JP2019114825A - Communication performance prediction system - Google Patents

Abstract

To provide a technique that predicts communication performance in optical space communication with improved accuracy.SOLUTION: A communication performance prediction device of the present invention includes processing means that records a communication record including a first communication performance which is performance of a first optical space communication performed between a first mobile body and a ground station, obtains communication setting which is setting of a second optical space communication performed between a second mobile body and the ground station, and predicts a second communication performance which is performance of the second optical space communication on the basis of the communication record and the communication setting.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a communication performance prediction apparatus and communication performance prediction method related to channel quality prediction technology in an optical space communication system.

  In recent years, with the increase in the number of satellites and the advancement of remote sensing technology, it is required to increase the capacity of communication between satellites and ground stations. Optical space communication is expected as a technology for realizing large-capacity communication between satellites and ground stations. In optical space communication between satellites and ground stations, communication performance changes due to the effects of "clouds" and "atmospheric fluctuations". Clouds cause the signal light to be greatly attenuated, which causes deterioration in communication quality and blocking of communication. In addition, atmospheric fluctuations cause changes in communication performance with a short cycle of about millisecond. Communication performance changes due to atmospheric fluctuations largely depend on "the satellite's elevation angle seen from the ground station" and "the state of the atmosphere". And, unlike clouds, atmospheric fluctuations can not predict the impact on communication visually.

  On the other hand, in a satellite constellation in which a large number of observation satellites are arranged around the earth, each satellite is required to quickly transfer measured data to the ground station and prepare for acquisition of the next observation data. Therefore, the ground station needs to perform large-capacity communication with a large number of satellites. In order to efficiently transfer data between a large number of satellites and a small number of ground stations, it is necessary to efficiently allocate limited ground station communication resources to the communication with satellites. And, for efficient allocation of communication resources, it is preferable that the communication performance between the satellite and the ground station and the time change thereof can be grasped in advance.

  In connection with this invention, patent document 1 discloses the communication performance prediction method which grasps a rain cloud and a rainfall area in communication between a satellite and a ground station using microwaves.

Japanese Patent Application Laid-Open No. 10-190550

  As described above, in optical space communication between a satellite and a ground station, attenuation of light by clouds and atmospheric fluctuation change communication performance mainly. When the technology of Patent Document 1 is applied to optical space communication between a satellite and a ground station, it is possible to predict blocking of communication due to clouds. However, since the technology of Patent Document 1 can not detect the atmospheric fluctuation intensity, the change in communication performance due to the atmospheric fluctuation can not be predicted. In optical space communication, since the influence of atmospheric fluctuation on communication performance is large, it is difficult to predict communication performance in optical space communication between a satellite and a ground station according to the technique described in Patent Document 1.

(Object of the Invention)
An object of the present invention is to provide a technique for more accurately predicting communication performance in optical space communication.

  A communication performance prediction apparatus according to the present invention records a communication record including a first communication performance, which is a performance of a first optical space communication performed between a first mobile unit and a ground station, and performs a second movement. Acquiring a communication setting which is a setting of a second optical space communication performed between a body and the ground station, and a second communication performance which is a performance of the second optical space communication, the communication record and the communication It comprises processing means for predicting based on the setting.

The communication performance prediction method of the present invention acquires a communication record including a first communication performance that is a performance of a first optical space communication performed between a first mobile unit and a ground station,
Acquiring a communication setting that is a setting of a second optical space communication performed between a second mobile unit and the ground station;
The second communication performance, which is the performance of the second optical space communication, is predicted based on the communication record and the communication setting.

  The communication performance prediction apparatus of the present invention can more accurately predict the time change of the communication performance between the satellite and the ground station.

It is a figure explaining the example of composition of communication performance prediction system 10 of a 1st embodiment. It is a block diagram showing an example of composition of ground station G11 of a 1st embodiment. FIG. 2 is a block diagram showing a configuration example of a communication performance prediction device 100. 5 is a flowchart illustrating an example of an operation procedure of the communication performance prediction device 100. It is a flowchart which shows the modification of the operation | movement procedure of the communication performance prediction apparatus 100. FIG. It is a figure which shows the example of the communication performance prediction system 20 of 2nd Embodiment. It is a block diagram which shows the structural example of ground station G21. FIG. 2 is a block diagram showing a configuration example of a communication performance prediction device 200. It is a figure showing an example of distribution of change of intensity of receiving light. It is a figure explaining the example of the procedure which calculates | requires atmospheric fluctuation intensity. 7 is a flowchart illustrating an example of an operation procedure of the communication performance prediction device 200. It is a block diagram which shows the example of the communication performance prediction system 30 of 3rd Embodiment. It is a block diagram which shows the structural example of ground station G31. FIG. 6 is a block diagram showing an example of configuration of a communication performance prediction device 300. 7 is a flowchart illustrating an example of an operation procedure of the communication performance prediction device 300. It is a figure explaining the modification of communication performance prediction system 30. As shown in FIG. It is a flow chart which shows an example of a prediction procedure of communication performance of a 4th embodiment.

  Embodiments of the present invention will be described in detail below with reference to the drawings.

First Embodiment
FIG. 1 is a diagram for explaining a configuration example of a communication performance prediction system 10 according to a first embodiment of this invention. The communication performance prediction system 10 includes a ground station G11 and satellites S12 and S13. The ground station G11 is installed on the ground, and performs two-way optical space communication with the satellites S12 and S13 using the optical transmission / reception device. The satellites S12 and S13 are satellites that move on the orbit B15 on the celestial sphere 19 and include optical transceivers for communicating with the ground station G11. The satellite S13 moves on the trajectory B15 following the satellite S12 as viewed from the ground station G11.

  The angle at which the satellite looks up from the ground station is called the elevation. The ground station G11 first communicates with the satellite S12, and after communication with the satellite S12 is completed, communicates with the subsequent satellite S13 and the satellite 12 at substantially the same elevation angle. Since the satellites S12 and S13 move also during communication with the ground station G11, the elevation angle of each satellite changes also during communication. Therefore, the range of elevation angle of the satellite S12 when the ground station G11 communicates with the satellite S12 and the range of elevation angle of the satellite S13 when the ground station G11 communicates with the satellite S13 are approximately equal. However, the communication time between the satellites S12 and S13 and the ground station G11 changes due to the difference in the communication amount and the communication condition, so the elevation angle range is not necessarily the same.

  In this embodiment, based on the communication result between the satellite S12 and the ground station G11, the performance in communication between the satellite S13 moving on the same orbit B15 as the satellite S12 and the ground station G11 is predicted. Ru. In the present embodiment, the satellite S12 may be referred to as the leading satellite S12, and the satellite S13 may be referred to as the prediction target satellite S13.

  FIG. 2 is a block diagram showing a configuration example of the ground station G11 according to the first embodiment of this invention. The ground station G11 includes an antenna 103, an optical transmission / reception device 104, and a communication performance prediction device 100. The antenna 103 is an optical transmitting / receiving antenna provided with a tracking function for the satellites S12 and S13, and is configured of, for example, a lens and a reflecting mirror. The optical transceiver 104 is an optical transceiver that includes an optical transmitter and an optical receiver. The optical transmission / reception device 104 may include an antenna. The optical transmission / reception device 104 inputs / outputs an optical signal including transmission data transmitted between the satellites S12 and S13 to / from the antenna 103, and inputs / outputs an electric signal including the transmission data to / from the communication device 105. . Also, the optical transmission / reception device 104 outputs a communication record, which is data at the time of communication with the satellite S12, to the communication performance prediction device 100.

  The communication performance prediction apparatus 100 calculates a communication performance prediction value based on the communication record acquired from the optical transmission / reception device 104, and outputs the calculated communication performance prediction value to the communication device 105. The communication device 105 transmits and receives transmission data to and from the optical transmission / reception device 104, and processes the communication performance prediction value acquired from the communication performance prediction device 100. Although the communication device 105 of this embodiment is connected to the outside of the ground station G11, the communication device 105 may be provided inside the ground station G11.

  FIG. 3 is a block diagram showing an exemplary configuration of the communication performance prediction apparatus 100 according to the first embodiment of this invention. The communication performance prediction apparatus 100 includes a first processing unit 101 and a second processing unit 102. The first processing unit 101 records, as a communication record, the time change of the communication performance and elevation angle of the leading satellite S12 and the time change of the position of the cloud on the transmission path at that time. The position of the cloud is acquired, for example, from imaging data of an all-sky camera on the ground connected to the ground station G11. The imaging data includes information of the position of the cloud on the sky at the imaging time.

  The communication performance is a value of a performance index such as throughput and packet error rate of communication between the preceding satellite S12 or the satellite S13 for prediction and the ground station G11, but is not limited to a specific index. Hereinafter, the communication performance indicating the communication result between the preceding satellite S12 and the ground station G11 is referred to as "the communication performance of the preceding satellite S12", and the communication performance in the communication between the prediction target satellite S13 and the ground station G11 is The predicted value is referred to as "the communication performance of the satellite S13 to be predicted". The communication record of the leading satellite S12 may be notified to the ground station G11 by the leading satellite S12, and the ground station G11 may record changes in communication performance and elevation angle when communicating with the leading satellite S12.

  Note that the communication performance of the preceding satellite can be referred to as "first communication performance", and the communication performance of the prediction target satellite can be referred to as "second communication performance". In addition, satellites other than the satellite targeted for prediction, such as the preceding satellite S12, can be called "first mobile", and communication between the first mobile and the ground station is "first optical space communication". It can be called. Also, the prediction target satellite can be called a "second mobile unit", and the communication between the second mobile unit and the ground station G11 can be called a "second optical space communication".

  The first processing unit 101 further predicts the temporal change of the cloud concentration on the propagation path of the light signal at the time of communication between the prediction target satellite S13 and the ground station G11. The temporal change of the cloud concentration on the propagation path can be predicted based on imaging data of a plurality of times, the position of the prediction target satellite S13 when communicating with the ground station G11, and the position of the ground station G11. For example, the position of the cloud at the communication time between the prediction target satellite S13 and the ground station G11 is predicted based on the movement amount and the movement direction of the cloud at the time of communication between the preceding satellite S12 and the ground station G11. Then, the cloud concentration may be obtained on a straight line connecting the ground station G11 and the prediction target satellite S13 (that is, the propagation path of the light signal). However, the procedure for obtaining the temporal change of the cloud concentration on the propagation path of the light signal when the prediction target satellite S13 and the ground station G11 communicate with each other is not limited to this.

  Furthermore, the first processing unit 101 predicts the time change of the communication performance of the prediction target satellite S13. The first processing unit 101 records the communication performance of the preceding satellite S12 together with the change of the elevation angle of the preceding satellite S12. At the time of processing of the first processing unit 101, the setting of the optical transmission / reception device 104 when the preceding satellite S12 communicates with the ground station G11, and the light transmission / reception when the prediction target satellite S13 communicates with the ground station G11 It is assumed that the setting of the device 104 is the same. If the communication performance by the cloud is the same at the time of communication between the leading satellite S12 and the ground station G11 and at the time of communication between the prediction target satellite S13 and the ground station G11, the communication performance of the prediction target satellite S13 is estimated as a predicted value. The communication performance of the leading satellite S12 can be used.

  The prediction procedure to the communication performance of the satellite S13 to be predicted due to the influence of clouds will be described. Errors in the communication between the satellite S13 to be predicted and the ground station G11 by finding the relationship between the cloud concentration and the change in communication performance (for example, error rate) based on experiments and actual measured values of communication performance in the past You can predict the rate of change. The communication performance may be measured on either side of the ground station G11 and the preceding satellite S12.

  For example, when the preceding satellite S12 communicates with the ground station G11, it is assumed that a cloud with a density N1 exists on the propagation path of the light signal and a cloud with a density N2 exists during the communication between the prediction target satellite S13 and the ground station G11. Suppose that it is predicted. Here, it is assumed that 0 <N1 <N2. The imaging data of the cloud by visible light can be used to determine the density of the cloud. In a general visible light black-and-white cloud image, the darker the white, the darker the cloud (ie, the thicker the cloud). Here, if it is known that the data error rate becomes M times as the cloud density changes from N1 to N2 on the gray scale, the data error also occurs during communication between the satellite S13 for prediction and the ground station G11. It can be expected that the rate will deteriorate M times. If the movement of the cloud is fast, the concentration of the cloud may be predicted at a plurality of times, and the temporal change in communication performance may be obtained as the concentration of the cloud changes. More simply, it is predicted that communication will not be possible in a period in which the presence of a cloud of a predetermined concentration or more is predicted on the propagation path of the optical signal within the period of communication between the prediction target satellite S13 and the ground station G11. Good. The first processing unit 101 outputs, to the second processing unit, a prediction result in which the influence of the cloud obtained in the above-described procedure is reflected on the communication performance of the preceding satellite S12.

  The second processing unit 102 reflects the difference between the setting of the preceding satellite S12 and the setting of the prediction target satellite S13 on the communication performance of the preceding satellite S12 and the prediction result based on the cloud image obtained by the first processing unit The communication performance of the target satellite S13 is predicted. That is, the second processing unit 102 corrects the prediction result input from the first processing unit 101 based on the difference between the setting information of the communication device of the preceding satellite S12 and the setting information of the communication device of the prediction target satellite S13. .

  The communication device is mounted on the leading satellite S12, the prediction target satellite S13, and the ground station G11, and is used for the communication between the leading satellite S12 and the ground station G11 and for the communication between the prediction target satellite S13 and the ground station G11. However, these communication devices may be different from one another. The communication device comprises an optical transmitter, an optical receiver, an optical system of light beams (e.g. an optical telescope). The communication devices of the ground station G11 are an antenna 103 and an optical transmission / reception device 104.

  The setting information of the communication device is a parameter of the communication device that contributes to the light intensity at the time of reception other than atmospheric fluctuation and clouds. The setting information includes, for example, the intensity of the transmission light of the satellites S12 and S13 and the ground station G11, the transmission beam divergence angle of the transmission light, the dispersion of the characteristics of the optical system, the sensitivity of the optical receiver (optical reception sensitivity), the optical signal There are modulation schemes and coding schemes. Depending on the setting information of these communication devices, the communication performance (ie, throughput and packet error rate, for example) of the optical space communication changes.

It is possible to know in advance the communication performance in the case where the setting of the communication devices of each satellite and the ground station G11 is different between the communication of the leading satellite S12 and the communication of the prediction target satellite S13. For example, the influence can be known by measurement using a simulation or an optical transceiver provided with communication devices in the same setting as the satellite and the ground station. Therefore, the influence on the communication performance due to the difference in the setting of the communication device between the preceding satellite S12 and the prediction target satellite S13 can be added to the prediction result obtained in the first processing unit 101. As a result, it is possible to reflect the influence of the cloud and the difference in the setting of the communication device in the prediction of the communication performance of the prediction target satellite S13. The setting information of the communication devices of the satellites S12 and S13 may be previously input to the ground station G11 by a maintenance person, and the ground station G11 may be acquired from these satellites when communicating with the satellites S12 and S13. The second processing unit 102 acquires the settings of the preceding satellite S12, the prediction target satellite S13, and the communication device of the ground station G11 prior to the prediction of the communication performance of the prediction target satellite S13. FIG. 4 shows the operation of the communication performance prediction apparatus 100. It is a flowchart which shows the example of a procedure. The first processing unit 101 acquires a time change of communication performance during communication between the preceding satellite S12 and the ground station G11 (step S011 in FIG. 3), and acquires the position and movement of the cloud on the transmission path at that time. (Step S012). Then, the first processing unit 101 predicts the cloud concentration on the propagation path of the optical signal at the time of communication between the prediction target satellite S13 and the ground station G11 (step S013). The presence or absence of a cloud may include information on the concentration of the cloud. Furthermore, the first processing unit 101 predicts the time change of the communication performance reflecting the movement of the position of the cloud at the time of the communication between the prediction target satellite S13 and the ground station G11 (step S014).

  The second processing unit 102 acquires settings of the preceding satellite S12, the prediction target satellite S13, and the communication device of the ground station G11 (step S015). The second processing unit 102 changes the time change of the communication performance in the communication between the prediction target satellite and the ground station G11 by the influence on the communication performance due to the difference in the setting of the communication device between the preceding satellite and the prediction target satellite. It compensates (step S016). Furthermore, the second processing unit 102 predicts the time change of the communication performance of the prediction target satellite (step S017). The prediction result of the time change of communication performance is output to the communication apparatus 105 as a communication performance prediction value.

  As described above, the communication performance prediction apparatus 100 according to the present embodiment predicts the cloud position at the time of communication of the preceding satellite and the cloud at the time of communication of the prediction target satellite with respect to the time change of the communication performance of the preceding satellite. Implement compensation that takes into account differences in position and individual differences in communication devices from satellite to satellite. As a result, it is possible to more accurately predict the time change of the communication performance in the prediction target satellite.

  The communication device 105 sets communication devices for the ground station G11 and the satellite S13 to be predicted based on the communication performance prediction value output by the communication performance prediction device 100. For example, it is assumed that the communication performance of the prediction target satellite S13 is expected to be lower than that of the preceding satellite S12. In such a case, the communication device 105 increases the transmission power of the optical signal transmitted by the ground station G11 and the prediction target satellite S13 when communicating with the prediction target satellite S13. The setting of the optical transmitter of the station G11 may be changed. Alternatively, the transmission rate may be reduced, and a modulation method or coding method with higher error tolerance may be employed.

  In the present embodiment, a cloud is described as an example of the shield of the light signal, but the shield is not limited to the cloud. For example, the same procedure can be used to predict the effects of volcanic fumes.

  Generally, in optical space communication between a satellite and a ground station, the communication performance changes significantly depending on the elevation angle of the satellite to be communicated due to atmospheric fluctuation. On the other hand, in the present embodiment, since the preceding satellite and the prediction target satellite are on the same satellite orbit, the communication record of the preceding satellite can be recorded with the prediction target satellite in almost the same (approximately the same) elevation angle. As a result, the communication performance of the prediction target satellite can be predicted based on the atmospheric fluctuation intensity close to the state at the time of communication of the prediction target satellite. Note that the communication record of the preceding satellite may be used, which is measured in a time zone in which the statistical nature of the atmospheric fluctuation can be regarded as substantially the same as the time of communication between the prediction target satellite S13 and the ground station G11. In this case, the influence of atmospheric fluctuation at the time of communication between the prediction target satellite S13 and the ground station G11 can be preferably reflected by the prediction result of the communication performance.

  As described above, the communication performance prediction apparatus 100 according to the first embodiment can reflect the influence of clouds and the influence of atmospheric fluctuation on the communication performance between a satellite and a ground station. As a result, it is possible to more accurately predict the communication performance at the time of communication between the prediction target satellite and the ground station, and it becomes possible to make efficient allocation of communication resources of the ground station that communicates with a large number of satellites.

(Modification of the first embodiment)
FIG. 5 is a flowchart showing a modification of the operation procedure of the communication performance prediction apparatus 100. Compared to the flowchart of FIG. 4, the flowchart of FIG. 4 omits steps S <b> 012 to S <b> 014 related to cloud image processing. Although the influence by the presence or absence of a cloud can be predicted by using a cloud image, the process by a cloud image is unnecessary when there is no cloud. Further, even when the analysis of the cloud image is not performed, the communication performance of the leading satellite S12 can be used to reflect the influence of the atmospheric fluctuation on the communication performance of the prediction target satellite S13. Therefore, the procedure shown in FIG. 5 also has the effect of more accurately predicting the communication performance at the time of communication between the prediction target satellite and the ground station.

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 6 is a diagram showing an example of the communication performance prediction system 20 according to the second embodiment of this invention. The communication performance prediction system 20 includes a ground station G21 and satellites S22, S23 and S24. The orbits B25 and B26 are satellite orbits on the celestial sphere 29. The satellites S22 and S23 are satellites traveling on the orbit B25, and the satellite S24 is a satellite traveling on the orbit B26.

  The communication performance prediction system 20 provides a procedure for predicting the communication performance of satellites having no preceding satellite on the same orbit as the satellite S24. In the description of this embodiment, the satellites S22 and S23 may be described as the other satellites S22 and S23, and the satellite S24 may be described as the satellite S24 to be predicted.

  FIG. 7 is a block diagram showing a configuration example of the ground station G21 of the second embodiment. The ground station G21 includes an antenna 103, an optical transmission / reception device 104, and a communication performance prediction device 200. The antenna 103 and the optical transmission / reception device 104 have the same functions as those provided in the ground station G11 of the first embodiment. However, the antenna 103 of the present embodiment has a tracking function for the satellites S22 to S24. The optical transmitting and receiving apparatus 104 inputs and outputs optical signals including transmission data transmitted to and from the satellites S22 to S24 with the antenna 103, and inputs and outputs electrical signals including the transmission data to and from the communication apparatus 105. . The optical transmission / reception device 104 also outputs a communication record during communication with the satellites S22 and S23 to the communication performance prediction device 200.

  The communication performance prediction apparatus 200 generates a communication performance prediction value based on the communication record acquired from the optical transmission / reception device 104, and outputs the generated communication performance prediction value to the communication device 105. The communication device 105 transmits and receives transmission data to and from the optical transmission / reception device 104, and processes the communication performance prediction value acquired from the communication performance prediction device 200. The communication device 105 of the present embodiment has the same function as the communication device 105 of the first embodiment, and may be provided inside the ground station G31.

  FIG. 8 is a block diagram showing a configuration example of the communication performance prediction apparatus 200 of the second embodiment. The communication performance prediction apparatus 200 includes a first fluctuation calculating unit 201, an elevation angle calculating unit 202, a second fluctuation calculating unit 203, and a communication performance calculating unit 204. The first fluctuation calculating unit 201 serves as a first fluctuation calculating unit that calculates the atmospheric fluctuation intensity from the communication recording (communication recording) including the communication performance of the other satellites S22 and S23. The first fluctuation calculating unit 201 may use only the communication performance of one of the other satellites S22 and S23. The atmospheric fluctuation intensity calculated by the first fluctuation calculating unit 201 can be referred to as a first index.

  The elevation angle calculation unit 202 takes an elevation angle calculation means by determining (modeling) the relationship between the atmospheric fluctuation intensity calculated by the first fluctuation calculation unit 201, the elevation angle of another satellite S22 and the elevation angle of another satellite S23. . The second fluctuation calculating unit 203 is responsible for a second fluctuation calculating unit that obtains the atmospheric fluctuation strength from the elevation angle of the prediction target satellite S24 based on the relationship obtained by the elevation angle calculation unit 202. The atmospheric fluctuation intensity calculated by the second fluctuation calculating unit 203 can be referred to as a second index. The communication performance calculation unit 204 serves as communication performance calculation means for converting the atmospheric fluctuation intensity obtained by the second fluctuation calculation unit 203 into the communication performance of the prediction target satellite S24. Each part which comprises the communication performance prediction apparatus 200 can be named generically, and can be called "processing means."

  The communication record used in the present embodiment is data including communication performance recorded at the time of communication between the other satellites S22 and S23 and the ground station G21, elevation angle at the time of the communication, setting of communication devices, and transmission distance. It is a group. The communication performance is a value of a performance indicator such as throughput and packet error rate as in the first embodiment, but is not limited to a specific indicator. As in the first embodiment, the setting of the communication device is a parameter that contributes to the light intensity at reception due to things other than atmospheric fluctuation and clouds. The transmission distance is the distance between the ground station G21 and the satellites S22 to S24. The communication performance prediction device 200 executes the prediction of the communication performance of the prediction target satellite S24 and the other satellites S22 and S23 performed before the time when the statistical property of the atmospheric fluctuation can be regarded as spatially constant. A communication record recorded in communication with the ground station G21 may be used.

  The atmospheric fluctuation intensity is a physical quantity that indicates the atmospheric fluctuation intensity, such as a freed parameter or a scintillation index, but is not limited to a specific physical quantity. The Freed parameter is a value that relates the atmospheric fluctuation intensity to the aperture of the telescope. The scintillation index is a standard deviation of the amount of fluctuation of signal intensity, and is an index indicating the amount of fluctuation of signal intensity.

  The first fluctuation calculating unit 201 calculates the atmospheric fluctuation strength at the time of measurement from the communication record in the communication between the other satellites S22 and S23 and the ground station G21. An example of calculation procedure of atmospheric fluctuation intensity is shown below.

  As the communication performance, the error rate of the data transmitted between the satellites S22 to S24 and the ground station G21 is used, and as the atmospheric fluctuation intensity, the dispersion value of the received light intensity caused by the atmospheric fluctuation is used. Here, assume the following two. One is that the error rate is determined by the fluctuation of the received light intensity caused by atmospheric fluctuation, and the other is that the distribution of the received light intensity fluctuation can be expressed by the γ-γ distribution shown in FIG. It is.

FIG. 9 is a diagram showing an example of the distribution of fluctuations in the intensity of received light. The γ-γ distribution is characterized by the variance value σ _R as the cumulative probability P (I) shown in equation (1). The received light intensity I is a value normalized by the received light intensity when there is no atmospheric fluctuation. This dispersion value σ _R is used as the atmospheric fluctuation intensity. Equation (1) indicates that the probability that the received light intensity is less than or equal to I is P (I).

... (1)

Here, α and β are represented by the following formulas. Also, I is the fluctuation of the received light intensity with 0 being the atmospheric fluctuation-free state, Γ is the gamma function, and Κ is the Bessel function.

Under the above assumption, a method of determining the dispersion value σ _R indicating the atmospheric fluctuation intensity will be described. First, from the setting of the communication device in the communication record of the other satellites S22 and S23, and the information of the transmission distance between the other satellites S22 and S23 and the ground station G21, the margin m of the received light intensity in the absence of atmospheric fluctuation Calculate the reception margin). For example, assuming that the transmission light intensity is T (dBm), the reception sensitivity is R (dBm), the free space loss due to light diffraction is L (dB), and there is no loss of light intensity other than atmospheric fluctuation, the margin m ( dB) can be expressed by the following equation (2).

... (2)

FIG. 10 is a diagram for explaining an example of the procedure for determining the atmospheric fluctuation intensity. In general, the larger the margin m, the smaller the dynamic range and the lower the error rate. Therefore, in the present embodiment, the cumulative probability is made to correspond to the error rate, and fitting to the γ-γ distribution is performed. Specifically, the variance value σ _R is determined from the equation (1) such that the margin m and the error rate in the communication record are on the curve of the cumulative probability P (I) of the equation (1) Let σ _R be the atmospheric fluctuation intensity.

  The elevation angle calculation unit 202 obtains the relationship between the atmospheric fluctuation intensity and the elevation angle from the data group of the atmospheric fluctuation intensity calculated by the first fluctuation calculation unit 201 and the elevation angles of the other satellites S22 and S23 at that time. The relationship between the atmospheric fluctuation intensity and the elevation angle can be determined, for example, as follows.

When the atmospheric fluctuation intensity is the above-mentioned dispersion value σ _R , the relationship between the dispersion value σ _R and the elevation angle θ (rad) can be expressed by the proportional relationship shown in the following equation (3).

... (3)

Then, the fitting by the equation (3) is performed on a data group in which the elevation angle θ obtained from the communication record of the other satellites S22 and S23 and the dispersion value σ _R obtained from the communication performance of those satellites. As a result, the relationship between the dispersion value σ _R and the elevation angle θ can be modeled. For example, by expressing the dispersion value σ _R as a function of the elevation angle θ, modeling of the relationship between the atmospheric fluctuation intensity and the elevation angle is performed. If there is a large amount of data in the communication record, modeling may be performed using a general function such as a high-order polynomial instead of equation (3).

  The second fluctuation calculation unit 203 applies the relationship between the elevation angles of the other satellites S22 and S23 and the atmospheric fluctuation intensity obtained by the elevation angle calculation unit 202 to the elevation angle of the prediction target satellite S24 to obtain the elevation angle of the prediction target satellite S24. Transform the change in the atmospheric pressure into the temporal change of atmospheric fluctuation intensity. That is, the second fluctuation calculating unit 203 obtains the atmospheric fluctuation intensity at the time of communication between the prediction target satellite S24 and the ground station G21 by applying the elevation angle of the prediction target satellite S24 to the model generated by the elevation angle calculation unit 202. When calculating the atmospheric fluctuation intensity in the second fluctuation calculation unit 203, it is dependent on the place by using only the recording of the communication performance of the satellites passing near the prediction target satellite S24 among the other satellites S22 and S23. It is possible to reduce the influence of atmospheric fluctuation differences.

  The communication performance calculation unit 204 is a satellite for prediction from the time variation of the atmospheric fluctuation intensity, the communication device settings of the satellites S22 to S24 and the difference between them, and the time variation of the transmission distance between the satellite for prediction S24 and the ground station G21. The time change of the communication performance (for example, error rate) of S24 is predicted. The communication device setting of the prediction target satellite S24 and the temporal change of the transmission distance between the prediction target satellite S24 and the ground station G21 can also be called "communication setting".

  The time change of the transmission distance is remarkable in the communication between the low orbit satellite and the ground station. By temporally changing the propagation loss due to light diffraction in accordance with the time change of the transmission distance, it is possible to reflect the time change of the transmission distance in the time change of the communication performance. The conversion from the atmospheric fluctuation intensity to the communication performance can be performed by the reverse procedure of the procedure described in FIG. Regarding the setting of the communication device, the difference between the setting of the preceding satellites S22 and S23 and the setting of the prediction target satellite S24 is reflected in the communication performance predicted value by the procedure of the first embodiment (step S015 and step S016 in FIG. 4). it can.

  FIG. 11 is a flowchart illustrating an example of the operation procedure of the communication performance prediction apparatus 200. The first fluctuation calculating unit 201 calculates the atmospheric fluctuation intensity at the time of measurement from the communication performance of the other satellites S22 and S23 (step S021 in FIG. 11). The elevation angle calculation unit 202 models the relationship between the atmospheric fluctuation intensity and the elevation angles of the other satellites S22 and S23 (step S022). The second fluctuation calculating unit 203 converts the elevation angle of the prediction target satellite S24 into the atmospheric fluctuation strength at the time of communication between the prediction target satellite S24 and the ground station G21 based on the relationship between the elevation angle and the atmospheric fluctuation strength obtained in step S022 Step S023). The communication performance calculation unit 204 predicts from the atmospheric fluctuation intensity obtained in step S023, the communication device settings for each of the satellites S22 to S24 and the ground station G21, and the transmission distance between the satellite S24 for prediction and the ground station G21. The communication performance of the satellite S24 is predicted.

  As described above, the communication performance prediction apparatus 200 of the present embodiment records the atmospheric fluctuation intensity between the satellite S24 for prediction and the ground G21, and the communication record between the other satellites S22 and S23 and the ground station G21. Use to predict. That is, the communication performance prediction apparatus 200 of the present embodiment can predict the communication performance of a prediction target satellite operating on a trajectory different from that of other satellites. In addition, when the communication time interval between the prediction target satellite and the preceding satellite on the same orbit is long, the prediction target satellite's can be obtained based on the communication records with other satellites without using the communication record of the preceding satellite. Communication performance can be predicted. That is, also in the second embodiment, it is possible to more accurately predict the time change of the communication performance between the satellite and the ground station.

  In the description of the present embodiment, the influence of the clouds performed in the first embodiment is not considered. However, the communication performance prediction value may be corrected using the procedure described in the first embodiment using a cloud image at the time of communication between another satellite S22 or S23 and the ground station G21. For example, by applying the procedures of steps S012 to S014 of FIG. 4 to step S024 of FIG. 11, the influence of clouds can be reflected on the predicted value of the communication performance. Thereby, also in this embodiment, it is possible to predict the communication performance in which the influence of the movement of the cloud is considered.

Third Embodiment
Next, a third embodiment of the present invention will be described. FIG. 12 is a block diagram showing an example of the communication performance prediction system 30 of the third embodiment. In the communication performance prediction system 30, the atmospheric fluctuation intensity is directly measured.

  The communication performance prediction system 30 includes a ground station G31, satellites S32 and S33 on the orbit B35 on the celestial sphere 39, and a satellite S34 on the orbit B36. Here, the satellites S31 and S32 are satellites that do not communicate with the ground station G31. In the communication performance prediction system 30, the satellite S32 emits light to the ground station G31. Alternatively, the ground station G31 emits light to the satellite S33 equipped with the corner reflector, and the satellite S33 reflects the light emitted from the ground station G31 by the corner reflector and emits the light to the ground station G31. The ground station G31 can measure the atmospheric fluctuation intensity directly by receiving any of these lights and detecting the time variation of the intensity.

  FIG. 13 is a block diagram showing a configuration example of the ground station G31 of the third embodiment. The ground station G31 includes an antenna 103, an optical transmission / reception device 104, and a communication performance prediction device 300. The antenna 103 and the optical transmission / reception device 104 have the same functions as those in the second embodiment. However, the antenna 103 of the present embodiment is an optical transmitting / receiving antenna provided with a tracking function for the satellites S32 to S34. The optical transmission / reception device 104 inputs / outputs an optical signal including transmission data transmitted to / from the satellite S34 with the antenna 103, and inputs / outputs an electric signal including the transmission data into / from the communication device 105. In addition, the light transmitting / receiving device 104 has a light transmitting / receiving function for measuring the atmospheric fluctuation intensity with at least one of the satellites S32 and S33, or the light intensity fluctuation received from at least one of the satellites S32 and S33. It has a function to obtain fluctuation strength.

  The communication performance prediction apparatus 300 generates a communication performance prediction value based on the communication record acquired from the optical transmission / reception device 104, and outputs the generated communication performance prediction value to the communication device 105. The communication device 105 transmits and receives transmission data to and from the optical transmission / reception device 104, and processes the communication performance prediction value acquired from the communication performance prediction device 300. The communication device 105 of this embodiment may have the same function as the communication device 105 of the first and second embodiments, and may be provided inside the ground station G31.

  FIG. 14 is a block diagram showing a configuration example of the communication performance prediction apparatus 300 of the third embodiment. The communication performance prediction apparatus 300 is different from the communication performance prediction apparatus 200 of the second embodiment in that a fluctuation measurement unit 301 is provided instead of the first fluctuation calculation unit 201. The communication performance prediction apparatus 300 includes an elevation angle calculation unit 202, a second fluctuation calculation unit 203, and a communication performance calculation unit 204, similar to the communication performance prediction apparatus 200 of the second embodiment. The functions of the units other than the fluctuation measuring unit 301 are the same as those of the second embodiment, and thus the description thereof is omitted.

  The communication performance prediction apparatus 300 measures the fluctuation of the light intensity received from the satellite S32 or S33. Then, the communication performance prediction apparatus 300 predicts the communication performance of the prediction target satellite without communicating with the satellites S32 to S34 by obtaining the atmospheric fluctuation intensity in the vicinity of the ground station G31 from the measurement result. For example, even if the ground station G31 does not transmit or receive transmission data, it is possible to predict the atmospheric fluctuation intensity using light received from another satellite.

  FIG. 15 is a flowchart illustrating an example of the operation procedure of the communication performance prediction apparatus 300. The fluctuation measurement unit 301 of the ground station G11 measures atmospheric fluctuation based on the fluctuation of light intensity received from another satellite S32 or S33 (step S031 in FIG. 15). The subsequent steps S032 to S034 are the same as steps S022 to S024 in FIG. 11 of the second embodiment.

  The preceding satellite S12 of the first embodiment and the other satellites S22 and S23 of the second embodiment may have the functions of the other satellites S32 and S33 of the present embodiment. The ground station G11 or G21 may measure the fluctuation of the intensity of the light received from the satellite S12, S22 or S23 in the same procedure as the present embodiment to obtain the atmospheric fluctuation intensity.

(Modification of the third embodiment)
FIG. 16 is a view for explaining a modification of the communication performance prediction system 30 of the third embodiment. The communication performance prediction system 31 differs from the communication performance prediction system 30 of the third embodiment in that the atmospheric fluctuation intensity is measured using the guide star S37 or the laser guide star S38.

  In FIG. 13, a guide star S37 is a bright star (for example, a star) existing in space. The laser guide star S38 is a pseudo star which emits light by exciting elements (for example, sodium) in the upper air layer by laser light emitted from the ground station G31. The ground station G31 calculates the atmospheric fluctuation by the fluctuation of the light intensity received from the guide star or the laser guide star. The other operations are the same as in the third embodiment.

Fourth Embodiment
Next, a fourth embodiment of the present invention will be described. In the present embodiment, any one of the first embodiment, the second embodiment, and the third embodiment is selected. FIG. 17 is a flowchart illustrating an example of a communication performance prediction procedure according to the fourth embodiment.

  First, it is determined whether there is a communication record with a satellite on the same orbit (preceding satellite) within the period from the scheduled time of communication between the prediction target satellite and the ground station to a predetermined time or earlier (Fig. 14 steps S041). The communication record includes the communication performance in the communication between the satellite and the ground station. If there is such a communication record (step S041: YES), the time change of communication performance is predicted according to the procedure of the first embodiment (step S042).

  If there is no communication record between the preceding satellite and the ground station (step S041: NO), it is determined whether there is a communication record with satellites (other satellites) other than the same orbit within the period (step S043). If there is a communication record with another satellite (step S043: YES), the time change of the communication performance is predicted according to the procedure of the second embodiment (step S044). If there is no communication record with another satellite (step S043: NO), the time change of the communication performance is predicted according to the procedure of the third embodiment (step S045).

  According to the procedure of the present embodiment, communication performance can be predicted by a procedure with higher prediction accuracy by selecting the procedure of each embodiment according to the presence or absence of the communication record.

  In addition, although embodiment of this invention may be described also like the following additional remarks, it is not limited to these.

(Supplementary Note 1)
A communication record including a first communication performance, which is a performance of a first optical space communication performed between a first mobile unit and a ground station, is recorded, and a second mobile unit and the ground station are recorded. Processing means for acquiring a communication setting which is a setting of a second optical space communication to be performed, and predicting a second communication performance which is a performance of the second optical space communication based on the communication record and the communication setting Prepare,
Communication performance prediction device.

(Supplementary Note 2)
The communication record is in the first optical space communication,
A relationship between an elevation angle of the first mobile body and the first communication performance;
Setting of the communication device of the first mobile, and
Including the configuration of the ground station communication device,
The communication setting is performed in the second optical space communication,
Including the setting of the elevation angle of the second mobile unit and the communication device of the second mobile unit and the setting of the communication device of the ground station;
The communication performance prediction device described in Supplementary Note 1.

(Supplementary Note 3)
The processing means predicts the second communication performance based on the communication record at the elevation angle of the first mobile body in a range substantially the same as the elevation angle of the second mobile body in the second optical space communication. The communication performance prediction device described in Appendix 1 or 2.

(Supplementary Note 4)
The processing means
First fluctuation calculating means for obtaining a first index indicating atmospheric fluctuation strength at the time of the first optical space communication;
Elevation angle calculation means for determining the relationship between the first index and the elevation angle of the first mobile body from the elevation angle of the first mobile body and the first index at the time of the first optical space communication;
Based on the relationship between the first index and the elevation angle of the first moving body, a second index indicating the atmospheric fluctuation intensity in the second optical space communication is determined from the elevation angle of the second moving body Second fluctuation calculation means,
Based on the second indicator, the settings of the communication devices of the first and second mobile units, and the distance between the second mobile unit and the ground station, the second communication performance prediction result is Communication performance calculation means to output,
The communication performance prediction apparatus described in any one of the additional claims 1 to 3 comprising

(Supplementary Note 5)
The first fluctuation calculation means uses the error rate in the first optical space communication as the first communication performance, and sets the relationship between the reception margin of the first optical space communication and the error rate to γ−. The communication performance prediction device described in appendix 4, wherein a dispersion value of cumulative probability when fitting to a γ distribution is used as the first index.

(Supplementary Note 6)
The communication performance calculation means is configured to calculate the second communication performance based on a difference between the first communication performance and the second communication performance which are generated by a difference between settings of communication devices of the first and second mobile units. The communication performance prediction apparatus described in appendix 4 or 5 which predicts.

(Appendix 7)
The communication performance calculation means outputs the prediction result of the second communication performance when the first mobile unit operates on the same orbit as the second mobile unit. The communication performance prediction device described in item 1.

(Supplementary Note 8)
The communication performance prediction device described in appendix 4, wherein the first fluctuation calculating means obtains the first index from the fluctuation of light intensity received from the first moving body.

(Appendix 9)
The communication according to appendix 8, wherein the communication performance calculation means outputs the prediction result of the second communication performance when the first mobile body is at a position different from that on the trajectory of the second mobile body. Performance prediction device.

(Supplementary Note 10)
The first fluctuation calculating means is configured to detect the fluctuation of the light intensity received from the laser guide star or the star on the celestial sphere, instead of the first index obtained from the fluctuation of the light intensity received from the first moving body. The communication performance prediction device according to any one of appendices 4 to 9, which is output as a first index.

(Supplementary Note 11)
The setting of the communication device of the first and second mobile units and the setting of the communication device of the ground station are respectively the intensity of the transmission light, the transmission beam divergence angle of the transmission light, the dispersion of the characteristics of the optical system, the light reception sensitivity The communication performance prediction device according to any one of appendices 1 to 10, comprising at least one of:

(Supplementary Note 12)
The first communication performance and the second communication performance based on the position of the shield of the optical signal in the first optical space communication and the predicted position of the shield in the second optical space communication The communication performance prediction apparatus according to any one of appendices 1 to 10, wherein the second communication performance is predicted using the calculated difference.

(Supplementary Note 13)
An optical transmitter / receiver that performs optical space communication with the first and second movable bodies and an optical receiver, and outputs the communication record and the communication setting;
The communication performance prediction apparatus described in any one of Appendices 1 to 12;
Ground station with.

(Supplementary Note 14)
A communication performance prediction system, comprising: the ground station described in Appendix 13; and a communication device that processes the second communication performance predicted by the communication performance prediction device provided in the ground station.

(Supplementary Note 15)
Obtaining a communication record including a first communication performance that is a performance of a first optical space communication performed between the first mobile unit and the ground station;
Acquiring a communication setting that is a setting of a second optical space communication performed between a second mobile unit and the ground station;
Predicting a second communication performance which is a performance of the second optical space communication based on the communication record and the communication setting;
Communication performance prediction method.

(Supplementary Note 16)
The communication record is in the first optical space communication,
A relationship between an elevation angle of the first mobile body and the first communication performance;
Setting of the communication device of the first mobile, and
Including the configuration of the ground station communication device,
The communication setting is performed in the second optical space communication,
Including the setting of the elevation angle of the second mobile unit and the communication device of the second mobile unit and the setting of the communication device of the ground station;
The communication performance prediction method described in appendix 15.

(Supplementary Note 17)
The second communication performance is predicted based on the communication record at the elevation angle of the first mobile body in a range substantially the same as the elevation angle of the second mobile body in the second optical space communication, Appendix 15 or The communication performance prediction method described in 16.

(Appendix 18)
Determining a first index indicating atmospheric fluctuation intensity in the first optical space communication;
The relationship between the first index and the elevation angle of the first moving body is obtained from the elevation angle of the first moving body and the first index during the first optical space communication,
Based on the relationship between the first index and the elevation angle of the first movable body, a second index indicating the atmospheric fluctuation intensity in the second optical space communication is obtained from the elevation angle of the second movable body ,
The second communication performance is predicted based on the second indicator, the settings of the communication devices of the first and second mobile units, and the distance between the second mobile unit and the ground station.
The communication performance prediction method according to any one of appendices 15 to 17.

(Appendix 19)
Accumulation when fitting the relationship between the reception margin of the first optical space communication and the error rate to the γ-γ distribution using the error rate in the first optical space communication as the first communication performance The communication performance prediction method described in appendix 18, wherein a variance value of probability is used as the first index.

(Supplementary Note 20)
The second communication performance is predicted on the basis of the difference between the first communication performance and the second communication performance which are caused by the difference between the settings of the communication devices of the first and second mobile units, or the second communication performance is predicted The communication performance prediction method described in 19.

(Supplementary Note 21)
The communication performance prediction method according to any one of appendices 18 to 20, which is executed when the first mobile unit travels on the same orbit as the second mobile unit.

(Supplementary Note 22)
The communication performance prediction method described in appendix 18, wherein the first index is obtained from the fluctuation of light intensity received from the first mobile body.

(Supplementary Note 23)
24. The communication performance prediction method according to appendix 21, executed when the first mobile body is at a position different from that on the trajectory of the second mobile body.

(Supplementary Note 24)
Note that the fluctuation of the light intensity received from the laser guide star or the star on the celestial sphere is used as the first index instead of the first index obtained from the fluctuation of the light intensity received from the first moving body The communication performance prediction method described in any one of items 18 to 23.

(Appendix 25)
The setting of the communication device of the first and second mobile units and the setting of the communication device of the ground station are respectively the intensity of the transmission light, the transmission beam divergence angle of the transmission light, the dispersion of the characteristics of the optical system, the light reception sensitivity The communication performance prediction method according to any one of appendages 15 to 24, including at least one of:

(Appendix 26)
The first communication performance and the second communication performance based on the position of the shield of the optical signal in the first optical space communication and the predicted position of the shield in the second optical space communication The communication performance prediction method according to any one of Appendices 15 to 25, wherein the second communication performance is predicted using the calculated difference.

(Appendix 27)
In the computer of the communication performance prediction device,
A procedure for acquiring a communication record including a first communication performance that is a performance of a first optical space communication performed between a first mobile unit and a ground station;
A procedure for acquiring a communication setting which is a setting of a second optical space communication performed between a second mobile unit and the ground station;
A procedure for predicting a second communication performance that is a performance of the second optical space communication based on the communication record and the communication setting;
Performance forecasting program for running.

  Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

  Further, the configurations described in the respective embodiments are not necessarily mutually exclusive. The actions and effects of the present invention may be realized by a combination of all or part of the above-described embodiments.

  The functions and procedures described in each of the above embodiments may be implemented by executing a program by a computer (Central Processing Unit, CPU) included in the communication performance prediction device of each of the embodiments. The program is recorded on a fixed, non-temporary recording medium. Although a semiconductor memory or a fixed magnetic disk drive is used as a recording medium, it is not limited thereto.

10, 20, 30, 31 Communication Performance Prediction System G11, G21, G31 Ground Station S12, S13, S22 to S24, S31 to S34 Satellite S37 Guide Star S38 Laser Guide Star B15, B25, B35, B36 Orbit 19, 29, 39 Celestial sphere 100, 200, 300 communication performance prediction device 101 first processing unit 102 second processing unit 103 antenna 104 light transmitting / receiving device 105 communication device 201 first fluctuation calculating unit 202 elevation angle calculating unit 203 second fluctuation calculating unit 204 communication performance calculating unit 301 Fluctuation measurement unit

Claims (10)

A communication record including a first communication performance, which is a performance of a first optical space communication performed between a first mobile unit and a ground station, is recorded, and a second mobile unit and the ground station are recorded. Processing means for acquiring a communication setting which is a setting of a second optical space communication to be performed, and predicting a second communication performance which is a performance of the second optical space communication based on the communication record and the communication setting Prepare,
Communication performance prediction device. The communication record is in the first optical space communication,
A relationship between an elevation angle of the first mobile body and the first communication performance;
Setting of the communication device of the first mobile, and
Including the configuration of the ground station communication device,
The communication setting is performed in the second optical space communication,
Including the setting of the elevation angle of the second mobile unit and the communication device of the second mobile unit and the setting of the communication device of the ground station;
The communication performance prediction device according to claim 1.   The processing means predicts the second communication performance based on the communication record at the elevation angle of the first mobile body in a range substantially the same as the elevation angle of the second mobile body in the second optical space communication. The communication performance prediction device according to claim 1 or 2. The processing means
First fluctuation calculating means for obtaining a first index indicating atmospheric fluctuation strength at the time of the first optical space communication;
Elevation angle calculation means for determining the relationship between the first index and the elevation angle of the first mobile body from the elevation angle of the first mobile body and the first index at the time of the first optical space communication;
Based on the relationship between the first index and the elevation angle of the first moving body, a second index indicating the atmospheric fluctuation intensity in the second optical space communication is determined from the elevation angle of the second moving body Second fluctuation calculation means,
Based on the second indicator, the settings of the communication devices of the first and second mobile units, and the distance between the second mobile unit and the ground station, the second communication performance prediction result is Communication performance calculation means to output,
The communication performance prediction device according to any one of claims 1 to 3, comprising:   The first fluctuation calculation means uses the error rate in the first optical space communication as the first communication performance, and sets the relationship between the reception margin of the first optical space communication and the error rate to γ−. The communication performance prediction device according to claim 4, wherein a variance value of cumulative probability at the time of fitting to a γ distribution is used as the first index.   The communication performance calculation means is configured to calculate the second communication performance based on a difference between the first communication performance and the second communication performance which are generated by a difference between settings of communication devices of the first and second mobile units. The communication performance prediction device according to claim 4 or 5, wherein   The communication performance calculation means outputs the prediction result of the second communication performance when the first mobile unit operates on the same orbit as the second mobile unit. The communication performance prediction device described in 1 or 2.   5. The communication performance prediction device according to claim 4, wherein the first fluctuation calculating means obtains the first index from the fluctuation of light intensity received from the first moving body.   9. The communication performance calculation means according to claim 8, wherein the prediction result of the second communication performance is output when the first mobile body is at a position different from that on the trajectory of the second mobile body. Communication performance prediction device. Obtaining a communication record including a first communication performance that is a performance of a first optical space communication performed between the first mobile unit and the ground station;
Acquiring a communication setting that is a setting of a second optical space communication performed between a second mobile unit and the ground station;
Predicting a second communication performance which is a performance of the second optical space communication based on the communication record and the communication setting;
Communication performance prediction method.

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