Distributed electromagnetic field spatial power synthesis method based on motion platform

Abstract

The present invention discloses a distributed electromagnetic field space power synthesis method based on a motion platform, which belongs to the technical field of radio transmission systems using radiation fields, including: obtaining key parameters affecting synthesis efficiency in typical scenarios based on theoretical calculation and analysis of synthesis efficiency influencing factors; constructing a database of synthesis elements and synthesis efficiency in typical scenarios; training a multi-source multi-platform collaborative control model based on reinforcement learning based on the constructed database; and implementing collaborative control of distributed electromagnetic field space power synthesis based on the trained control model. The present invention can realize efficient synthesis and superposition of electromagnetic fields in free space, solving the problem that the effective distance and miniaturization of electromagnetic wave interference rejection equipment cannot be taken into account at the same time; through reinforcement learning of the posture adjustment of the motion platform and the transmitting antenna, as well as the output phase and pulse delay control strategy of the microwave source, the problem that the synthesis efficiency cannot be guaranteed when the motion platform is mounted is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio transmission systems using radiation fields, and more specifically, relates to a distributed electromagnetic field spatial power synthesis method based on a moving platform. Background Art

[0002] Electromagnetic interference rejection equipment has broad application prospects in the future intelligence. However, high-power systems based on high-power electromagnetic wave sources are often too large and inflexible to use, and are increasingly unable to meet the needs of equipment. Therefore, the development trend of electromagnetic interference rejection equipment is to pursue a larger effective distance while taking into account miniaturization. The increase in effective distance is usually achieved by increasing the transmission power. However, due to limitations such as power capacity and process, increasing the output power of a single electromagnetic wave source has encountered a major technical bottleneck; and miniaturization usually means sacrificing transmission power and shortening the effective distance of the equipment, which is difficult to balance with high power. Therefore, it is urgent to carry out research on electromagnetic wave spatial synthesis technology and explore ways to break through the output power limit of a single electromagnetic wave source, so as to further increase the total energy and total power of electromagnetic wave radiation.

[0003] The spatial synthesis of electromagnetic waves can be divided into two categories: energy synthesis and power synthesis. Energy synthesis is to increase the total energy of electromagnetic waves at the target by combining microwave pulses from a temporal perspective, without making special requirements for the pulse delay and phase of multi-source pulses. The power density at the synthesis point increases linearly with the increase in the number of electromagnetic wave transmitting devices; power synthesis is to increase the total radiation power of the system through spatial coherence methods and enhance the electromagnetic field intensity in space. The power density at the synthesis point increases quadratically with the increase in the number of electromagnetic wave transmitting devices, and therefore has greater application prospects and research value.

[0004] In terms of implementation, electromagnetic wave spatial power synthesis is divided into waveguide synthesis, phased array-based synthesis, and distributed synthesis. The comparison diagram of the three types of power synthesis is shown in the figure. Figure 1 As shown. Channel power synthesis technology is to synthesize the power of several electromagnetic wave sources in the channel. The synthesized electromagnetic wave power is radiated through an antenna. Due to the power capacity of the microwave channel and the number of microwave devices, the synthesized power that can be obtained is limited, and multiple microwave sources need to be arranged in the same position. Phased array-based synthesis is that each phase-locked electromagnetic wave source is adjusted according to the amplitude and phase, and then fed to each radiating array element through a transmission waveguide and a phase shifter to synthesize the radiation power in space. However, both methods require multiple microwave sources to be centrally arranged in space, which cannot achieve true equipment miniaturization.

[0005] Distributed electromagnetic field space power synthesis is to disperse multiple low-power electromagnetic wave sources within a certain range, emit electromagnetic waves with the same frequency and phase that conform to a specific relationship, and converge at the target by precisely controlling the time and phase of microwave pulses, so that the power is coherently superimposed during the propagation of space, and realize the efficient synthesis of multiple microwave beams in space. Compared with the previous space power synthesis method, this method can disperse multiple electromagnetic wave sources in space, reducing the volume and weight requirements for a single carrier platform, so that the electromagnetic wave sources used for synthesis can be independently carried on multiple moving platforms, so that the electromagnetic wave interference denial equipment has the ability to fight forward, and the actual action range of the equipment can be improved by using the movement of the carrier platform itself and the multi-source power synthesis, which can truly achieve a balance between a large action range and miniaturization of equipment.

[0006] On the one hand, since spatial power synthesis is generally at the signal level by default, that is, spatial coherence must be achieved at all times, and this is too demanding on the stability and control accuracy of the device, making it almost impossible to achieve. However, for the electromagnetic wave interference rejection system, signal-level spatial coherence is not required, and the purpose of interference rejection can be achieved by achieving high field strength through spatial coherence synthesis at certain moments, which greatly reduces the difficulty of achieving spatial power synthesis. On the other hand, artificial intelligence technology, especially reinforcement learning technology, which has been rapidly developed in recent years, can continuously learn the best action sequence according to the reward value of the selected action, and has low requirements for prior knowledge of the control environment. It can achieve good learning performance in large spaces and complex nonlinear systems. It has been increasingly widely used in resource scheduling, industrial manufacturing, traffic control, robotics and other fields, thus providing a solution for the realization of distributed electromagnetic field spatial power synthesis. Summary of the invention

[0007] In view of the above defects or improvement needs of the prior art, the present invention proposes a distributed electromagnetic field spatial power synthesis method based on a moving platform. By independently mounting multiple low-power electromagnetic wave sources on multiple moving platforms and arranging them in a dispersed manner within a certain spatial range, and by controlling key parameters such as the pulse delay and phase of the emitted electromagnetic waves and converging them in space, efficient synthesis and superposition of electromagnetic fields in free space are achieved, thereby solving the problem that the effective range and miniaturization of electromagnetic wave interference rejection equipment cannot be taken into account at the same time.

[0008] To achieve the above object, the present invention provides a distributed electromagnetic field spatial power synthesis method based on a motion platform, based on independently mounting multiple electromagnetic wave sources on multiple motion platforms, and the multiple motion platforms are dispersedly arranged within a certain spatial range. The method includes:

[0009] Based on theoretical calculation and analysis of factors affecting synthesis efficiency, key parameters affecting synthesis efficiency in typical scenarios are obtained;

[0010] Build a database of synthesis elements and synthesis efficiency in typical scenarios;

[0011] Based on the constructed database, a multi-source and multi-platform collaborative control model based on reinforcement learning is trained;

[0012] The coordinated control implementation of distributed electromagnetic field spatial power synthesis is realized based on the trained control model.

[0013] In some optional embodiments, the key parameters include: pulse delay error, phase error, alignment error and polarization error.

[0014] In some optional implementation schemes, the step of constructing a database of synthesis elements and synthesis efficiencies in typical scenarios includes:

[0015] Use high-speed data acquisition equipment to obtain pulse delay errors;

[0016] Use phase detector and laser rangefinder to obtain phase error;

[0017] Use gyroscopes, servo encoders, and differential positioning devices to obtain alignment and polarization errors;

[0018] A database is constructed based on the acquired pulse delay error, phase error, alignment error and polarization error.

[0019] In some optional implementations, the training of the multi-source and multi-platform collaborative control model based on reinforcement learning based on the constructed database includes:

[0020] Each motion platform and its electromagnetic wave source are regarded as an intelligent entity, and the environment is the relative position relationship between each motion platform and the convergence target, the disturbance of the platform posture, and the frequency and phase output stability of the microwave source;

[0021] The instantaneous reward is given according to the instantaneous change of the synthesis efficiency, and the value function represents the overall consistency of alignment, phase, delay and polarization, that is, how close each parameter is to achieving the highest overall synthesis efficiency;

[0022] The strategy is to adjust the position and posture of the motion platform and the transmitting antenna, as well as the output phase and pulse delay of the microwave source;

[0023] The constructed database is used to train the model parameters for use in the actual control process.

[0024] In some optional implementation schemes, the coordinated control implementation of distributed electromagnetic field spatial power synthesis based on the trained control model includes:

[0025] By sensing the changes in the posture of the platform, the servo system adjusts the direction and rotation angle of the electromagnetic wave transmitting antenna to achieve the convergence of each electromagnetic wave beam at the designated target and ensure the consistency of polarization direction;

[0026] By adjusting the parameters of the injected small signal, the pulse phase and timing of the final output of the electromagnetic wave source are adjusted, so that the pulse time coincidence and phase consistency of each electromagnetic wave beam at the designated target can be achieved, ultimately achieving efficient spatial power synthesis of the distributed electromagnetic field.

[0027] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0028] (1) Break through the power limit of a single low-power microwave source and achieve efficient superposition of electromagnetic fields in free space. Its synthesis effect is better than traditional energy synthesis. The power density at the synthesis point increases squarely with the increase in the number of electromagnetic wave transmitting devices. Its superposition effect is better than the linear increase rate of traditional energy synthesis.

[0029] (2) The low-power electromagnetic wave sources used for synthesis are independently mounted on multiple moving platforms, and the rapid movement of the mounting platforms themselves is used to increase the actual effective range of the equipment. This can truly achieve a balance between a large effective range and miniaturized equipment. The flexibility of the synthesis method is better than that of traditional waveguide power synthesis and phased array power synthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of three synthesis methods provided by an embodiment of the present invention;

[0031] Figure 2 It is a block diagram of a distributed spatial power synthesis implementation scheme provided by an embodiment of the present invention;

[0032] Figure 3 It is a schematic diagram of a database collection device provided by an embodiment of the present invention;

[0033] Figure 4 It is a relationship diagram of key elements of reinforcement learning provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] The present invention (1) constructs an implementation framework for realizing high power density energy delivery by using distributed space power synthesis; (2) analyzes the influence of being mounted on a moving platform on the efficiency of space power synthesis, and provides control elements and control methods.

[0036] Distributed space power synthesis implementation plan Figure 2 shown.

[0037] (1) Theoretical calculation and analysis of factors affecting synthesis efficiency

[0038] In the actual process of spatial power synthesis, the influence of various factors makes it difficult to achieve the maximum synthesis efficiency, mainly including electromagnetic wave frequency error, pulse delay error, phase error, amplitude error, alignment error and polarization error, etc. The following takes phase error as an example to briefly introduce the analysis process of the influence of various errors on synthesis efficiency.

[0039] Assuming that the binary array transmits a sinusoidal signal with the same polarization direction and angular frequency of ω, the synthetic field strength in the far field is: E(t) = A1 cos(ωt+θ1) + A2cos(ωt+θ2), where A1 and A2, θ1 and θ2 are the electric field strength and phase of the two signals respectively. Considering the effect of phase difference, let A1 = A2 = A. The power density at a certain far field position is: In the formula, Z0 represents the free space wave impedance. Assume that the phase error is Δθ=θ1-θ2, which obeys the normal distribution, with a mean of 0 and a variance of σ 2 =Δθ 2 . Then the expected value of power density is: Because the maximum value of P max =4e 2 / Z0, so: By extension, for an N-element identical array, the composite loss caused by the phase is: Each phase error is independent, and all errors obey variable distribution. When k = m, σ km =0; when k≠m, the phase difference variable therefore, When N→∞, the above formula is simplified to: That is, when the number of units N=2 and the standard deviation of the phase error is 30°, the expected synthesis efficiency is 0.885 times the maximum value; and when the standard deviation of the phase error is 90°, the expected synthesis efficiency is 0.543 times the maximum value. It can be seen that a larger phase error will significantly reduce the overall synthesis efficiency.

[0040] The above is the analysis process of phase error. The analysis process of other factors is similar and will not be repeated here. When the number of units is different and the standard deviation level of each type of error is different, the degree of influence on the synthesis efficiency is different. In the typical scenario of distributed electromagnetic field spatial power synthesis based on a moving platform, the pulse delay error, phase error, alignment error and polarization error have a greater impact on the synthesis efficiency. Therefore, these four types of errors are not only the main parameters for database construction, but also the adjustment objects during collaborative control.

[0041] (2) Construction of a database of synthesis elements and synthesis efficiency in typical scenarios, which refers to distributed interference denial scenarios in this embodiment of the present invention.

[0042] Among the four types of errors, pulse delay error, phase error, alignment error and polarization error: pulse delay error comes from the asynchronous trigger pulse time of the microwave source, which can be obtained using high-speed data acquisition equipment; phase error comes from the phase error of the microwave source output and the path difference caused by the relative displacement between the moving platforms, which can be obtained using phase detectors and laser rangefinders; alignment error and polarization error come from the mechanical vibration of the moving platform, the motion delay of the servo mechanism and the positioning error of the moving platform itself, which can be obtained using gyroscopes, servo encoders and differential positioning equipment. The acquisition devices required for database construction are as follows: Figure 3 shown.

[0043] (3) Multi-source and multi-platform collaborative control model training based on reinforcement learning

[0044] The typical framework of reinforcement learning is shown in Figure 4. Each motion platform and its electromagnetic wave source can be regarded as an intelligent agent; the environment is the relative position relationship between each motion platform and the convergence target, the disturbance of the platform posture, the stability of the microwave source frequency and phase output, etc.; the instantaneous reward can be given according to the instantaneous change of the synthesis efficiency; the value function represents the overall consistency of alignment, phase, delay and polarization, that is, the degree of proximity of each parameter to the highest overall synthesis efficiency; the strategy is the posture adjustment of the motion platform and the transmitting antenna, as well as the output phase and pulse delay of the microwave source. Under the above reinforcement learning framework, the model parameters are trained using the database constructed in step (2) for use in the actual control process.

[0045] (4) Implementation of coordinated control of distributed electromagnetic field spatial power synthesis

[0046] By sensing the changes in the posture of the carrying platform and adjusting the orientation and rotation angle of the electromagnetic wave transmitting antenna through the servo system, the various electromagnetic wave beams can be converged at the designated target and the polarization direction can be consistent. The pulse phase and timing of the final output of the electromagnetic wave source can be adjusted by adjusting the parameters of the injected small signal, so that the pulse time overlap and phase consistency of each electromagnetic beam at the designated target can be achieved, ultimately realizing efficient spatial power synthesis of distributed electromagnetic fields.

[0047] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0048] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A distributed electromagnetic field spatial power synthesis method based on a motion platform, characterized in that: Based on the fact that multiple electromagnetic wave sources are independently mounted on multiple motion platforms, and the multiple motion platforms are dispersedly arranged within a certain spatial range, the method includes: Based on theoretical calculation and analysis of factors affecting synthesis efficiency, key parameters affecting synthesis efficiency in typical scenarios are obtained; Build a database of synthesis elements and synthesis efficiency in typical scenarios; Based on the constructed database, a multi-source and multi-platform collaborative control model based on reinforcement learning is trained; The coordinated control implementation of distributed electromagnetic field spatial power synthesis is realized based on the trained control model; The multi-source and multi-platform collaborative control model based on reinforcement learning is trained based on the constructed database, including: Each motion platform and its electromagnetic wave source are regarded as an intelligent entity, and the environment is the relative position relationship between each motion platform and the convergence target, the disturbance of the platform posture, and the frequency and phase output stability of the microwave source; The instantaneous reward is given based on the instantaneous change in the synthesis efficiency, and the value function represents the overall consistency of alignment, phase, delay, and polarization; The strategy is to adjust the position and posture of the motion platform and the transmitting antenna, as well as the output phase and pulse delay of the microwave source; The constructed database is used to train the model parameters for use in the actual control process.

2. The method according to claim 1, characterized in that The key parameters include: pulse delay error, phase error, alignment error and polarization error.

3. The method according to claim 2, characterized in that The database of synthesis elements and synthesis efficiency in typical scenarios is constructed, including: Use high-speed data acquisition equipment to obtain pulse delay errors; Use phase detector and laser rangefinder to obtain phase error; Use gyroscopes, servo encoders, and differential positioning devices to obtain alignment and polarization errors; A database is constructed based on the acquired pulse delay error, phase error, alignment error and polarization error.

4. The method according to claim 3, characterized in that The coordinated control implementation of distributed electromagnetic field spatial power synthesis based on the trained control model includes: By sensing the changes in the posture of the platform, the servo system adjusts the direction and rotation angle of the electromagnetic wave transmitting antenna to achieve the convergence of each electromagnetic wave beam at the designated target and ensure the consistency of polarization direction; By adjusting the parameters of the injected small signal, the pulse phase and timing of the final output of the electromagnetic wave source are adjusted, so that the pulse time coincidence and phase consistency of each electromagnetic wave beam at the designated target can be achieved, ultimately achieving efficient spatial power synthesis of the distributed electromagnetic field.

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