阅读说明：本技术 一种海上浮标卫星通信自动跟踪装置及跟踪方法 (Automatic tracking device and method for satellite communication of offshore buoy ) 是由 张瑞士 梁显锋 赵晖 于 2020-12-04 设计创作，主要内容包括：本发明属于卫星通信跟踪的技术领域,具体地说,涉及一种海上浮标卫星通信跟踪装置,包括：AP板、惯导单元、GPS单元、中央控制单元、伺服控制器、多个驱动器、方位轴步进电机和俯仰轴步进电机；所述AP板,用于获取AGC数据；所述惯导单元,用于获取某海上浮标的惯导数据；所述GPS单元,用于获取该海上浮标的GPS数据；所述中央控制单元,用于计算卫星天线需要调整的方位角和俯仰角,并将其输入至伺服控制器；还用于圆锥扫描算法,对获取的AGC数据进行处理,得到处理后的AGC数据,并将其输入至伺服控制器；所述伺服控制器,用于根据获得的卫星天线需要调整的方位角和俯仰角,对应地驱动方位轴步进电机和俯仰轴步进电机。(The invention belongs to the technical field of satellite communication tracking, and particularly relates to a satellite communication tracking device for an offshore buoy, which comprises: the system comprises an AP board, an inertial navigation unit, a GPS unit, a central control unit, a servo controller, a plurality of drivers, an azimuth axis stepping motor and a pitch axis stepping motor; the AP board is used for acquiring AGC data; the inertial navigation unit is used for acquiring inertial navigation data of a certain offshore buoy; the GPS unit is used for acquiring GPS data of the offshore buoy; the central control unit is used for calculating an azimuth angle and a pitch angle of the satellite antenna to be adjusted and inputting the azimuth angle and the pitch angle to the servo controller; the method is also used for a cone scanning algorithm, the acquired AGC data are processed to obtain processed AGC data, and the processed AGC data are input to a servo controller; and the servo controller is used for correspondingly driving the azimuth axis stepping motor and the pitch axis stepping motor according to the obtained azimuth angle and pitch angle which need to be adjusted by the satellite antenna.)

1. An offshore buoy satellite communication tracking device, the device comprising: the system comprises an AP board, an inertial navigation unit, a GPS unit, a central control unit, a servo controller, a plurality of drivers, an azimuth axis stepping motor and a pitch axis stepping motor;

the AP board is used for acquiring AGC data and inputting the AGC data to the central control unit;

the inertial navigation unit is used for acquiring inertial navigation data of a certain offshore buoy, performing Kalman filtering processing on the inertial navigation data based on a feedforward compensation method of Kalman filtering, and inputting the processed inertial navigation data to the central control unit;

the GPS unit is used for acquiring GPS data of the offshore buoy and inputting the GPS data to the central control unit;

the central control unit is used for acquiring an azimuth angle and a pitch angle of the satellite antenna to be adjusted according to the acquired GPS data and the processed inertial navigation data, inputting the azimuth angle and the pitch angle to the servo controller, and performing primary alignment of the satellite antenna and the satellite;

the system is also used for processing the acquired AGC data according to a cone scanning algorithm to obtain processed AGC data, inputting the processed AGC data to a servo controller and carrying out realignment on the satellite antenna and the satellite;

the servo controller is used for correspondingly driving the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the obtained azimuth angle and pitch angle which need to be adjusted by the satellite antenna;

and the system is also used for correspondingly driving the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the received processed AGC data so as to realize real-time tracking of the offshore buoy.

2. The marine buoy satellite communication tracking device as claimed in claim 1, wherein the AGC data is an automatic gain control value obtained by using an AP board to reflect satellite signal strength;

the inertial navigation data is attitude data of a certain offshore buoy detected by adopting an inertial navigation unit, and the attitude data of the certain offshore buoy comprises: azimuth, pitch and roll angles;

the GPS data is a GPS unit which is used for acquiring the geographic position coordinate value of a certain offshore buoy as the GPS value of the offshore buoy, and the GPS value of the offshore buoy comprises: longitude, latitude and altitude of a certain buoy at sea.

3. A maritime buoy satellite communication tracking method, which is implemented based on the maritime buoy satellite communication tracking device of any one of claims 1-2, and comprises the following steps:

initially finding a satellite, and adjusting a satellite antenna platform on a certain buoy to be in a horizontal plane;

the central control unit obtains an azimuth angle and a pitch angle of the satellite antenna to be adjusted according to the pre-obtained GPS data and the processed inertial navigation data, and the satellite antenna is aligned to the satellite for the first time;

the servo controller drives an azimuth axis stepping motor through a driver according to the obtained azimuth angle required to be adjusted of the satellite antenna, and the azimuth angle of the satellite antenna is adjusted by using the azimuth axis stepping motor;

the servo controller drives a pitch axis stepping motor through a driver according to the obtained pitch angle required to be adjusted of the satellite antenna, and the pitch angle of the satellite antenna is adjusted by using the pitch axis stepping motor;

the central control unit processes the acquired AGC data according to a cone scanning algorithm to obtain processed AGC data, inputs the processed AGC data into the servo controller and aligns the satellite antenna again; the servo controller correspondingly drives the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the received processed AGC data;

the marine buoy is tracked in real time according to a satellite antenna.

4. The offshore buoy satellite communication tracking method as claimed in claim 3, wherein the AGC data is an automatic gain control value obtained by using an AP board and used for reflecting satellite signal strength;

the inertial navigation data is attitude data of a certain offshore buoy detected by adopting an inertial navigation unit, and the attitude data of the certain offshore buoy comprises: azimuth, pitch and roll angles;

the GPS data is a GPS unit which is used for acquiring the geographic position coordinate value of a certain offshore buoy as the GPS value of the offshore buoy, and the GPS value of the offshore buoy comprises: longitude, latitude and altitude of a certain buoy at sea.

5. The offshore buoy satellite communication tracking method of claim 3, wherein the initial satellite finding, adjusting the satellite antenna platform on the buoy to be in the horizontal plane; the specific process comprises the following steps:

acquiring an initial pitch angle and an initial roll angle of a certain offshore buoy on the sea, and judging whether a satellite antenna platform on the offshore buoy is in a horizontal plane or not;

if the pitch angle and the roll angle of the offshore buoy are both 0, the satellite antenna platform on the buoy is positioned on the horizontal plane;

if the pitch angle or the roll angle of the offshore buoy is not 0, the satellite antenna platform on the buoy has an included angle, the satellite antenna platform on the buoy is adjusted until the pitch angle and the roll angle of the buoy are both 0, the satellite antenna platform on the buoy is positioned on the horizontal plane, and the azimuth angle or the pitch angle on the satellite antenna platform is adjusted, so that the sky satellite lines are parallel to the horizontal plane.

6. The maritime buoy satellite communication tracking method as claimed in claim 3, wherein the central control unit obtains an azimuth angle and a pitch angle of the satellite antenna to be adjusted according to pre-obtained GPS data and processed inertial navigation data, and aligns the satellite antenna to the satellite for the first time; the specific process comprises the following steps:

establishing a global coordinate system O of a satellite₀x₀y₀z₀The position coordinates of the satellite are then expressed as (x)₀,y₀,z₀): wherein the origin is O₀Is the center of the earth, x₀Pointing to the north pole, y, for the X-axis₀The Y axis points to the intersection point of the meridian and the equator; z is a radical of₀The Z axis points to the intersection point of 90 degrees E and the equator; calculating the rectangular coordinates of the satellite in the terrestrial coordinate system:

wherein h is the height from the satellite to the ground; λ is the longitude under the satellite spot;the latitude under the satellite point is taken as the latitude; a certain buoy at sea is located at O_eOrigin of a geographical coordinate system of origin, λ_nLongitude of a certain buoy at sea;the latitude of a certain buoy at sea; re is the radius of the earth;is a geosynchronous orbit satellite;

establishing a northeast geographical coordinate system of the satellite, and performing matrix conversion on the earth coordinate vector of the satellite to obtain a geographical coordinate (x) of the satellite_e,y_e,z_e)；

Wherein R is₂About λ_nThe rotation matrix of (a); r₁To relate toThe rotation matrix of (a); x is the number of_eIs directed to the north direction in the X-axis, y_eThe Y axis points to the east, z_eThe Z axis is directed to the sky vertical to the horizontal plane;

wherein the content of the first and second substances,

according to the formulas (1), (2), (3) and (4), the geographical coordinates (x) of the satellite are obtained through sorting_e，y_e，z_e)：

Calculating a primary azimuth angle A and a primary pitch angle E of the satellite antenna to be adjusted according to the position of the satellite in the geographic coordinate system and the formula (5);

respectively and correspondingly winding an x axis, a y axis and a z axis in a northeast geographic coordinate system of the satellite around O_eX_e、O_eY_eAnd O_eZ_eRotating and establishing a buoy inertial navigation coordinate system:

[D_j]＝M_R·M_P·M_H·[D_m] (8)

wherein [ D ]_j]Is satellite buoyCoordinate vectors in an inertial navigation coordinate system; [ D ]_m]Is a coordinate vector of the satellite in a geographic coordinate system; m_RIs a rotation matrix about the roll angle R; m_PIs a rotation matrix about a pitch angle P; m_HIs a rotation matrix for heading angle H:

wherein H is a course angle; p is a pitch angle; r is a transverse rolling angle;

combining the formulas (9), (10) and (11) to obtain coordinate vectors of the sorted satellites in the northeast geographic coordinate system;

according to the formula (12), calculating the azimuth angle A of the satellite antenna to be adjusted in the buoy inertial navigation coordinate system_jAnd a pitch angle E_j；

E_j＝arcsin[sin R cos E sin(A-H)-cos R sin P cos E cos(A-H)+cos R cos P sin E] (14)。

7. The maritime buoy satellite communication tracking method as claimed in claim 3, wherein the central control unit processes the acquired AGC data according to a cone scanning algorithm to obtain processed AGC data, inputs the processed AGC data to the servo controller, and realigns the satellite antenna; the servo controller correspondingly drives the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the received processed AGC data; the specific process comprises the following steps:

an AGC closed loop tracking method based on cone scanning is adopted, a cone scanning mode is utilized to establish the sine and cosine function relationship between the signal intensity AGC of a wave beam at any point on a cone motion track formed by the cone scanning and the angle theta of each point on a circumference formed by the cone motion track,

within a complete cone scanning period, obtaining a plurality of signal strength AGC sampling values according to AGC data obtained in advance, and selecting the maximum value AGC with the signal strength AGC from the signal strength AGC sampling values_maxSum minimum AGC_minThen the maximum value AGC_maxAnd the minimum AGC_minRespectively recording the points Q and W at the intersection points of the connecting line of the circle center and the satellite position and the circumference;

assuming that the position of the satellite is S, the point P is the center of a certain cone scan, and the scanning radius of the cone scan is α, the re-adjusted azimuth angle amplitude Δ a and the re-adjusted pitch angle amplitude Δ E are respectively:

where PQ is the center of the cone sweep to the maximum AGC_maxA distance vector between the corresponding points;the included angle between the position of the satellite antenna deviating from the satellite and the horizontal direction is formed;

if it isIf the value is positive, the adjustment to the right is indicated; if it isIf the number is negative, the adjustment is carried out to the left; if it isIf the number is positive, the adjustment is upward;if the number is negative, downward adjustment is indicated;

determining the precise direction to be adjusted of the circle center by the obtained amplitude Delta A of the azimuth angle to be adjusted again and the amplitude Delta E of the pitch angle to be adjusted again, thereby determining the azimuth angle and the pitch angle of the satellite antenna to be adjusted again, taking the azimuth angle and the pitch angle as processed AGC data, inputting the processed AGC data to a servo controller, and aligning the satellite antenna again; the servo controller correspondingly drives the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the received processed AGC data, finely adjusts the satellite antenna and further aligns the satellite antenna to the satellite again;

wherein, the sampled signal strength AGC sampling value is sampled and smoothed for a plurality of times to obtain more stable and accurate maximum AGC_maxAnd the minimum AGC_min；

Aiming at the current complete cone scanning, the maximum AGC obtained in the current cone scanning process is judged_maxWhether the AGC value is less than the preset threshold AGC value_th；

AGC if maximum value obtained in the current cone scanning process_maxAGC less than preset threshold AGC value_th(ii) a Determining the precise direction of the circle center to be adjusted according to the adjusted azimuth angle amplitude delta A and the adjusted pitch angle amplitude delta E obtained by calculation; and areRepeating the above process until the maximum value AGC obtained in the next cone scanning process_maxGreater than or equal to preset threshold AGC value AGC_th(ii) a Stopping the cone scan;

AGC if maximum value obtained in the current cone scanning process_maxGreater than or equal to preset threshold AGC value AGC_th(ii) a The cone scan is stopped.

Technical Field

The invention belongs to the technical field of satellite communication tracking, and particularly relates to an automatic tracking device and an automatic tracking method for satellite communication of an offshore buoy.

Background

With respect to the technology of communication in motion, satellite communication is a communication behavior performed by utilizing a satellite as a relay between radio communication stations on the earth. The traditional satellite communication mode belongs to 'silent center communication', namely, under the condition that the space position of the communication equipment is not changed, the communication function is realized, and the antenna base is fixed and immovable. With the improvement of the scientific and technical level and the change of the requirements of people on communication quality, communication speed and communication flexibility, in order to expand the application field of satellite communication, the technology of 'communication in motion' is increasingly applied to the satellite communication field. The object is moving at any moment, however, the satellite antenna has directivity during communication, which needs to isolate the movement of the object under the condition of the movement of the object, so as to ensure that the satellite antenna can be always aligned to the satellite without being influenced by the movement of the object, which is the technology of 'communication in motion'.

The traditional ship-borne communication-in-motion technology is applicable to a relatively stable ship platform, the antenna aperture is relatively large, the requirements on quick response capability and tracking control accuracy are not high, generally, a carrier of offshore satellite communication is a buoy, the posture of the buoy is changed violently when the buoy advances on the sea, and due to the size limitation of the buoy, the antenna aperture is relatively small, so that the requirements on high speed and high accuracy of tracking control of the offshore buoy cannot be met.

Therefore, currently, the existing tracking method for marine buoy satellite communication has two problems: firstly, how to realize fast satellite alignment, namely fast satellite finding, under the condition that the posture of a buoy is constantly changed; secondly, how to make the satellite antenna still keep correct pointing under the condition of the change of the buoy attitude, namely, stable tracking.

Disclosure of Invention

In order to solve the above defects in the prior art, the invention provides a satellite communication tracking device for an offshore buoy, which comprises: the system comprises an AP board, an inertial navigation unit, a GPS unit, a central control unit, a servo controller, a plurality of drivers, an azimuth axis stepping motor and a pitch axis stepping motor;

the AP board is used for acquiring AGC data and inputting the AGC data to the central control unit;

the inertial navigation unit is used for acquiring inertial navigation data of a certain offshore buoy, performing Kalman filtering processing on the inertial navigation data based on a feedforward compensation method of Kalman filtering, and inputting the processed inertial navigation data to the central control unit;

the GPS unit is used for acquiring GPS data of the offshore buoy and inputting the GPS data to the central control unit;

the central control unit is used for acquiring an azimuth angle and a pitch angle of the satellite antenna to be adjusted according to the acquired GPS data and the processed inertial navigation data, inputting the azimuth angle and the pitch angle to the servo controller, and performing primary alignment of the satellite antenna and the satellite; the system is also used for processing the acquired AGC data according to a cone scanning algorithm to obtain processed AGC data, inputting the processed AGC data to a servo controller and carrying out realignment on the satellite antenna and the satellite;

and the servo controller is used for correspondingly driving the azimuth axis stepping motor and the pitch axis stepping motor respectively by utilizing respective drivers according to the obtained azimuth angle and the pitch angle which need to be adjusted by the satellite antenna, and is also used for correspondingly driving the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the received processed AGC data so as to realize real-time tracking of the marine buoy.

As one improvement of the above technical solution, the AGC data is an automatic gain control value obtained by using an AP board and used for reflecting satellite signal strength;

the inertial navigation data is attitude data of a certain offshore buoy detected by adopting an inertial navigation unit, and the attitude data of the certain offshore buoy comprises: azimuth, pitch and roll angles;

the GPS data is a GPS unit which is used for acquiring the geographic position coordinate value of a certain offshore buoy as the GPS value of the offshore buoy, and the GPS value of the offshore buoy comprises: longitude, latitude and altitude of a certain buoy at sea.

The invention also provides a satellite communication tracking method for the marine buoy, which comprises the following steps:

initially finding a satellite, and adjusting a satellite antenna platform on a certain buoy to be in a horizontal plane;

the central control unit obtains an azimuth angle and a pitch angle of the satellite antenna to be adjusted according to the pre-obtained GPS data and the processed inertial navigation data, and the satellite antenna is aligned to the satellite for the first time;

the servo controller drives an azimuth axis stepping motor through a driver according to the obtained azimuth angle required to be adjusted of the satellite antenna, and the azimuth angle of the satellite antenna is adjusted by using the azimuth axis stepping motor;

the servo controller drives a pitch axis stepping motor through a driver according to the obtained pitch angle required to be adjusted of the satellite antenna, and the pitch angle of the satellite antenna is adjusted by using the pitch axis stepping motor;

the central control unit processes the acquired AGC data according to a cone scanning algorithm to obtain processed AGC data, inputs the processed AGC data into the servo controller and aligns the satellite antenna again; the servo controller correspondingly drives the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the received processed AGC data;

the marine buoy is tracked in real time according to a satellite antenna.

As one improvement of the above technical solution, the AGC data is an automatic gain control value obtained by using an AP board and used for reflecting satellite signal strength;

the inertial navigation data is attitude data of a certain offshore buoy detected by adopting an inertial navigation unit, and the attitude data of the certain offshore buoy comprises: azimuth, pitch and roll angles;

the GPS data is a GPS unit which is used for acquiring the geographic position coordinate value of a certain offshore buoy as the GPS value of the offshore buoy, and the GPS value of the offshore buoy comprises: longitude, latitude and altitude of a certain buoy at sea.

As one improvement of the above technical solution, the initial satellite finding adjusts the satellite antenna platform on the buoy to be in the horizontal plane; the specific process comprises the following steps:

acquiring an initial pitch angle and an initial roll angle of a certain offshore buoy on the sea, and judging whether a satellite antenna platform on the offshore buoy is in a horizontal plane or not;

if the pitch angle and the roll angle of the offshore buoy are both 0, the satellite antenna platform on the buoy is positioned on the horizontal plane;

if the pitch angle or the roll angle of the offshore buoy is not 0, the satellite antenna platform on the buoy has an included angle, the satellite antenna platform on the buoy is adjusted until the pitch angle and the roll angle of the buoy are both 0, the satellite antenna platform on the buoy is positioned on the horizontal plane, and the azimuth angle or the pitch angle on the satellite antenna platform is adjusted, so that the sky satellite lines are parallel to the horizontal plane.

As one improvement of the above technical solution, the central control unit obtains an azimuth angle and a pitch angle of the satellite antenna to be adjusted according to pre-obtained GPS data and processed inertial navigation data, and initially aligns the satellite antenna to the satellite; the specific process comprises the following steps:

establishing a global coordinate system O of a satellite₀x₀y₀z₀The position coordinates of the satellite are then expressed as (x)₀,y₀,z₀): wherein the origin is O₀Is the center of the earth, x₀Pointing to the north pole, y, for the X-axis₀The Y axis points to the intersection point of the meridian and the equator; z is a radical of₀The Z axis points to the intersection point of 90 degrees E and the equator; calculating the rectangular coordinates of the satellite in the terrestrial coordinate system:

wherein h is the height from the satellite to the ground; λ is the longitude under the satellite spot;the latitude under the satellite point is taken as the latitude; a certain buoy at sea is located at O_eOrigin of a geographical coordinate system of origin, λ_nLongitude of a certain buoy at sea;the latitude of a certain buoy at sea; re is the radius of the earth;is a geosynchronous orbit satellite;

establishing a northeast geographical coordinate system of the satellite, and performing matrix conversion on the earth coordinate vector of the satellite to obtain a geographical coordinate (x) of the satellite_e,y_e,z_e)；

Wherein R is₂About λ_nThe rotation matrix of (a); r₁To relate toThe rotation matrix of (a); x is the number of_eIs directed to the north direction in the X-axis, y_eThe Y axis points to the east, z_eThe Z axis is directed to the sky vertical to the horizontal plane;

wherein the content of the first and second substances,

according to the formulas (1), (2), (3) and (4), the geographical coordinates (x) of the satellite are obtained through sorting_e,y_e,z_e)：

Calculating a primary azimuth angle A and a primary pitch angle E of the satellite antenna to be adjusted according to the position of the satellite in the geographic coordinate system and the formula (5);

respectively and correspondingly winding an x axis, a y axis and a z axis in a northeast geographic coordinate system of the satellite around O_eX_e、O_eY_eAnd O_eZ_eRotating and establishing a buoy inertial navigation coordinate system:

[D_j]＝M_R·M_P·M_H·[D_m] (8)

wherein [ D ]_j]Is the coordinate vector of the satellite in the buoy inertial navigation coordinate system; [ D ]_m]Is a coordinate vector of the satellite in a geographic coordinate system; m_RIs a rotation matrix about the roll angle R; m_PIs a rotation matrix about a pitch angle P; m_HIs a rotation matrix for heading angle H:

wherein H is a course angle; p is a pitch angle; r is a transverse rolling angle;

combining the formulas (9), (10) and (11) to obtain coordinate vectors of the sorted satellites in the northeast geographic coordinate system;

according to the formula (12), calculating the azimuth angle A of the satellite antenna to be adjusted in the buoy inertial navigation coordinate system_jAnd a pitch angle E_j；

E_j＝arcsin[sin R cos E sin(A-H)-cos R sin P cos E cos(A-H)+cos R cos P sin E] (14)。

As one improvement of the above technical solution, the central control unit processes the acquired AGC data according to a cone scanning algorithm to obtain processed AGC data, and inputs the processed AGC data to the servo controller to realign the satellite antenna; the servo controller correspondingly drives the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the received processed AGC data; the specific process comprises the following steps:

an AGC closed loop tracking method based on cone scanning is adopted, a cone scanning mode is utilized to establish the sine and cosine function relationship between the signal intensity AGC of a wave beam at any point on a cone motion track formed by the cone scanning and the angle theta of each point on a circumference formed by the cone motion track,

within a complete cone scanning period, obtaining a plurality of signal strength AGC sampling values according to AGC data obtained in advance, and selecting the maximum value AGC with the signal strength AGC from the signal strength AGC sampling values_maxSum minimum AGC_minThen the maximum value AGC_maxAnd the minimum AGC_minRespectively recording the points Q and W at the intersection points of the connecting line of the circle center and the satellite position and the circumference;

assuming that the position of the satellite is S, the point P is the center of a certain cone scan, and the scanning radius of the cone scan is α, the re-adjusted azimuth angle amplitude Δ a and the re-adjusted pitch angle amplitude Δ E are respectively:

where PQ is the center of the cone sweep to the maximum AGC_maxA distance vector between the corresponding points;the included angle between the position of the satellite antenna deviating from the satellite and the horizontal direction is formed;

if it isIf the value is positive, the adjustment to the right is indicated; if it isIf the number is negative, the adjustment is carried out to the left; if it isIf the number is positive, the adjustment is upward;if the number is negative, downward adjustment is indicated;

determining the precise direction to be adjusted of the circle center by the obtained amplitude Delta A of the azimuth angle to be adjusted again and the amplitude Delta E of the pitch angle to be adjusted again, thereby determining the azimuth angle and the pitch angle of the satellite antenna to be adjusted again, taking the azimuth angle and the pitch angle as processed AGC data, inputting the processed AGC data to a servo controller, and aligning the satellite antenna again; the servo controller correspondingly drives the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the received processed AGC data, finely adjusts the satellite antenna and further aligns the satellite antenna to the satellite again;

wherein, the sampled signal strength AGC sampling value is sampled and smoothed for a plurality of timesProcessing to obtain more stable and accurate maximum AGC_maxAnd the minimum AGC_min；

Aiming at the current complete cone scanning, the maximum AGC obtained in the current cone scanning process is judged_maxWhether the AGC value is less than the preset threshold AGC value_th；

AGC if maximum value obtained in the current cone scanning process_maxAGC less than preset threshold AGC value_th(ii) a Determining the precise direction of the circle center to be adjusted according to the adjusted azimuth angle amplitude delta A and the adjusted pitch angle amplitude delta E obtained by calculation; and repeating the above process until the maximum value AGC obtained in the next cone scanning process_maxGreater than or equal to preset threshold AGC value AGC_th(ii) a Stopping the cone scan;

AGC if maximum value obtained in the current cone scanning process_maxGreater than or equal to preset threshold AGC value AGC_th(ii) a The cone scan is stopped.

Compared with the prior art, the invention has the beneficial effects that:

the tracking method of the invention aims at the two-axis satellite antenna with low profile and small volume, and realizes that the satellite antenna can be quickly aligned to the satellite, and under the four-stage sea condition, the satellite antenna can stably and correctly point to the satellite, thereby carrying out normal communication and realizing automatic tracking.

Drawings

FIG. 1 is a schematic structural diagram of an automatic satellite communication tracking device for an offshore buoy of the invention;

FIG. 2 is a schematic structural diagram of an earth coordinate system and a northeast geographic coordinate system established in an automatic tracking method for satellite communication of an offshore buoy according to the present invention;

fig. 3 is a schematic position diagram of a satellite in a northeast geographic coordinate system, which is obtained after matrix conversion of coordinates in an earth coordinate system of the satellite in the automatic tracking method for satellite communication of the marine buoy according to the present invention;

FIG. 4 is a schematic diagram of a buoy inertial navigation coordinate system established in an automatic tracking method for offshore buoy satellite communication according to the present invention;

FIG. 5 is a flow chart of the method for automatically tracking satellite communication of an offshore buoy according to the present invention to obtain the azimuth angle and the pitch angle required by the satellite antenna to align with the satellite;

FIG. 6 is a schematic structural diagram of a cone scan in a satellite communication tracking method for an offshore buoy according to the present invention;

FIG. 7 is a schematic diagram of the cone scanning signal intensity in a satellite communication tracking method for an offshore buoy according to the present invention;

FIG. 8 is a flow chart of a method for marine buoy satellite communication tracking of the present invention with fine tuning based on AGC data;

fig. 9 is a schematic flow chart of a method for marine buoy satellite communication tracking according to the present invention.

Detailed Description

The invention will now be further described with reference to the accompanying drawings.

As shown in fig. 1, the present invention provides a satellite communication tracking device for a marine buoy, comprising: the system comprises an AP board, an inertial navigation unit, a GPS unit, a central control unit, a servo controller, a plurality of drivers, an azimuth axis stepping motor and a pitch axis stepping motor;

the AP board is used for acquiring AGC data and inputting the AGC data to the central control unit;

the inertial navigation unit is used for acquiring inertial navigation data of a certain offshore buoy, performing Kalman filtering processing on the inertial navigation data based on a feedforward compensation method of Kalman filtering, and inputting the processed inertial navigation data to the central control unit;

the GPS unit is used for acquiring GPS data of the offshore buoy and inputting the GPS data to the central control unit;

the central control unit is used for acquiring an azimuth angle and a pitch angle of the satellite antenna to be adjusted according to the acquired GPS data and the processed inertial navigation data, inputting the azimuth angle and the pitch angle to the servo controller, and performing primary alignment of the satellite antenna and the satellite;

the system is also used for processing the acquired AGC data according to a cone scanning algorithm to obtain processed AGC data, inputting the processed AGC data to a servo controller and carrying out realignment on the satellite antenna and the satellite;

specifically, in the tracking process, a cone scanning algorithm is adopted, the acquired AGC data is input to the central control unit for processing, and the processed AGC data is input to the servo controller, and the servo controller only receives the processed AGC data sent by the central control unit. The processed AGC data are an azimuth angle and a pitch angle of the satellite antenna which need to be adjusted again;

the servo controller is used for correspondingly driving the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the obtained azimuth angle and pitch angle which need to be adjusted by the satellite antenna;

and the device is also used for correspondingly driving the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the obtained processed AGC data, and adjusting the axial angle of the satellite antenna in real time so as to ensure that the satellite antenna is aligned with the satellite again, realize accurate alignment and further realize real-time tracking of the offshore buoy.

Wherein, the axial angle of satellite antenna includes: azimuth and pitch. The drivers are respectively connected with the azimuth axis stepping motor and the pitch axis stepping motor;

the AGC data is an automatic gain control value which is obtained by adopting an AP board and is used for reflecting the satellite signal intensity;

the inertial navigation data is attitude data of a certain offshore buoy detected by adopting an inertial navigation unit, and the attitude data of the certain offshore buoy comprises: azimuth, pitch and roll angles;

the GPS data is a GPS unit which is used for acquiring the geographic position coordinate value of a certain offshore buoy as the GPS value of the offshore buoy, and the GPS value of the offshore buoy comprises: longitude, latitude and altitude of a certain buoy at sea.

The invention also provides a satellite communication tracking method for the marine buoy, as shown in fig. 9, the whole method process comprises the following steps: two processes of rough adjustment and fine adjustment:

wherein, the coarse adjustment process: the central control unit accurately obtains a pitch angle and an azimuth angle required by the satellite antenna to align the satellite according to the received processed inertial navigation data and GPS data, then inputs the pitch angle and the azimuth angle to the servo controller, the servo controller controls and drives a corresponding driver, and correspondingly rotates a corresponding azimuth axis stepping motor and a corresponding pitch axis stepping motor according to the obtained pitch angle and the obtained azimuth angle, so as to realize the primary alignment of the satellite antenna to the satellite; the feedforward compensation method based on Kalman filtering solves the problem of measurement delay of inertial navigation data. In the conventional method, the inertial navigation data output by the inertial navigation unit is directly adopted, so that the problem of measurement delay of the data is caused.

Fine adjustment process: because the processed inertial navigation data and the GPS data have delay or are insufficient in accuracy, the satellite antenna needs to be matched with AGC data to perform further accurate adjustment, so that the satellite antenna is ensured to be truly aligned to the satellite, the alignment accuracy is improved, and the corresponding marine buoy can be ensured to be accurately tracked.

After the fine tuning process is finished, the satellite antenna is precisely aligned to the satellite at the moment. The specific process is as follows: after the buoy enters an initial alignment state, the central control unit acquires the processed inertial navigation data and GPS data at fixed time intervals to acquire attitude information, when the buoy moves in a floating mode, due to the fact that sea waves and the like shake violently, the pitch angle and the roll angle of inertial navigation change correspondingly, the central control unit acquires inertial navigation change information and then adjusts the azimuth angle and the pitch angle of the satellite in time, so that the correct orientation between the satellite antenna and the satellite can be maintained continuously, namely the satellite antenna is maintained to be aligned to the satellite accurately, and then closed-loop tracking is performed by matching with an AGC value transmitted by an AP board, and accurate alignment is achieved. If the pointing deviation is too large in the whole process of adjusting the azimuth angle and the pitch angle of the satellite antenna, the initial satellite searching needs to be carried out again to return to the initial alignment state, the satellite antenna is automatically tracked after the coarse adjustment process and the fine adjustment process, and the process is repeated in a circulating mode.

The method specifically comprises the following steps:

initially finding a satellite, and adjusting a satellite antenna platform on a buoy to be in a horizontal plane;

specifically, the whole tracking device is powered on, the satellite antenna is turned to a zero position, then a self-checking process is started, after the normal work is determined, the initial pitch angle and the initial roll angle of a certain offshore buoy are obtained, and whether the satellite antenna platform on the offshore buoy is in the horizontal plane or not is judged;

if the pitch angle and the roll angle of the offshore buoy are both 0, the satellite antenna platform on the offshore buoy is positioned on the horizontal plane;

if the pitch angle or the roll angle of the offshore buoy is not 0, the satellite antenna platform on the offshore buoy has an included angle, the satellite antenna platform on the offshore buoy is adjusted until the pitch angle and the roll angle of the offshore buoy are both 0, the satellite antenna platform on the offshore buoy is positioned on the horizontal plane, and the azimuth angle or the pitch angle on the satellite antenna platform is adjusted, so that the sky satellite line is parallel to the horizontal plane, namely the satellite antenna platform on the offshore buoy is positioned on the horizontal plane, the initial angle error of the satellite antenna platform is eliminated, and the accuracy of tracking the offshore buoy is ensured;

acquiring an azimuth angle and a pitch angle of the satellite to be adjusted according to the processed inertial navigation data and GPS data which are acquired in advance, and aligning a satellite antenna to the satellite for the first time;

specifically, as shown in fig. 2 and 5, an earth coordinate system O of the satellite is established₀x₀y₀z₀The position coordinates of the satellite are then expressed as (x)₀,y₀,z₀): wherein the origin is O₀Is the center of the earth, x₀Pointing to the north pole, y, for the x-axis₀The y axis points to the intersection point of the meridian and the equator; z is a radical of₀The z axis points to the intersection point of 90 degrees E and the equator; calculating the rectangular coordinates of the satellite in the terrestrial coordinate system:

wherein h is the height from the satellite to the ground; lambda is longitude under a satellite point, namely the longitude of the satellite under an earth coordinate system;the latitude under the satellite point is the latitude of the satellite under the terrestrial coordinate system; a certain buoy at sea is located at O_eOrigin of a geographical coordinate system of origin, λ_nLongitude of a certain buoy at sea;the latitude of a certain buoy at sea; re is the radius of the earth;is a geosynchronous orbit satellite; wherein h, λ andis a known value; lambda [ alpha ]_nAndfor dynamic real-time measurement acquisition from the GPS unit.

As shown in fig. 3, when the geographic coordinate system of the satellite in the northeast is established, the direction of the antenna in the geographic coordinate system of the satellite is deduced, that is, in a static state, without external disturbance, the earth coordinate vectors of the satellite are subjected to matrix transformation, specifically, (x) is first performed₀,y₀,z₀) Around O₀x₀The axis is in accordance withR of (A) to (B)₁Perform counterclockwise rotation (i.e., counterclockwise rotation)) Then wound around the rotated O₀z_eAxis according to a relation of_nR of (A) to (B)₂Perform clockwise rotation (i.e., clockwise rotation λ)_n) Finally, the matrix relating to the earth radius Re is subtracted to obtain the geographic coordinates (x) of the satellite_e,y_e,z_e)；

Wherein R is₂About λ_nThe rotation matrix of (a); r₁To relate toThe rotation matrix of (a); x is the number of_eIs directed to the north direction in the X-axis, y_eThe Y axis points to the east, z_eThe Z axis is directed to the sky vertical to the horizontal plane;

wherein the content of the first and second substances,

according to the formulas (1), (2), (3) and (4), the geographical coordinates (x) of the satellite are obtained through sorting_e,y_e,z_e)：

As shown in fig. 3, according to the position of the satellite in the geographic coordinate system and the definition of the geographic coordinate system, and formula (5), a primary azimuth angle a and a primary pitch angle E of the satellite antenna to be adjusted are calculated;

since the offshore buoy is susceptible to wave fluctuation, the attitude of the buoy is easy to change in the actual working process, and the attitude data of the buoy needs to be integrated into the antenna pointing calculation under the geographic coordinate system, so as to obtain more accurate azimuth angle and pitch angle. In a buoy inertial navigation coordinate system of a certain offshore buoy, the satellite antenna pointing derivation (namely a derivation formula of satellite pointing in the inertial navigation coordinate system) isolates external disturbance;

as shown in fig. 2 and 4, the x-axis, y-axis and z-axis in the northeast geographic coordinate system of the satellite are respectively and correspondingly wound around O_eX_e、O_eY_eAnd O_eZ_eRotating, establishing a buoy inertial navigation coordinate system, and counteracting the influence of the movement of the offshore buoy:

[D_j]＝M_R·M_P·M_H·[D_m] (8)

wherein [ D ]_j]Is the coordinate vector of the satellite in the buoy inertial navigation coordinate system; [ D ]_m]Is the coordinate vector of the satellite in the northeast geographic coordinate system; as shown in FIG. 3, [ D ] is first introduced_m]Around O_ey_ePerforming M with respect to H_HRotate clockwise (i.e., rotate clockwise H), and then rotate about O_ez_eM for P according to the right-hand rule_PRotate (i.e. rotate P according to right-hand rule) and finally around O_ex_eCarrying out M with respect to R_RRotation R (i.e., rotation R); m_RIs a rotation matrix about R; m_PIs a rotation matrix about P; m_HIs a rotation matrix for H:

h is a heading angle, namely an included angle between the buoy advancing direction and true north, the true north is taken as a reference, and the clockwise direction is taken as the positive direction; p is a pitch angle, namely the included angle between the longitudinal axis of the buoy and the local horizontal plane is positive upwards; r is a roll angle, the buoy takes the advancing direction as an included angle between an axis and the horizontal plane, and the right inclination of the buoy is positive.

Combining the formulas (9), (10) and (11) to obtain coordinate vectors of the sorted satellites in the northeast geographic coordinate system;

according to the formula (12), calculating the azimuth angle A of the satellite antenna to be adjusted in the buoy inertial navigation coordinate system_jAnd a pitch angle E_j；

E_j＝arcsin[sin R cos E sin(A-H)-cos R sin P cos E cos(A-H)+cos R cos P sin E] (14)

Therefore, as shown in fig. 2, a flowchart of a specific calculation method of the azimuth angle and the pitch angle required by the satellite antenna to be aligned with the satellite is provided, and the coordinate conversion is mainly realized by constructing different coordinate systems. Three coordinate systems are established in the flow chart: earth coordinate system, northeast geographic coordinate system and buoy inertial navigation coordinate system. The earth coordinate system takes the earth center as an origin, the X axis points to the north pole, the Y axis points to the intersection point of the meridian and the equator, and the Z axis points to the intersection point of 90 degrees E and the equator. Because the actual environment is located in the eastern hemisphere and the northern hemisphere, a northeast geographic coordinate system needs to be established again, wherein the X axis points to the right north, the Y axis points to the right east, and the Z axis points to the sky vertical to the horizontal plane. Since the inertial navigation system is fixed with a certain offshore buoy, the inertial navigation coordinate system of the buoy can also be called a carrier coordinate system, namely, the coordinate system abstracted by regarding the carrier as mass points, wherein the X axis points to the front of the motion of the carrier, the Y axis points to the right of the motion of the carrier, and the Z axis is perpendicular to the direction of the carrier surface. Wherein, the carrier is a certain offshore buoy. Wherein the longitude and latitude, and the altitude of the satellite antenna are defined according to a geographical coordinate system.

The servo controller drives an azimuth axis stepping motor through a driver according to the obtained primary azimuth angle required to be adjusted by the satellite, and the azimuth angle of the satellite is adjusted by the azimuth axis stepping motor;

the servo controller drives a pitch axis stepping motor through a driver according to the obtained primary pitch angle required to be adjusted by the satellite, and the pitch angle of the satellite is adjusted by the pitch axis stepping motor;

the central control unit processes the acquired AGC data according to a cone scanning algorithm to obtain processed AGC data, inputs the processed AGC data into the servo controller and aligns the satellite antenna again; the servo controller correspondingly drives the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the received processed AGC data; further aligning the satellite antenna to the satellite again; tracking the offshore buoy in real time according to the satellite antenna;

specifically, as shown in fig. 6, a schematic diagram of a cone scanning method adopted in the tracking process is provided, where an O point is an antenna position, and S is a satellite position, the OS is an ideal accurate pointing direction of the satellite antenna, the OS 'is a pointing direction which is not actually aligned completely, OO' is a central axis of the antenna, the satellite antenna rotates around the central axis, α is a rotational offset angle, and a path of the satellite antenna rotating around the central axis for one circle is T. If β is the angle between the actual antenna beam direction and the precise direction, the magnitude of β and the received satellite signal strength are constantly changing during a rotation period. When the antenna is pointed at the satellite accurately, i.e. when OS and OO' coincide, then β no longer changes and the satellite signal strength is strongest.

As shown in fig. 7, a cone scan signal strength diagram is provided. The cone scanning action is decomposed into the azimuth direction and the pitch direction, then the azimuth motion and the pitch motion are found to obey the sine and cosine curve law, the phase difference between the azimuth motion and the pitch motion is 1/4 circles, and the resultant direction of the two motions is circular motion. According to the prior art, it can be known that the level fading away from the maximum gain of the antenna is only related to the angle of the antenna pointing away from the maximum gain, and in combination with the conical scanning mode, the signal intensity of the beam at any point on the conical motion track has a sine-cosine function relationship with the angle theta of each point on the circumference.

An AGC closed loop tracking method based on cone scanning is adopted, a cone scanning mode is utilized to establish the sine and cosine function relationship between the signal intensity AGC of a wave beam at any point on a cone motion track formed by the cone scanning and the angle theta of each point on a circumference formed by the cone motion track,

as shown in FIG. 8, the threshold AGC value AGC is set in one complete cone scanning period_th(ii) a Collecting a plurality of signal strength AGC sampling values according to AGC data obtained in advance, and selecting the maximum value AGC with the signal strength AGC from the signal strength AGC sampling values_maxSum minimum AGC_minThen the maximum value AGC_maxAnd the minimum AGC_minRespectively recording the points Q and W at the intersection points of the connecting line of the circle center and the satellite position and the circumference;

assuming that the position of the satellite is S, the point P is the center of a certain conical scan, the scanning radius of the conical scan is α, and the center position of the conical scan center points to the direction of the point corresponding to the maximum satellite intensity value, so that the tracking adjustment direction of the center of the conical scan center is the direction of the vector PQ, the azimuth angle amplitude Δ a of the readjustment and the pitch angle amplitude Δ E of the readjustment are respectively:

where PQ is the center of the cone sweep to the maximum AGC_maxA distance vector between the corresponding points;the included angle between the position of the satellite antenna deviating from the satellite and the horizontal direction is formed;

if it isIf the value is positive, the adjustment to the right is indicated; if it isIf the number is negative, the adjustment is carried out to the left; if it isIf the number is positive, the adjustment is upward;if the number is negative, downward adjustment is indicated;

determining the precise direction to be adjusted of the circle center by the obtained amplitude Delta A of the azimuth angle which is adjusted again and the amplitude Delta E of the pitch angle which is adjusted again, thereby determining the azimuth angle and the pitch angle which are adjusted again of the satellite antenna as processed AGC data, inputting the processed AGC data to a servo controller, and aligning the satellite antenna again; finely adjusting the satellite antenna, and further accurately aligning the satellite antenna to the satellite; the circle center does not need to be adjusted according to the traditional method of successive approximation, so that the satellite antenna can be aligned to the satellite more quickly and accurately; inputting the processed AGC data to a servo controller, and aligning the satellite antenna again; the servo controller correspondingly drives the azimuth axis stepping motor and the pitch axis stepping motor by utilizing respective drivers according to the received processed AGC data, finely adjusts the satellite antenna and further aligns the satellite antenna to the satellite again;

wherein, the sampled signal strength AGC sampling value is sampled and smoothed for a plurality of times to obtain more stable and accurate maximum AGC_maxAnd the minimum AGC_minTherefore, the stability and the accuracy of the AGC sampling value are ensured, and the satellite antenna angle adjustment is more accurate.

Aiming at the complete cone scanning of the current time, the method judges the cone scanning of the current timeMaximum value AGC_maxWhether the AGC value is less than the preset threshold AGC value_th；

AGC if maximum value obtained in the current cone scanning process_maxAGC less than preset threshold AGC value_th(ii) a Determining the accurate direction of the circle center to be adjusted according to the calculated amplitude Delta A of the readjusted azimuth angle and the amplitude Delta E of the readjusted pitch angle; and repeating the above process, adjusting the precise direction of the circle center to be adjusted again for the next conical scanning period, finely adjusting the satellite antenna, and further precisely aligning the satellite antenna to the satellite until the maximum AGC obtained in the next conical scanning process_maxGreater than or equal to preset threshold AGC value AGC_th(ii) a Stopping cone scanning, feeding back the received AGC sampling value in real time, acquiring the corresponding re-adjusted azimuth angle amplitude delta A and the re-adjusted pitch angle amplitude delta E, and adjusting the position of the circle center in real time to meet the requirement that the satellite antenna is aligned to the satellite;

AGC if maximum value obtained in the current cone scanning process_maxGreater than or equal to preset threshold AGC value AGC_th(ii) a The offshore buoy can be accurately tracked directly according to the previously aligned satellite antenna without calculating the readjusted azimuth angle amplitude delta a and the readjusted pitch angle amplitude delta E.

If cone scanning is carried out continuously, resources are easily wasted, and power consumption is increased; if cone scanning is not performed in time, satellite loss is easily caused, signal interruption is caused, a satellite antenna cannot be aligned with a satellite, initial satellite finding needs to be set again, and time cost is increased_thWhen the scanning signal strength AGC value of the scanning period is greater than or equal to the threshold AGC value, no adjustment is carried out; when the scanning signal strength AGC value of the scanning period is smaller than the threshold AGC value, timely adjustment is carried out to prevent the phenomenon of satellite loss.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.