阅读说明：本技术 复杂遮挡环境下动中通系统跟踪方法 (Communication-in-motion system tracking method under complex shielding environment ) 是由 高巍 程金博 赵亮 雒骏鹏 吴红艳 张铮 兰琪 刘兆明 马行军 于 2020-05-23 设计创作，主要内容包括：本发明提出一种复杂遮挡环境下动中通系统跟踪方法,在动中通系统进入跟踪阶段后,在每个采样周期进行AGC信号电平判别,当信号电平不小于退出门限时,计时变量T置0,并是否是波束扫描调整周期中的最后时刻,若不是则执行常规跟踪策略,否则判断电平变化幅度数组最大值,如果小于AGC变化幅度阈值β,则执行对卫星的常规跟踪策略,否则系统天线保持进入遮挡前一刻时的波束指向；当信号电平小于退出门限时,T自增；并将T与设定阈值比较,判断是保持进入遮挡前一刻时的波束指向或是执行扫描策略。本发明可避免动中通系统在部分遮挡情况下拉偏天线指向的问题,并且在长时间遮挡情况下,出遮挡时电平恢复速度较快。(The invention provides a method for tracking a communication-in-motion system in a complex shielding environment, after the communication-in-motion system enters a tracking stage, AGC signal level discrimination is carried out in each sampling period, when the signal level is not less than a quit threshold, a timing variable T is set to be 0, whether the signal level is the last moment in a beam scanning adjustment period or not is judged, if not, a conventional tracking strategy is executed, otherwise, the maximum value of a level change amplitude array is judged, if the signal level is less than an AGC change amplitude threshold value beta, the conventional tracking strategy for a satellite is executed, otherwise, a system antenna keeps beam pointing at the moment before shielding; when the signal level is less than the exit threshold, T is increased automatically; and comparing the T with a set threshold value, and judging whether the beam direction is kept before entering the shielding or a scanning strategy is executed. The invention can avoid the problem that the deflecting antenna points under the condition of partial shielding of the communication-in-motion system, and the level recovery speed is higher when the communication-in-motion system goes out of the shielding under the condition of long-time shielding.)

1. A communication-in-motion system tracking method under a complex shielding environment is characterized by comprising the following steps: the method comprises the following steps:

step 1: in the initial satellite searching stage, when the AGC signal level received by the communication-in-motion system exceeds a tracking threshold, the AGC signal level under each sampling period is recorded; for each sampling period, recording AGC signal level values at the first n sampling periods to form an array, e.g., for the tn th sampling period, recording an array P of AGC signal level values at the first n sampling periods_tn＝{p_t1,p_t2…p_tn}；

Step 2: for each sampling period, screening AGC signal level values recorded in the first n sampling periods to obtain the maximum value and the minimum value, and recording the difference value between the maximum value and the minimum value, for example, obtaining P for the tn th sampling period_tnMaximum value Pmax of middle AGC signal level_tnAnd a minimum value Pmin_tnAnd recording the difference between the two as v_tn＝Pmax_tn-Pmin_tn(ii) a Thus, for each sampling period, the difference value between the maximum value and the minimum value in the level value array corresponding to the previous m sampling periods can be recorded to form a level change amplitude array, for example, for the tm sampling periodFlat variation amplitude array V_tm＝{v_t1,v_t2…v_tm}；

And step 3: under the condition of no shielding, the system finishes the satellite finding and tracking of the satellite; in the tracking stage, according to the processes in the first step and the second step, a corresponding level value array and a corresponding level change amplitude array are recorded in each sampling period;

and 4, step 4: after entering a tracking stage, performing AGC signal level discrimination in each sampling period:

when the signal level is not less than the exit threshold, setting a preset timing variable T to 0, and judging whether the current sampling period is the last moment in the beam scanning adjustment period, if not, executing a conventional tracking strategy for the satellite by the system, if so, judging the maximum value in a level change amplitude array corresponding to the current sampling period, if the maximum value is less than a set AGC change amplitude threshold value beta, determining that the system is not blocked at the moment, still executing the conventional tracking strategy for the satellite, otherwise, determining that the system is partially blocked, and keeping the beam direction of the system antenna before the blocking moment;

when the signal level is less than the exit threshold, the timing variable T is automatically increased;

if the signal level is zero, the system is in a complete shielding condition, whether a timing variable T exceeds a set T3 is judged, if not, the system antenna keeps the beam direction at the moment before shielding, and if so, a scanning strategy is executed;

if the signal level is greater than zero, judging whether a timing variable T exceeds a set T1, if so, executing a scanning strategy, and if not, keeping the system antenna to enter a beam direction blocking the previous moment;

the scanning strategy is as follows: carrying out azimuth direction scanning at the current pointing position of the antenna, wherein the initial scanning direction of the azimuth direction scanning is consistent with the course correction direction adopted by the satellite when a conventional tracking strategy is executed before the satellite communication system in motion; if the scanning time exceeds the set duration of T2 and the AGC level still does not reach or exceed the exit threshold, the system re-enters the star finding phase.

2. The method for tracking the communication-in-motion system in the complex occlusion environment according to claim 1, wherein the method comprises the following steps: the conventional tracking strategy includes a conical scanning tracking strategy or a single pulse tracking strategy.

3. The method for tracking the communication-in-motion system in the complex occlusion environment according to claim 1, wherein the method comprises the following steps: and the AGC variation amplitude threshold value beta is obtained by adding a set margin to the maximum drop value of the level in the tracking stage of the non-shielded area of the system.

4. The method for tracking the communication-in-motion system in the complex occlusion environment according to claim 3, wherein: the set margin is taken 1 dB.

5. The method for tracking the communication-in-motion system in the complex occlusion environment according to claim 1, wherein the method comprises the following steps: and T3 is determined according to the heading drift speed of the inertial navigation component in the system and the beam width of the antenna, and the value is the time required by twice the beam width of the heading drift after the inertial navigation component is electrified.

6. The method for tracking the communication-in-motion system in the complex occlusion environment according to claim 1, wherein the method comprises the following steps: t1 is determined according to the heading drift speed of an inertial navigation component in the system, the beam width of an antenna and the system performance; and testing the level drop average value PdB of the communication-in-motion system in the tracking stage under the condition of no shielding, calculating a beam azimuth direction deviation angle theta corresponding to the PdB level drop according to an antenna directional diagram, and determining the time required by testing the heading drift angle theta after the inertial navigation component is electrified as T1.

7. The method for tracking the communication-in-motion system in the complex occlusion environment according to claim 1, wherein the method comprises the following steps: t2 takes the value 40S.

Technical Field

The invention relates to the field of satellite communication, in particular to a method for tracking a communication-in-motion system in a complex shielding environment.

Background

The communication-in-motion system is widely applied to the military field and the emergency communication field. The communication-in-motion system is inevitably shielded by buildings or trees in actual use occasions. For the case that the antenna system is completely shielded and the shielding time is short, the tracking method is easy, namely, the antenna keeps the current pointing direction when the AGC signal level is judged to be zero. However, when the antenna passes through the forest and other partial shielding conditions, the AGC signal is not completely zero, even within the antenna tracking threshold, and at this time, when the tracking methods such as conical scanning are adopted, the level generated by partial shielding may generate an incorrect course correction value during operation, resulting in the antenna pointing being biased. The other situation is that the beam is pointed to deviate from a target due to the problem of course drift when the antenna is shielded by long-distance tunnel and other long-time shielding, and the signal level recovery speed is slow if tracking methods such as conical scanning are still adopted; when the course drift is fast, the antenna can not even track into the main beam of the antenna, and the communication performance is seriously influenced.

Disclosure of Invention

Aiming at the problems, the invention provides a method for tracking a communication-in-motion system under the shielding of a complex environment, which can avoid the problem that a bias antenna points under the condition of partial shielding of the communication-in-motion system, and has higher level recovery speed when the communication-in-motion system is shielded for a long time.

The technical scheme of the invention is as follows:

the communication-in-motion system tracking method under the complex shielding environment is characterized by comprising the following steps: the method comprises the following steps:

step 1: in the initial satellite searching stage, when the AGC signal level received by the communication-in-motion system exceeds a tracking threshold, the AGC signal level under each sampling period is recorded; for each sampling period, recording AGC signal level values at the first n sampling periods to form an array, e.g., for the tn th sampling period, recording an array P of AGC signal level values at the first n sampling periods_tn＝{p_t1,p_t2…p_tn}；

Step 2: for each sampling period, screening AGC signal level values recorded in the first n sampling periods to obtain the maximum value and the minimum value, and recording the difference value between the maximum value and the minimum value, for example, obtaining P for the tn th sampling period_tnMaximum value Pmax of middle AGC signal level_tnAnd a minimum value Pmin_tnAnd recording the difference between the two as v_tn＝Pmax_tn-Pmin_tn(ii) a Thus, for each sampling period, the difference value between the maximum value and the minimum value in the level value array corresponding to the previous m sampling periods can be recorded to form a level change amplitude array, for example, for the tm sampling period, the level change amplitude array V_tm＝{v_t1,v_t2…v_tm}；

And step 3: under the condition of no shielding, the system finishes the satellite finding and tracking of the satellite; in the tracking stage, according to the processes in the first step and the second step, a corresponding level value array and a corresponding level change amplitude array are recorded in each sampling period;

and 4, step 4: after entering a tracking stage, performing AGC signal level discrimination in each sampling period:

when the signal level is not less than the exit threshold, setting a preset timing variable T to 0, and judging whether the current sampling period is the last moment in the beam scanning adjustment period, if not, executing a conventional tracking strategy for the satellite by the system, if so, judging the maximum value in a level change amplitude array corresponding to the current sampling period, if the maximum value is less than a set AGC change amplitude threshold value beta, determining that the system is not blocked at the moment, still executing the conventional tracking strategy for the satellite, otherwise, determining that the system is partially blocked, and keeping the beam direction of the system antenna before the blocking moment;

when the signal level is less than the exit threshold, the timing variable T is automatically increased;

if the signal level is zero, the system is in a complete shielding condition, whether a timing variable T exceeds a set T3 is judged, if not, the system antenna keeps the beam direction at the moment before shielding, and if so, a scanning strategy is executed;

if the signal level is greater than zero, judging whether a timing variable T exceeds a set T1, if so, executing a scanning strategy, and if not, keeping the system antenna to enter a beam direction blocking the previous moment;

the scanning strategy is as follows: carrying out azimuth direction scanning at the current pointing position of the antenna, wherein the initial scanning direction of the azimuth direction scanning is consistent with the course correction direction adopted by the satellite when a conventional tracking strategy is executed before the satellite communication system in motion; if the scanning time exceeds the set duration of T2 and the AGC level still does not reach or exceed the exit threshold, the system re-enters the star finding phase.

Further, the conventional tracking strategy includes a cone scanning tracking strategy or a single pulse tracking strategy.

Further, the AGC variation amplitude threshold value beta is the maximum drop value of the level of the system in the non-shielding area tracking stage plus the set margin.

Further, the setting margin is 1 dB.

Further, T3 is determined according to the heading drift speed of the inertial navigation component in the system and the beam width of the antenna, and the value is the time required by the heading drift twice the beam width after the inertial navigation component is powered on.

Further, T1 is determined according to the heading drift speed of an inertial navigation component in the system, the beam width of the antenna and the system performance; and testing the level drop average value PdB of the communication-in-motion system in the tracking stage under the condition of no shielding, calculating a beam azimuth direction deviation angle theta corresponding to the PdB level drop according to an antenna directional diagram, and determining the time required by testing the heading drift angle theta after the inertial navigation component is electrified as T1.

Further, T2 takes the value 40S.

Advantageous effects

The invention has the beneficial effects that:

1) the problem that the deflecting antenna is pointed under the complex shielding condition of the communication-in-motion system can be effectively solved;

2) the antenna stays in a partial shielding area for a long time and cannot deviate from a target, and the recapture speed is high after the shielding disappears;

3) the method is simple and effective, has stable performance, and can be applied to communication-in-motion systems in various antenna forms.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a flowchart of a communication-in-motion system tracking method in a complex occlusion environment after the tracking is started.

Detailed Description

The following detailed description of embodiments of the invention is intended to be illustrative, and not to be construed as limiting the invention.

In the initial satellite finding stage of the communication-in-motion system, after the AGC signal level received by the system gradually increases and exceeds a tracking threshold, the AGC signal level under each sampling period is recorded to form a level value array with the length of n, the AGC signal level values (including the current period) of the first n sampling periods of the current sampling period are recorded in the level value array, the AGC signal level obtained earliest in the level value array is removed when the subsequent sampling period comes, and the latest AGC signal level is recorded, so that cyclic recording is performed, for example, for the tn sampling period, the AGC signal level under the first n sampling periods is recordedThe flat value array is P_tn＝{p_t1,p_t2…p_tn}。

The value of n can be optimized to be the optimal parameter, because the value is too small, the misjudgment condition caused by shielding can occur, and the level convergence speed is slow after shielding is performed due to too large value, in this embodiment, the n sampling periods are selected to be 1.5 seconds as the optimal parameter in cooperation with the system sampling period.

Similarly, for each sampling period, the AGC signal level values recorded in the previous n sampling periods are screened to obtain the maximum value and the minimum value, the difference value between the maximum value and the minimum value is recorded as the AGC signal level change amplitude corresponding to the current sampling period, for example, for the tn th sampling period, P is obtained_tnMaximum value Pmax of middle AGC signal level_tnAnd a minimum value Pmin_tnAnd recording the difference between the two as v_tn＝Pmax_tn-Pmin_tn. Thus, a level change amplitude array with length m can be established, and the level change amplitude array records the AGC signal level change amplitudes (including the current period) corresponding to the m previous sampling periods of the current sampling period, for example, for the tm sampling period, the level change amplitude array V_tm＝{v_t1,v_t2…v_tm}; and the level change amplitude array also adopts a cyclic recording mode.

Under the condition of no shielding, the system finishes the satellite finding and tracking of the satellite, and the corresponding level value array and the level change amplitude array are recorded in each sampling period in the tracking stage according to the process.

After entering the tracking phase, as shown in fig. 1, AGC signal level discrimination is performed at each sampling period:

when the signal level is not less than the exit threshold, setting a preset timing variable T to be 0, judging whether the current sampling period is the last moment in the beam scanning adjustment period, if not, executing a conventional tracking strategy for the satellite by the system, such as a conical scanning tracking strategy or a single pulse tracking strategy, and carrying out course correction in the tracking process; if the maximum value is smaller than the set AGC variation amplitude threshold value beta, the system is not shielded at the moment, the conventional tracking strategy for the satellite is still executed, otherwise, the system is considered to be partially shielded, the course correction is not carried out at the moment, and the system antenna keeps the beam pointing direction at the moment before shielding.

The value of beta needs to be noticed, and if the value is too small, the level drop under the normal tracking state of the system is counted into the shielding condition; too large can result in ineffective processing in the case of occlusions, both of which can pull the pointing direction off. Therefore, in this embodiment, the AGC variation amplitude threshold β is preferably a set margin obtained by adding 1dB to the maximum drop value of the system level in the tracking stage of the non-occluded area.

When the signal level is less than the exit threshold, the timing variable T is automatically increased;

if the signal level is zero, the system is in a complete shielding condition, whether a timing variable T exceeds a set T3 is judged, if not, the system antenna keeps the beam direction at the moment before shielding, and if so, a scanning strategy is executed;

if the signal level is greater than zero, judging whether a timing variable T exceeds a set T1, if so, executing a scanning strategy, and if not, keeping the system antenna to enter a beam direction blocking the previous moment;

the scanning strategy is as follows: carrying out azimuth direction scanning at the current pointing position of the antenna, wherein the initial scanning direction of the azimuth direction scanning is consistent with the course correction direction adopted by the satellite when a conventional tracking strategy is executed before the satellite communication system in motion; if the scanning time exceeds the set duration of T2 and the AGC level still does not reach or exceed the exit threshold, the system re-enters the star finding phase. The scan range is preferably five times the beam width of the antenna.

The above threshold parameter is determined by the following procedure:

the T3 is determined according to the heading drift speed of the inertial navigation component in the system and the beam width of the antenna, the value is the time required by twice the beam width of the heading drift after the inertial navigation component is electrified, and the T3 can be obtained by taking an average value through multiple tests.

T1 is determined according to the heading drift speed of an inertial navigation component in the system, the beam width of an antenna and the system performance; and testing the level drop average value PdB of the communication-in-motion system in the tracking stage under the condition of no shielding, calculating a beam azimuth direction deviation angle theta corresponding to the PdB level drop according to an antenna directional diagram, and determining the time required by testing the heading drift angle theta after the inertial navigation component is electrified as T1. It can also be obtained by averaging preferably a plurality of tests.

T2 takes the value 40S.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.