Wide angle domain real-time stabilization pointing and tracking system for phased array feed systems

Abstract

The application discloses a wide-angle domain real-time stable pointing and tracking scattering antenna system based on a phased array feed system, which comprises a multichannel digital phased array feed and a three-axis self-stable platform, the three-axis self-stable platform is used for determining the target direction of an antenna service beam in real time, and the multichannel digital phased array feed is used for real-time tracking and pointing determination of the antenna; the array scale of the multichannel digital phased array feed is n, there are M columns of units in an azimuth plane and N rows of units in an elevation plane, the array spacing is half of the wavelength of high frequency, in the n units, n-1 units are pure receiving channels, and the center unit is a transceiving shared unit; the multichannel digital phased array feed system guarantees real-time tracking and pointing determination of the antenna, and since the multichannel digital phased array feed can calculate the optimal path in millisecond, it is simple and easy for the scattering antenna to point to the optimal scattering angle in real time during the movement of a carrier.

Description

Technical Field

[0001] This invention belongs to the field of scattering communication technology, specifically relating to a wide-angle domain real-time stable pointing and tracking system for a phased array feed system. Background Technology

[0002] Currently, scattering communication systems require the system to be stationary during operation. If the system is on a moving platform, the communication antenna cannot point and track the scattering object in real time, preventing the system from establishing a scattering communication link and affecting communication reliability. There are two documented design methods for scattering communication systems on moving platforms. One is a wide-beam antenna guidance method, which involves adding a small antenna with a wide beam. This small antenna is used to scan and point the scattering communication angle, and then the pointing angle of the large antenna is changed to that of the small antenna. The other method uses a phased array antenna, which allows for rapid scanning and tracking.

[0003] Wide-beam antenna guidance methods have the following problems:

[0004] 1. Increased complexity and cost of base station construction. To achieve wide beam guidance, wide beam antennas must have their own independent system. This means that each base station needs to be equipped with two antennas, and the communication system also needs to be configured twice. Two systems will inevitably increase the overall system complexity of the base station and cause a sharp increase in construction costs.

[0005] 2. Wide and narrow beamwidths cause pointing angle errors. A wide beamwidth means that the antenna can obtain a scattering communication path over a wider angular domain, and the system cannot accurately determine the optimal scattering path. When a narrow-beam antenna switches to the scattering communication angular domain that a wide-beam antenna is pointing at, the pointing angle may not be the optimal scattering communication angle.

[0006] 3. System errors between the two antenna systems can cause antenna pointing errors. Each antenna system requires its own servo mechanism. Different servo mechanisms, due to their different implementation structures and electrical components, exhibit system errors. Even under calibration, it is difficult to eliminate these system errors between the two servo systems.

[0007] 4. It cannot achieve real-time tracking of the optimal scattering angle;

[0008] However, adaptive beamforming methods based on phased array antennas have the following problems:

[0009] 1. Significant gain loss: The beam pointing of a phased array antenna in a direction that deviates from the normal of the array surface will cause gain loss. This gain loss increases with the increase of the deviation angle in a cosine trend.

[0010] 2. The construction cost remains high. The cost of phased array antennas mainly includes three aspects: First, the channel cost. If the equivalent aperture of the antenna reaches 1.5 meters, at least 2,000 transmit and receive channels are required, resulting in huge hardware costs. Second, the beam control cost. To ensure real-time pointing and tracking, it is necessary to quickly and in real time calculate the signals received by all channels. Calculating the scattered signals received by 2,000 channels requires the system to have powerful computing capabilities, which is very costly. Third, the scattering cost. To ensure the long-term stable operation of the system, a good heat dissipation system design is required for the equipment. The cost of heat dissipation for such a large-scale array is also questionable.

[0011] 3. The system beam pointing has random pointing error. The phased array needs to adjust the phase and amplitude of each channel. In particular, the phase adjustment directly affects the beam characteristics. The phase adjustment of the phased array device has random deviation and cannot accurately reflect the actual phase information of the channel. This phase error will inevitably cause random pointing error of the beam pointing and also cause unnecessary gain loss.

[0012] 4. The power consumption is huge. To achieve a phased array with an equivalent aperture of 1.5 meters, at least 2,000 transmit and receive channels are required. At the same time, it is necessary to equip it with a computing unit with powerful computing capabilities. The cumulative power consumption of such an antenna system is often in the kilowatt level, which is at least 5 times that of the current antenna system. Summary of the Invention

[0013] The purpose of this invention is to provide a wide-angle domain real-time stable pointing and tracking system for a phased array feed system, so as to solve the problems mentioned in the background art.

[0014] To achieve the above objectives, the present invention provides the following technical solution: a wide-angle domain real-time stable pointing and tracking system for a phased array feed system, comprising a multi-channel digital phased array feed and a three-axis self-stabilizing platform, wherein the three-axis self-stabilizing platform is used to determine the real-time pointing direction of the antenna service beam, and the multi-channel digital phased array feed is used to perform real-time tracking and pointing determination of the antenna;

[0015] The array size of the multi-channel digital phased array feed is n, with M columns of elements in the azimuth plane and N rows of elements in the elevation plane. The array spacing is half the wavelength of the high frequency. In the n-channel elements, n-1 channels are pure receiving channels, and the central element is a shared receiving and transmitting element. The multi-channel digital phased array feed includes a feed group, a multi-channel digital receiving component, a data processing unit, an amplitude and phase calibration network, and a host.

[0016] As a preferred technical solution of the present invention, the feed group mainly consists of n feeds, wherein the feed placed at the focal point is mainly used for service communication, and the remaining n-1 feeds are connected to the receiving channel. The received signals of the n channels are used as the basic input for optimal propagation path calculation.

[0017] As a preferred technical solution of the present invention, the multi-channel digital receiving component is used to amplify and down-convert the received frequency band signal and transmit it to the multi-channel focal plane field analysis network.

[0018] As a preferred technical solution of the present invention, the host is used to control the system status and complete real-time system monitoring and control strategies.

[0019] As a preferred technical solution of the present invention, it also includes a multi-channel focal field analysis network and an RF transceiver unit. The multi-channel focal field analysis network is used to perform preliminary sampling and analysis on the focal field information collected from the n received signals and convert the data into digital quantities to be transmitted to the host. The RF transceiver unit is used for processing RF signals for business communication. The RF transceiver unit receives the intermediate frequency transmission signal from the host, up-converts it, amplifies it, and transmits it to the feedhorn. It also amplifies and down-converts the RF signal received by the feedhorn, processes it into a digital signal, and transmits it to the data processing unit.

[0020] As a preferred technical solution of this invention, the data processing unit mainly performs digital information processing, including focal plane analysis of digital information from n receiving channels to obtain the current optimal signal transmission path. Simultaneously, it processes the digital signals for managing business communication.

[0021] As a preferred technical solution of the present invention, the steps for using the scattering communication antenna based on a multi-channel digital phased array feed are as follows:

[0022] Step 1: The system is powered on and initialized. The antenna control system obtains the current direction of the antenna beam and calculates the angle of the communication scatterer relative to the antenna.

[0023] Step 2: The three-axis system drives the antenna to rotate, so that the beam of the feed at the antenna focal point points towards the scatterer, and coarse alignment begins;

[0024] Step 3: The feed at the focal point of the reflector emits an electromagnetic wave signal towards the scatterer. This electromagnetic wave signal will be transmitted to other base stations through the scatterer, and the system link establishment will begin.

[0025] Step 4: The N channels receive electromagnetic wave signals emitted by other base stations and scattered by the scatterer. After receiving the signals, the N channels analyze the frequency and system time of the incoming wave signals.

[0026] Step 5: Repeat steps 3 and 4 until any one of the N channels successfully synchronizes frequency and time with the other base station;

[0027] Step 6: The system selects the feed source closest to the focal point of the reflector in the successfully established channel, and calculates the elevation angle θE and azimuth angle θA between the feed source's radiated beam and the focal axis of the reflector. The turntable drives the antenna to rotate by -θE in the elevation angle and -θA in the azimuth angle, so that the feed source beam at the focal point is aligned with the optimal scattering angle, and the fine alignment is completed.

[0028] Step 7: Except for the feed source at the focal point which transmits and receives signals, all other feed sources switch to receiving mode;

[0029] Step 8: Based on the scattered signals received from n channels, the system calculates the focal plane field distribution characteristics of the reflecting surface in real time and evaluates the optimal scattering angle (EL, EA).

[0030] Step 9: The system rotates the antenna beam pointing (-EL, -EA) in real time according to the optimal scattering angle calculated in Step 8, so that the beam of the feed at the focal point of the reflector always points to the optimal scattering angle.

[0031] Step 10; Repeat steps 8 and 9. The system will maintain communication at the optimal scattering angle in real time, thus isolating the scattering angle changes introduced during the carrier's movement.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] The multi-channel digital phased array feed system ensures real-time antenna tracking and pointing determination. Furthermore, because the multi-channel digital phased array feed can calculate the optimal path in milliseconds, aligning the scattering antenna becomes simple and easy. During alignment, multiple azimuth and elevation scans are no longer required to obtain the optimal scattering communication angle. Moreover, this calculation is based on digital computation, and the time consumed by this process is negligible. Therefore, based on the multi-channel digital phased array, the current optimal scattering alignment angle can be obtained in real time. Even if the scattering communication equipment is installed on a mobile platform, after initial angle alignment, the multi-channel digital phased array feed can support the system to quickly and in real-time obtain the current optimal scattering angle. Attached Figure Description

[0034] Figure 1 This is a diagram of the scattering communication system of the multi-channel digital phased array feed of the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1

[0037] Please see Figure 1 This invention provides a technical solution: a wide-angle domain real-time stable pointing and tracking system for a phased array feed system, comprising a multi-channel digital phased array feed and a three-axis self-stabilizing platform. The three-axis self-stabilizing platform is used to determine the real-time pointing direction of the antenna service beam. The multi-channel digital phased array feed is used to perform real-time tracking and pointing determination of the antenna. The multi-channel digital phased array feed mainly utilizes the characteristic that when the incoming wave illuminates the reflector, the incoming wave will be converged to the focal plane. When the incoming wave converges to the focal plane of the reflector, if multiple feeds are placed at certain intervals on the focal plane of the reflector, and the signals received by these feeds are subjected to post-shaping processing, the receiving gain can be maximized and the receiving efficiency can be improved. Similarly, after obtaining the field distribution characteristics of the focal plane through multiple feeds, the incoming wave direction corresponding to the current field distribution can also be obtained by integral calculation.

[0038] The multi-channel digital phased array feed has an array size of n, with M columns of elements in the azimuth plane and N rows of elements in the elevation plane. The array spacing is half the wavelength of the high frequency. In the n-channel elements, n-1 channels are pure receiving channels, and the central element is a shared transmitting and receiving unit. The multi-channel digital phased array feed includes a feed group, a multi-channel digital receiving component, a data processing unit, an amplitude and phase calibration network, and a host. In scattering communication, there is a multipath effect in the direction of arrival. After the antenna service beam is pointed to the predicted angle according to the host command, it is necessary to perform multiple scans at the azimuth and elevation angles to find the optimal communication path within a small air-to-ground angle. When the reflector surface used by the scattering antenna is equipped with a multi-channel digital phased array feed... After the source, since the multi-channel digital phased array feed can calculate the optimal path in milliseconds, the alignment of the scattering antenna becomes simple and easy. Since the optimal scattering communication angle can be obtained without multiple azimuth and elevation scans during the alignment process, and this calculation is based on digital computation, the time consumed by this calculation process is negligible. Therefore, based on the multi-channel digital phased array, the current optimal scattering alignment angle can be obtained in real time. Obviously, even if the scattering communication equipment is installed on a mobile carrier, after the initial angle alignment is completed, the multi-channel digital phased array feed can support the system to quickly obtain the current optimal scattering angle in real time.

[0039] The multi-channel digital phased array feed can support the system to perform digital calculations to obtain the optimal path within ±θA of the azimuth plane and ±θE of the elevation plane, which means that when the carrier is moving, the system can determine the optimal scattering angle within ±θA of the current service beam azimuth plane and ±θE of the elevation plane in real time based on the data. Based on this data, combined with the current moving attitude of the carrier, the system can predict the alignment angle of the scattered beam in real time.

[0040] In this embodiment, the feed group mainly consists of n feeds, of which the feed placed at the focal point is mainly used for service communication, and the remaining n-1 feeds are connected to the receiving channel. The received signals of the n channels are used as the basic input for optimal propagation path calculation.

[0041] In this embodiment, the multi-channel digital receiving component is used to amplify and down-convert the received frequency band signal and transmit it to the multi-channel focal plane field resolution network.

[0042] In this embodiment, the host is responsible for controlling the system status and implementing real-time system monitoring and control strategies.

[0043] This embodiment also includes a multi-channel focal field analysis network and an RF transceiver unit. The multi-channel focal field analysis network is used to perform preliminary sampling and analysis on the focal field information collected from the n received signals and convert the data into digital quantities to be transmitted to the host. The RF transceiver unit is used for processing RF signals for business communication. The RF transceiver unit receives the intermediate frequency transmission signal from the host, up-converts it, amplifies it, and transmits it to the feed source. It also amplifies and down-converts the RF signal received by the feed source, processes it into a digital signal, and transmits it to the data processing unit.

[0044] In this embodiment, the data processing unit mainly processes digital information, including focal plane analysis of digital information from n receiving channels to obtain the current optimal signal transmission path. Simultaneously, it processes the digital signals for managing service communication.

[0045] In this embodiment, the steps for using the scattering communication antenna based on a multi-channel digital phased array feed are as follows:

[0046] Step 1: The system is powered on and initialized. The antenna control system obtains the current direction of the antenna beam and calculates the angle of the communication scatterer relative to the antenna.

[0047] Step 2: The three-axis system drives the antenna to rotate, so that the beam of the feed at the antenna focal point points towards the scatterer, and coarse alignment begins;

[0048] Step 3: The feed at the focal point of the reflector emits an electromagnetic wave signal towards the scatterer. This electromagnetic wave signal will be transmitted to other base stations through the scatterer, and the system link establishment will begin.

[0049] Step 4: The N channels receive electromagnetic wave signals emitted by other base stations and scattered by the scatterer. After receiving the signals, the N channels analyze the frequency and system time of the incoming wave signals.

[0050] Step 5: Repeat steps 3 and 4 until any one of the N channels successfully synchronizes frequency and time with the other base station;

[0051] Step 6: The system selects the feed source closest to the focal point of the reflector in the successfully established channel, and calculates the elevation angle θE and azimuth angle θA between the feed source's radiated beam and the focal axis of the reflector. The turntable drives the antenna to rotate by -θE in the elevation angle and -θA in the azimuth angle, so that the feed source beam at the focal point is aligned with the optimal scattering angle, and the fine alignment is completed.

[0052] Step 7: Except for the feed source at the focal point which transmits and receives signals, all other feed sources switch to receiving mode;

[0053] Step 8: Based on the scattered signals received from n channels, the system calculates the focal plane field distribution characteristics of the reflecting surface in real time and evaluates the optimal scattering angle (EL, EA).

[0054] Step 9: The system rotates the antenna beam pointing (-EL, -EA) in real time according to the optimal scattering angle calculated in Step 8, so that the beam of the feed at the focal point of the reflector always points to the optimal scattering angle.

[0055] Step 10; Repeat steps 8 and 9. The system will maintain communication at the optimal scattering angle in real time, thus isolating the scattering angle changes introduced during the carrier's movement.

[0056] Example 2

[0057] The difference from Example 1 is that all n channels have transmit and receive characteristics, each channel can transmit and receive independently, and the system selects the best communication channel for system communication.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wide angle domain real-time stabilized pointing and tracking system for a phased array feed system, characterized by: The application relates to a multi-channel digital phased array feed and a three-axis self-stabilizing platform for determining the real-time pointing direction of an antenna service beam to a target direction, and the multi-channel digital phased array feed is used for real-time tracking and pointing determination of the antenna; the array scale of the multi-channel digital phased array feed is n, the azimuth plane is arranged with M columns of units, the elevation plane is arranged with N rows of units, the array interval is half a wavelength of high frequency, in the n units, n-1 units are pure receiving channels, and the center unit is a transceiving shared unit; the multi-channel digital phased array feed comprises a feed group, a multi-channel digital receiving and transmitting assembly, a data processing unit, an amplitude and phase calibration network and a host computer; the feed group mainly comprises n feeds, wherein the feed arranged at the focal point mainly performs service communication, the remaining n-1 feeds are connected with the receiving channels, and the receiving signals of the n channels are used as basic input channels for optimal propagation path calculation; the multi-channel digital receiving assembly is used for completing amplification and frequency down conversion of the receiving frequency band signals, and transmitting the signals to a multi-channel focal plane field analysis network; the host computer is used for controlling the system state, completing real-time system monitoring and control strategies; the multi-channel focal plane field analysis network and a radio frequency receiving and transmitting unit are further included, wherein the multi-channel focal plane field analysis network is used for preliminarily sampling and analyzing the focal plane field information collected by the n receiving channels, and transmitting the data to the host computer in the form of digital quantity; the radio frequency receiving and transmitting unit is used for processing the radio frequency signals of the service communication transmitting and receiving, the radio frequency receiving and transmitting unit receives the intermediate frequency transmitting signals from the host computer, performs frequency up conversion, amplification and transmission to the feed, and also amplifies, frequency down converts, processes into digital signals and transmits to the data processing unit; the data processing unit mainly performs digital quantity information processing, mainly including focal plane analysis of the digital quantity information of the n receiving channels, obtaining the current optimal signal transmission path, and processing the transmitting and receiving signals of the management communication service in the form of digital quantity.

2. A wide angle domain real-time stabilized pointing and tracking system for a phased array feed system according to claim 1, characterized in that: The use steps of the scattering communication antenna based on the multi-channel digital phased array feed are as follows: Step one: system power-on initialization, the antenna control system obtains the direction of the current antenna beam pointing and the angle of the system calculation communication scatterer relative to the antenna; Step two: the three-axis system drives the antenna to rotate, so that the beam of the feed at the focal point of the reflector points to the direction of the scatterer, and coarse alignment is started; Step three: the feed at the focal point of the reflector transmits electromagnetic wave signals to the scatterer, the electromagnetic wave signals are transmitted to other base stations through the scatterer, and system link establishment is started; Step four: the n-channel receives the electromagnetic wave signals scattered by the scatterer and transmitted by other base stations, and analyzes the frequency and system time of the incoming wave signals after the n-channel receives the signals; Step five: steps three and four are repeated until any one of the n channels and the opposite base station successfully calibrate the frequency and time; Step six: the system selects the feed closest to the focal point of the reflector from the channel with successful link establishment, calculates the elevation angle theta E and the azimuth angle theta A between the radiation beam of the feed and the focal axis of the reflector, and drives the antenna to rotate at the elevation angle -theta E and the azimuth angle -theta A, so that the feed beam at the focal point of the feed is aligned with the optimal scattering angle, and fine alignment is completed. Step seven: except the focal point feed transmits and receives signals, other feeds turn into receiving state; Step eight: the system calculates the focal plane field distribution characteristics of the reflector according to the scattering signals received by the n channels, and evaluates the optimal scattering angle (EL, EA); Step nine: the system points the antenna beam to rotate (-EL, -EA) according to the optimal scattering angle calculated in step eight, so that the beam of the focal point feed is always pointed to the optimal scattering angle; Step ten: repeat steps eight and nine, the system will maintain real-time communication at the optimal scattering angle, and isolate the scattering angle change problem introduced during the carrier movement.

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