WO2019224894A1

WO2019224894A1 - Communication system and signal processing method

Info

Publication number: WO2019224894A1
Application number: PCT/JP2018/019563
Authority: WO
Inventors: 川口淳一郎
Original assignee: 合同会社パッチドコニックス
Priority date: 2018-05-22
Filing date: 2018-05-22
Publication date: 2019-11-28

Abstract

The present invention comprises a plurality of dispersed entities 101, 102 for wirelessly receiving an observation signal from an object F2 of observation and a broadcast entity 100 (F1) for wirelessly broadcasting, to the plurality of dispersed entities, a prescribed reference signal and a signal based on the observation signal from the object F2 of observation. Each of the dispersed entities 101, 102 has a signal processing unit for generating, from the signal based on the observation signal and the reference signal from the broadcast entity 100 (F1) and the observation signal received from the object F2 of observation, a signal that should be received by the broadcast entity 100 as an individual observation result signal not dependent on a first relative position between the dispersed entity and the broadcast entity 100 or a second relative position between the dispersed entity and the object F2 of observation. The signals generated by the signal processing units are wirelessly transmitted to the broadcast entity.

Description

Communication system and signal processing method

The present invention relates to a communication system and a signal processing method that generate and accumulate observation results based on signals generated in each of a plurality of distributed individuals that receive an observation signal from an observation target by radio.

In general, in order to receive and integrate radiated signals and transmitted signals from the observation target, the length of the optical path to the point where the light is collected from the target, in other words, collected, is strictly in the wavelength order. Must be managed. The points that are accumulated are also called focal points. This is a requirement to construct an interferometer in a broad sense if it is extended to the communication system or the wavelength of light, and if it is integrated and collected at one point in the same phase, it corresponds to constructing a telescope To do. Therefore, until now, the receiving and receiving surfaces have basically a rigid structure, and an integrated rigid body constitutes a telescope.

In recent years, interferometers that are not limited to integration and condensing but actively correct the phase of the obtained signals and synthesize them to obtain observation outputs are becoming mainstream, particularly in the radio wave region. On the other hand, the application of a retrodirective method has been progressing, in which the phase of signals from a plurality of reception points is manipulated to recursively transmit and receive signals at one point in the same phase. In particular, there is a high interest in retrodirective power transmission and reception, which is composed of a large number of multipoint moving distributed individuals such as spacecrafts and satellites. Basically, the retrodirective method is one of so-called interferometer technologies. A special application refers to processing on distributed individuals that recursively retransmits in the same phase.

Fig. 1 describes the signal generation method using a recursive directional transponder.

In FIG. 1, the original signal from the transmission source (Transmitter) is cosωt. The received signal at the transponder is

It is. Here, the receiving individual is based on this

Shall be transmitted. Here, z indicates the distance from the transponder in an arbitrary direction. That is, z = 0 indicates the position of the transponder itself.

During this transmission, the phases of the received signal and the transmitted signal are synchronized as follows.

The transmission signal y '

It becomes.

In a special case, the phase and time at the original transmission source position is the direction to return to the transmission source (Transmitter).

Because

And the same phase as the original transmission signal. This is the principle of a recursive-oriented (retrodirective) transponder.

In general, transponder received signal y

In contrast, a transmission signal (conjugate signal) in which y ′ below returns with the same phase is given.

In this method, even if the frequency to be transmitted is multiplied, it is promised that the phase of the returned signal is synchronized with the signal multiplied by the original signal. For example

It is.

When a location is at a distance x from the transmission point, the received signal there

Local transmitter output

And mix and pass through the Low Pass filter (LPF)

Get.

θ ₀ is the initial phase of the local transmitter. This indicates “backward wave”, and if you replace the variable with -z = x,

Get.

The distance to the original transmission point is x, and the arrival time of the signal is

Thus, it can be seen that the original signal is synchronized with a certain phase difference. This method is composed only of electronic circuits and is called a hardware retrodirective method.

If θ ₀ is common to all the distributedly arranged transmitters, the phases of all the distributed transmitters returning to the original can be made common and aggregated. However, the initial phase θ ₀ of each transmitter is disjoint. Even if a single θ ₀ is generated by the reference signal source and delivered by radio waves, the distance from the signal source to each dispersed individual varies, so θ ₀ is shared by all distributed transmitters. It cannot be made. Therefore, the reference signal can no longer be a reference, and this method does not solve the problem.

The time synchronization itself of the local transmitter (local oscillator) can be synchronized by transmitting it from the reference signal source with multiple waves. At this stage, there is no problem of local synchronization for the retrodirective method alone. However, the retrodirective method is still impractical because the return wave is forced to have the same frequency as the received wave. Also, in order to function as an interferometer, it is necessary to return a signal having the same phase at a frequency different from a specified reception frequency in an arbitrary direction, and the problem cannot be solved.

An example of a typical prior art described in Patent Document 1 is shown in FIG. In FIG. 2, each node is supplied with a phase reference signal (reference signal), but the method described in the specification is as the supply method:
`` To ensure an identical reference phase at each node, phase-matched transmission lines (ie, transmission lines having matched propagation delays L / v, where L is the linelength and v is the propagation velocity) transport the reference signal from the source to each array node. ”To ensure the same reference phase at each node, the phase matched transmission line (ie transmission line matched transmission delay; line length (L ) / Having a transmission speed (v)) is to transmit the reference signal from the signal source to the nodes of each array.), And a wired cable whose phase shift associated with the supply is known in advance may be used. It is a premise. Therefore, it is difficult to realize a freely flying spacecraft, which is a great restriction. Therefore, the technique of Patent Document 1 does not deal with a “compensation method for a phase related to spatial propagation of a reference signal and a reproduction / relay signal of an observation signal” as in the present invention described later.

The technique described in Patent Document 2 does not deal with conjugate phase generation but relates to a wireless charging method. As in the present invention to be described later, “reference signal and reproduction / relay signal of observation signal” It does not deal with the "phase compensation method related to spatial propagation of".

The technique described in Patent Document 3 has only one beacona as a pilot signal, and cannot compensate for a phase shift caused by a spatial distance from the reference signal generator. Thus, it does not deal with the “phase compensation method related to the spatial propagation of the reference signal and the reproduction / relay signal of the observation signal”.

The technique described in Patent Document 4 has only one pilot generator as a pilot signal. As in the present invention to be described later, “compensation of the phase related to the spatial propagation of the reference signal and the reproduction / relay signal of the observation signal” It does not deal with "law".

The technique described in Patent Document 5 has only one Communication Source as a pilot signal. As in the present invention described later, “compensation of a phase related to spatial propagation of a reference signal and a reproduction / relay signal of an observation signal” It does not deal with "law".

The technique described in Patent Document 6 has only one input to the Conjugator IV as a pilot signal. As in the present invention described later, “the reference signal and the phase related to the spatial propagation of the regenerated / relayed signal of the observation signal” It does not deal with "compensation law".

The technique described in Patent Document 7 does not deal with conjugate phase generation but relates to a wireless charging method. As in the present invention to be described later, a reference signal and a reproduction / relay signal of an observation signal are used. It does not deal with the "phase compensation method related to spatial propagation of".

The technique described in Patent Document 8 has only one beacona as a pilot signal, and cannot compensate for a phase shift caused by a spatial distance from the reference signal generator. Thus, it does not deal with the “phase compensation method related to the spatial propagation of the reference signal and the reproduction / relay signal of the observation signal”.

The technique described in Patent Document 9 has only one pilot generator as a pilot signal. As in the present invention to be described later, “the compensation of the phase related to the spatial propagation of the reference signal and the reproduction / relay signal of the observation signal” It does not deal with "law".

The technique described in Patent Document 10 has only one Communication Source as a pilot signal. As in the present invention to be described later, “compensation of the phase related to the spatial propagation of the reference signal and the reproduction / relay signal of the observation signal” It does not deal with "law".

The technique described in Patent Document 11 has only one input to the Conjugator IV as a pilot signal. As in the present invention to be described later, “the reference signal and the phase related to the spatial propagation of the observation signal reproduction / relay signal” It does not deal with "compensation law".

The system described in Patent Document 12 has a configuration in which each individual includes an optical phase synchronization mechanism. According to this system, although the problem of recursion orientation is solved, a multi-element antenna having a very large number of elements is required, and each individual is expensive, which is not practical.

The technique described in Patent Document 13 deals with a device that spreads the pilot signal to spread spectrum and accurately synchronizes the signal. As in the present invention described later, “reproduction / relay of reference signal and observation signal” It does not deal with the “phase compensation method related to signal spatial propagation”.

The technology described in Patent Document 14 deals with a system in which pilot signals are distributed to each power transmission unit by a distributor and are passed through a phase difference detection cable, but there is only one pilot signal, and the present invention described later This does not deal with the “phase compensation method related to spatial propagation of the reference signal and the reproduction / relay signal of the observation signal”.

The technique described in Patent Document 15 has only one pilot signal, and deals with a “compensation method for a phase related to spatial propagation of a reference signal and a reproduction / relay signal of an observation signal” as in the present invention described later. Not a thing.

US Patent Application Publication No. 20130002472 (Active retrodirective antenna array with a virtual beacon) U.S. Patent No. 9,900,057 (Systems and methods for assigning groups of antenas of a wireless power transmitter to different wireless power receivers, and determining effective phases to use for wirelessly transmitting power using the assigned groups of U.S. Patent No. 9,887,589 (Systems and methods for improved phase determinations in wireless power delivery environments) US Patent No. 9,356,666 (Originator andcipirecipient based transmissions in wireless communications) U.S. Patent No. 9,325,403 (Digital-retro-directive-communication-system-and-method-thereof) US Patent No. 8,072,380 (Wireless power transmission system and method) U.S. Patent No. 9,900,057 (Systems and methods for assigning groups of antenas of a wireless power transmitter to different wireless power receivers, and determining effective phases to use for wirelessly transmitting power using the assigned groups of U.S. Patent No. 9,887,589 (Systems and methods for improved phase determinations in wireless power delivery environments) US Patent No. 9,356,666 (Originator andcipirecipient based transmissions in wireless communications) U.S. Patent No. 9,325,403 (Digital-retro-directive-communication-system-and-method-thereof) US Patent No. 8,072,380 (Wireless power transmission system and method) JP 2005-328650 A (Retrodirective array antenna device and space solar power generation system using the device) JP 2005-319853 (Satellite, Earth Station) JP 2004-007932 A (Microwave Transmission System) Japanese Patent Laid-Open No. 06-327172 (Solar Power Transmission Device)

The keywords characterizing the present invention are “wireless system”, “real-time processing”, “exclusion of two-way communication”, and “realization of a communication system as an interferometer”. These simultaneous solutions are problems in the prior art.
Being “wireless” greatly reduces the difficulty of use in free-flying vehicles and moving vehicles. In the prior art, the wired system was exclusively used.
According to “real-time processing”, offline correlation processing, equipment and work can be eliminated. In conventional methods, offline processing such as correlation processing is often requested.
“Exclusion of bidirectional communication” is realized by one-way transmission from a broadcast individual. Conventional methods are often premised on the use of bidirectional communication.
By “implementing a communication system as an interferometer”, it is possible to return an in-phase signal at a frequency different from a predetermined reception frequency in an arbitrary direction. That is, it is possible to steer. This was not possible with the conventional method. The retrodirective type is only an example of realizing a communication system as the simplest interferometer. It stays at a stage where it can reply to the original signal source at the same frequency as it was received. The present invention is not necessarily recursive, and makes it possible to return a signal in the same phase at a frequency different from a predetermined reception frequency in an arbitrary designated direction.

The phase processing of signals from each of a plurality of individuals (communication devices) in a communication system as an interferometer is currently an off-run statistical method called correlation processing. Engineeringly, among many interferometer technologies, the methods related to recursive folding accumulation and collection are retrodirective, and the uncertainty of distance from the observation target is removed in real time. The method to do is being taken.

However, many problems remain in the current retrodirective method, and they are common in the space astronomy field and the surface observation field.

Typically,
1. The signal processing in each distributed individual is governed by the initial phase of the local signal source on the same individual, that is, it is difficult to manage the time between the individuals receiving accumulation and light collection.
2. The time synchronization itself can be realized on each distributed individual if signals distributed from the reference signal source are delivered at a plurality of different frequencies. However, even with the current retrodirective method, which is a typical interferometer process, for example, it is impossible to synchronize the time with respect to the observation target, in other words, to remove the uncertainty of the distance from the observation target. Only in the case of the loopback process in which the response transmission frequency matches the frequency from the target, it is only possible to cancel and eliminate the distance information for each individual target.

The point to be solved is that the phase of the signal returned by the response remains synchronized regardless of the distance from the observation target, and is accumulated in real time regardless of the distance from the reference signal source. The response from the individual, that is, the return signal is to maintain phase synchronization. As a result, the system can be configured with a wireless medium by releasing the physical restriction of requiring a cable system, that is, a cable, and the integration and condensing functions can be demonstrated in real time instead of correlation processing. Processing that depends on the information received from the observation target and reference signal source, and each distributed individual can be integrated and a condensing system can be configured (independent dispersion method), not just a simple recursive loopback, but a response It is possible to construct a group of dispersed individuals that can collect and collect light in which the return signals are specified in advance and are in the same phase.

That is, the present invention constitutes a communication system as a wireless interferometer that eliminates cables and uses radio waves, functions in real time rather than statistically, and each distributed individual receives received information. Independent distributed processing that performs processing depending only on the signal, and sends a return signal that is not necessarily recursive, and is always collected and collected in-phase to an integrated individual that is not necessarily fixed in space. A communication system that performs signal processing.

A communication system according to the present invention has a plurality of distributed individuals that wirelessly receive an observation signal from an observation target, and generates an observation result signal based on signals generated in each of the plurality of distributed individuals Receiving an observation signal from the observation target, generating a signal based on the observation signal, and broadcasting the signal based on the observation signal together with a predetermined reference signal to the plurality of distributed individuals by radio Each of the plurality of distributed individuals includes a signal based on the observation signal from the broadcast individual, the reference signal, and the observation signal received from the observation target. An individual observation result signal that does not depend on the first relative position between the individual and the broadcast individual and the second relative position between the distributed individual and the observation target should be received by the broadcast individual. A signal processing unit for generating a signal, and wirelessly transmitting the signal generated by the signal processing unit to the broadcast individual, wherein the broadcast individual receives the individual observation signal from each of the plurality of distributed individuals. As a result, an observation result signal is generated based on the received signal.

FIG. 1 is a diagram illustrating signal generation of a recursive directional transponder. FIG. 2 is a diagram showing a typical example of a conventional retrodirective method. FIG. 3 is a diagram illustrating the principle of signal processing in the communication system according to the embodiment of the present invention. FIG. 4 is a system diagram of the signal processing shown in FIG. FIG. 5 is a diagram illustrating a first configuration example of a communication system applied to observation. FIG. 6 is a diagram illustrating a second configuration example of a communication system applied to observation. FIG. 7 is a diagram illustrating a first application example of the communication system for returning a retro directive. FIG. 8 is a diagram illustrating a second application example of the communication system for returning a retro directive. FIG. 9 is a diagram illustrating the principle of signal processing in a communication system including a target individual. FIG. 10 is a system diagram of the signal processing shown in FIG. FIG. 11 is a diagram illustrating a configuration example of a communication system (including a target individual) applied to astronomical observation. FIG. 12 is a diagram illustrating a configuration example of a communication system (including target individuals) applied to real-time orbit determination of a deep space probe. FIG. 13 is a diagram showing a communication system (including target individuals) applied to astronomical observation on a hemisphere scale. FIG. 14 is a diagram for displaying a list of frequencies assigned to the deep space communication band-1. FIG. 15 is a diagram showing a list of frequencies assigned to deep space communication band-2.

A feature of the communication system according to an embodiment of the present invention is that an individual generating a reference signal to be shared has a signal from an original observation target at the same individual position in addition to the reference signal. Receiving, reproducing, relaying, and processing through the mixed / high / low-pass filter for each distributed individual. In other words, it is in “How to compensate for phase related to spatial propagation of reference signal, observation signal reproduction, and relay signal”. The communication system includes an observation target, a broadcast individual (communication device), and a plurality of distributed individuals (communication devices) used for observation scattered as a group.

The principle of signal processing in the communication system according to the embodiment of the present invention will be described with reference to FIG.

Here, the signal emitted wirelessly from the target transmission source (observation target)

Assume that φ ₀ is observation information.

For a broadcast individual F1 that broadcasts a reference signal, the signal from the signal source is

It is. _x2F1 is a relative position between the observation object F2 and the broadcast individual F1.

Becomes a signal that is transferred to each distributed individual and received. Multiplication does not require phase synchronization, and the received signal may be multiplied by product. x ₁ is the relative position between each distributed individual and broadcast individual F1 (first relative position).

The reference signal is a signal from the local oscillator (LOC)

For each distributed individual.

And received.

Similarly, the signal from the original observation target F2 is received by each distributed individual and multiplied by m.

Is obtained. x ₂ is the relative position of each distributed individual as an observation target F2 (second relative position). If a high / low-pass filter (signal processing unit) is used in each distributed individual, the phase returned to the broadcast individual F1 will eventually be

It becomes. z is a position in the direction toward the broadcast individual F1 with respect to each distributed individual.

Fig. 4 shows a system diagram of signal processing, which is the basis of this method. The signal sent from the broadcast individual F1 to each distributed individual receives the reference signal obtained by processing such as multiplication and the signal from the observation target F2 at the broadcast individual F1, and the reproduced signal is not changed. It is a signal to be relayed obtained by moving in the frequency domain such as multiplying. In addition to these, each distributed individual receives a signal from the original observation target F2. As shown in FIG. 4, each distributed individual returns a signal obtained through independent processing to the broadcast individual F1.

The above-described configuration of this communication system is a form intended to obtain a strong signal by accumulating signals received by each distributed individual in the same phase by the broadcast individual F1.
In the signal along this route, the distance and time in space are

The signal transmitted from each distributed individual and received by the broadcast individual F1 is obtained by substituting the above into the previous equation, and there can be a condition that does not depend on the direction,

It is. Independence from x1 (first relative position) indicates that it was able to synchronize with the broadcast individual F1, and independence from x2 (second relative position) means that the distance from the original observation target F2 to each distributed individual Indicates that there is no need to know. That is, this condition corresponds to collecting and condensing the signal from the original observation target F2 in the broadcast individual F1 in phase with all dispersed individuals. The broadcast individual F1 may be the original observation target direction, but the directions may be different.

p or q takes a negative value, which corresponds to the phase difference extraction processing by the Low Pass Filter. Since m can be taken freely, the final collected signal can be obtained with the original signal typically up-converted. The phase of the signal collected and collected by the broadcast individual F1 does not depend on the distance of each distributed individual from the broadcast individual F1 or the observation target F2.

It is.

Noteworthy is that this result is that not only the dependence on x1 (first relative position) but also the dependence on x2 (second relative position) can be erased and removed at the same time. With this processing, time synchronization and observation signal synchronization can be achieved in a moving body, particularly a group of satellites that fly in formation, without using a wired signal line. This means that a telescope that collects and focuses the broadcast individual F1 saddle point can be constructed.

A specific signal processing method will be described below.
Here is an example for p = 6, q = -6, m = 5. Configure the system with q '=-q / 2 = 3.

Receive signal

And

This is for broadcast individual F1 and each distributed individual

And received.

The signal that is the basis of the reference signal generated by the individual F1

And

From the broadcast individual F1, a signal relayed to each distributed individual, received by each distributed individual, and multiplied is as follows.

First, when the signal of the first term and the signal of the third term are combined and passed through the High Pass Filter (signal processing unit)

And combining the reference signal of the second term and passing through the Low Pass Filter (signal processor) twice

Get.

When a signal from each distributed individual is received by the broadcast individual F1, the distance and time in space from the original observation target F2

Therefore, the signal gathered in the broadcast individual F1 is independent of the distance (x ₂ , x ₁ ) between each distributed individual and the observation target F2 and the broadcast individual F1.

Thus, they are collected and condensed (observation results) as a 5 times-multiplied wave (individual observation result signal).

In this communication system, selection of the frequency used in the system is important.
If the condition of p + q = 0 is to be realized at once, the two types of signals transmitted from the broadcast individual F1 have the same frequency, so that each distributed individual cannot receive. To be precise, identification becomes difficult.

For this reason, p or q is broadcasted at a different frequency corresponding to the divisor, and each distributed individual side (signal processing unit) performs multiple times of synthesis and filtering to the original frequency. . Further, in the natural celestial object observation described later, for example, when the signal from the original observation target F2 is twice the frequency of the processing target, “2” should be avoided as p and q. Of course, “1” must be avoided. Specific examples are shown below.

For example, when p = 6, on each distributed individual side, the operation of q = -6 is performed twice, and the difference processing of the phase by the LowqPass Filter (signal processing unit) of q '=-q / 2 = 3 is performed twice. By doing so, it can be achieved while avoiding interference. One selection method is to select the second greatest common divisor of absolute values of p and q as q ′. m can be chosen freely, and since p + q = 0 、, the transmission frequency from each distributed individual is mω, for example, the deep space band is intentionally selected for application to planetary probes In some cases, it should be set at an appropriate frequency.

FIG. 5 shows a first configuration example of a communication system applied to observation. This first configuration example is an application example in remote sensing, which is expected to produce results in practical use. In FIG. 5, an individual 100 in a group of a plurality of distributed

individuals

100, 101, 102 is a broadcast individual F1, and this individual 100 (broadcast individual F1) is a signal from other individuals (distributed individuals) 101, 102. Are also accumulated. In this communication system, there is another individual 103 that emits a reference signal, and the observation target F2 reflects the signal wave emitted from the individual 103 and emits a reflected wave. A reflected wave is transmitted from the observation target F2 in a state where random phase noise (observation signal) is carried, and is received by each individual 100, 101, 102 of the satellite group which is a distributed individual. The individual 103 that emits the reference signal may be the same as the broadcast individual 100 (F1).

The above-described configuration example of the communication system can be used for remote sensing on the ground surface, and leads to an application in which a synthetic aperture radar is configured without a cable with a large number of satellites forming a group. Radar observation can be realized by multiple independent satellites that are independent in space.

The observation by the communication system described above can be realized only by one-way communication. That is, it is an independent distributed method that does not require bidirectional relative position measurement. As a result, it becomes possible to freely set and disperse the group of distributed individuals, and the participating individuals and the number of individuals may be unknown, which opens the way for widespread use. In addition, the amount of communication is very small and constant, no matter how the number of distributed individuals increases, and drastically reduces facilities and equipment investment in the construction of observation and communication systems composed of large groups. Can do.

In the communication system described above, distributed individuals that receive and respond are free to participate and discrete. This means, for example, that a small spacecraft is free to suddenly join the system or lose function and leave. Numerous small satellites can participate in or leave large missions.

In realizing the above-described communication system, it is not necessary to have a high-performance reception and reproduction capability for a plurality of weak radio waves. Weak signals are limited to only signals from the original observation target, etc. Especially in actual applications where the reference signal is emitted from a short-distance broadcast individual F1, there is no high requirement for receiver performance, and restrictions related to mountability There are few.

The communication system according to the embodiment of the present invention provides a communication system as an interferometer wirelessly. That is, the broadcast individual F1 that transmits the reference signal receives the signal from the same observation target F2 etc. as the distributed individual in addition to transmitting the reference signal to the individual (distributed individual) group. By transmitting and relaying within the distributed population, both the spatial distance from each distributed individual to the broadcast individual F1 that transmits the reference signal and the spatial distance to the observation target F2 are offset, and the effect is reduced. It is to eliminate.

Generally, when the reference signal is one wave, it cannot be excluded that the distance from the reference signal source, that is, the broadcast individual F1 to each distributed individual is unknown. That is, by means of one-wave radio, it is not possible to synchronize the time between each distributed individual and the broadcast individual F1 as a reference signal source. On the other hand, when the reference signal has two or more waves, it is solved that the distance from the reference signal source, that is, the broadcast individual F1 to each distributed individual is unknown, and time synchronization itself is possible. However, the distance from the observation target F2 to each distributed individual is unknown, and it cannot be excluded that it is not managed. The only technology that can be achieved at this stage is the retrodirective type recursive return reply, which leaves the problem that the return frequency matches the observed frequency.

In addition to the reference signal of one wave, the signal from the observation target etc. is received by the reference signal source, that is, the broadcast individual F1, and in addition to the transmission of the reference signal, the reference signal is transmitted and relayed. Both the unknown distance from the source broadcast individual F1 to each distributed individual and the unknown distance to each distributed individual from the observation target F2 are resolved, and the direction of the default observation target F2 In other directions, the light can be collected and condensed, that is, steered at a predetermined folding frequency, and a communication system as an interferometer can be configured. A similar configuration is possible even when there are a plurality of broadcast reference signals.

Hereinafter, actual examples (examples) that exhibit effective effects will be described.

Application example-1:
<Extended example of remote sensing observation>
In the configuration example of the communication system shown in FIG. 5, the radio wave source (individual 103) to be irradiated is only one specific individual. On the other hand, in the configuration example of the communication system shown in FIG. 6, the observation target F2 is irradiated with a signal from a group of many (a plurality of) irradiation individuals 103 (1), 103 (2), and 103 (3) satellites. The This communication system assumes a plurality of GPS satellites or the like as radio wave sources (individuals 103 (1), 103 (2), 103 (3)). This is an extension of remote sensing observation, where the ground surface that has received radar irradiation from multiple satellites becomes a virtual observation target F2, that is, a source of observation signals. In recent years, remote sensing using GNSS (navigation satellite) radio waves has emerged, which makes it possible to eliminate new irradiated individuals. There is a strong demand to receive an observation signal with a stronger intensity and with a higher resolution, that is, with a large aperture, and the present invention provides a means for securing the increase in area in real time even though it is a wireless medium. In particular, this method can be realized with one-way communication and broadcast means (broadcast individual F1), so it is possible to freely set and disperse individual satellites as distributed individuals, and there is no need for specific individual identification. This is advantageous compared to other communication systems.

<Retro directive type return example>
This is an application example to the distributed retrodirective method in which all individuals transmit toward the original observation target direction, that is, the reference signal source.

In this case, the distance and time in space along the route are

There is a condition that the signal transmitted from each distributed individual and received at the same distance from the original observation target F2 as the broadcast individual F1 does not depend on x ₁ and x _2.

It becomes.

The phase of the transmitted signal from each distributed individual on the same plane does not depend on the distance from each distributed individual F1 or F2

is there.

Specific signal processing will be described below.

Here is an example for p = 6, q = -6, m = 4.5. Configure the system with q '=-q / 2 = 3.
The uplink signal from the earth station that is the observation target F2,

And

This is for broadcast individual F1 and each distributed individual

And received.

The reference signal generated by the individual F1

And

When the reference signal of the second term is synthesized and passed through the Low Pass Filter (signal processing unit) twice, the result is

Is obtained.

Therefore, the signal gathered in the broadcast individual F1 is independent of the distance of each distributed individual to the earth (observation target F2) and the broadcast individual F1.

Then, it is transmitted in the direction of the earth (observation target F2) as 4.5 multiplied wave (individual observation result signal).

Through the processing described above, it is possible for a group of satellites flying in formation to form a single large antenna and primary mirror, and transmit to the Earth with increased intensity in phase without using a wired signal line. Become. For example, the transmitter and the antenna group arranged on the non-rigid film surface do not need to be coherent transponders individually, and data can be transmitted back to the earth with high gain. This corresponds to a communication application in which recursion is to be ensured, and corresponds to an example in which a large high-gain antenna is configured with a large number of independent child transponders in space.

Similarly, a system free from a distribution mechanism such as a cable can be provided when energy transmission is performed in a solar power generation satellite or the like. The present invention can be applied not only to communication but also to a case where individual flying satellites transmit power individually, and solar power generation satellites can eliminate the process of collecting individual generated power.

各 Each distributed individual is not necessarily limited to an application in which free flight is performed. As described above, when many small transponders are arranged on the film surface, the physical position and distance are generally known, but the same phase in communication cannot be guaranteed, or it varies from moment to moment. If it is possible, it will be an effective application example.

FIG. 7 shows that the distributed

individuals

101, 102, 103, 104, and 105 that have received the signal of the marker station to be observed placed on the ground E by the above-described method are the reference signal and the individual 100 from the broadcast individual 100. The example of the communication system which receives the signal which relayed the signal from the received marker station, and sends it back in phase with the marker station is shown. Two uncertainties for the broadcast individual 100 at the positions of the distributed

individuals

101, 102, 103, 104, and 105 and the uncertainty for the marker station are eliminated simultaneously.

This method can be applied to a deep space probe when a large antenna is composed of distributed individuals. FIG. 8 shows an application in a spacecraft having a film surface structure in which it is difficult to construct one large primary mirror, for example. The group of distributed

individuals

101, 102, 103, 104, and 105 on the membrane surface S uses the present method to determine the uncertainty of the position of the distributed

individuals

101, 102, 103, 104, and 105 with respect to the broadcast individual 100 and the ground. This is an example in which two uncertainties with respect to the station E are eliminated at the same time and function as a single large mirror. In the group of distributed

individuals

101, 102, 103, 104, and 105 on the film surface S, it is also possible to perform broadcast transmission from the broadcast individual 100 to each distributed individual by wire.

In the deep space band, in the x-band Uplink zone, a retrodirective-type reference signal is sent from the earth station to the spacecraft. With down link 信号, you can generate a phase-matched signal at the earth station. That is, a retrodirective antenna can be configured.

Tables 1 and 2 shown in FIGS. 14 and 15 list related frequency assignments internationally assigned for deep space communication. It can be confirmed that this retrodirective downlink return is actually possible.

Application example-2:
In the above-described communication system example (application example-1), three types of individuals are included: the observation object F2, the broadcast individual F1, and a plurality of distributed individuals participating in the observation. Next, a case where a target individual is newly introduced and the communication system is configured by four types of individuals will be described.

Referring to FIG. 9, a method for processing a signal obtained by down-converting a signal of a certain band with high randomness of a natural celestial body at a frequency of 1/2 by a target satellite will be described first.

The target signal has large phase fluctuations and noise, and it is difficult to receive it with coherency maintained. Here, the frequency of the original observation information is set to 2ω. Assume that the target individual F2, which is an artificial signal source, is placed in the direction of the observation target. Thereby, it is possible to avoid interference with signals from the original observation target.

Express the signal from the observation object etc. with the phase φ ₀ as the observation information,

And

At this time, the target individual F2

At each distributed individual in the group, with its own local transmitter

To obtain a down-converted signal.

In each distributed individual, the following are obtained as signals from the target individual F2 and the observation target.

When these products are detected and passed through the Low Pass Filter (signal processor)

Get.

The phase of the second term, the third term and the fourth term in parentheses is a signal that can be shared or broadcast within the group. After all, when viewed from each distributed individual, As if the signal was

It can be assumed that

Therefore, it is not necessary to treat the frequency of the object to be observed as 2ω, which is essentially equivalent to receiving a signal of ω. In general, as long as stable transmission is performed, an arbitrary real number x times xω may be assumed.

The main purpose of providing a signal source for the target individual F2 is to supplement the phase stability of the signal of the observation target itself. For example, when the observation target is a distant galaxy, it is distributed in a broad spectrum, in other words, the phase is unstablely distributed. When the broadcast individual F1 relays the signal from the observation target, the original signal with a very wide bandwidth and the clear center frequency cannot be displayed on the broadcast individual F1, and retransmitted. That is, it is not easy to perform the replayed relay. This causes the same difficulty even when phase processing is performed on signals from observation targets on distributed individuals. By providing the target individual F2 or target satellite, the signal from the observation target is shifted to a stable intermediate frequency range, and the signal from the observation target is converted into phase information distributed around a stable transmission spectrum. This corresponds to providing observation targets.

The broadcast individual F1 can receive in synchronization with the phase of a clear center frequency, and can simultaneously relay the surrounding phase information. The phase operation on the distributed individuals can also be performed assuming that the observation signal is signal processing from this virtual observation target (target individual F2). Since the signal from the target individual F2 is reproduced and relayed by the broadcast individual F1, the distance information between the target individual F2 and the broadcast individual F1 can be reflected. It is important that the uncertainty of the distance between the individual F2 and each distributed individual can be removed, and it is not just a transition of the frequency range. This means that a virtual communication / observation plane perpendicular to the line connecting the target individual F2 and the broadcast individual F1 is constructed.

Since (observation wavelength / baseline length) gives the angular resolution of the observation system (communication system), the distance at which the target individual F2 is placed is the distance of this (length scale / angular resolution at which the communication and observation system is deployed) It must be above. Even in a group satellite system in orbit around the earth, the distance to the target individual F2 in some cases is well comparable to the Earth's attractive range.

Target target F2 is not limited to artificial celestial bodies. It is not easy in terms of cost to arrange the artificial celestial body far enough. Applications where the background radio celestial body plays the role of the target individual F2 are promising, especially in communication and observation systems that use distributed individuals with long base lines, such as intercontinental and earth-hemisphere scales. It must be a radio celestial object at infinity.

In FIG. 9, by simultaneously receiving signals from the observation target and the target individual F2 by the broadcast individual F1 and the distributed individual, the observation target and the target individual F2 can be identified as one observation target. it can. As a result, the discussion in the communication system composed of the three types of individuals described above can be directly applied to the communication system to which the target individual F2 is added.

FIG. 10 shows a system diagram of signal processing when the target individual F2 is introduced and implemented, and FIG. 11 shows a typical configuration example of a communication system composed of four types of individuals including the target individual F2. .

The broadcast individual 100 (F1) and the distributed

individuals

101 and 102 receive signals from the observation target and the target individual 110 and process them as if they were signals from one observation target. In this example, a plurality of satellites as a plurality of distributed

individuals

101 and 102 perform astronomical observation.

As an example of VLBI observation constructed on the ground, for example, when observing 30 GHz (wavelength is 1 cm) in kilometers, the spatial resolution obtained is 10 ^ -5 radians. Therefore, in a group satellite observation system (communication system) of the same scale, when the target individual 110 is artificially provided, if the individual individual 110 is placed at a distance of 10 ^ 5 km or more, the spatial resolution is maintained and You can build an interferometer that works in time. Of course, it is further advantageous in terms of resolution that the target individual 110 is an infinite radio wave object. By using the target individual 110 as an artificial satellite or the like, it will be possible to expand the degree of freedom in selecting the direction of the observation target. In the 300 GHz band (wavelength 1 mm), a real-time interferometer can be constructed by placing the target at 10 ^ 6 km10, that is, near the Lagrange point of the solar-earth system.

FIG. 12 shows a configuration example of a communication system (including a target individual) applied to real-time orbit determination of a deep space probe.

The ground station F2 across continents receives signals from deep space probes from the earth's hemisphere. In the prior art, in order to ensure time synchronization between ground stations, atomic clocks placed on the ground stations and time signals supplied from navigation satellites are used, and the geographical position of each ground station is also used. In order to eliminate uncertainty, radio sources with a stable background and radio celestial bodies have been used. As time synchronization means and reference signal generation means, signals from these stationary or high altitude satellites can be used. It is an effective method to use a satellite that stays at a high altitude with a very long visible time, such as a geostationary satellite that can be simultaneously visible from the ground station F2 on the hemisphere. As for the uncertainty of the position of the ground station that is each of the dispersed

individuals

101 and 102, as provided by the present invention, the above-mentioned stationary or high altitude is obtained using astronomical radio waves such as a stable radio source of the background that is the target individual F2. Uncertainty can be removed by broadcasting the signal received by the satellite together with the reference signal to the ground stations as the distributed

individuals

101 and 102. According to the communication system having such a configuration, the uncertainty of the position of the deep space probe in addition to the uncertainty of the position of each ground station is also based on the signal received by each ground station as the distributed

individuals

101 and 102. Retransmitted and aggregated in phase with the above-mentioned geostationary or high altitude satellite (broadcast individual 100).

For the purpose of orbit determination, on the above-mentioned geostationary or high-altitude satellites, the distance, declination and red longitude values of the target deep space probe in advance orbital elements or geocentric systems are calculated. Originally, the phase of the signal to be broadcast is artificially manipulated, and the combined signal obtained from each ground station by the above-mentioned geostationary or high altitude satellites has the maximum intensity, orbital element or geocentric system The trajectory is determined by calculating the distance, declination, and red longitude As a secondary effect, the mirror surface areas of a plurality of ground stations are combined, so an improvement in reception performance itself is also expected.

FIG. 13 shows a communication system (including a target individual) applied to hemispherical astronomical observation as an example of physical observation. In this example, space VLBI observation is performed, which consists of a group of ground stations including spacecraft. The method is similar to the method in the deep space probe orbit determination in FIG. Target individual F2 should be a radio celestial object at infinity. The obtained observation signals are retransmitted from the terrestrial radio telescope and the space telescope, which are the dispersed

individuals

101 and 102, and can be collected and collected in the same phase by a stationary or high altitude satellite (a window individual 100).

The effect of the communication system described above can be directly exhibited when a spacecraft such as an artificial satellite or a spacecraft is used as a group. What can be achieved with this communication system, regardless of the individual positions of the group satellites,
・ Be able to carry out observations of observation objects with a large number of individuals,
・ Up to now, it is possible to improve the light gathering power, which has been limited by a single mirror or plate-shaped light receiving and receiving means, by integrating with many dispersed individual satellites. The high-efficiency, narrow-field transmission means provided by the antennas can be realized with a large number of individuals that are not necessarily position-controlled,
It is.

The group of dispersed individuals may be distributed over a wide area, and any individual spacecraft can participate, such as a spacecraft that exists on a global scale, that is, on the hemisphere on the ground surface, or in the vicinity of the same hemisphere. is there. In such a case, geostationary satellites can be assumed as useful broadcast individuals F2 or aggregate individuals. Of course, depending on the observation target, as a useful target individual F2, a geostationary satellite or a satellite with a high altitude at a far point that can cover the hemisphere for a long time can be assumed.

In each communication system described above, each signal transmitted and received may generally be an electromagnetic wave including light or may be a sound wave.

Further, the present invention is not limited to the above-described embodiments, various examples, modified examples, and application examples. Various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

The present invention changes the fixed concept of centralized control and proposes that a large number of distributed individuals perform independent distributed processing for a certain common purpose. It can be applied in a wide range of applications, from scientific astronomical observation to engineering technology such as ultra-long-distance communications, and further to remote sensing observation as industrial technology. Applications can be expected in a wide range of industries.
If the synchronism of a large number of radars is established in accordance with the present invention, there will be no influence on the industry, such as fine weather information that could not be obtained with a conventional single mirror.

Claims

A communication system having a plurality of distributed individuals that wirelessly receive observation signals from an observation target, and generating an observation result signal based on signals generated in each of the plurality of distributed individuals,
Broadcast that receives an observation signal from the observation target, generates a signal based on the observation signal, and broadcasts the signal based on the observation signal to the plurality of distributed individuals together with a predetermined reference signal Have an individual,
Each of the plurality of distributed individuals is
From the signal based on the observation signal from the broadcast individual and the reference signal, and the observation signal received from the observation target, a first relative position between the distributed individual and the broadcast individual, the distributed individual, and the A signal processing unit that generates a signal to be received by the broadcast individual as an individual observation result signal independent of the second relative position with respect to the observation target; and the signal generated by the signal processing unit is wireless Sent to the broadcast individual,
The broadcast individual generates an observation result signal based on the signal received as the individual observation signal from each of the plurality of distributed individuals.
The communication system according to claim 1, wherein the broadcast individual is one of the plurality of distributed individuals.
The communication system according to claim 1 or 2, further comprising a target individual arranged in the direction of the observation target and transmitting a signal as the observation signal to each of the plurality of distributed individuals and the broadcast individual.
The communication system according to claim 3, wherein the signal transmitted as the observation signal from the target individual is a signal having a frequency of an integer fraction or a rational number ratio of the frequency of the observation signal from the observation target.
At least one of the broadcast individual and the plurality of distributed individuals is a geostationary satellite or a satellite that stays at a high altitude that can cover the earth hemisphere for a long time. The communication system described.
The communication system according to any one of claims 1 to 5, wherein a signal transmitted from the broadcast individual to each of the plurality of distributed individuals includes a signal of three or more waves.
The signal transmitted from the broadcast individual to each of the plurality of distributed individuals is composed of a plurality of discrete or continuous spectrum waves obtained by combining a plurality of waves. A communication system according to claim 1.
The communication system according to any one of claims 1 to 7, wherein the signal is a sound wave or light.
A plurality of distributed individuals that wirelessly receive observation signals from the observation target, and a broadcast individual that receives the observation signals from the observation target wirelessly and can broadcast to the plurality of distributed individuals. A signal processing method in a communication system, comprising:
The broadcast individual receives an observation signal from the observation target, generates a signal based on the observation signal, and wirelessly transmits the signal based on the observation signal to the plurality of distributed individuals together with a predetermined reference signal. A first step of broadcasting,
Each of the plurality of distributed individuals is
From the signal based on the observation signal from the broadcast individual and the reference signal, and the observation signal received from the observation target, a first relative position between the distributed individual and the broadcast individual and the distributed individual A second signal that is to be received by the broadcast individual as an individual observation result signal independent of the second relative position with respect to the observation target is generated, and the generated signal is transmitted to the broadcast individual by radio. Steps,
The signal processing method, wherein the broadcast individual generates an observation result signal based on the signal received as the individual observation signal from each of the plurality of distributed individuals.
The communication system is arranged in the direction of the observation target, and has a target individual that transmits a signal as the observation signal to each of the plurality of distributed individuals and the broadcast individual,
In the first step, the broadcast individual receives a signal from the target individual as the observation signal,
The signal processing method according to claim 9, wherein each of the plurality of distributed individuals receives a signal from the target individual as the observation signal.
11. The signal processing method according to claim 10, wherein the signal transmitted as the observation signal from the target individual is a signal having a frequency of an integer fraction or a rational number ratio of the frequency of the observation signal from the observation target.