Emulator and method for adjusting antenna direction

Abstract

The purpose of the present disclosure is to provide an emulator that can simulate signals emitted from aerial stations and a method that is for adjusting an antenna direction using the emulator. An emulator according to the present disclosure performs a process for determining a first parameter value as the installation position of an earth station, a process for determining second parameter values as the arrangement of a plurality of aerial stations, and a process for acquiring the antenna direction of the earth station. The emulator further performs a process for generating a plurality of simulation signals that respectively simulate signals which can be received from the plurality of aerial stations arranged according to the second parameter values, when the earth station directs an antenna to the antenna direction at the position indicated by the first parameter value, and a process for outputting the plurality of simulation signals to the earth station.

Description

Emulator and Antenna Direction Adjustment Method

[0001] The present disclosure relates to an emulator and a method for adjusting the antenna direction of an earth station using the emulator.

[0002] A technique for adjusting the antenna direction of an earth station based on a beacon signal from an overhead station in order to capture a target overhead station (such as a communication satellite) is known (see Patent Document 1).

[0003] International Publication No. 2021 / 199218

[0004] When installing an earth station, a field test for adjusting the antenna direction called UAT (Uplink Access Test; pre-line-opening test) is conducted. In this test, after confirming the operation of the program to be executed on the earth station, the antenna of the earth station is actually operated to test whether the earth station accurately captures the target overhead station.

[0005] In order to pass the field test without problems, in the manufacturing test that the manufacturer independently conducts prior to the field test, it is desirable to impose stricter conditions on the earth station than in the field test. Specifically, a test that targets an overhead station that is particularly difficult to capture due to the distance from other overhead stations and the frequency situation of the beacon signal is applicable. However, since such an overhead station itself is rare in such a situation, it is substantially impossible for the manufacturer to test the earth station under the desired conditions. For these reasons, a technique for simulating the signal emitted by the overhead station has been eagerly awaited.

[0006] An object of the present disclosure is to provide an emulator capable of simulating a signal emitted by an overhead station and an antenna direction adjustment method using the emulator in order to solve the above problems.

[0007] A first aspect of this disclosure is preferably an emulator configured to perform the following: a process of determining a first parameter value as the installation location of an earth station; a process of determining a second parameter value as the arrangement of a plurality of air stations; a process of obtaining the antenna direction of the earth station; a generation process of generating a plurality of simulated signals that simulate signals that can be received from each of the plurality of air stations arranged according to the second parameter value when the earth station points its antenna in the direction of the antenna at the location indicated by the first parameter value; and a process of outputting the plurality of simulated signals to the earth station.

[0008] A second embodiment is preferably an antenna direction adjustment method comprising: an emulator determining a first parameter value which is the installation location of an earth station; a second parameter value which is the arrangement of a plurality of air stations; obtaining the antenna direction of the earth station; generating a plurality of simulated signals which simulate beacon signals that can be received from each of the plurality of air stations arranged according to the second parameter value when the earth station points its antenna in the direction indicated by the first parameter value; and outputting the plurality of simulated signals to the earth station, wherein the earth station receives the plurality of simulated signals and adjusts its antenna angle based on the plurality of simulated signals.

[0009] According to this disclosure, it is possible to provide an emulator capable of simulating signals emitted by an airborne station, and a method for adjusting the antenna direction using the emulator.

[0010] This figure shows an aerial communication system with an earth station installed according to Embodiment 1. This is a schematic diagram illustrating the antenna direction adjustment performed by the earth station to acquire a target aerial station according to Embodiment 1. This is a flowchart illustrating the process performed by the earth station in the antenna direction adjustment shown in Figure 2. This figure illustrates the situation of an aerial station that is particularly difficult to acquire, according to Embodiment 1. This figure illustrates the situation of an aerial station that is commonly seen, according to Embodiment 1. This figure shows an earth station antenna direction adjustment method using an emulator according to Embodiment 1. This is a schematic diagram of the antenna pattern in the AZ direction of the earth station stored by the emulator according to Embodiment 1. This is a schematic diagram of the antenna pattern in the EL direction of the earth station stored by the emulator according to Embodiment 1. This is a schematic diagram of the antenna pattern in the POL direction of the earth station stored by the emulator according to Embodiment 1. This is a schematic diagram of aerial station data stored by the emulator according to Embodiment 1. This is a block diagram showing an example configuration of the emulator and earth station according to Embodiment 1. This figure shows the hardware configuration of the emulator according to Embodiment 1. This is a flowchart illustrating the process executed by the CPU of the emulator according to Embodiment 1. This figure shows an earth station antenna direction adjustment method using an emulator according to Embodiment 2. This is a schematic diagram of the upper-air station data stored by the emulator according to Embodiment 2. This is a block diagram showing an example configuration of the emulator and earth station according to Embodiment 2. This is a flowchart illustrating the processing performed by the CPU of the emulator according to Embodiment 2.

[0011] Embodiments of this disclosure will be described with reference to the drawings. The same or corresponding components will be denoted by the same reference numerals, and repetition of the description may be omitted.

[0012] Embodiment 1 Figure 1 shows an aerial communication system 100 with an earth station 4 installed according to Embodiment 1. The aerial communication system 100 comprises a base station 2 as a master station, an aerial station 3, and an earth station 4.

[0013] Earth station 4 transmits and receives communication signals 10 with base station 2 via air station 3. Earth station 4 is assumed to be a mobile station such as a Very Small Aperture Terminal (VSAT), but it is not limited to mobile stations and can be any radio station used on the ground.

[0014] The airborne station 3 is a radio station that moves in the airspace, including outer space, or moves in the airspace, including outer space, but appears to be stationary relative to the ground. The airborne station 3 constantly transmits a beacon signal 34 to indicate its position. The beacon signal 34 is, for example, an unmodulated wave at a specific frequency. Generally, the frequency of the beacon signal 34 is assigned to be unique to the airborne station 3, or rarely overlaps with other airborne stations 3. However, in rare cases, the beacon signals 34 of multiple airborne stations 3 may use the same frequency.

[0015] Examples of the above-ground station 3 include high-altitude pseudo-satellites (HAPS: High Altitude Platform Station) located at an altitude of approximately 20 km, LEO (Low Earth Orbit) communication satellites, MEO (Medium Earth Orbit) communication satellites, GEO (Geostationary Orbit) communication satellites, etc. Alternatively, the above-ground station 3 may also be a drone, airship, unmanned aerial vehicle, aircraft, etc., and is not limited to these.

[0016] Figure 2 is a schematic diagram illustrating the antenna direction adjustment performed by the earth station 4 to acquire the target air station 3 according to Embodiment 1. Figure 3 is a flowchart illustrating the process performed by the earth station 4 in the antenna direction adjustment shown in Figure 2. The flowchart in Figure 3 will be explained below, with references to Figure 2 being made as appropriate.

[0017] First, the earth station 4 stores location information, beacon signal information (frequency, polarization, etc.), and control signal information for the airborne station 3 that is the target of the target to be acquired (step S01).

[0018] Furthermore, the system acquires its own latitude and longitude information and, based on the acquired information, calculates the antenna direction for acquiring the target airborne station 3, expressed as AZ (azimuth angle), EL (elevation angle), and POL (polarization angle) (step S02). GPS (Global Positioning System), map data, etc., are used to acquire the system's own latitude and longitude information. Please refer to Figure 2 for the directions indicated by AZ, EL, and POL.

[0019] Furthermore, the receiving antenna (hereinafter referred to as antenna) 410 is pointed in the calculated direction, an attempt is made to receive the beacon signal 34 from the aerial station 3, and the antenna angles are adjusted in the three directions of AZ, EL, and POL so that the reception strength of the beacon signal 34 is maximized (step S03).

[0020] Furthermore, by executing step S03, the system receives a control signal 24 from base station 2 via the acquired airborne station 3 and checks whether to synchronize with the received control signal 24 (step S04). The control signal 24 is unique to each airborne communication system provided by the telecommunications carrier and can only be synchronized between the same airborne communication systems. Therefore, if synchronization with the control signal 24 is confirmed (Yes), the system determines that it has been confirmed that the acquired airborne station 3 is the target airborne station 3 and terminates the direction adjustment.

[0021] On the other hand, if synchronization is not confirmed (No), it is determined that the captured airborne station 3 is not the target airborne station 3, and the system returns to step S02 to perform direction adjustment again.

[0022] Figure 4 illustrates the situation of an upper-air station that is particularly difficult to acquire according to Embodiment 1. In this figure, upper-air station 3 is assumed to be a geostationary satellite. In this figure, an earth station 4 is installed on the ground in Japan, and eight upper-air stations 3, from upper-air station 3-1 to upper-air station 3-8, are located in the southern sky at different east longitudes. Here, upper-air station 3-4 is assumed to be the upper-air station 3 that earth station 4 is trying to acquire.

[0023] Figure 4 shows the location of each airborne station 3 and the frequency of the beacon signal 34. Specifically, airborne station 3-1 is located in the direction of A degrees east longitude, and the frequency of the beacon signal 34 is A (Hz). Similarly, airborne station 3-2 is located in the direction of B degrees east longitude, and the frequency of the beacon signal 34 is B (Hz). Airborne station 3-3 is located in the direction of C degrees east longitude, and the frequency of the beacon signal 34 is A (Hz). The target airborne station 3-4 is located in the direction of D degrees east longitude, and the frequency of the beacon signal 34 is A (Hz). Airborne station 3-5 is located in the direction of E degrees east longitude, and the frequency of the beacon signal 34 is A (Hz). Airborne station 3-6 is located in the direction of F degrees east longitude, and the frequency of the beacon signal 34 is B (Hz). Airborne station 3-7 is located in the direction of G degrees east longitude, and the frequency of the beacon signal 34 is C (Hz). The aerial station 3-8 is located in the direction of East longitude H degrees, and the frequency of the beacon signal 34 is D (Hz).

[0024] In Figure 4, the multiple aerial stations 3 are arranged at the minimum spacing in an internationally coordinated geostationary satellite configuration. In this case, the earth station 4 needs to precisely adjust its antenna 410 so that it points towards the target aerial station 3-4 from among the multiple aerial stations 3 arranged at the minimum spacing.

[0025] Furthermore, the two adjacent airborne stations 3-3 and 3-5 to the target airborne station 3-4 are transmitting a beacon signal 34 at the same frequency as the target airborne station 3-4, which is A (Hz). This could potentially cause the earth station 4 to misidentify the station.

[0026] Therefore, given the arrangement of the airborne stations 3 and the frequency of the beacon signals 34, it can be said that airborne stations 3-4 in Figure 4 are particularly difficult for the earth station 4 to accurately acquire. In the manufacturing tests of the earth station 4 conducted voluntarily by the manufacturer, it is desirable for the earth station 4 to acquire airborne stations 3 in such conditions.

[0027] Figure 5 is a diagram illustrating the situation of the airborne station 3, which is commonly seen in Embodiment 1. Similar to Figure 4, in this diagram as well, the earth station 4 is installed on the ground in Japan. However, in this diagram, of the eight airborne stations 3 in Figure 4, only airborne station 3-2, the target airborne station 3-4, and airborne station 3-7 are located in the air.

[0028] In Figure 5, the distance between the target aerial station 3-4 and the two adjacent aerial stations 3 (aerial stations 3-2 and 3-7) is greater than the minimum distance in an internationally coordinated geostationary satellite configuration. Furthermore, the frequency of the beacon signal 34 of the target aerial station 3-4 is different from the frequency of the beacon signals 34 of the two adjacent aerial stations 3. In many cases, aerial stations 3 are in a situation like that shown in Figure 5. Therefore, tests to have earth station 4 acquire aerial station 3, which is considered particularly difficult to acquire, are practically impossible. For this reason, technology to simulate the signals emitted by aerial stations 3 is eagerly awaited.

[0029] Figure 6 shows a method for adjusting the antenna direction of an earth station 4 using the emulator 1 according to Embodiment 1. The earth station 4 is equipped with the emulator 1.

[0030] Emulator 1 determines the installation location information of Earth Station 4 (latitude, longitude, height, inclination of the ground surface, direction Earth Station 4 is facing, etc.). The installation location information is not limited to the actual installation location of Earth Station 4 and can be determined to any parameter value. The installation location information may be notified to Emulator 1 from Earth Station 4, or it may be determined by Emulator 1 itself.

[0031] Furthermore, emulator 1 obtains an angle control value 50 from earth station 4 that indicates the direction of the antenna 410 of earth station 4.

[0032] The emulator 1 stores control data 11, which is necessary for generating the simulated signal 60 described later, in a storage device 110 (not shown). The control data 11 includes earth station data and upper-air station data.

[0033] Earth station data includes the receiving amplifier gain and antenna pattern of earth station 4. Air station data includes the placement conditions of multiple air stations 3, the frequency of the beacon signal 34, and the power reaching the ground surface.

[0034] The airborne station data does not have to be based on actual airborne station 3 data, and can be determined with arbitrary parameter values. Therefore, emulator 1 may have multiple sets of airborne station data, each with different parameter values.

[0035] When the Earth Station 4 points its antenna 410 in the direction indicated by the angle control value 50 at the location indicated by the installation location information, the emulator 1 generates multiple simulated signals 60 that simulate multiple beacon signals 34 that can be received from each of the multiple airborne stations 3 arranged according to the arrangement conditions (generation process). The generated multiple simulated signals 60 reflect the received strength, frequency, and polarization of the corresponding beacon signal 34 at the Earth Station 4. The emulator 1 outputs the generated multiple simulated signals 60 to the Earth Station 4.

[0036] Earth station 4 identifies the simulated signal 60 of the target air station 3 from among the multiple simulated signals 60 it has received, and adjusts its antenna angle based on the simulated signal 60 of the target air station 3. Each time the antenna angle is changed, Earth station 4 notifies emulator 1 of the angle control value 50, causing emulator 1 to output multiple simulated signals 60 corresponding to the angle control value 50. Earth station 4 adjusts its antenna angle so that the intensity of the simulated signal 60 of the target air station 3 is maximized. In this way, Earth station 4 simulates acquiring the target air station 3.

[0037] Figures 7, 8, and 9 are schematic diagrams of the antenna patterns of Earth Station 4 stored by Emulator 1. In these figures, the vertical axis represents the received signal strength at Antenna 410. The horizontal axis represents the angle of Antenna 410, with 0° being the direction in which the antenna of the upper station 3 and the antenna 410 of Earth Station 4 face each other. However, Figure 7 shows the angle of Antenna 410 in the AZ (azimuth) direction, Figure 7 shows the EL (elevation) direction, and Figure 8 shows the POL (polarization) direction. Furthermore, for the POL direction in Figure 9, both the antenna pattern for forward polarization and the antenna pattern for reverse polarization are shown. Emulator 1 stores the antenna patterns in these three directions as Earth Station data.

[0038] Furthermore, as shown in Figure 9, it is preferable to store in the emulator 1 not only an antenna pattern with polarized polarity (same polarization as the beacon signal 34) but also an antenna pattern with reverse polarization in the POL direction. This allows the emulator 1 to reflect the characteristics of both polarized and reverse polarization in the simulated signal 60. When the earth station 4 receives the simulated signal 60, it becomes easier to adjust the antenna 410 in the polarized (0°) direction by utilizing the characteristics of reverse polarization.

[0039] Furthermore, if the antenna pattern has polarization dependence in the AL and EL directions, it is desirable to store the antenna pattern for each polarization in emulator 1.

[0040] Figure 10 is a schematic diagram of the airborne station data stored by the emulator 1 according to Embodiment 1. The emulator 1 stores airborne station data for multiple airborne stations 3 as a table.

[0041] The first row shows the placement conditions of multiple airborne stations 3 in terms of longitude. The direction of the airborne stations 3 (reference direction) for the purpose of allowing the Earth station 4 to simulate the direction of longitude X degrees is set as the reference direction. There are four directions decreasing by 2 degrees (X-2, X-4, X-6, X-8) and four directions increasing by 2 degrees (X+2, X+4, X+6, X+8), for a total of nine directions in which the airborne stations 3 are positioned. The second row shows the frequency (Hz) and ground surface power (dBm) of the H-polarization beacon signal 34 of each airborne station 3. The third row shows the frequency (Hz) and ground surface power of the V-polarization beacon signal 34 of each airborne station 3. The ground surface power may be an actual measured value or a calculated value.

[0042] Figure 11 is a block diagram showing an example configuration of emulator 1 and earth station 4 according to Embodiment 1.

[0043] First, the emulator 1 will be described. The storage device 110 stores the control data 11 input from an external device (not shown). The storage device 110 is a volatile or non-volatile semiconductor memory such as a RAM, ROM, flash memory, or a magnetic disk, flexible disk, optical disk, DVD, etc. Note that the storage device 110 may be placed outside the emulator 1 as a server or cloud server.

[0044] The control circuit 120 acquires the angle control value 50 from the earth station 4 using the input interface 150. Also, the control circuit 120 determines the first parameter value as the installation position information of the earth station 4. Further, the control circuit 120 determines the second parameter value as the arrangement of the plurality of upper air stations 3. The second parameter value is determined based on the upper air station data included in the control data 11.

[0045] Furthermore, when the earth station 4 points the antenna 410 in the direction indicated by the angle control value 50 at the position indicated by the first parameter value, the control circuit 120 generates a plurality of simulated signals 60 each simulating a plurality of beacon signals 34 that can be received from each of the plurality of upper air stations 3 arranged according to the second parameter value.

[0046] The generation process of the simulated signal 60 includes a process of reflecting the reception intensity, frequency, and polarization of the corresponding beacon signal 34 in each of the plurality of simulated signals 60. Specifically, the control circuit 120 calculates the reception intensity of the beacon signal 34 received by the earth station 4 from each of the plurality of upper air stations 3. In the calculation, the reception amplifier gain of the earth station 4, the reception antenna pattern, and the ground surface arrival power of the beacon signal 34 of each upper air station 3 are considered. Further, the control circuit 120 reflects the calculated reception intensity in the intensity of the simulated signal 60 for each of the plurality of upper air stations 3. Also, the control circuit 120 performs frequency conversion so that the frequency of the simulated signal 60 matches the frequency of the corresponding beacon signal 34 for each of the plurality of upper air stations 3. Also, the control circuit 120 performs polarization adjustment so that the polarization of the simulated signal 60 matches the polarization of the corresponding beacon signal 34 for each of the plurality of upper air stations 3.

[0047] Furthermore, the control circuit 120 sends the generated digital analog signal 60 to the signal adjustment circuit 130. The signal adjustment circuit 130 converts the digital analog signal 60 into an analog signal using the built-in D / A (digital / analog) converter 131 and outputs it to the earth station 4. Note that the frequency band of the analog signal 60 may be output in an intermediate frequency band (IF band) or a radio frequency band (RF band) according to the input interface on the earth station 4 side.

[0048] Next, the earth station 4 will be described. The modem 420 includes an input interface 421 and a demodulation circuit 422. The input interface 421 receives a plurality of analog signals 60 from the emulator 1. The demodulation circuit 422 demodulates each of the plurality of analog signals 60. The plurality of demodulated analog signals 60 are used for the direction adjustment of the antenna 410.

[0049] The antenna control circuit 430 includes an angle control value acquisition circuit 432, an output interface 433, a receiving amplifier 431, and a capture determination circuit 434. The angle control value acquisition circuit 432 acquires the angle control value 50 every time the angle of the antenna 410 is changed and notifies the output interface 433. The output interface 433 transmits the notified angle control value 50 to the emulator 1.

[0050] The receiving amplifier 431 is originally used for amplifying the signal received by the antenna 410. The capture determination circuit 434 is used to determine whether the target space station 3 is captured based on the signal amplified by the receiving amplifier 431. However, when adjusting the direction of the antenna 410 using the emulator 1, reception by the antenna 410 is not assumed. Therefore, the signal path from the receiving amplifier 431 to the modem 420 is disconnected.

[0051] In FIG. 11, the output interface 433 is arranged in the earth station 4, and it has been described that the angle control value 50 is notified from the output interface 433 to the emulator 1. However, the angle control value 50 may be notified from a dedicated communication device or a maintenance communication terminal arranged outside the earth station 4 to the emulator 1.

[0052] Figure 12 shows the hardware configuration of emulator 1 according to Embodiment 1. The processing performed by emulator 1 may be executed by a program using a computer equipped with a CPU and memory, in which a simulated signal generation program is stored. Alternatively, it may be executed by a program using an integrated circuit such as an FPGA (Field Programmable Gate Array). The simulated signal generation program may be provided by recording it on a storage medium or by providing it via a network.

[0053] Emulator 1 has an input unit 40, an output unit 41, a communication unit 42, a CPU (Central Processing Unit, also called a processor) 43, memory 44, and an HDD (Hard Disk Drive) 45 connected via a bus 46, and functions as a computer. Furthermore, Emulator 1 is configured to input and output data to and from a storage medium 47 that can be read by a computer.

[0054] The input unit 40 is, for example, a keyboard and mouse. The output unit 41 is, for example, a display device such as a display.

[0055] The communication unit 42 is a communication interface that communicates with, for example, the earth station 4.

[0056] Memory 44 refers to volatile or non-volatile semiconductor memory such as RAM, ROM, and flash memory, or magnetic disks, flexible disks, optical disks, and DVDs.

[0057] The CPU 43 controls each component of the emulator 1 and performs predetermined processing. The memory 44 and HDD 45 are storage devices 110 that store, for example, a program for generating simulated signals, control data 11, etc.

[0058] The storage medium 47 is capable of storing programs for generating simulated signals that execute the functions of the emulator 1. The storage medium 47 is a USB (Universal Serial Bus) memory, a CD-ROM (Compact Disc Read Only Memory), etc.

[0059] Note that the architecture comprising emulator 1 is not limited to the example shown in Figure 12.

[0060] Figure 13 is a flowchart illustrating the process executed by the CPU 43 of the emulator 1 according to Embodiment 1. The CPU 43 reads the simulated signal generation program stored in memory 44 or HDD 45 and executes the following process.

[0061] First, the first parameter value is determined as the installation location information for Earth Station 4 (Step S11). Next, the second parameter value is determined as the arrangement of the multiple airborne stations 3 (Step S12). Then, the angle control value 50 for Earth Station 4 is obtained (Step S13).

[0062] Furthermore, for each of the multiple air stations 3 arranged according to the second parameter value, it is determined whether the air station 3 is capable of receiving the beacon signal 34 for the earth station 4, which has its antenna 410 pointed in the direction indicated by the angle control value 50 at the position indicated by the first parameter value (step S14). In this determination, if the direction of the air station 3 as seen from the earth station 4 is outside the range of the earth station 4's antenna pattern, it is determined that the air station 3 is not capable of receiving the beacon signal 34 for the earth station 4. On the other hand, if the direction of the air station 3 as seen from the earth station 4 is within the range of the earth station 4's antenna pattern, it is determined that the air station 3 is capable of receiving the beacon signal 34 for the earth station 4.

[0063] If the air station 3 is not an air station from which the earth station 4 can receive the beacon signal 34 (No), the signal from the air station 3 is not simulated (step S15). In this case, the process returns to step S13 and waits until a new angle control value 50 is notified.

[0064] On the other hand, if the Earth station 4 is an airborne station capable of receiving the beacon signal 34 (Yes), a simulated signal 60 that mimics the beacon signal 34 of the airborne station 3 is generated and output to the Earth station 4 (step S16). Then the process returns to step S13.

[0065] In this way, the emulator 1 generates a simulated signal 60 targeting only the airborne stations 3 from which the earth station 4 can receive the beacon signal 34, out of the multiple airborne stations 3 arranged based on the second parameter. This reduces the overhead required for generating the simulated signal 60.

[0066] As described above, this disclosure provides an emulator 1 capable of simulating signals emitted by an airborne station 3, and a method for adjusting the antenna direction using the emulator 1.

[0067] Embodiment 2: In this embodiment, the emulator 1 simulates not only the beacon signal 34 but also the control signal 24. The changes from Embodiment 1 will be described below.

[0068] Figure 14 shows a method for adjusting the antenna direction of an earth station 4 using an emulator 1 according to Embodiment 2. The signal output from emulator 1 to earth station 4 includes a plurality of simulated signals 60 that simulate a plurality of beacon signals 34 transmitted from each of a plurality of airborne stations 3, and a simulated control signal 70 that simulates a control signal 24 transmitted from only one of the plurality of airborne stations 3.

[0069] Similar to Embodiment 1, the earth station 4 simulates acquiring the target airborne station 3 by adjusting the antenna angle using multiple simulated signals 60. Furthermore, the earth station 4 in this embodiment makes a final confirmation that the simulated airborne station 3 is the target airborne station 3 by determining whether or not it is synchronized with the simulated control signal 70 received from the emulator 1.

[0070] Figure 15 is a schematic diagram of the airborne station data stored by the emulator 1 according to Embodiment 2. In Figure 15, a fourth row has been added to the table shown in Figure 10 of Embodiment 1. The fourth row contains the frequency (Hz), polarization, modulation information, and ground surface power (dBm) of the control signal 24 for the airborne station 3 intended to be simulated and acquired by the earth station 4. The modulation information includes the modulation method, frame configuration, modulation speed, etc.

[0071] Furthermore, these data related to the control signals 24 do not necessarily have to be data specific to the actual airborne station 3, and can be determined to arbitrary parameter values.

[0072] Figure 16 is a block diagram showing an example configuration of emulator 1 and earth station 4 according to Embodiment 2. First, in emulator 1, the control circuit 120 generates a plurality of simulated signals 60, similar to Embodiment 1. In addition, in this embodiment, when earth station 4 points its antenna 410 in the direction indicated by the angle control value 50 at the position indicated by the first parameter value, the control circuit 120 generates a simulated control signal 70 that simulates the control signal 24 emitted from the target air station 3 positioned according to the second parameter value.

[0073] The process for generating the simulated control signal 70 includes reflecting the received intensity, frequency, and polarization of the control signal 24 at the earth station 4 in the simulated control signal 70. Specifically, the control circuit 120 calculates the received intensity of the control signal 24 that the earth station 4 receives from the target aerial station 3. In the calculation, the receiving amplifier gain of the earth station 4, the receiving antenna pattern, and the ground surface power of the control signal 24 from the target aerial station 3 are taken into consideration. Furthermore, the control circuit 120 reflects the calculated received intensity in the intensity of the simulated control signal 70. The control circuit 120 also performs frequency conversion so that the frequency of the simulated control signal 70 matches the frequency of the control signal 24. In addition, the control circuit 120 adjusts the polarization of the simulated control signal 70 so that it matches the polarization of the control signal 24.

[0074] Furthermore, the control circuit 120 sends the generated digital simulated control signal 70 to the control signal adjustment circuit 160. The control signal adjustment circuit 160 modulates the simulated control signal 70 using its built-in modulator 161. The modulator 161 modulates the simulated control signal 70 based on the modulation method, frame configuration, modulation speed, etc., specified in the modulation information of the air station data. The modulation may be digital or analog. The control signal adjustment circuit 160 then outputs the modulated simulated control signal 70 to the earth station 4. The control signal adjustment circuit 160 may also convert the digital simulated control signal 70 to analog using a D / A (digital / analog) converter (not shown) before outputting it to the earth station 4.

[0075] Next, let's describe the earth station 4. The input interface 421 receives multiple simulated signals 60 and one simulated control signal 70 from the emulator 1. The demodulation circuit 422 demodulates each of the signals received by the input interface 421. The demodulated multiple simulated signals 60 and one simulated control signal 70 are used to adjust the direction of the antenna 410.

[0076] The components whose explanations have been omitted are the same as those in Figure 11.

[0077] Figure 17 is a flowchart illustrating the process executed by the CPU 43 of the emulator 1 according to Embodiment 2. The process from step S21 to step S26 is the same as the process from step S11 to step S16 in Figure 13, so the explanation is omitted.

[0078] In this embodiment, step S27 is added after step S23. Step S27 is a process that is performed in parallel with step S24.

[0079] In step S27, it is determined whether the earth station 4, with its antenna 410 pointed in the direction indicated by the angle control value 50 at the position indicated by the first parameter value, can receive the control signal 24 from the target air station 3, which is positioned according to the second parameter value. In this determination, if the apparent direction of the air station 3 from the earth station 4 is outside the range of the earth station 4's antenna pattern, the earth station 4 is determined not to be able to receive the control signal 24 from the target air station 3. On the other hand, if the apparent direction of the air station 3 from the earth station 4 is within the range of the earth station 4's antenna pattern, the earth station 4 is determined not to be able to receive the control signal 24 from the target air station 3.

[0080] If the earth station 4 is unable to receive the control signal 24 from the target air station 3 (No), the process proceeds to step S25, and the signal from the air station 3 is not simulated.

[0081] On the other hand, if Earth Station 4 can receive the control signal 24 from the target air station 3 (Yes), it generates a simulated control signal 70 that simulates the control signal 24 of the air station 3 and outputs it to Earth Station 4 (step S28). Then the process returns to step S23.

[0082] In this embodiment, the emulator 1 outputs multiple simulated signals 60 transmitted by each of the multiple airborne stations 3, and a simulated control signal 70 transmitted by only one of the multiple airborne stations 3. The earth station 4 makes a final confirmation based on the simulated control signal 70 whether the simulated airborne station 3 is the target airborne station 3. This makes it possible for the earth station 4 to perform antenna direction adjustment more reliably than in Embodiment 1.

[0083] This disclosure is not limited to the embodiments described above, and various modifications can be made during implementation without departing from its essence. Furthermore, each embodiment and its modifications may be combined as appropriate, and the combined effects can be obtained in such cases.

[0084] 1: Emulator, 2: Base station, 3: Air station, 4: Earth station, 10: Communication signal, 11: Control data, 24: Control signal, 34: Beacon signal, 40: Input unit, 41: Output unit, 42: Communication unit, 43: CPU, 44: Memory, 45: HDD, 46: Bus, 47: Storage medium, 50: Angle control value, 60: Simulated signal, 70: Simulated control signal, 100: Air communication system, 110: Storage device, 120: Control circuit, 130: Signal adjustment circuit, 131: Converter, 150: Input interface, 160: Control signal adjustment circuit, 161: Modulator, 410: Receiving antenna, 420: Modem, 421: Input interface, 422: Demodulation circuit, 430: Antenna control circuit, 431: Receiving amplifier, 432: Angle control value acquisition circuit, 433: Output interface, 434: Acquisition determination circuit

Claims

1. An emulator configured to perform the following: a process of determining a first parameter value as the installation location of an earth station; a process of determining a second parameter value as the arrangement of multiple air stations; a process of obtaining the antenna direction of the earth station; a generation process of generating multiple simulated signals that simulate the signals that can be received from each of the multiple air stations arranged according to the second parameter value when the earth station points its antenna in the direction indicated by the first parameter value; and a process of outputting the multiple simulated signals to the earth station.

2. The emulator according to claim 1, wherein the generation process further includes, for each of the plurality of air stations, a process for calculating the received intensity of the signal that the earth station receives from the air stations, and a process for reflecting the calculated received intensity in the intensity of the simulated signal.

3. The emulator according to claim 1 or 2, further comprising: a process for generating a simulated control signal that simulates a control signal transmitted by only one of the multiple air stations; and a process for outputting the simulated control signal to the earth station.

4. An antenna direction adjustment method comprising: an emulator determining a first parameter value which is the installation location of an earth station; a second parameter value which is the arrangement of a plurality of air stations; obtaining the antenna direction of the earth station; generating a plurality of simulated signals which simulate beacon signals that can be received from each of the plurality of air stations arranged according to the second parameter value when the earth station points its antenna in the direction indicated by the first parameter value; and outputting the plurality of simulated signals to the earth station; and the earth station receiving the plurality of simulated signals and adjusting the antenna angle based on the plurality of simulated signals.

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