Multi-target signal self-tracking method based on feedback

Abstract

A multi-target signal self-tracking method based on feedback judges and decides a tracking mode of a target signal in real time through continuous feedback excitation in a scanning process, controls an antenna to switch back and forth between two pointing modes of airspace scanning and fixed-point tracking, obviously improves tracking efficiency and tracking sensitivity of the multi-target signal, and improves tracking accuracy of the multi-target signal. Tracking is carried out if signals exist, scanning is carried out if no signals exist, and the signal tracking requirement in a multi-target scene can be better met.

Description

Technical Field

[0001] The present invention relates to a feedback-based multi-target signal self-tracking method, belonging to the field of satellite communication technology. Background Art

[0002] In recent years, the world has been accelerating the deployment of satellite Internet. Countries around the world have competing to propose a series of low-Earth orbit satellite constellation plans and supporting mobile satellite applications, which make up for the deficiencies of ground communication systems in terms of insufficient coverage, high communication costs for ships and aircraft, and limited communication ranges, and provide fast and inexpensive access for remote and underdeveloped areas. However, the satellite Internet communication system has the characteristics of complex and variable constellation topology and high dynamics, and the connection relationship between ground communication terminals and overhead satellites is constantly switching. Therefore, researching and mastering the method of scanning and tracking the communication signals of various satellite Internet ground terminals in the area below the forward direction of the satellite, enabling them to quickly switch to the communication state, is of great significance for promoting the development and application of satellite Internet technology.

[0003] The Tianjin Jinhang Computing Technology Research Institute disclosed a drone-borne omnidirectional satellite signal tracking device and method in its patent literature "A Drone-Borne Omnidirectional Satellite Signal Tracking Device and Method" (application number 202210919297, publication number CN115276773A). This method selects the antenna unit facing the target communication satellite as the communication antenna, calculates the pointing angle of the target satellite relative to the communication antenna, and controls the beam of the communication antenna to face the pointing angle. It can achieve omnidirectional tracking without communication dead spots, enabling the drone to communicate with the satellite when the roll angle is relatively large. However, the still existing deficiencies of this method are: it is only applicable to communicating with cooperative satellites whose position information is known, and cannot scan and capture target signals without prior information. Once the position information of the target communication satellite is lost, tracking can no longer be achieved.

[0004] Beijing Beimu Spectroscopy Technology Co., Ltd. discloses a multi-target self-tracking antenna in its patent document "A Multi-target Self-tracking Antenna" (application number 202010391037, publication number CN111600138A). The multi-target self-tracking antenna includes an omnidirectional antenna module, a low-noise module, and a self-tracking module that are electrically connected in sequence. The omnidirectional antenna module is designed to perform diversity reception of multiple independent measurement and control signals within a 360-degree azimuth (full horizontal direction), equivalently realizing a digital antenna beam for simultaneously self-tracking multiple targets and improving the gain of the ground measurement and control antenna. The low-noise module amplifies and filters the signals. The self-tracking module realizes functions such as target signal classification, independent tracking of multiple signal directions, and diversity synthesis of multi-antenna signals. This method can ensure omnidirectional reception in azimuth, improve the equivalent gain of the antenna, and enhance the reception effect of weak signals. However, the still existing deficiencies of this method are: the antenna system is complex in composition, includes multiple modules, the cost of the omnidirectional antenna is high, and it is not conducive to mass production and use. Summary of the Invention

[0005] The technical problem solved by the present invention is: aiming at the problems in the current prior art that the antenna system is complex in composition, the cost of the omnidirectional antenna is high, and continuous tracking cannot be achieved, a multi-target signal self-tracking method based on feedback is proposed.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] A multi-target signal self-tracking method based on feedback, including:

[0008] Perform power-on initialization processing on the payload integrated processor, broadband signal acquisition and processing machine, and broadband dual-beam phased array antenna carried on the satellite;

[0009] Control the broadband dual-beam phased array antenna to enter the airspace scanning mode through the payload integrated processor, and perform a zigzag scan on the airspace below the forward direction of the carried satellite;

[0010] Control the broadband signal acquisition and processing machine to receive the dual-beam acquisition signals, respectively judge the target signals for the dual-beam acquisition signals, and report the judgment results to the payload integrated processor in real time;

[0011] According to the judgment results, control the payload integrated processor to set the satellite antenna pointing mode of the dual-beams in the current pointing calculation cycle within each pointing calculation cycle;

[0012] According to the satellite antenna pointing mode of the dual-beams in the current pointing calculation cycle, calculate the pointing angle values of the dual-beams respectively, and perform independent pointing control on the dual-beams according to the pointing angle values.

[0013] The broadband dual-beam phased array antenna includes two independently operating beams, both of which are used for independent pointing control. The operating frequency bands of the two beams include the X band, Ku band, and Ka band, and the operating frequency bands are determined according to the tracking task requirements and the antenna operating frequency range;

[0014] Z-shaped scanning is to control the two beams to swing left and right in a plane orthogonal to the forward direction of the satellite carrying the antenna, and to scan the airspace below as the satellite carrying the antenna moves forward.

[0015] The method for judging the target signal of the dual-beam acquisition signal is as follows:

[0016] Judge whether there is a target signal in the acquisition signals of the two beams. If there is a target signal in the acquisition signal of any one beam, report the time when the target signal is found and the beam where the target signal is located to the payload integrated processor; otherwise, report the no-signal state to the payload integrated processor, and at the same time continue to maintain the Z-shaped scanning of the airspace in the no-signal state;

[0017] The time when the target signal is found is the real-time time obtained by the broadband signal acquisition and processing machine after correcting the time accuracy at the microsecond level based on the second pulse of the satellite platform and the broadcast time per second.

[0018] The method for judging whether there is a target signal in the acquisition signals of the two beams is as follows:

[0019] After performing digital channelization and FFT processing on the acquisition signals of the two beams, perform frequency-domain energy accumulation and evaluation, and compare with the set signal threshold. When the frequency-domain energy accumulation value of any one beam is less than the signal threshold, it is considered that there is no target signal, otherwise it is considered that there is a target signal;

[0020] When there is a target signal in the acquisition signal of only one beam, report the time when the target signal of one beam is found and the beam where it is located, and at the same time report the no-signal state of the other beam.

[0021] The satellite antenna pointing modes of the dual beams include the airspace scanning mode and the fixed-point tracking mode. The method for setting the satellite antenna pointing mode of the dual beams in the current pointing calculation period is as follows:

[0022] If there is no target signal in the acquisition signals of the two beams, set the satellite antenna pointing modes of the two beams as the airspace scanning mode in the current pointing calculation period, and perform Z-shaped scanning in the airspace below the forward direction of the satellite;

[0023] If there is a target signal in the acquisition signal of any beam, it is judged whether there is a target signal in the acquisition signal of the current beam in the previous pointing calculation period. If not, and if a target signal is detected at any time during the two pointing calculation periods, the satellite antenna pointing mode of the current beam is switched to the fixed-point tracking mode. The longitude, latitude, and altitude of the ground position pointed by the satellite antenna during the scanning process are deduced based on the time when the target signal is detected, and fixed-point tracking is performed by calling the fixed-point pointing algorithm. If so, the satellite antenna pointing mode of the current beam is maintained, and fixed-point tracking is maintained for the target signal in the acquisition signal of the current beam in the previous pointing calculation period. For the satellite antenna pointing mode of the corresponding beam without a target signal in the current pointing calculation period, the airspace scanning mode is maintained.

[0024] If there are target signals in the acquisition signals of both beams, independent judgments are made according to the satellite antenna pointing modes of the two beams in the previous pointing calculation period, and the satellite antenna pointing modes of the two beams are set respectively according to the satellite antenna pointing mode setting method when there is a target signal in the acquisition signal of any beam.

[0025] Based on the appearance time of the target signal, the switching situations of the satellite antenna pointing modes of the dual beams in the current and previous pointing calculation periods, and the pointing angle values of the dual beams in the current pointing calculation period, self-tracking processing of the target corresponding to the target signal that appears in the current pointing calculation period is realized.

[0026] The duration and time accuracy of the pointing calculation period are set according to the pointing control frequency range of the broadband dual-beam phased array antenna, and the pointing calculation period is minimized on the premise of meeting the tracking task requirements to improve the self-tracking accuracy.

[0027] The fixed-point pointing algorithm adopted in the fixed-point tracking mode takes the attitude position information of the satellite at the current moment and the longitude, latitude, and altitude of the ground point as input data, and takes the calculated off-axis angle and azimuth angle of the phased array antenna beam pointing to the ground fixed point as output data.

[0028] After the independent pointing control of the dual beams in the current pointing calculation period is completed, when waiting for the next pointing calculation period to arrive, the payload integrated processor repeats the judgment on whether there is a target signal according to the acquisition signals of the two beams, and re-performs the independent pointing control of the dual beams in the next pointing calculation period according to the judgment result.

[0029] The advantages of the present invention compared with the prior art are as follows:

[0030] (1) A multi-target signal self-tracking method based on feedback provided by the present invention improves the tracking efficiency and tracking sensitivity of multi-target signals. During the scanning process, through continuous feedback excitation, it is used to judge and make decisions on the tracking mode of target signals in real time, control the phased array antenna to switch back and forth between two pointing modes of airspace scanning and fixed-point tracking. When there is a signal, it tracks; when there is no signal, it scans, which can significantly improve the signal tracking efficiency in a multi-target scenario;

[0031] (2) The step switching control of the present invention is flexible and applicable to the self-tracking of various types of signals. By adjusting the judgment method or judgment criteria of the presence or absence of signals, it can conveniently achieve self-tracking of various signals with different frequency bands and different modulation methods. At the same time, it can perform multi-beam independent control, improving the probability of successful tracking of target signals. The broadband dual-beam phased array antenna adopted by the present invention has two independent working beams, which can realize the scanning of the airspace and the fixed-point tracking of target signals at the same time, or can also realize the fixed-point tracking of different target signals at the same time, which can significantly improve the probability of successful signal tracking in a multi-target scenario and obtain more target signal data within the same time period. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a self-tracking scenario diagram of multi-target signals provided by the invention;

[0033] Figure 2 is a flow chart of the switching control of the self-tracking of multi-target signals provided by the invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] A multi-target signal self-tracking method based on feedback, during the scanning process, through continuous feedback excitation, is used to judge and make decisions on the tracking mode of target signals in real time, control the antenna to switch back and forth between two pointing modes of airspace scanning and fixed-point tracking, significantly improving the tracking efficiency and tracking sensitivity of multi-target signals. When there is a signal, it tracks; when there is no signal, it scans, which can better meet the signal tracking requirements in a multi-target scenario.

[0035] The steps of the multi-target signal self-tracking method based on feedback are as follows:

[0036] Perform power-on initialization processing on the payload integrated processor, broadband signal acquisition and processing processor, and broadband dual-beam phased array antenna on the satellite;

[0037] Control the broadband dual-beam phased array antenna to enter the airspace scanning mode through the payload integrated processor, and perform a zigzag scan on the airspace below the forward direction of the satellite;

[0038] Control the broadband signal acquisition and processing processor to receive the dual-beam acquisition signals, respectively judge the target signals for the dual-beam acquisition signals, and report the judgment results to the payload integrated processor in real time;

[0039] Control the load integrated processor to set the satellite antenna pointing mode of the dual-beams in the current pointing calculation period according to the judgment result within each pointing calculation period;

[0040] According to the satellite antenna pointing mode of the dual-beams in the current pointing calculation period, calculate the respective pointing angle values of the dual-beams, and perform independent pointing control of the dual-beams according to the pointing angle values respectively.

[0041] The wideband dual-beam phased array antenna includes two independently operating beams, both of which are used for independent pointing control. The operating frequency bands of the two beams include the X-band, Ku-band, and Ka-band, and the operating frequency band is determined according to the tracking mission requirements and the antenna operating frequency range;

[0042] The Z-shaped scan is to control the two beams to swing left and right in the plane orthogonal to the advancing direction of the carried satellite, and realize the scan of the lower airspace as the carried satellite advances.

[0043] The method for judging the target signal for the signals collected by the dual-beams is as follows:

[0044] Judge whether there is a target signal in the collected signals of the two beams. If there is a collected signal of any beam that is a target signal, report the moment when the target signal is found and the beam where the target signal is located to the load integrated processor; otherwise, report the no-signal state to the load integrated processor, and at the same time continue to maintain the Z-shaped scan of the airspace in the no-signal state;

[0045] The moment when the target signal is found is the real-time time obtained by the wideband signal acquisition and processing machine after performing us-level time accuracy correction based on the second pulse of the satellite platform and the broadcast time per second.

[0046] The method for judging whether there is a target signal in the collected signals of the two beams is as follows:

[0047] Perform digital channelization and FFT processing on the collected signals of the two beams, then perform frequency-domain energy accumulation and evaluation, and compare with the set signal threshold. When the frequency-domain energy accumulation value of any beam is less than the signal threshold, it is considered that there is no target signal, otherwise it is considered that there is a target signal;

[0048] When there is a target signal only in the collected signals of one beam, report the moment when the target signal of one beam is found and the beam where it is located, and at the same time report the no-signal state of the other beam.

[0049] The satellite antenna pointing modes of the dual-beams include the airspace scan mode and the fixed-point tracking mode. The method for setting the satellite antenna pointing mode of the dual-beams in the current pointing calculation period is as follows:

[0050] If there is no target signal in the acquisition signals of both beams, set the satellite antenna pointing modes of both beams to the airspace scanning mode in the current pointing calculation cycle, and perform a zigzag scan in the airspace below the satellite's forward direction;

[0051] If there is a target signal in the acquisition signal of any beam, determine whether there was a target signal in the acquisition signal of the current beam in the previous pointing calculation cycle. If not, and a target signal is detected at any time during the two pointing calculation cycles, switch the satellite antenna pointing mode of the current beam to the fixed-point tracking mode. Based on the time when the target signal is detected, inversely calculate the longitude, latitude, and altitude of the ground position pointed by the satellite antenna during the scanning process, and perform fixed-point tracking by invoking the fixed-point pointing algorithm; If there is, maintain the satellite antenna pointing mode of the current beam, and maintain fixed-point tracking of the target signal in the acquisition signal of the current beam in the previous pointing calculation cycle; For the satellite antenna pointing mode of the corresponding beam without a target signal in the current pointing calculation cycle, maintain the airspace scanning mode;

[0052] If there are target signals in the acquisition signals of both beams, judge according to the satellite antenna pointing modes of both beams in the previous pointing calculation cycle. If the satellite antenna pointing modes of both beams were the same in the previous pointing calculation cycle, then switch or maintain the satellite antenna pointing modes of both beams to the fixed-point tracking mode in the current pointing calculation cycle; If they are different, set the satellite antenna pointing modes of both beams respectively according to the satellite antenna pointing mode setting method when there is a target signal in the acquisition signal of any beam.

[0053] Based on the occurrence time of the target signal, the switching situations of the satellite antenna pointing modes of the dual beams in the current and previous pointing calculation cycles, and the pointing angle values of the dual beams in the current pointing calculation cycle, realize the self-tracking processing of the target corresponding to the target signal that appears in the current pointing calculation cycle.

[0054] The field of view and time accuracy of the pointing calculation cycle are set according to the pointing control frequency range of the broadband dual-beam phased array antenna, and the pointing calculation cycle is minimized on the premise of meeting the tracking task requirements to improve the self-tracking accuracy.

[0055] The fixed-point pointing algorithm adopted in the fixed-point tracking mode uses the attitude position information of the satellite at the current moment and the ground point longitude, latitude, and altitude as input data, and is used to calculate the off-axis angle and azimuth angle of the phased array antenna beam pointing to the ground fixed point as output data.

[0056] When the independent pointing control of the dual beams in the current pointing calculation cycle is completed, when waiting for the next pointing calculation cycle to arrive, the payload integrated processor repeats the judgment of whether there is a target signal based on the acquisition signals of the two beams, and re-performs the independent pointing control of the dual beams in the next pointing calculation cycle according to the judgment result.

[0057] The following is a further description in conjunction with the accompanying drawings of the specification and preferred embodiments:

[0058] In the current embodiment, a multi-target signal self-tracking method based on feedback is applicable to the search and self-tracking of airspace target signals in satellite-borne or UAV-borne scenarios. Initially, the phased array antenna is set to the airspace scanning mode to continuously scan the airspace below the forward direction of the satellite or UAV. During the process of scanning the signal, the feedback on the presence or absence of the target signal and the feedback on the time of detecting the target signal from the broadband signal acquisition and processing machine are received in real time, and the longitude, latitude, and altitude of the location where the target signal is located are deduced based on the time information. Subsequently, the beam pointing calculation method of the phased array antenna is changed, and the phased array antenna is controlled to switch from airspace scanning to fixed-point tracking mode to continuously track the target location where the signal is detected; when the broadband signal acquisition and processing machine feedbacks that there is no signal, the phased array antenna is switched back to the airspace scanning mode, and the signal is continued to be searched in the airspace below the forward movement of the satellite or UAV.

[0059] Specifically, it includes the following steps:

[0060] (1) Power on the payload integrated processor, broadband signal acquisition and processing machine, and broadband dual-beam phased array antenna, and perform boot loading and software initialization;

[0061] (2) After initialization is completed, the payload integrated processor controls the broadband dual-beam phased array antenna to enter the airspace scanning mode and perform a zigzag scan on the airspace below the forward direction of the satellite or UAV it carries;

[0062] (3) The broadband signal acquisition and processing machine continuously receives and processes the signals collected by the two beams of the antenna, respectively determines whether the signals of the two beams are target signals, and reports the judgment results to the payload integrated processor in real time: if so, the moment of detecting the target signal and the antenna beam where the target signal is located are reported to the payload integrated processor; if not, the no-signal state is reported to the payload integrated processor, and at the same time, it continues to maintain this state for airspace scanning and judgment;

[0063] (4) The payload integrated processor checks the signal presence or absence status reported by the broadband signal acquisition and processing machine in each pointing calculation cycle, and decides the antenna pointing mode in the current calculation cycle according to the signal presence or absence status:

[0064] (4a) If there is no signal in both beam 1 and beam 2, then in this pointing calculation, switch the pointing modes of the two beams of the phased array antenna to the airspace scanning mode, and continue to perform a zigzag scan on the airspace below the forward direction of the satellite / UAV;

[0065] (4b) If only beam 1 has a signal, continue to judge the signal presence status of beam 1 during the previous pointing calculation: If beam 1 had no signal during the previous pointing calculation, it indicates that the target signal was detected at a certain moment between these two calculation cycles. Switch the pointing mode of phased array antenna beam 1 to the fixed-point tracking mode, reverse-calculate the latitude, longitude, and altitude of the ground position pointed by the antenna at this moment during the scanning process based on the reported signal detection time of beam 1, and call the fixed-point pointing algorithm to perform fixed-point tracking on this position; If beam 1 had a signal during the previous pointing calculation, maintain the current state unchanged and still perform fixed-point tracking on the signal detected in the previous pointing calculation cycle; Since beam 2 has no signal, switch the pointing mode of phased array antenna beam 2 to the airspace scanning mode and continue to perform a zigzag scan in the airspace below the forward direction of the satellite / drone; At the same time, record the signal presence status and signal detection time of the two beams during the current pointing calculation cycle for subsequent judgment;

[0066] (4c) If only beam 2 has a signal, continue to judge the signal presence status of beam 2 during the previous pointing calculation: If beam 2 had no signal during the previous pointing calculation, it indicates that the target signal was detected at a certain moment between these two calculation cycles. Switch the pointing mode of phased array antenna beam 2 to the fixed-point tracking mode, reverse-calculate the latitude, longitude, and altitude of the ground position pointed by the antenna at this moment during the scanning process based on the reported signal detection time of beam 2, and call the fixed-point pointing algorithm to perform fixed-point tracking on this position; If beam 2 had a signal during the previous pointing calculation, maintain the current state unchanged and still perform fixed-point tracking on the signal detected in the previous cycle; Since beam 1 has no signal, switch the pointing mode of phased array antenna beam 1 to the airspace scanning mode and continue to perform a zigzag scan in the airspace below the forward direction of the satellite / drone; At the same time, record the signal presence status and signal detection time of the two beams during the current pointing calculation cycle for subsequent judgment;

[0067] (4d) If both beam 1 and beam 2 have signals, first judge the state of beam 1 during the previous pointing calculation and complete the decision on the pointing mode of beam 1 during this pointing calculation cycle according to the processing method of beam 1 described in step (4b); Subsequently, judge the state of beam 2 during the previous pointing calculation and complete the decision on the pointing mode of beam 2 during this pointing calculation cycle according to the processing method of beam 2 described in step (4c); At the same time, record the signal presence status and signal detection time of the two beams during the current pointing calculation cycle for subsequent judgment;

[0068] (5) The payload integrated processor sends the pointing angle values calculated for the two antenna beams during this pointing calculation cycle to the phased array antenna for independent pointing control of the two beams;

[0069] (6) Return to step (3), and the broadband signal acquisition and processing machine continues to process and judge the acquired signals, and reports the results to the payload integrated processing machine. When waiting for the next pointing calculation cycle to arrive, the payload integrated processing machine decides whether its pointing mode is airspace scanning or fixed-point tracking based on the signal presence / absence status of the two beams, and performs pointing calculation and antenna control in the corresponding mode.

[0070] In the broadband dual-beam phased array antenna in step (1), its two beams work independently and can be independently controlled for pointing. The working frequency bands of this broadband dual-beam phased array antenna include, but are not limited to: X band, Ku band, Ka band, etc., specifically depending on user requirements and the antenna working frequency range.

[0071] The Z-shaped scan in step (2) means controlling the beam of the phased array antenna to swing left and right in a plane orthogonal to the forward direction of the satellite / drone, and realizing the scanning of the airspace below it as the satellite / drone moves forward.

[0072] The moment of detecting the target signal in step (3) refers to the real-time time obtained by the broadband signal acquisition and processing machine based on the second pulse sent by the spaceborne or airborne platform and the broadcast time per second, and then performing time accuracy correction at the microsecond level, so as to record the moment of detecting the target signal with the maximum accuracy.

[0073] The method of judging whether the acquired signal in step (3) is a target signal is to perform digital channelization, FFT and other processing on the acquired signal, then accumulate and evaluate the frequency domain energy, and compare it with the set signal threshold. If the energy accumulation value is greater than the signal threshold, it is considered a target signal, otherwise it is considered noise. Other methods can also be used for signal presence / absence judgment, specifically depending on the signal mode and user requirements.

[0074] The pointing calculation cycle in step (4) can have a value of 200 milliseconds, 100 milliseconds or other time accuracies, limited by the acceptable pointing control frequency of the broadband dual-beam phased array antenna; within the acceptable pointing control frequency range, the pointing calculation cycle should be shortened as much as possible to achieve fast response tracking of the target signal, which is a conventional algorithm available to those skilled in the art.

[0075] The fixed-point pointing algorithm in step (4) is a pointing calculation algorithm that takes the attitude position information of the satellite / drone at the current moment and the ground point longitude, latitude and altitude as inputs, and outputs the off-axis angle and pointing azimuth angle of the phased array antenna beam to the ground fixed point, which is a conventional algorithm available to those skilled in the art.

[0076] The dual-beam independent pointing control in step (5) means that beam 1 and beam 2 can independently perform airspace scanning or fixed-point tracking, without affecting each other and having no restrictive relationship.

[0077] Embodiment 1:

[0078] A satellite or a drone flies over a certain area, and there are multiple target signals in the airspace on the ground, such as Figure 1 shown.

[0079] As Figure 2 shown, the design steps of this embodiment are as follows:

[0080] Step 1, power on the payload integrated processor, the broadband signal acquisition and processing machine, and the broadband dual-beam phased array antenna, and perform boot loading and software initialization;

[0081] For the described broadband dual-beam phased array antenna, its two beams work independently and can be independently controlled in terms of pointing. The operating frequency band of this broadband dual-beam phased array antenna includes but is not limited to: X-band, Ku-band, Ka-band, etc., specifically depending on user requirements and the antenna operating frequency range.

[0082] Step 2, after initialization is completed, the payload integrated processor controls the broadband dual-beam phased array antenna to enter the airspace scanning mode, and performs a zigzag scan on the airspace below the forward direction of the satellite or drone it carries;

[0083] The so-called zigzag scan refers to controlling the beam of the phased array antenna to swing left and right in a plane orthogonal to the forward direction of the satellite / drone, and realizing the scan of the airspace below it as the satellite / drone moves forward.

[0084] Step 3, the broadband signal acquisition and processing machine continuously receives and processes the signals collected by the two beams of the antenna. After respectively performing digital channelization, FFT and other processing on them, it accumulates and evaluates the frequency domain energy, and compares it with the set signal threshold. The comparison result shows that the energy accumulation value of the signal of beam 1 is less than the threshold, that is, it is considered that no target signal is collected; the energy accumulation value of the signal of beam 2 is greater than the threshold, that is, it is considered that a target signal is collected. The broadband signal acquisition and processing machine reports the moment t1 when beam 1 discovers the target signal to the payload integrated processor; it also reports the signal-free state of beam 2 to the payload integrated processor;

[0085] The moment t1 when the target signal is discovered refers to the real-time time obtained by the broadband signal acquisition and processing machine after performing a time accuracy correction at the microsecond level on the basis of the second pulse sent by the spaceborne or airborne platform and the broadcast time per second, so as to record the moment when the target signal is discovered with the highest accuracy.

[0086] Step 4, the payload integrated processor checks the signal presence / absence status reported by the broadband signal acquisition and processing machine in each pointing calculation cycle, and decides the antenna pointing mode in the current calculation cycle according to the signal presence / absence status:

[0087] The current status report shows that there is no signal in beam 1. Then, during this pointing calculation, the pointing mode of phased array antenna beam 1 is switched to the airspace scanning mode, and continue to perform a zigzag scan in the airspace below the forward direction of the satellite / drone;

[0088] The current status report shows that there is a signal in beam 2, and the moment when the signal is detected is t1. Then, continue to judge the signal presence / absence status of beam 2 during the previous pointing calculation: it is found that there was no signal in beam 2 during the previous pointing calculation, which indicates that the target signal was detected between these two calculation cycles. Switch the pointing mode of phased array antenna beam 2 to the fixed-point tracking mode, and based on the reported signal detection moment t1 of beam 2, reverse-calculate the latitude, longitude, and altitude of the ground position pointed by the antenna at this moment during the scanning process, which is point S3, as Figure 1 shown. Subsequently, the payload integrated processor obtains the broadcast attitude position information of the satellite / drone at the current moment. Using the body attitude position and the ground point's latitude, longitude, and altitude as inputs, call the fixed-point pointing algorithm to calculate the off-axis angle and pointing azimuth angle of the phased array antenna pointing to the ground fixed point S3 at the current moment. At the same time, the payload integrated processor records the signal presence / absence status of the two beams during the current pointing calculation cycle, that is, there is no signal in beam 1, there is a signal in beam 2, and the signal detection moment is t1, for subsequent judgment;

[0089] Among them, the fixed-point pointing algorithm is an evolution of some existing algorithms in the tracking algorithm. During the actual calculation process, there are many algorithms involved in the pointing calculation, which will not be elaborated here.

[0090] In the embodiment of the present invention, the duration of the pointing calculation cycle is 50 milliseconds.

[0091] Step 5, the payload integrated processor sends the pointing angle values calculated for each of the two antenna beams during this pointing calculation cycle to the phased array antenna for independent pointing control of the two beams, that is, beam 1 continues the airspace scan, and beam 2 performs fixed-point tracking on the ground target point S3;

[0092] Step 6, return to step 3, and the broadband signal acquisition and processing machine continues to process and judge the collected signals, and report the results to the payload integrated processor. When waiting for the next pointing calculation cycle to arrive, the payload integrated processor decides whether its pointing mode is airspace scan or fixed-point tracking based on the signal presence / absence status of the two beams, and performs the pointing calculation and antenna control in the corresponding mode.

[0093] Although the present invention has been disclosed above with preferred embodiments, it is not used to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention,

[0094] Equivalent variations and modifications all fall within the protection scope of the technical solution of the present invention.

[0095] The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. A feedback-based multi-objective signal self-tracking method, characterized in that Including: Power-on initialization processing for the payload integrated processor, broadband signal acquisition processor, and broadband dual-beam phased array antenna on the satellite; Controlling the broadband dual-beam phased array antenna to enter the airspace scanning mode through the payload integrated processor, and performing a zigzag scan on the airspace below the forward direction of the satellite; Controlling the broadband signal acquisition processor to receive the dual-beam acquisition signal, respectively judging the target signal for the dual-beam acquisition signal, and reporting the judgment result to the payload integrated processor in real time; Controlling the payload integrated processor to set the satellite antenna pointing mode of the dual-beams in the current pointing calculation cycle within each pointing calculation cycle according to the judgment result; Calculating the pointing angle values of the dual-beams respectively according to the satellite antenna pointing mode of the dual-beams in the current pointing calculation cycle, and performing independent pointing control of the dual-beams respectively according to the pointing angle values.

2. The multi-target signal self-tracking method based on feedback according to claim 1, characterized in that: The broadband dual-beam phased array antenna includes two independently operating beams, both of which are used for independent pointing control. The operating frequency bands of the two beams include the X-band, Ku-band, and Ka-band, and the operating frequency band is determined according to the tracking task requirements and the antenna operating frequency range; The zigzag scan is to control the two beams to swing left and right in a plane orthogonal to the forward direction of the satellite, and realize the scan of the airspace below as the satellite advances.

3. The multi-target signal self-tracking method based on feedback according to claim 2, characterized in that: The method for judging the target signal for the dual-beam acquisition signal is: Judging whether there is a target signal in the acquisition signals of the two beams. If there is a target signal in the acquisition signal of any beam, report the moment when the target signal is found and the beam where the target signal is located to the payload integrated processor; otherwise, report the no-signal state to the payload integrated processor, and at the same time continue to maintain the zigzag scan of the airspace in the no-signal state; The moment when the target signal is found is the real-time time obtained by the broadband signal acquisition processor after performing us-level time accuracy correction based on the second pulse of the satellite platform and the broadcast time per second.

4. The multi-target signal self-tracking method based on feedback according to claim 3, characterized in that: The method for judging whether there is a target signal in the acquisition signals of the two beams is: Performing digital channelization and FFT processing on the acquisition signals of the two beams, then performing frequency-domain energy accumulation evaluation, and comparing with the set signal threshold. When the frequency-domain energy accumulation value of any beam is less than the signal threshold, it is considered that there is no target signal, otherwise it is considered that there is a target signal; When there is a target signal in the acquisition signal of only one beam, report the moment when the target signal of one beam is found and the beam where it is located, and at the same time report the no-signal state of the other beam.

5. The multi-target signal self-tracking method based on feedback according to claim 4, characterized in that: The satellite antenna pointing modes of the dual-beams include the airspace scanning mode and the fixed-point tracking mode. The method for setting the satellite antenna pointing modes of the dual-beams in the current pointing calculation cycle is: If there is no target signal in the acquisition signals of both beams, the satellite antenna pointing modes of the two beams are set to the airspace scanning mode in the current pointing calculation cycle, and a zigzag scan is performed in the airspace below the satellite's forward direction; If there is a target signal in the acquisition signal of any beam, it is judged whether there is a target signal in the acquisition signal of the current beam in the previous pointing calculation cycle. If not, and a target signal is found at any time during the two pointing calculation cycles, the satellite antenna pointing mode of the current beam is switched to the fixed-point tracking mode, and the latitude, longitude, and altitude of the ground position pointed by the satellite antenna during the scanning process are deduced based on the time when the target signal is found, and fixed-point tracking is performed; if so, the satellite antenna pointing mode of the current beam is maintained, and fixed-point tracking is maintained for the target signal in the acquisition signal of the current beam in the previous pointing calculation cycle; for the satellite antenna pointing mode of the corresponding beam without a target signal in the current pointing calculation cycle, the airspace scanning mode is maintained; If there are target signals in the acquisition signals of both beams, independent judgments are made according to the satellite antenna pointing modes of the two beams in the previous pointing calculation cycle, and the satellite antenna pointing modes of the two beams are set respectively according to the satellite antenna pointing mode setting method when there is a target signal in the acquisition signal of any beam.

6. A feedback-based multi-target signal self-tracking method according to claim 5, characterized in that: Self-tracking processing of the target corresponding to the target signal that appears in the current pointing calculation cycle is realized according to the appearance time of the target signal, the switching conditions of the satellite antenna pointing modes of the dual beams in the current and previous pointing calculation cycles, and the pointing angle values of the dual beams in the current pointing calculation cycle.

7. A feedback-based multi-target signal self-tracking method according to claim 5, characterized in that: The duration and time accuracy of the pointing calculation cycle are set according to the pointing control frequency range of the broadband dual-beam phased array antenna, and the pointing calculation cycle is minimized to improve the self-tracking accuracy on the premise of meeting the tracking task requirements.

8. A feedback-based multi-target signal self-tracking method according to claim 5, characterized in that: The fixed-point pointing algorithm adopted by the fixed-point tracking mode uses the attitude position information of the satellite at the current moment and the ground point latitude, longitude, and altitude as input data, and the pointing off-axis angle and pointing azimuth angle of the phased array antenna beam to the ground fixed point calculated as output data.

9. A feedback-based multi-target signal self-tracking method according to claim 5, characterized in that: After the independent pointing control of the dual beams in the current pointing calculation cycle is completed, when waiting for the next pointing calculation cycle to arrive, the payload integrated processor repeats the judgment of whether there is a target signal according to the acquisition signals of the two beams, and re-performs the independent pointing control of the dual beams in the next pointing calculation cycle according to the judgment result.

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