Distributed high-dynamic node system and its transmit beam coherent synthesis method

Abstract

The present invention discloses a distributed high-dynamic node system and a transmission beam coherent synthesis method thereof, which belongs to the field of antenna technology. The method comprises the following steps: first, N transmitting nodes enable reset to keep signal synchronization, and provide two working modes of single transmission and simultaneous transmission of modulation signal and positive / negative single-tone signal, and N nodes transmit wireless signals after keeping the signal carrier homology; then, the received modulation signal or multi-tone signal is down-converted and low-pass filtered at the receiving node; then, the phase difference between the transmitting nodes is estimated according to the positive / negative single-tone signal transmitted by the N nodes; finally, the phase difference result is fed back to the transmitting node for pre-compensation, maximizing the distributed node transmission coherent synthesis gain. The present invention has the advantages of flexible expansion, high real-time performance and easy implementation.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and more specifically, to a distributed high-dynamic node system and a transmission beam coherent synthesis method thereof. Background Art

[0002] Distributed coherent systems are often used in many fields such as deep space telemetry and remote control, ultra-long-range radar detection, and radio astronomy. Transmit beam coherence is achieved by coherently adjusting the transmitted signals of distributed nodes so that they can reach the receiving node simultaneously and in phase and focus the energy, thereby maximizing the gain of the transmitting node beam synthesis, thereby achieving long-distance and high-precision communication, detection and tracking.

[0003] Existing distributed transmit beam coherence methods typically assume that the positions of each transmitting and receiving node are precisely known. This is necessary to determine the phase difference between each transmitting node and perform phase pre-compensation, thereby achieving transmit beam coherence synthesis gain. However, when distributed nodes are highly dynamic, their position information is difficult to obtain in real time, making it impossible to accurately estimate the phase difference between each transmitting node, which in turn leads to a significant loss in the synthesis gain of the distributed transmit coherence system. Therefore, finding a real-time and efficient phase difference estimation method suitable for highly dynamic nodes is crucial to improving the gain and efficiency of distributed transmit coherence synthesis. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a distributed high-dynamic node system and a transmission beam coherent synthesis method thereof, which is suitable for distributed high-dynamic node systems, has flexible expansion, high real-time performance and is easy to implement.

[0005] The object of the present invention is achieved through the following solutions:

[0006] A distributed highly dynamic node system, comprising:

[0007] A distributed node signal transmission model building module is used to enable and reset N transmitting nodes to maintain signal synchronization. It also provides two working modes: single transmission and simultaneous transmission of modulated signals and positive / negative single-tone signals. N nodes maintain the same signal carrier and then transmit wireless signals.

[0008] The frequency conversion module is used to down-convert the modulated signal and the multi-tone signal transmitted by the distributed transmitting node at the receiving node to obtain a zero-frequency signal for subsequent processing;

[0009] The filtering module is used to perform low-pass filtering on each zero-frequency received signal obtained by the frequency conversion module, and decouple the positive / negative single-tone signals transmitted by N nodes respectively;

[0010] A parameter estimation module is used to estimate the phase difference between any two transmitting nodes using the positive / negative single-tone signals decoupled by the filtering module;

[0011] The performance evaluation module is used to feed back the phase difference estimated by the parameter estimation module to the N transmitting nodes for pre-compensation, and then calculate the gain and efficiency of the coherent synthesis of the transmit beam at the receiving node.

[0012] Furthermore, the N transmitting nodes specifically include two transmitting nodes.

[0013] Furthermore, the performing down-conversion processing on the modulated signal and the multi-tone signal transmitted by the distributed transmitting node specifically includes: performing down-conversion processing on the modulated signal and the multi-tone signal transmitted by the distributed transmitting node in sequence.

[0014] Furthermore, performing low-pass filtering on each zero-frequency receiving signal obtained by the frequency conversion module specifically includes: performing low-pass filtering on each zero-frequency receiving signal obtained by the frequency conversion module in sequence.

[0015] Furthermore, estimating the phase difference between any two transmitting nodes using the positive / negative single-tone signals decoupled by the filtering module specifically includes estimating the phase difference between any two transmitting nodes using four positive / negative single-tone signals decoupled by the filtering module.

[0016] A method for coherently synthesizing transmit beams of a distributed high-dynamic node system comprises the following steps:

[0017] First, N transmitting nodes are enabled and reset to maintain signal synchronization. They provide two operating modes: single-transmission and simultaneous transmission of the modulated signal and positive / negative single-tone signals. The N nodes maintain the same signal carrier and then transmit the wireless signal.

[0018] Then, at the receiving node, the received modulated signal or multi-tone signal is down-converted and low-pass filtered respectively;

[0019] Then, the phase difference between the transmitting nodes is estimated based on the positive / negative single-tone signals transmitted by N nodes;

[0020] Finally, the phase difference result is fed back to the transmitting node for pre-compensation to maximize the coherent synthesis gain of the distributed node transmission.

[0021] Furthermore, the N transmitting nodes are enabled and reset to maintain signal synchronization, and provide two working modes of single transmission and simultaneous transmission of the modulated signal and the positive / negative single-tone signal. The N nodes transmit wireless signals after maintaining the same signal carrier. Specifically, the sub-steps are as follows:

[0022] Step 1-1: Denote the modulated signal transmitted by the nth transmitting node as s n (t), the transmitted positive / negative single tone signals are represented as s n1 (t), s n2 (t), its specific expression is:

[0023]

[0024] Where n = 1,…,M, p(t) represents the narrowband modulated signal transmitted by the node; f0 represents the frequency of the carrier signal of the same source of N transmitting nodes, f n Represents the positive / negative single-tone signal frequency transmitted by the nth transmitting node; τ n ,θ n They represent the propagation delay and initial phase from the nth transmitting node to the receiving node respectively;

[0025] Step 1-2: The specific expression of the received signal at the receiving node is:

[0026]

[0027] Step 1-3: If the first transmitting node is used as a reference, the phase difference between the nth transmitting node and the first transmitting node is:

[0028] ΔΦ n1 =2πf0(τ n -τ1)+(θ n -θ1),n=2,…,N。

[0029] Furthermore, down-converting the received modulated signal or multi-tone signal is performed at the receiving node, specifically including the sub-steps of: down-converting the signals received at the receiving node in sequence to obtain the following zero-frequency modulated signal and positive / negative single-tone signal:

[0030]

[0031] Furthermore, the received modulated signal or multi-tone signal is low-pass filtered at the receiving node, specifically including the sub-steps of: low-pass filtering the zero-frequency modulated signal and the positive / negative single-tone signal in sequence, and the low-pass filter is set as follows:

[0032]

[0033] Through low-pass filter processing, the modulation signal s of N transmitting nodes is decoupled and obtained n (t) and positive / negative tone signal s n1 (t), s n2 (t).

[0034] Furthermore, estimating the phase difference between transmitting nodes based on the positive / negative single-tone signals transmitted by N nodes specifically includes the following sub-steps:

[0035] Step 4-1: Transform the signal s n1 (t) and s n2 (t) multiplied by

[0036]

[0037] Step 4-2: Taking the first transmitting node as reference, and Multiplying the conjugate of

[0038]

[0039] Step 4-3: Estimate the phase difference between the nth transmitting node and the first transmitting node for:

[0040] Where, ≮(·) means solving for the phase;

[0041] Step 4-4: Transmit the signal and Multiplying the conjugate of

[0042] right Taking the phase we get:

[0043] ΔΨ=2πf0(τ n -τ1)+(θ n -θ1)+2πf n τ n -2πf11τ1;

[0044] =ΔΦ ab +2π(f n -f1)τ1+2πf n (τ n -τ1);

[0045] =ΔΦ ab +2πf n (τ n -τ1)+2π(f n -f1)τ1;

[0046] Step 4-5: and After multiplication, we can get the phase:

[0047]

[0048] Step 4-6: The positive and negative single-tone signal frequencies of the transmitting node are set to meet the following requirements:

[0049]

[0050] Then, ΔΦ n1 The correct estimate of is obtained by taking the phase corresponding to the smaller value of |ΔΨ2|, |ΔΨ1|, thereby solving the 180-degree ambiguity in the phase.

[0051] Furthermore, the phase difference result is fed back to the transmitting node for pre-compensation to maximize the distributed node transmission coherent synthesis gain, which specifically includes the following sub-steps:

[0052] Step 5-1: Based on the estimated phase difference After pre-compensation of transmitting nodes 2 to N respectively, the modulated signal s transmitted by N nodes is obtained by low-pass filtering at the receiving node. n (t) The coherently synthesized signal is:

[0053]

[0054] Step 5-2: Calculate the gain and efficiency of the coherent synthesis of N transmitting nodes:

[0055]

[0056] The beneficial effects of the present invention include:

[0057] (1) High real-time performance. The system provided by the embodiment of the present invention provides two working modes: single transmission and simultaneous transmission of the modulated signal and the positive / negative single-tone signal, which realizes the real-time estimation and pre-compensation of the phase difference between the transmitting nodes, and maximizes the distributed transmission coherent synthesis gain;

[0058] (2) Phase difference deambiguation. The embodiment of the present invention provides a transmission coherent synthesis method suitable for highly dynamic distributed nodes. It does not require prior information about the locations of the transmitting and receiving nodes, and accurately estimates the phase difference between any two transmitting nodes by reasonably setting the frequency of the single-tone signal.

[0059] (3) Flexible system expansion. The embodiment of the present invention provides a distributed high-dynamic transmit beam coherent synthesis method that can be expanded to a coherent synthesis system with any number of transmit nodes, and the easy-to-implement method ensures the stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0061] Figure 1 This is a block diagram of the structural principle of the system according to an embodiment of the present invention;

[0062] Figure 2 Schematic diagram of the spatial geometry of transmitting nodes A, B and receiving node C;

[0063] Figure 3 The modulated signal transmitted by nodes A and B;

[0064] Figure 4 Four-channel single-tone signals transmitted by nodes A and B;

[0065] Figure 5 is the sum of the four-channel single-tone signals and the modulated signal received by node C;

[0066] Figure 6 Node C sequentially down-converts the four received single-tone signals;

[0067] Figure 7 The receiving node C sequentially low-pass filters the down-converted four-channel single-tone signals;

[0068] Figure 8 The phase pre-compensation signal of the modulated signal at the transmitting node B and the coherently synthesized signal at the receiving node C;

[0069] Figure 9 The node C performs down-conversion and low-pass filtering on the received coherent signal. DETAILED DESCRIPTION

[0070] All features disclosed in all embodiments in this specification, or steps in all methods or processes implicitly disclosed, except for mutually exclusive features and / or steps, can be combined and / or expanded or replaced in any manner.

[0071] In view of the current situation, the present invention addresses the problem that it is difficult to estimate and compensate the phase difference between transmitting nodes in real time under high dynamic conditions of distributed nodes, resulting in serious loss of transmit coherent synthesis gain. The following technical solutions are proposed:

[0072] Figure 1 This is a block diagram of the structural principle of the system of an embodiment of the present invention. In a preferred embodiment, a distributed high-dynamic node system is proposed, which is specifically configured as follows:

[0073] A distributed node signal transmission model building module is used to enable and reset N transmitting nodes to maintain signal synchronization. It also provides two working modes: single transmission and simultaneous transmission of modulated signals and positive / negative single-tone signals. N nodes maintain the same signal carrier and then transmit wireless signals.

[0074] The frequency conversion module is used to down-convert the modulated signal and the multi-tone signal transmitted by the distributed transmitting node at the receiving node to obtain a zero-frequency signal for subsequent processing;

[0075] The filtering module is used to perform low-pass filtering on each zero-frequency received signal obtained by the frequency conversion module, and decouple the positive / negative single-tone signals transmitted by N nodes respectively;

[0076] A parameter estimation module is used to estimate the phase difference between any two transmitting nodes using the positive / negative single-tone signals decoupled by the filtering module;

[0077] The performance evaluation module is used to feed back the phase difference estimated by the parameter estimation module to the N transmitting nodes for pre-compensation, and then calculate the gain and efficiency of the coherent synthesis of the transmit beam at the receiving node.

[0078] On the other hand, in a preferred embodiment, a transmit beam coherent synthesis method for a distributed high-dynamic node system is proposed, comprising the following steps:

[0079] First, N transmitting nodes are enabled and reset to maintain signal synchronization. They provide two operating modes: single-transmission and simultaneous transmission of the modulated signal and positive / negative single-tone signals. The N nodes maintain the same signal carrier and then transmit the wireless signal.

[0080] Then, at the receiving node, the received modulated signal or multi-tone signal is down-converted and low-pass filtered respectively;

[0081] Then, the phase difference between the transmitting nodes is estimated based on the positive / negative single-tone signals transmitted by N nodes;

[0082] Finally, the phase difference result is fed back to the transmitting node for pre-compensation to maximize the coherent synthesis gain of the distributed node transmission.

[0083] In other optional preferred embodiments, the present invention proposes a method for transmitting beam coherent synthesis of a distributed high dynamic node system, see Figure 2-Figure 6 As shown, further specifically perform the following steps:

[0084] Step 1: Establish a distributed node signal transmission model. Two transmitting nodes are enabled and reset to maintain signal synchronization. The system provides two operating modes: single transmission and simultaneous transmission of modulated signals and positive / negative single-tone signals. The two nodes transmit wireless signals while maintaining the same signal carrier.

[0085] Step 2: Establish a frequency conversion module. At the receiving node, the frequency conversion module down-converts the modulated signal and the positive / negative signal transmitted by the distributed transmitting node in sequence to obtain a zero-frequency signal for subsequent processing.

[0086] Step 3: Establish a filtering module, which performs low-pass filtering on each zero-frequency received signal obtained by the frequency conversion module in sequence, and decouples them to obtain four positive / negative single-tone signals transmitted by the two nodes;

[0087] Step 4: Establish a parameter estimation module. The parameter estimation module uses the four positive / negative single-tone signals decoupled by the filtering module to estimate the phase difference between the two transmitting nodes.

[0088] Step 5: Establish a performance evaluation module. The performance evaluation module feeds back the phase difference estimated by the parameter estimation module to the two transmitting nodes for pre-compensation, and then calculates the gain and efficiency of the transmit beam coherent synthesis at the receiving node.

[0089] To further illustrate the distributed high dynamic transmit beam coherent synthesis method, the following is the method:

[0090] Establish a distributed node signal transmission model. Figure 2 As shown in Figure 1, a spatial geometry diagram of two transmitting nodes and a single receiving node is given; the position coordinates of transmitting node A are (1,0,0)m, the position coordinates of transmitting node B are (1,1,2)m, and the position coordinates of receiving node C are (0,0,1)m. Therefore, the propagation delay from transmitting node A to receiving node C is τ a =4.71ps; the propagation delay from the transmitting node B to the receiving node C is τ b =5.77ps. Here, the system adopts a mode in which the modulation signal and the positive / negative single-tone signals are transmitted simultaneously.

[0091] See Figure 3-Figure 5 , the four-way single-tone signals and modulation signals transmitted by the transmitting node A and the transmitting node B to the receiving node C are given, which are represented as s 11 (t),s 12 (t),s 21 (t),s 22 (t). The frequency of the homologous carrier signal is f0 = 2.2 GHz, and the bandwidth of the modulated signal p(t) transmitted by the transmitting nodes A and B is 2 MHz. In order to resolve the ambiguity of the phase difference, the single tone frequency is set to meet the following requirements:

[0092]

[0093] The positive and negative single-tone signal frequencies of transmitting node A and transmitting node B are f1 = 6 MHz and f2 = 12 MHz respectively; the initial phase values ​​of transmitting node A and transmitting node B are θ a =0.021(rad),θ b =0.034(rad).

[0094] Create a frequency conversion module. Figure 6 , gives the result of down-converting the four single-tone signals received at the receiving node C in sequence, and obtains four zero-frequency received signals:

[0095]

[0096] Create a filter module. Figure 7 , gives the results of low-pass filtering four zero-frequency received signals in sequence, and the low-pass filter settings are as follows:

[0097]

[0098] Where w0 = 5MHz. Through low-pass filter processing, the signal at the receiving node C can be decoupled in turn to obtain the above four single-tone signals s 11 (t),s 12 (t),s 21 (t) and s 22 (t).

[0099] Establishing a parameter estimation module includes the following steps:

[0100] Step 4-1: Transform the signal s 11 (t) and s 12 (t) multiplied by

[0101]

[0102] Step 4-2: Transform the signal s 21 (t) and s 22 (t) multiplied by

[0103]

[0104] Step 4-3: Taking the first transmitting node as a reference, and Multiplying the conjugate of

[0105]

[0106] Step 4-3: Estimate the phase difference between the second transmitting node and the first transmitting node for

[0107]

[0108] Here, ≮(·) indicates solving for the phase.

[0109] Step 4-4: Transmit the signal and Multiplying the conjugate of

[0110]

[0111] right Taking the phase we get:

[0112] ΔΨ=2πf0(τ n -τ1)+(θ n -θ1)+2πf n τ n -2πf1τ1;

[0113] =ΔΦ ab +2π(f n -f1)τ1+2πf n (τ n -τ1);

[0114] =ΔΦ ab +2πf n (τ n -τ1)+2π(f n -f1)τ1;

[0115] Step 4-5: and Multiplication can be followed by phase shift to obtain:

[0116]

[0117]

[0118] Then, ΔΦ n1 The correct estimate of can be obtained by taking the phase corresponding to the smaller value of |ΔΨ2|, |ΔΨ1|, thus solving the 180-degree ambiguity in the phase.

[0119] Establish a performance evaluation module. The specific steps include:

[0120] See Figure 8 , pre-compensate the phase difference at the transmitting node B The subsequent modulated signal and the coherent synthesized signal at the receiving node C.

[0121] See Figure 9 After down-converting and low-pass filtering the modulated signals transmitted by nodes A and B, the coherent synthesis result at the receiving node C is:

[0122]

[0123] The gain and efficiency of the coherent synthesis of the signals at the receiving node C are calculated as follows:

[0124]

[0125] The specific implementation of the present invention is not limited to the above-mentioned methods. The above description is only the preferred embodiment of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. It is obvious that various changes, adjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the principles and concepts of the present invention, it can also include more other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A distributed highly dynamic node system, characterized in that: include: Distributed node signal transmission model building module is used to Each transmitting node is enabled and reset to keep the signal synchronized, and provides two working modes: single transmission and simultaneous transmission of the modulation signal and the positive and negative single-tone signals. Each node transmits wireless signals after keeping the signal carrier from the same source; The frequency conversion module is used to down-convert the modulated signal and the multi-tone signal transmitted by the distributed transmitting node at the receiving node to obtain a zero-frequency signal for subsequent processing; The filter module is used to perform low-pass filtering on each zero-frequency receiving signal obtained by the frequency conversion module, and decouple them to obtain Positive and negative tone signals transmitted by each node; A parameter estimation module is used to estimate the phase difference between any two transmitting nodes using the positive and negative single-tone signals decoupled by the filtering module; The performance evaluation module is used to feed back the phase difference estimated by the parameter estimation module to the The pre-compensation is performed on each transmitting node, and then the gain and efficiency of the transmit beam coherent synthesis are calculated at the receiving node.

2. The distributed high-dynamic node system according to claim 1, characterized in that: described The transmitting nodes specifically include two transmitting nodes.

3. The distributed high-dynamic node system according to claim 1, characterized in that: The down-converting the modulated signal and the multi-tone signal transmitted by the distributed transmitting node specifically includes: sequentially down-converting the modulated signal and the multi-tone signal transmitted by the distributed transmitting node.

4. The distributed high-dynamic node system according to claim 1, characterized in that: The performing low-pass filtering on each zero-frequency receiving signal obtained by the frequency conversion module specifically includes: performing low-pass filtering on each zero-frequency receiving signal obtained by the frequency conversion module in sequence.

5. The distributed high-dynamic node system according to claim 1, characterized in that: The method of estimating the phase difference between any two transmitting nodes by using the positive and negative single-tone signals decoupled by the filtering module specifically includes estimating the phase difference between any two transmitting nodes by using four positive and negative single-tone signals decoupled by the filtering module.

6. A coherent transmission beam synthesis method for a distributed high-dynamic node system, characterized in that: The steps include: first, Each transmitting node is enabled and reset to keep the signal synchronized, and provides two working modes: single transmission and simultaneous transmission of the modulation signal and the positive and negative single-tone signals. Each node transmits wireless signals after keeping the signal carrier from the same source; Then, at the receiving node, the received modulated signal and multi-tone signal are down-converted and low-pass filtered respectively; Then, according to The positive and negative single-tone signals transmitted by each node estimate the phase difference between the transmitting nodes; Finally, the phase difference result is fed back to the transmitting node for pre-compensation to maximize the coherent synthesis gain of the distributed node transmission.

7. The transmit beam coherent synthesis method for a distributed high-dynamic node system according to claim 6, characterized in that: described Each transmitting node is enabled and reset to keep the signal synchronized, and provides two working modes: single transmission and simultaneous transmission of the modulation signal and the positive and negative single-tone signals. The nodes transmit wireless signals after keeping the signal carriers from the same source, specifically including the following sub-steps: Step 1-1: The modulated signal transmitted by a transmitting node is expressed as , the transmitted positive and negative single tone signals are expressed as , , its specific expression is: ； ； ； in, , Represents the narrowband modulated signal transmitted by the node; express The carrier signal frequency of the transmitting nodes is the same as that of the Indicates the The positive and negative single tone signal frequencies transmitted by the transmitting nodes; , Respectively represent The propagation delay and initial phase from the transmitting node to the receiving node; Step 1-2: The specific expression of the received signal at the receiving node is: ； Step 1-3: If the first transmitting node is used as a reference, the The phase difference between the transmitting node and the first transmitting node is: 。 8. The transmit beam coherent synthesis method for a distributed high-dynamic node system according to claim 7, characterized in that: Down-converting the received modulated signal or multi-tone signal at the receiving node, specifically comprising the sub-steps of: down-converting the signals received at the receiving node in sequence to obtain the following zero-frequency modulated signal and positive and negative single-tone signals, respectively: ； ； 。 9. The transmit beam coherent synthesis method for a distributed high-dynamic node system according to claim 8, characterized in that: At the receiving node, the modulated signal and the multi-tone signal are low-pass filtered. Specifically, the low-pass filtering is performed on the zero-frequency modulated signal and the positive and negative single-tone signals in sequence. The low-pass filter settings are as follows: Through low-pass filter processing, decoupling is obtained The modulated signal of the transmitting node and positive and negative tone signals 、 .

10. The transmit beam coherent synthesis method for a distributed high-dynamic node system according to claim 9, characterized in that: The basis The phase difference between the transmitting nodes is estimated by using the positive and negative single-tone signals transmitted by the nodes, which specifically includes the following sub-steps: Step 4-1: Transmit the signal and Multiplying together, we get : ； Step 4-2: Taking the first transmitting node as reference, and Multiplying the conjugate of : ； Step 4-3: Estimate the The phase difference between the transmitting node and the first transmitting node for: ;in, Indicates the phase to be solved; Step 4-4: Transmit the signal and Multiplying the conjugate of : ; right Taking the phase we get: ； ； ； Step 4-5: and After multiplication, we can get the phase: ； ； ； Step 4-6: The positive and negative single-tone signal frequencies of the transmitting node are set to meet the following requirements: So, The correct estimate of , The phase corresponding to the smaller value in is obtained, thereby solving the 180-degree ambiguity in the phase.

11. The transmit beam coherent synthesis method for a distributed high-dynamic node system according to claim 10, characterized in that: Feeding back the phase difference result to the transmitting node for pre-compensation to maximize the distributed node transmission coherent synthesis gain specifically includes the following sub-steps: Step 5-1: Based on the estimated phase difference For each transmitting node arrive After pre-compensation, low-pass filtering is performed at the receiving node to obtain The modulated signal transmitted by each node The coherently synthesized signal is: ； Step 5-2: Calculation The gain and efficiency of the coherent synthesis of the transmitting nodes are: 。

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