A scatterer positioning and tracking method for tropospheric scatter communication

Abstract

The present invention discloses a scatterer positioning and tracking method for tropospheric scattering communication, which belongs to the field of wireless communication. In the present invention, in the stage of establishing scattering communication, the master and slave stations exchange the position information of the opposite end through Beidou, control the antenna to rotate to the initial azimuth, send synchronous waveforms to each other at the initial azimuth, locate the azimuth and elevation angle corresponding to the best scatterer by comparing the received synchronous waveform quality information, and control the antenna to rotate to the position; in the normal communication stage, the received signal quality information is compared with the best received signal quality information stored locally, if the deviation is within the tolerance range, the azimuth and elevation angle of the antenna are not adjusted, otherwise, the master and slave station antennas perform secondary scanning in turn, track the scatterer with the best transmission capacity, and control the antenna to rotate to the position. The present invention can accurately locate and track the scatterer in real time, and reduce the influence of scatterer changes on the stability of the received signal.

Description

Technical Field

[0001] The invention relates to the field of wireless communications, and in particular discloses a scatterer positioning and tracking method suitable for tropospheric scatter communications. Background Art

[0002] Tropospheric scatter communication is a communication method that uses the scattering effect of the troposphere to achieve beyond-line-of-sight transmission. The intersection area formed by the beams of the transmitting and receiving antennas in the troposphere is called a scatterer. Due to the atmospheric turbulence constantly generated in the troposphere, the physical properties of the scatterer, such as temperature, humidity and pressure, change randomly, which in turn causes irregular changes in the density and refractive index of the scatterer. The random change of the scatterer is the main factor restricting the reception of radio wave signals, which will cause random changes in the strength, phase and delay of the received signal. Therefore, it is very necessary to accurately locate and track the best scatterer in real time to ensure the relative stability of the strength, phase and delay of the received signal. Summary of the invention

[0003] In view of this, the present invention proposes a scatterer positioning and tracking method for tropospheric scatter communication, which can accurately locate and track the scatterer in real time to reduce the impact of scatterer changes on the stability of received signals.

[0004] The technical solution adopted by the present invention is:

[0005] A scatterer positioning and tracking method for tropospheric scatter communication comprises the following steps:

[0006] Step 1: The master station and the slave station send short messages to each other via Beidou satellites to send the latitude and longitude information of the local end to the other end;

[0007] Step 2: The master station pan / tilt and the slave station pan / tilt calculate the initial azimuth angle to be rotated according to the latitude and longitude information of the local end and the remote end, and control the antenna to rotate to the initial azimuth angle to achieve preliminary positioning of the scatterer in the horizontal direction;

[0008] Step 3: The master station antenna and the slave station antenna send synchronization waveforms to each other at the initial azimuth angle. The slave station antenna adjusts the pitch angle of the local antenna according to the quality of the received synchronization signal, and takes the position with the best quality of the received synchronization signal as the pitch angle position of the slave station antenna. At this time, the slave station antenna sends a pitch angle scanning completion instruction to the master station antenna. After receiving the pitch angle scanning completion instruction sent by the slave station antenna, the master station antenna starts pitch scanning and rotates the master station antenna to the position with the best quality of the received synchronization signal. At this time, the master station antenna sends a pitch angle scanning completion instruction to the slave station antenna.

[0009] Step 4: After receiving the elevation scan completion instruction sent by the master antenna, the slave antenna makes a fine adjustment of the azimuth to adjust the azimuth to the position with the best quality of the received synchronization signal, and sends an azimuth adjustment completion instruction to the master antenna; after receiving the azimuth adjustment completion instruction sent by the slave antenna, the master antenna makes a fine adjustment of the azimuth to adjust the azimuth to the position with the best quality of the received synchronization signal; the master antenna and the slave antenna store the best received signal strength and signal-to-noise ratio at the azimuth and elevation angle at the respective ends;

[0010] Step 5: During normal communication, the master station antenna and the slave station antenna monitor the received signal quality in real time and compare it with the best signal quality information stored in the local end; if the difference between the two is within the preset tolerance range, the master station antenna and the slave station antenna do not adjust the azimuth and elevation, and continue to monitor the difference between the current signal quality and the best signal quality; if the difference between the two exceeds the preset tolerance range, indicating that the best scatterer position has moved, the master station antenna and the slave station antenna perform a second scan based on the current azimuth and elevation angles, and execute step 6;

[0011] Step 6: The master station antenna sends a pitch secondary scanning instruction to the slave station antenna. After receiving the pitch secondary scanning instruction sent by the master station antenna, the slave station antenna performs a secondary scanning in the pitch direction and adjusts the pitch angle to an angle with the best received signal quality.

[0012] Step 7: The secondary station antenna sends a secondary pitch scan completion instruction to the primary station antenna. After receiving the secondary pitch scan completion instruction sent by the secondary station antenna, the primary station antenna performs a secondary scan in the pitch direction and adjusts the pitch angle to an angle with the best received signal quality.

[0013] Step 8: The antenna of the master station sends a secondary pitch scan completion instruction to the antenna of the slave station. After receiving the secondary pitch scan completion instruction sent by the antenna of the master station, the antenna of the slave station performs a secondary azimuth scan and adjusts the azimuth to an angle with the best received signal quality.

[0014] Step 9, the slave station antenna sends a secondary azimuth scan completion instruction to the master station antenna. After receiving the secondary azimuth scan completion instruction sent by the slave station antenna, the master station antenna performs a secondary azimuth scan and adjusts the azimuth to the angle with the best received signal quality. After the secondary pitch and azimuth scans are completed during the communication process, the best signal quality at this time is stored as a comparison benchmark for subsequent communication processes.

[0015] Furthermore, in step 3 and step 4, if the synchronization signal cannot be correctly parsed because the communication has just been initiated, the received signal strength is used to characterize the signal quality; after the synchronization signal can be correctly parsed, the signal-to-noise ratio is used to characterize the received signal quality.

[0016] Furthermore, in step 5 to step 9, the quality of the received signal is represented only by the received signal strength.

[0017] The beneficial effects of the present invention are:

[0018] 1. The present invention locates and tracks scatterers both during the communication establishment phase and during normal data communication, and can fully capture the real-time changes of the best scatterer to optimize communication performance.

[0019] 2. In the present invention, in the stage of establishing scattering communication, the master and slave stations exchange the position information of the opposite end through Beidou, control the antenna to rotate to the initial azimuth, send synchronous waveforms to each other at the initial azimuth, locate the azimuth and elevation angle corresponding to the best scatterer by comparing the received synchronous waveform quality information, and control the antenna to rotate to this position; in the normal communication stage, the received signal quality information is compared with the best received signal quality information stored locally. If the deviation is within the tolerance range, the azimuth and elevation angle of the antenna are not adjusted. Otherwise, the master and slave station antennas perform secondary scanning in turn to track the scatterer with the best transmission capacity, and control the antenna to rotate to this position. This method can accurately locate and track the scatterer in real time, reducing the impact of scatterer changes on the stability of the received signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 It is a schematic diagram of sending and receiving tropospheric scatter communication provided by an embodiment of the present invention.

[0022] Figure 2 The present invention provides a flowchart of scatterer positioning during the process of establishing tropospheric scatter communication.

[0023] Figure 3 The present invention provides a flowchart of performing secondary tracking and positioning of a scatterer during normal communication in tropospheric scatter communication according to an embodiment of the present invention. Implementation

[0024] In the following description, specific details such as specific device structures and techniques are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following will be described through specific embodiments in conjunction with the accompanying drawings.

[0026] A scatterer positioning and tracking method for tropospheric scatter communication, comprising:

[0027] The master station antenna and the slave station antenna exchange the location information of the other end through Beidou, and control the antenna of each station to rotate to the initial azimuth to achieve the preliminary positioning of the scatterer in the horizontal direction;

[0028] The master station antenna and the slave station antenna send synchronous waveforms to each other at the initial azimuth. The master station antenna and the slave station antenna adjust the antenna pitch angle according to the quality of the received synchronization signal, and locate the vertical pitch angle of the scatterer. The pitch angle with the best quality of the received synchronization signal is the best vertical pitch angle facing the scatterer.

[0029] The master station antenna and the slave station antenna are at the best elevation position. The antenna azimuth is fine-tuned according to the quality of the received synchronous waveform signal to determine the best azimuth angle, so as to achieve accurate positioning of the scatterer in the horizontal direction. The master station antenna and the slave station antenna store the best receiving signal quality at this azimuth and elevation angle at the end, and the opening process is completed;

[0030] In this process, the quality of the synchronization signal can be characterized in two ways: when the terminal processors of the master station antenna and the slave station antenna are not synchronized with the received signal, the received synchronization signal cannot be correctly parsed. In this case, the received signal strength is used to characterize the quality of the received signal; when the terminal processors of the master station antenna and the slave station antenna are synchronized with the signal sent by the other end, the received synchronization signal can be correctly parsed. In this case, the signal-to-noise ratio of the received synchronization signal is used to characterize the quality of the received synchronization signal.

[0031] During normal communication, the master antenna and the slave antenna detect the quality of the received signal in real time and compare it with the best signal quality information stored at the local end. If the difference between the two is within the preset tolerance range, the master antenna and the slave antenna do not adjust the azimuth and elevation. If the difference between the two exceeds the preset tolerance range, indicating that the position of the best scatterer has moved, the master antenna and the slave antenna perform a secondary scan of azimuth and elevation based on the current azimuth and elevation, and rotate the master antenna and the slave antenna to the position with the best quality of the received signal in the secondary scan, update the best received signal quality information at the local end, and realize real-time tracking of the best scatterer. The scanning range of the secondary azimuth and elevation is smaller than the scanning range of the azimuth and elevation during the link establishment process.

[0032] The preset tolerance range is obtained by simulation under the condition of considering the Doppler spread and multipath model of the scattering channel.

[0033] In normal communication, as the communication symbol rate increases, the signal-to-noise ratio of the received signal decreases. Therefore, in the real-time tracking stage of scatterers, the quality of the received signal is only characterized by the received signal strength, and when compared with the communication establishment process, only the received signal strength information is compared.

[0034] The secondary scanning process information of the master antenna and the slave antenna in azimuth and elevation is exchanged through link maintenance instructions. The scattering channels experienced by the master antenna and the slave antenna in receiving signals are symmetrical, so the secondary scanning conditions of the master antenna and the slave antenna in azimuth and elevation are met at the same time. The master antenna sends a secondary elevation scanning instruction to the slave antenna through link maintenance information. After receiving the instruction, the slave antenna performs secondary scanning in the elevation direction and adjusts the elevation angle to the angle with the best received signal quality. The slave antenna sends a secondary elevation scanning completion instruction to the master antenna. The master antenna starts secondary scanning in the elevation direction and adjusts the elevation angle to the angle with the best received signal quality. The master antenna sends an azimuth secondary scanning instruction to the slave antenna. After receiving the instruction, the slave antenna performs secondary scanning in azimuth and adjusts the azimuth to the angle with the best received signal quality. The slave antenna sends a secondary azimuth scanning completion instruction to the master antenna. The master antenna starts secondary scanning in azimuth and adjusts the azimuth to the angle with the best received signal quality. The master antenna sends a secondary adjustment completion instruction to the slave antenna.

[0035] During the secondary scanning process, when the opposite end antenna rotates, the azimuth and elevation of the local end antenna remain unchanged.

[0036] In one possible implementation, the pitch scanning range of the secondary scan is no more than ±5°, the azimuth scanning range is no more than ±1°, the scanning interval is 0.3°, each position stays for 3 seconds, and the channel quality information collected in 3 seconds is averaged as the received signal quality at this angle.

[0037] A device suitable for locating and tracking scatterers in tropospheric scatter communications comprises a master station antenna control pan-tilt and a slave station antenna control pan-tilt.

[0038] When scatterer positioning is performed during the communication establishment process, the gimbal controls the antenna at the end to rotate to the pitch angle and azimuth angle with the best quality for receiving the synchronization signal.

[0039] When scatterer tracking is performed during normal communication, the gimbal controls the antenna at the end to rotate to the pitch angle and azimuth angle for receiving the best quality of normal communication signals.

[0040] like Figure 1 As shown in the figure, the antenna control pan / tilt and antenna constitute the master station and slave station of tropospheric scatter communication. The intersection of the antenna beam angles of the master station and the slave station in the troposphere is called a scatterer. The radio wave signals emitted by the master station / slave station are scattered by the scatterer, and only a small part of the signal falls into the beam angle of the receiving antenna and is received by the slave station / master station, forming tropospheric scatter communication.

[0041] Due to the existence of atmospheric turbulence in the troposphere, the physical properties of the scatterer, such as temperature, pressure and humidity, are constantly changing randomly, causing the density and refractive index of the scatterer to change irregularly, and the scatterer's ability to transmit signals is also constantly changing. Therefore, during the establishment of tropospheric scattering communication and normal communication, this method uses the pan-tilt control antenna to track and locate the scatterer with the best transmission capacity, thereby optimizing the communication performance.

[0042] Figure 2 The present invention shows a scatterer positioning method applicable to the tropospheric scatter communication establishment process, comprising the following steps:

[0043] Step 1: The master station and the slave station send short messages to each other through Beidou to send the latitude and longitude information of the local end to the other end;

[0044] Step 2: The master station gimbal and the slave station gimbal calculate the initial azimuth angle that needs to be rotated according to the latitude and longitude information of the local and remote ends, and control the antenna to rotate to the initial azimuth angle to achieve preliminary positioning of the scatterer in the horizontal direction.

[0045] Step 3: The master antenna and the slave antenna send synchronization waveforms to each other at the initial azimuth. The slave antenna adjusts the elevation angle of the local antenna according to the quality of the received synchronization signal. The position with the best quality of the received synchronization signal is the elevation angle position of the slave antenna. At this time, the slave antenna sends a pitch scan completion instruction to the master antenna. After receiving the instruction, the master antenna starts the pitch scan and rotates the master antenna to the position with the best quality of the received synchronization signal. At this time, the master antenna sends a pitch scan completion instruction to the slave antenna. Step 3 realizes the vertical positioning of the transceiver antenna on the scatterer.

[0046] Step 4: The slave station antenna first makes a fine adjustment of the azimuth to the position where the quality of the received synchronization signal is best, and sends an azimuth adjustment completion instruction to the master station antenna; after receiving the instruction, the master station antenna makes a fine adjustment of the azimuth to the position where the quality of the received synchronization signal is best; the master station antenna and the slave station antenna store the best received signal strength and signal-to-noise ratio at this azimuth and elevation angle at their respective ends, and the opening process is completed.

[0047] It should be noted that: in this embodiment, there are two ways to characterize the quality of the synchronization signal during the communication establishment process. The terminal processors of the master station antenna and the slave station antenna are not synchronized with the received signal, and the received synchronization signal cannot be correctly parsed. In this case, the received signal strength is used to characterize the quality of the received signal; the terminal processors of the master station antenna and the slave station antenna are synchronized with the signal sent by the other end, and the received synchronization signal can be correctly parsed. In this case, the signal-to-noise ratio of the received synchronization signal is used to characterize the quality of the received synchronization signal.

[0048] Figure 3 The present invention shows a scatterer tracking and positioning method applicable to the normal communication process of tropospheric scatter, which includes the following steps:

[0049] Step 1: During normal communication, the master station antenna and the slave station antenna monitor the quality of the received signal in real time and compare it with the best signal quality information stored at the local end;

[0050] Step 2: If the difference between the two is within the preset tolerance range, the master station antenna and the slave station antenna do not adjust the azimuth and elevation, and return to step 1 to continue monitoring the difference between the current signal quality and the best signal quality; if the difference between the two exceeds the preset tolerance range, it indicates that the best scatterer position has moved, and the master station antenna and the slave station antenna will perform a second scan based on the current azimuth and elevation angles, and continue to step 3;

[0051] Step 3: The antenna of the master station sends a secondary pitch scanning instruction to the antenna of the slave station. After receiving the instruction, the antenna of the slave station performs secondary scanning in the pitch direction and adjusts the pitch angle to an angle with the best received signal quality.

[0052] Step 4, the slave station antenna sends a secondary pitch scan completion instruction to the master station antenna;

[0053] Step 5: The antenna of the master station performs a second scan in the pitch direction and adjusts the pitch angle to an angle with the best received signal quality;

[0054] Step 6: The master station antenna sends a secondary pitch scan completion instruction to the slave station antenna;

[0055] Step 7: The slave station antenna performs a second azimuth scan and adjusts the azimuth to an angle with the best received signal quality;

[0056] Step 8, the slave station antenna sends a secondary azimuth scanning completion instruction to the master station antenna;

[0057] Step 9: The antenna of the master station performs a secondary azimuth scan and adjusts the azimuth to the angle with the best received signal quality. After the secondary scans of elevation and azimuth are completed during the communication process, the best signal quality at this time is stored as a comparison benchmark for subsequent communication processes.

[0058] It should be noted that, in the normal communication process, as the communication symbol rate increases, the signal-to-noise ratio of the received signal tends to decrease. Therefore, in the real-time tracking stage of the scatterer, the quality of the received signal is only measured by the receiving

[0059] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A scatterer positioning and tracking method for tropospheric scatter communication, It is characterized in that The following steps are involved: Step 1: The master station and the slave station send short messages to each other via Beidou satellites to send the latitude and longitude information of the local end to the other end; Step 2: The master station pan / tilt and the slave station pan / tilt calculate the initial azimuth angle to be rotated according to the latitude and longitude information of the local and remote terminals, and control the antenna to rotate to the initial azimuth angle to achieve preliminary positioning of the scatterer in the horizontal direction; Step 3: The master station antenna and the slave station antenna send synchronization waveforms to each other at the initial azimuth angle. The slave station antenna adjusts the pitch angle of the local antenna according to the quality of the received synchronization signal, and takes the position with the best quality of the received synchronization signal as the pitch angle position of the slave station antenna. At this time, the slave station antenna sends a pitch angle scanning completion instruction to the master station antenna. After receiving the pitch angle scanning completion instruction sent by the slave station antenna, the master station antenna starts pitch scanning and rotates the master station antenna to the position with the best quality of the received synchronization signal. At this time, the master station antenna sends a pitch angle scanning completion instruction to the slave station antenna. Step 4: After receiving the elevation scan completion instruction sent by the master antenna, the slave antenna makes a fine adjustment of the azimuth to adjust the azimuth to the position with the best quality of the received synchronization signal, and sends an azimuth adjustment completion instruction to the master antenna; after receiving the azimuth adjustment completion instruction sent by the slave antenna, the master antenna makes a fine adjustment of the azimuth to adjust the azimuth to the position with the best quality of the received synchronization signal; the master antenna and the slave antenna store the best received signal strength and signal-to-noise ratio at the azimuth and elevation angle at the respective ends; Step 5: During normal communication, the master station antenna and the slave station antenna monitor the received signal quality in real time and compare it with the best signal quality information stored in the local end; if the difference between the two is within the preset tolerance range, the master station antenna and the slave station antenna do not adjust the azimuth and elevation, and continue to monitor the difference between the current signal quality and the best signal quality; if the difference between the two exceeds the preset tolerance range, indicating that the best scatterer position has moved, the master station antenna and the slave station antenna perform a second scan based on the current azimuth and elevation angles, and execute step 6; Step 6: The master station antenna sends a pitch secondary scanning instruction to the slave station antenna. After receiving the pitch secondary scanning instruction sent by the master station antenna, the slave station antenna performs a secondary scanning in the pitch direction and adjusts the pitch angle to an angle with the best received signal quality. Step 7: The slave antenna sends a secondary pitch scan completion instruction to the master antenna. After receiving the secondary pitch scan completion instruction sent by the slave antenna, the master antenna performs a secondary scan in the pitch direction and adjusts the pitch angle to an angle with the best received signal quality. Step 8: The antenna of the master station sends a secondary pitch scan completion instruction to the antenna of the slave station. After receiving the secondary pitch scan completion instruction sent by the antenna of the master station, the antenna of the slave station performs a secondary azimuth scan and adjusts the azimuth to an angle with the best received signal quality. Step 9: The secondary station antenna sends a secondary azimuth scan completion instruction to the primary station antenna. After receiving the secondary azimuth scan completion instruction sent by the secondary station antenna, the primary station antenna performs a secondary azimuth scan and adjusts the azimuth to an angle with the best received signal quality. After the second scan of pitch and azimuth is completed during the communication process, the best signal quality at this time is stored as a comparison benchmark for subsequent communication processes.

2. A scatterer positioning and tracking method for tropospheric scatter communication according to claim 1, It is characterized in that In step 3 and step 4, if the synchronization signal cannot be correctly parsed because the communication has just been initiated, the received signal strength is used to characterize the signal quality; after the synchronization signal can be correctly parsed, the signal-to-noise ratio is used to characterize the received signal quality.

3. The scatterer positioning and tracking method for tropospheric scatter communication according to claim 1, It is characterized in that In step 5 to step 9, the quality of the received signal is represented only by the received signal strength.

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