiving station device 20. The number obtained by subtracting (the number excluding the receiver 23x) divided by n−1 is a value obtained by adding “1” to the remainder. That is, for example, if n = 10, the encoded data identification information corresponding to the partial data Pdi corresponding to the partial data Pdi corresponding to the i-th portion of the data to be transmitted is “(i mod (n -1)) +1 "is set.

As a result, the space-side transmitting station apparatus 10 uses “1”, “2”, “n−1”, “1”, etc. as encoded data identification information in the encoded data C1, C2,. The repeated information is combined with a predetermined position such as a position corresponding to the header of the encoded data.

Further, the space-side transmitting station apparatus 10 divides the status information into partial status information having the same size as the partial data, and encodes each partial status information to obtain post-coding status information.

The space-side transmitting station apparatus 10 uses, as the encoded status information, encoded data identification information (eg, number “n”) indicating that the receiver 23 x is in charge of a predetermined position such as a position corresponding to the header. To join.

Then, the space-side transmitting station apparatus 10 generates an information sequence including the encoded data related to the observation data and the encoded status information by concatenating the encoded data and the encoded status information, Modulate with a predetermined radio frequency and transmit to the ground station side. Since the status information is generated irregularly, the space-side transmitting station apparatus 10 normally performs the encoded data related to the observation data (the encoded data identification information is “1”, “2”..., “N− 1), “1”... Are transmitted, and when the status information is generated, the encoded status information whose encoded data identification information is “n” is transmitted. It becomes. In this case, each receiver 23 of the ground side receiving station apparatus 20 is n-1 times slower than the bit rate r of the data transmitted from the space side transmitting station apparatus 10 and faster than the bit rate r / (n-1). Anything that works can be used.

Accordingly, for example, as illustrated in FIG. 8, the encoded data C1, C2,... Cn-1 (“1”, “2”,. Is encoded status information SC1 ("n" is combined as encoded data identification information) is modulated and transmitted, and subsequently encoded data Cn, Cn + 1, ... C2n-2 Next to (n-1 encoded data, each having “1”, “2”..., “N-1” as encoded data identification information combined) A single carrier signal is transmitted such that the encoded data C2n-1, C2n,... Are modulated and transmitted.

The ground-side receiving station device 20 that receives this single carrier signal duplicates the received single carrier signal by the number n of the receivers 23 and outputs the duplicated signal to each receiver 23. Again, the single carrier signal may be replicated after being converted to an intermediate frequency and output to each receiver 23.

Each receiver 23 includes the encoded data identification information that is determined in advance so that the signal of the portion including the encoded data identification information of the single carrier signal that is copied and input is included in the receiver 23. A signal for a predetermined time (a signal obtained by modulating the encoded data or the encoded status information corresponding to the encoded data identification information) is taken in from the signal representing the signal and demodulated.

Here, it is assumed that the

receivers

23a, 23b,... 23 (n-1) are in charge of demodulation and decoding of the encoded data corresponding to the encoded data identification information "1", "2", and "n-1", respectively. Further, the receiver 23x is set to be in charge of demodulation and decoding of the encoded status information corresponding to the encoded data identification information “n”.

Therefore, the receivers 23a to 23 (n-1) sequentially output partial data related to the observation data. The receiver 23x outputs partial status information related to status information one after another.

The terrestrial receiving station device 20 refers to the partial data identification information included in the partial data Pdi (i = 1, 2,...) Output from the receivers 23a to 23 (n−1), respectively. Are combined in ascending order, and the observation data is reproduced and output.

The terrestrial receiving station apparatus 20 reproduces and outputs the status information by combining only the partial status information in order of output time with respect to the partial status information output by the receiver 23x.

Furthermore, although the example in which only the status information is assigned to the single receiver 23x has been described here, as another example, the status information indicating the situation such as the attitude of the artificial satellite 2 and the ground are optically imaged. When transmitting the optical observation data and the radar observation data observed by the radar to one ground station side, the status information is assigned to a specific receiver 23x, and the optical observation data is received by the receivers 23a, b, c, and the radar observation data may be assigned to the receivers 23d, e, and so on. This setting can be performed in consideration of the data amount of each type of data, for example.

For example, when the amount of data of the second type of data is k times that of the first type of data, the number of receivers 23 that are k times higher than the number of receivers 23 in charge of the first type of data. For example, two types of data may be assigned.

In this case, the space-side transmitting station apparatus 10 concatenates each type of data into a series of data for each type of data for which the set of receivers 23 to be handled is different. Each is divided and encoded into partial data of a predetermined size (depending on the input unit of the encoding unit 33 as described above) to obtain post-encoding data corresponding to each partial data.

At this time, each partial data is set with unique partial data identification information for each series of data and for each partial data. This partial data identification information may be, for example, a serial number for each series of data.

For example, as described above, when the optical observation data is set to be in charge of the receivers 23a, b, and c, and the radar observation data is set to be in charge of the receivers 23d and e, the space-side transmitting station apparatus 10 Serial numbers “1”, “2”,... Are set as partial data identification information for partial data PId1, PId2,... Obtained by dividing optical observation data, and the partial data identification information is set to corresponding partial data PId1. , PId2...

The space-side transmitting station apparatus 10 also sets serial numbers “1”, “2”... As partial data identification information for the partial data PLd1, PLd2,. The data identification information is included as a header or the like in the corresponding partial data PLd1, PLd2,.

In this case as well, the space-side transmitting station apparatus 10 divides the status information into partial status information as in the case of the partial data, and encodes each partial status information to obtain post-coding status information.

The space-side transmitting station apparatus 10 performs predetermined encoding (error correction code) on partial data PId1, PId2,... Obtained by dividing optical observation data, and partial data PLd1, PLd2,. To generate post-encoding data.

The space-side transmitting station apparatus 10 also encodes the encoded data so that the receiver 23 included in the set sequentially performs demodulation and decoding for each set of the receivers 23 in charge of demodulation and decoding. Set identification information.

As described above, the setting of the encoded data identification information is set as an example in which the optical observation data is assigned to the receivers 23a, b, c and the radar observation data is assigned to the receivers 23d, e. An example will be described as follows. In the following description, for example, the receiver 23a is in charge of demodulation / decoding of the encoded data whose encoded data identification information is “a”, and the receiver 23b has the encoded data identification information “b”. It is assumed that the post-encoding data is demodulated / decoded in advance, and so on.

The space-side transmitting station apparatus 10 encodes the partial data PId1, PId2,... Obtained by dividing the optical observation data, and generates CI1, CI2,. Further, the space-side transmitting station apparatus 10 encodes the partial data PLd1, PLd2,... Obtained by dividing the radar observation data to generate CL1, CL2,. Then, the space-side transmitting station apparatus 10 adds the encoded data identification information “a”, “b”, “c”, “a”... To each of the partial data PId1, PId2, PId3, PId4,. The encoded data identification information for specifying the receiver 23 in charge of the optical observation data in order and repeatedly is set.

Similarly, the space-side transmitting station apparatus 10 uses the encoded data identification information “d”, “e”, “d”,... For the partial data PLd1, PLd2, PLd3,. As described above, the encoded data identification information for designating the receiver 23 in charge of demodulation / decoding of the partial data related to the radar observation data in order and repeatedly is set.

Furthermore, the space-side transmitting station apparatus 10 includes, in the encoded status information, encoded data identification information (for example, “f”) indicating that a specific receiver 23f is in charge, a position corresponding to the header, etc. , And set in a predetermined position.

Then, the space-side transmitting station apparatus 10 arranges the encoded data in the order in which the receivers 23 in charge are sequentially changed and connects them. When the status information is obtained, at that time, the encoded data string is arranged including the encoded status information and connected to each other. As a specific example, the space-side transmitting station apparatus 10 follows the partial data PId1, PId2, and PId3 in which the encoded data identification information “a”, “b”, and “c” is attached to the header, If the pieces of information “d” and “e” are connected to the partial data PLd1 and PLd2 and then status information is generated, the encoded data identification information “f” is encoded here. The post status information SC1 is linked. Then, the space-side transmitting station apparatus 10 then receives partial data PId4, PId5, and PId6 different from the above-described partial data in which the encoded data identification information “a”, “b”, and “c” is attached to the header. As shown in the figure, the encoded data and the encoded status information are repeatedly connected. The space-side transmitting station device 10 modulates the information sequence obtained by the connection with a predetermined radio frequency and transmits the modulated information sequence to the ground station side.

Here, the

receivers

23a, 23b, and 23c are set to be in charge of demodulation and decoding of the encoded data corresponding to the encoded data identification information “a”, “b”, and “c”, respectively. 23e is set to be in charge of demodulation and decoding of the encoded data corresponding to the encoded data identification information "d" and "e", respectively, and the receiver 23f is a code corresponding to the encoded data identification information "f" Since it is set to be in charge of demodulation and decoding of the status information after conversion, the ground side receiving station apparatus 20 operates as follows.

That is, the receivers 23a to 23c output partial data related to the optical observation data one after another, the receivers 23d and 23e output partial data related to the radar observation data one after another, and the receiver 23f displays the status information. The partial status information is output one after another. In any receiver 23, when the number of receivers 23 is n (here, n = 6), the bit rate R of the single carrier signal is R / (n-1) or more (status information is Since it occurs irregularly, it only needs to be demodulated and decoded at a bit rate (divided by n-1), so it can be demodulated and decoded by a relatively slow process, and it is extremely expensive and high-speed reception. There is no need to use a vessel.

The ground-side receiving station device 20 refers to the partial data identification information included in the partial data PIdi (i = 1, 2,...) Output from the receivers 23a to 23c, and combines them in ascending order of the partial data identification information. , Reproduce and output optical observation data. Similarly, the ground side receiving station apparatus 20 refers to the partial data identification information included in the partial data PLdi (i = 1, 2,...) Output from the receivers 23d and 23e, respectively, and the partial data identification information is small. Combine in order to reproduce and output radar observation data.

The terrestrial receiving station apparatus 20 reproduces and outputs the status information by combining only the partial status information in order of output time with respect to the partial status information output by the receiver 23f.

[Example of different bit error rate for each data type]
In the above example, the required bit error rate (BER) differs depending on the type of data. For example, the required BER differs significantly between radar observation data and optical observation data, and is less than 10 ⁻⁴ for radar observation data and less than 10 ^{−10 for} compressed optical observation data. Therefore, for example, if the communication quality is determined in accordance with the strictest BER (less than 10 ^{−10 in the} above two examples) in order to secure the necessary BER, the quality of some types of data becomes excessive, and the data The problem arises that the communication time and bandwidth cannot be used effectively.

Therefore, in an example of the present embodiment, the type of encoding method and the method of modulation, such as an error correction code, may be different for each type of data. In this case, when the modulation method is different, the encoded data is modulated by different modulation methods such as a common carrier wave. For example, encoded data related to optical observation data may be modulated by 32APSK (AmplitudemplPhase-Shift Keying), and encoded data related to radar observation data may be modulated by 64APSK.

At this time, the

receivers

23a, 23b, 23c, which are in charge of demodulation of the encoded data for the optical observation data, demodulate the 32APSK signal to obtain the encoded data for the optical observation data, and decode it. . Also, the receivers 23d and e in charge of demodulating the encoded data of the radar observation data demodulate the 64APSK signal to obtain the encoded data of the radar observation data and decode it.

[Example of one receiver in charge]
In the example of the present embodiment, for each data type, the receiver 23 of the terrestrial receiving station device 20 that is in charge of demodulation and decoding of the signal related to the type of data is set to a value less than the bit rate R of the single carrier signal. In addition, the ground side in charge of the demodulation and decoding of the signals related to each type of data by making the signal of a bit rate equal to or higher than the average bit rate R ′ of the type of data high enough to be demodulated and decoded. One receiver 23 of the receiving station apparatus 20 can be provided.

In this case, if the outputs of the respective receivers 23 are concatenated in order of decoding time series, they can be taken out as they are as the reproduction results of the respective types of data, so it is necessary to combine the outputs of the plurality of receivers 23 Absent.

[Effect of the embodiment]
According to the embodiment of the present invention, by dividing the data to be transmitted on the artificial satellite side, individually encoding and modulating each, and sequentially transmitting as a single carrier signal, the ground station side A signal corresponding to each partial data can be processed in a time-sharing manner using a plurality of receivers, and communication using a single carrier method can be realized while using a relatively low-speed and inexpensive receiver.

DESCRIPTION OF SYMBOLS 1 Communication system, 2 Artificial satellite, 3 facilities, 10 Space side transmission station apparatus, 11 Control part, 12 Memory | storage part, 13 Data input part, 14 Radio | wireless part, 20 Ground side receiving station apparatus, 21 Radio | wireless receiving part, 22 Divider , 23 receiver, 24 output unit, 31 receiving unit, 32 dividing unit, 33 encoding unit, 34 communication control unit.

Claims

A communication system comprising a space-side transmitting station device and a ground-side receiving station device,
The space side transmitting station device accepts data to be transmitted to one ground side receiving station device;
Dividing means for dividing the data to be transmitted into a plurality of partial data having a smaller size than the data;
Encoding means for encoding including the partial data identification information unique to each partial data obtained by the division,
Transmitting means for attaching each of the encoded partial data with predetermined encoded data identification information, connecting them to each other, and transmitting as a single carrier signal;
Have
The ground side receiving station device is
Distribution means for replicating and outputting the transmitted single carrier signal;
A plurality of receivers that accept respective inputs of a plurality of single carrier signals output by the distributing means, and each receiver is attached with encoded data identification information that it is in charge of according to a predetermined rule. A receiver that decodes the encoded partial data and outputs the partial data including the partial data identification information obtained by decoding;
Accepting partial data output by at least a part of the plurality of receivers, determining a combining method with reference to partial data identification information included in the received partial data, and using the determined method, partial data identification information A combining means for combining the deleted partial data and reproducing the data;
A communication system.
A space-side transmitting station device that transmits a single carrier signal to one ground-side receiving station device,
Receiving means for receiving data to be transmitted to one ground-side receiving station device;
Dividing means for dividing the data to be transmitted into a plurality of partial data having a smaller size than the data;
Encoding means for encoding including the partial data identification information unique to each partial data obtained by the division,
Transmitting means for attaching each of the encoded partial data with predetermined encoded data identification information, connecting them to each other, and transmitting as a single carrier signal;
A space-side transmitting station apparatus.
The partial data obtained by dividing the transmission target data from the space side transmitting station apparatus is encoded including the partial data identification information, and predetermined encoded data identification information is attached to each of the encoded partial data. Terrestrial receiving station device that receives the concatenated data as a single carrier signal,
Distribution means for replicating and outputting the received single carrier signal;
A plurality of receivers that accept respective inputs of a plurality of single carrier signals output by the distributing means, and each receiver is attached with encoded data identification information that it is in charge of according to a predetermined rule. A receiver that decodes the encoded partial data and outputs the partial data including the partial data identification information obtained by decoding;
Accepting partial data output by at least a part of the plurality of receivers, determining a combining method with reference to partial data identification information included in the received partial data, and using the determined method, partial data identification information A combining means for combining the deleted partial data and reproducing the data;
A terrestrial receiving station apparatus.
The space side transmitting station apparatus according to claim 2,
The accepting means accepts a plurality of different types of data as data to be transmitted,
The dividing means performs division into partial data so as to include predetermined types of data in the transmission target data in partial data not including other types of data,
The transmission means is a space-side transmitting station apparatus that transmits predetermined encoded data identification information to data obtained by encoding partial data including the predetermined type of data.
The space side transmitting station apparatus according to claim 2,
The accepting means accepts a plurality of different types of data as data to be transmitted,
The dividing means performs division into partial data so that different types of data are included in partial data not including other types of data, respectively.
The transmitting means uses encoded data identification information unique to each of the different types of data, and the encoded data identification information corresponding to the type of data included in the partial data is obtained by encoding the partial data. Space side transmitting station equipment that sends out
The space-side transmitting station apparatus according to claim 5,
The space-side transmitting station apparatus, wherein the encoding means encodes the partial data using an encoding method selected according to the type of data included in the partial data.
A space side transmitting station apparatus according to claim 5 or 6,
For each of the encoded partial data, the transmission means generates a signal modulated by a modulation scheme selected according to the type of data included in the partial data, and connects the signals to each other in time series. A space-side transmitter station that transmits as a single carrier signal.
It is the ground side receiving station apparatus of Claim 3, Comprising:
The space-side transmitting station apparatus includes predetermined types of data included in transmission target data in partial data that does not include other types of data, encodes the partial data including partial data identification information, Along with data encoded with partial data identification information included in partial data including types of data, data that is connected with predetermined encoded data identification information attached to each encoded partial data is transmitted as a single carrier signal. And
The ground side receiving station apparatus receives the single carrier signal,
Among the receivers, a receiver in charge of encoded data identification information attached to data obtained by encoding partial data including the predetermined type of data decodes the encoded partial data in charge. The partial data including the partial data identification information obtained by decoding is output as it is,
Among the receivers, a receiver in charge of encoded data identification information attached to data obtained by encoding partial data not including the predetermined type of data decodes the encoded partial data in charge. And outputting partial data including partial data identification information obtained by decoding to the combining means,
The combining means receives partial data output by a part of the plurality of receivers, determines a combining method with reference to partial data identification information included in the received partial data, and uses the determined method to A terrestrial receiving station device that reproduces data by combining partial data from which data identification information has been deleted.
A space side transmitting station device that sends a single carrier signal to the ground side receiving station device,
An acceptance means for accepting data to be transmitted;
Dividing means for dividing the data to be transmitted into a plurality of partial data having a smaller size than the data;
Encoding means for encoding including the partial data identification information unique to each partial data obtained by the division,
Transmitting means for attaching each of the encoded partial data with predetermined encoded data identification information, connecting them to each other, and transmitting as a single carrier signal;
Program to function as.