CN107492717B - Inertial navigation course correction method for communication-in-moving antenna cosine scanning - Google Patents

Inertial navigation course correction method for communication-in-moving antenna cosine scanning Download PDF

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Publication number
CN107492717B
CN107492717B CN201710480204.3A CN201710480204A CN107492717B CN 107492717 B CN107492717 B CN 107492717B CN 201710480204 A CN201710480204 A CN 201710480204A CN 107492717 B CN107492717 B CN 107492717B
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agc
cosine
scanning
antenna
offset
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CN201710480204.3A
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Chinese (zh)
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CN107492717A (en
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韩泉城
杨志群
苗萍
石宝民
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山东航天电子技术研究所
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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/005Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using remotely controlled antenna positioning or scanning

Abstract

The invention discloses an inertial navigation course correcting method for cosine scanning of a communication-in-moving antenna, wherein a cosine scanning method is used for searching satellite signals, and the method only has rotation of an azimuth axis, saves pitching motion and reduces control complexity; under the condition that the accuracy of the beacon machine is not high, a signal deviation curve obtained by a conical scanning mode has randomness, so that the method is more suitable for communication-in-motion equipment with low accuracy of the beacon machine, and further saves the cost; according to the method, because the linear relation and the optimal linear coefficient between the left and right difference values of the cosine scanning of the AGC signal and the azimuth deviation angle are found out, a complex calculation process is omitted, the compensation is more stable through proportional control, and the click disturbance is smaller.

Description

Inertial navigation course correction method for communication-in-moving antenna cosine scanning

Technical Field

The invention belongs to the technical field of satellite communication, and particularly relates to an inertial navigation course correction method for cosine scanning of a communication-in-moving antenna, which is suitable for occasions with low cost inertial navigation and requiring a system to keep the accuracy of tracking a satellite by the antenna for a long time.

Background

The satellite communication system is a broadband mobile satellite communication system which establishes and maintains a satellite link between a carrier and a target satellite in a static state and a moving state by utilizing fixed service satellite resources and an antenna system installed on the carrier. The essence is to constantly maintain the antenna azimuth, elevation and polarization in three-dimensional alignment with the satellite in the moving state. Most communication-in-motion products in the prior art need an expensive Attitude and Heading Reference System (AHRS) to obtain the Attitude of the carrier, so that the disturbance of the antenna caused by the change of the Attitude of the carrier is compensated, and the antenna is always kept in three-dimensional alignment with a target satellite. Because the high-precision AHRS product is expensive, the low-cost MEMS inertial navigation is used for replacing the expensive high-precision AHRS product, and the high-precision AHRS product becomes a research hotspot of the current communication-in-motion system.

Aiming at MEMS inertial navigation with low precision, according to the error propagation characteristic of an inertial navigation system, the pitch angle and the roll angle of a carrier meet the relaxation oscillation period of 84.4min, and the pitch angle and the roll angle of the carrier are kept oscillating within a certain angle range under the limitation of the relaxation oscillation period. Because the attitude calculation precision of the inertial navigation system is higher and is limited by the relaxation cycle, the long-term drift error of the two horizontal attitude angles of the carrier is smaller, and the influence of the long-term drift error on the satellite tracking precision of the antenna can be ignored. However, the course angle of the inertial navigation system does not satisfy the period of the shula oscillation, the error of the inertial navigation system increases continuously along with the increase of time, and the course angle has larger error accumulation in the long-time use process of the inertial navigation system, so that the pointing accuracy of the satellite of the antenna system is continuously deteriorated. The method is characterized in that a high-precision navigation technology of an inertial navigation system is used for realizing a long-term high-precision satellite signal tracking function of the communication-in-moving antenna system, the cost is high, the defect that the course angle error of a low-cost inertial navigation system is accumulated continuously along with the time is overcome, and the realization of the high-precision stable satellite tracking function of the antenna system under the condition of long-time uninterrupted operation is a difficulty of the communication-in-moving system based on the inertial navigation scheme at present.

Disclosure of Invention

In view of this, the present invention provides an inertial navigation course correction method for cosine scanning of a mobile communication antenna, which realizes closed-loop tracking of satellite signals and solves the problem of influence of course drift error generated by an inertial navigation system on mobile communication.

An inertial navigation course correction method for cosine scanning of a communication-in-moving antenna comprises the following steps:

step 1, a communication-in-motion antenna carries out 360-degree scanning satellite finding to finish initialization and satellite alignment; then, reversely resolving the inertial navigation course angle by using the satellite signal, and calibrating the course angle of the inertial navigation according to the inertial navigation course angle;

step 2, resolving an azimuth error angle and a pitch error angle according to the satellite coordinates, the antenna coordinates and the attitude data of inertial navigation, and realizing antenna tracking control through a PID control method; wherein a cosine function control quantity E is superimposed on the azimuth angle control quantity of the antennacosThe cosine scanning movement is carried out through a PID tracking control antenna; wherein the content of the first and second substances,a is cosine scanning amplitude control quantity, N is scanning beat control variable, TcosIs a cosine scan period, TconFor controlling the beat period, N has a value range of

Step 3, adopting an azimuth deviation angle EoffsetCorrecting the azimuth error of the cosine scanning movement of the antenna, wherein Eoffset=KAAGCoffset,KAFor proportional control coefficients, AGCoffset=AGCL-AGCR,AGCRAGC value, AGC, collected when scanning to the right side in the process of cosine scanning movement of an antennaLThe AGC value collected when the left side is scanned in the process of carrying out cosine scanning movement on the antenna;

step 4, when the antenna completes a cosine scanning period, Y is superposed on the course angle output by inertial navigationoffsetCorrecting the inertial navigation course angle Y by the correction quantityoffset(ii) a Wherein, Yoffset=KBAGCoffset,KBIs a proportional control coefficient.

Preferably, in the step 3, the azimuth deviation angle E is obtained in the process of performing error correction on the cosine scanning motion of the antennaoffsetDispersed into the fixed beat of the first half period of the cosine scanning movement of the antenna.

Preferably, the azimuth deviation angle EoffsetUniformly dispersing the signals into fixed beats in the first half period of the antenna cosine scanning movement, and when the number of the control beats is X, adjusting the orientation error on each beat

Preferably, AGCRAnd AGCLThe calculation method comprises the following steps: the number of beats of the antenna per period of cosine scanning is NmaxIf the left side is the starting point of cosine scan, then the right sideRespectively recording AGC values by five control beats, and calculating AGC according to the following formulaR

NmaxIs the number of scanning beats;

similarly, the right side is the starting point of the cosine scan, and the left side isRecording AGC values respectively for five control beats and calculating AGCLThe value of (c).

Preferably, AGCoffsetSetting an upper limit value and a lower limit value; AGC obtained when calculatingoffsetWhen the value is larger than the upper limit value, AGC is performed at the momentoffsetTaking the upper limit value; AGC obtained when calculatingoffsetWhen the value is less than the lower limit value, AGC is performed at the momentoffsetThe lower limit is taken.

The invention has the following beneficial effects:

1. the invention uses the cosine scanning method to search the satellite signal, compared with the traditional cone scanning method in a mechanical scanning mode, the method only has the rotation of the azimuth axis, saves the pitching motion and reduces the control complexity. And under the condition that the accuracy of the beacon machine is not high, the signal deviation curve obtained by the cone scanning mode has randomness, so that the method is more suitable for communication-in-motion equipment with low accuracy of the beacon machine, and further saves the cost.

2. According to the method, the antenna azimuth deviation is compensated by using the AGC signal difference value through a proportional control method, compared with a mode of performing azimuth compensation by reversely solving the course through the AGC signal maximum value in the traditional cone scanning method, the method omits a complex calculation process due to the fact that the linear relation and the optimal linear coefficient between the AGC signal cosine scanning left and right difference values and the azimuth deviation angle are found, and compensation is more stable and click disturbance is smaller through proportional control.

3. Through the two processes, the drift of the inertial navigation course with low precision in the low-cost communication-in-motion process is effectively compensated.

Drawings

FIG. 1 is a flow chart of inertial navigation course correction according to the present invention;

FIG. 2 is a static drift velocity test chart of the RIU300 inertial navigation heading;

FIG. 3 is an antenna azimuth beacon signal pattern;

FIG. 4 is a graph of the relationship between the AGC difference and the center position deviation angle;

FIG. 5 is a graph of an azimuth deviation angle and an inertial navigation course angle after correction by cosine scanning;

FIG. 6 is a diagram illustrating the effect of calibrating a proportional control inertial navigation heading.

Detailed Description

The invention is described in detail below by way of example with reference to the accompanying drawings.

As shown in FIG. 1, the inertial navigation course correction method of the present invention comprises the following specific steps:

step 1, initialization: the communication-in-motion antenna carries out 360-degree scanning and satellite finding to finish the initialization and the alignment of the satellite. And then, reversely resolving the inertial navigation course angle by using the satellite signal, and calibrating the inertial navigation course angle.

Step 2, inertial navigation tracking control: and resolving the azimuth and pitch error angle according to the satellite coordinates, the antenna coordinates and the inertial navigation attitude data, and realizing antenna tracking control through a PID control algorithm. In the tracking process, due to the drift of the inertial navigation course, the azimuth direction of the antenna gradually deviates from the satellite, so that the signal is lost. Static heading drift test data of the Ruter RIU300 inertial navigation is shown in FIG. 2, and it can be seen that the inertial navigation will have a heading drift of about 1 degree per minute, so that closed-loop tracking of the satellite by means of the satellite beacon signal is required.

Step 3, the invention realizes the correction of the azimuth error through a cosine scanning method: superimposing the cosine function control quantity E on the azimuth angle control quantity of the antennacosAnd realizing that the antenna continuously performs cosine scanning movement by PID tracking control, wherein the superposed cosine scanning control function is as follows:

wherein EcosFor the control quantity of the orientation error cosine superposition, A cosine scan amplitudeDegree control quantity, N is scanning beat control variable, TcosIs a cosine scan period, TconFor controlling the beat period, the value range of NThe value of A is set according to the sensitivity of the beacon machine, the larger the value is, the larger the cosine scanning range is, but the power of a link signal is damaged.

In this example, A is taken to be 0.1 DEG and T is taken to becosIs 1s, TconIs 0.01s, the value range of N belongs to [1,100 ]]. Namely, one cosine scanning is completed at 100 control beats, and the scanning amplitude is +/-0.1 degrees.

Step 4, cosine scanning correction:

superimposing a cosine control quantity E on the azimuth error anglecosRealizing orientation cosine scanning, and controlling cosine scanning beats through N.

Collecting AGC values at the leftmost side and the rightmost side of cosine scanning, reducing the noise error by adopting a method of sampling for multiple times and averaging to reduce the noise error of the AGC values, and if the beat number of the cosine scanning in each period is NmaxThe left side is taken as the starting point of cosine scanning, and the right side is taken as the starting point of cosine scanningThe AGC values recorded in the five control beats are calculated according to the following formula.

AGCRCollecting AGC value for cosine scanning right side, obtaining AGC by the same methodLThe AGC value is collected on the left.

When the control tempo N is NmaxWhen the single cosine scan ends, according to AGCRAnd AGCLCalculating an azimuth deviation angle Eoffset

The antenna azimuth pattern in the above real-time example is shown in fig. 3, where the x-axis represents an azimuth deviation angle, and the deviation angle of the antenna in the direction in which the antenna faces the satellite is taken as 0, and the y-axis represents the AGC change condition in the course of the deviation angle change along with the antenna scanning. Observing the directional diagram, knowing that the AGC value takes the maximum value when the antenna is just opposite to the satellite direction, the AGC value is gradually reduced along with the increase of the azimuth deviation angle, and the AGC curve is close to a quadratic curve.

Since the scanning amplitude of the cosine scanning is 0.1 degree, the angle difference between the left end point and the right end point of the cosine scanning is 0.2 degree, and a relation curve of the AGC difference value at an interval of 0.2 degrees and the deflection angle of the point from the center position is drawn, as shown in figure 4. As can be seen from the figure, the AGC left and right difference value and the AGC center position deviation angle are approximately in linear relation, and a fitting straight line R2=0.9798。

Let AGCoffset=AGCL-AGCRAnd correcting the azimuth deviation by adopting a proportional control mode, wherein an azimuth deviation angle control formula is as follows:

Eoffset=KAAGCoffset

KAis a proportional control coefficient, is related to inertial navigation drift velocity, and can carry out K according to the control effectAParameter setting, KAToo big, the correction is too big, can cause PID tracking control disturbance, leads to adjusting the regulation and vibrates, and the motor shakes. KAIf the correction is too small, the correction is too slow, the accumulated deviation angle gradually changes greatly along with time, AGC is reduced, and signal gain is sacrificed.

To prevent excessive adjustment, AGC is setoffsetUpper and lower limit values, AGCoffsetThe upper limit is set to AGCoffsetMAX, lower limit of AGCoffsetMIN when AGCoffsetGreater than AGCoffsetWhen is-MAX, get AGCoffset=AGCoffsetMAX when AGCoffsetLess than AGCoffsetWhen MIN is constant, AGC is takenoffset=AGCoffset_MIN。

Obtaining an azimuth deviation angle EoffsetAnd then correcting the azimuth error. To further reduce the disturbance of the azimuth error correction to the PID tracking control, the azimuth deviation angle E is setoffsetDispersing the deviation angle to the fixed beat of the first half period of cosine scanning to make the azimuth motor realize the compensation of the deviation angle stably in the time period, for example, in 1-40 control beats, adjusting each beat

After the cosine scanning correction process, the antenna realizes closed-loop tracking of satellite signals, and the azimuth deviation angle realizes following of inertial navigation course drift. KAThe control effect of 0.3 is shown in fig. 5. For ease of viewing, the heading angle is offset by-176 °.

Step 5, inertial navigation course correction:

as can be seen from fig. 5, the inertial navigation heading angle drifts over time. The invention utilizes AGCoffsetCorrecting the course angle of inertial navigation, and adopting a proportional control algorithm for calibration, wherein a control equation is as follows:

Yoffset=KBAGCoffset

wherein Y isoffsetCorrecting the angle, K, for inertial navigation headingBIs a proportional control coefficient. When a cosine scanning period is finished, Y is superposed on a course angle output by inertial navigationoffsetAnd correcting the inertial navigation course angle by the correction quantity. The corrected course angle influences the azimuth direction through PID attitude control, and further influences the azimuth deviation angle E calculated by cosine scanningoffsetAnd closed-loop control is formed, and finally real-time inertial navigation course correction is realized.

While the controller corrects the inertial navigation course angle, YoffsetThe value is as small as possible to reduce the disturbance of PID attitude control and prevent the antenna from generating azimuth motor shake. To achieve this goal, KPThe value should be as small as possible. Get KPThe control tracking effect is shown in fig. 6, which is equal to 0.1. E _ OFFSET is azimuth deviation angle EoffsetAnd Y _ K is inertial navigation course correction angle YkYAW is the heading angle of inertial navigation output, which is offset by-175.5 degrees for easy observation.

In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (3)

1. An inertial navigation course correction method for cosine scanning of a communication-in-moving antenna is characterized by comprising the following steps of:
step 1, a communication-in-motion antenna carries out 360-degree scanning satellite finding to finish initialization and satellite alignment; then, reversely resolving the inertial navigation course angle by using the satellite signal, and calibrating the course angle of the inertial navigation according to the inertial navigation course angle;
step 2, resolving an azimuth error angle and a pitch error angle according to the satellite coordinates, the antenna coordinates and the attitude data of inertial navigation, and realizing antenna tracking control through a PID control method; wherein a cosine function control quantity E is superimposed on the azimuth angle control quantity of the antennacosThe cosine scanning movement is carried out through a PID tracking control antenna; wherein the content of the first and second substances,a is cosine scanning amplitude control quantity, N is scanning beat control variable, TcosIs a cosine scan period, TconFor controlling the beat period, N has a value range of
Step 3, adopting an azimuth deviation angle EoffsetCorrecting the azimuth error of the cosine scanning movement of the antenna, wherein Eoffset=KAAGCoffset,KAFor proportional control coefficients, AGCoffset=AGCL-AGCR,AGCRAGC value, AGC, collected when scanning to the right side in the process of cosine scanning movement of an antennaLThe AGC value collected when the left side is scanned in the process of carrying out cosine scanning movement on the antenna;
step 4, when the antenna completes a cosine scanning period, Y is superposed on the course angle output by inertial navigationoffsetCorrecting the inertial navigation course angle by using the correction quantity; wherein, Yoffset=KBAGCoffset,KBIs a proportional control coefficient;
in the step 3, in the process of correcting the error of the cosine scanning motion of the antenna, the azimuth deviation angle E is calculatedoffsetDispersed to the skyLine cosine scanning in a fixed beat of the first half period of motion;
the AGCRAnd AGCLThe calculation method comprises the following steps: the number of beats of the antenna per period of cosine scanning is NmaxIf the left side is the starting point of cosine scan, then the right sideRespectively recording AGC values by five control beats, and calculating AGC according to the following formulaR
NmaxIs the number of scanning beats;
similarly, the right side is the starting point of the cosine scan, and the left side isRecording AGC values respectively for five control beats and calculating AGCLThe value of (c).
2. The inertial navigation course correction method for cosine scanning of mobile communication antenna as claimed in claim 1, wherein the azimuth deviation angle E isoffsetUniformly dispersing the signals into fixed beats in the first half period of the antenna cosine scanning movement, and when the number of the control beats is X, adjusting the orientation error on each beat
3. The inertial navigation heading correction method for cosine scanning of mobile communication antenna as claimed in claim 1, wherein the heading correction method is AGCoffsetSetting an upper limit value and a lower limit value; AGC obtained when calculatingoffsetWhen the value is larger than the upper limit value, AGC is performed at the momentoffsetTaking the upper limit value; AGC obtained when calculatingoffsetWhen the value is less than the lower limit value, AGC is performed at the momentoffsetThe lower limit is taken.
CN201710480204.3A 2017-06-22 2017-06-22 Inertial navigation course correction method for communication-in-moving antenna cosine scanning CN107492717B (en)

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CN102679978B (en) * 2012-05-14 2014-10-29 北京理工大学 Initial alignment method of static base of rotary type strap-down inertial navigation system
CN103217158B (en) * 2012-12-31 2016-06-29 贾继超 A kind of method improving vehicle-mounted SINS/OD integrated navigation precision
CN104181572B (en) * 2014-05-22 2017-01-25 南京理工大学 Missile-borne inertia/ satellite tight combination navigation method
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