Satellite tracking antenna system with improved tracking characteristics and operating method thereof

A satellite tracking antenna system with improved tracking characteristics and operating method thereof are disclosed. The system independently controls an elevation angle and an azimuth angle of an antenna according to the movement of a vehicle, controls the elevation angle of the antenna only when a satellite elevation-angle variation is equal to or higher than a reference value, so that it can improve the tracking speed and performance of the satellite. The system includes an antenna unit, a GPS receiver, an azimuth-angle gyro-sensor, a control board, a motor unit. The control board includes an elevation-angle controller and a main controller. The motor unit includes an elevation-angle motor and an azimuth-angle motor.

BACKGROUND

The present invention relates to a satellite tracking antenna system with improved tracking characteristics, which independently controls an elevation angle and an azimuth angle of an antenna according to the movement of a vehicle, controls the elevation angle of the antenna only when a satellite elevation-angle variation is equal to or higher than a reference value, so that it can improve the tracking speed and performance of the satellite, and a method for controlling the satellite tracking antenna system.

2. Description of the Related Technology

Generally, the conventional satellite tracking antenna system has been installed in a moving vehicle, so that it must continuously track the satellite location according to the movement of the vehicle, and must rotate the direction of the antenna.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

Embodiments of the present invention have been made in view of the problems with conventional satellite antenna tracking systems, and it is an object of the present invention to provide a satellite tracking antenna system with improved tracking characteristics, which captures/tracks an elevation angle of a satellite using a GPS, controls an elevation angle of an antenna only when the satellite elevation-angle variation is equal to or higher than a reference value, and captures/tracks an azimuth angle of the satellite separately from the above-mentioned elevation-angle control process so as to control the azimuth angle of the antenna, thereby quickly and correctly perform the satellite tracking function, and a method for controlling the satellite tracking antenna system.

In accordance with one embodiment of the present invention, the above and other objects can be accomplished by the provision of a satellite tracking antenna system comprising: an antenna unit for receiving a satellite signal from a satellite; a GPS receiver for receiving a GPS signal from a GPS satellite; an azimuth-angle gyro-sensor for detecting the movement of an azimuth angle of a vehicle; a control board including: an elevation-angle controller for analyzing the GPS signal received from the GPS receiver, calculating an initial elevation-angle location of the satellite, and capturing the calculated elevation angle location, and a main controller for analyzing the satellite signal received from the antenna unit, capturing the azimuth angle of the satellite, analyzing the azimuth-angle movement of the vehicle detected by the azimuth-angle gyro-sensor, and tracking the azimuth angle of the satellite; and a motor unit including: an elevation-angle motor for rotating an elevation angle of the antenna unit toward an elevation-angle directional location upon receiving a control signal from the elevation-angle controller, and an azimuth-angle motor for rotating the azimuth angle of the antenna unit toward the azimuth-angle directional location of the satellite upon receiving a control signal from the main controller.

In one aspect, the elevation-angle controller tracks a satellite elevation-angle variation caused by the movement of the vehicle, controls the elevation-angle motor if the elevation angle variation is equal to or higher than a reference value, and rotates the elevation angle of the antenna unit toward a changed satellite elevation angle directional location.

In one aspect, the elevation-angle controller stores the changed satellite elevation-angle information in a memory, determines whether the GPS signal is not received when the initial elevation-angle of the satellite is captured, and determines the elevation angle stored in the memory to be a directional elevation angle of the antenna unit.

Also, in one aspect, the elevation-angle controller transmits an elevation-angle change signal to the main controller when the elevation angle of the antenna unit is changed to another angle.

In still another aspect, the main controller receives the elevation-angle change signal caused by the capturing of the initial elevation angle of the satellite from the elevation-angle controller, and captures/tracks the azimuth angle of the satellite.

In embodiment of the present invention, there is provided a satellite tracking method for use in a satellite tracking antenna system comprising: a) analyzing a GPS signal received from a GPS satellite, calculating/capturing an initial elevation angle of the satellite, and rotating an elevation angle of an antenna unit toward an initial elevation-angle directional location of the satellite; b) analyzing a satellite signal received from the antenna unit, capturing the azimuth angle of the satellite, analyzing the azimuth-angle movement of the vehicle detected by an azimuth-angle gyro-sensor, continuously tracking the azimuth angle of the satellite, and rotating an azimuth angle of the antenna unit toward an azimuth-angle directional location of the satellite; and c) tracking a satellite elevation-angle variation caused by the movement of the vehicle, controlling an elevation-angle motor if the elevation angle variation is equal to or higher than a reference value, and rotating the elevation angle of the antenna unit toward a changed satellite elevation-angle directional location.

In one aspect, the method further can include storing the changed satellite elevation-angle information in a memory if a directional elevation angle of the antenna unit is changed to another angle, determining whether the GPS signal is not received when the initial elevation-angle of the satellite is captured, and determining the elevation angle stored in the memory to be the directional elevation angle of the antenna unit if it is determined that the GPS signal has not been received when the initial elevation-angle of the satellite is captured.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Generally, satellite tracking antenna systems can be classified into a 1-axis satellite tracking antenna systems and a 2-axis satellite tracking antenna systems. The 1-axis satellite tracking antenna system fixes the directional elevation angle of the antenna, and tracks only the azimuth angle. The 2-axis satellite tracking antenna system tracks the elevation angle and the azimuth angle of the antenna.

The 1-axis satellite tracking antenna system has a fixed satellite directional elevation-angle of the antenna. Therefore, in the case where the reception range of the satellite signal becomes wider because the vehicle moves far away, and the elevation angle of the satellite is changed to another angle, the conventional satellite tracking antenna system cannot easily receive the satellite signal from the satellite.

Recently, the 2-axis satellite tracking antenna system has been widely used. This 2-axis satellite tracking antenna system can track both the elevation angle and the azimuth angle of the satellite, so that it can receive the satellite signal in a wider area. However, the 2-axis satellite tracking antenna system must track the elevation angle and the azimuth angle, so that its satellite tracking algorithm is more complicated than the 1-axis satellite tracking antenna system, resulting in deterioration of the tracking speed and the performance. In order to solve the above-mentioned deterioration of the tracking speed and the performance, there is proposed a new method for tracking the satellite location using the gyro-sensor such as a gyroscope.

However, although the gyro-sensor is used, the 2-axis satellite tracking antenna system must adjust all of the elevation angle and the azimuth angle to track the satellite location, so that an initial capturing time for searching for the satellite location becomes longer. If the 2-axis satellite tracking antenna system passes a blind area in which the satellite signal is blocked, it requires a long period of time to re-track the satellite location.

Embodiments of the present invention have been made in view of the problems with conventional satellite antenna tracking systems, and embodiments of the present invention provide a satellite tracking antenna system with improved tracking characteristics.

FIG. 1is a perspective view illustrating an example of a satellite tracking antenna system according to the present invention.FIG. 2is a front view illustrating an example of a satellite tracking antenna system according to the present invention.FIG. 3is an example of a block diagram illustrating a satellite tracking antenna system according to the present invention.

Referring toFIGS. 1 to 3, the satellite tracking antenna system according to the present invention includes: an antenna unit100for receiving a satellite signal; an azimuth angle gyro-sensor400for detecting the movement of an azimuth angle of a vehicle; a GPS receiver500for receiving a GPS signal from a GPS (Global Positioning System) satellite; a control board200for analyzing signals received in the antenna unit100, the azimuth-angle gyro-sensor400, and the GPS receiver500, and capturing/tracking a location of the satellite; a motor unit300for rotating the antenna unit100toward a directional location of the satellite upon receiving a control signal from the control board200; and a rotary joint600for transmitting the satellite signal received from the antenna unit100to the satellite broadcast receiver700.

The above-mentioned constituent components are installed on a base plate (BP) contained in the case C. This base plate (BP) is installed in the case C so that it can be horizontally rotated on the basis of the rotary joint600. A cap (not shown) is coupled to the top of the case C, so that it can protect the above-mentioned components.

The antenna unit100includes an antenna110for receiving a satellite signal from the satellite, and a LNB (Low Noise Block down converter)120for converting the received satellite signal into an intermediate-frequency (IF) satellite signal, and transmitting the IF satellite signal to the control board200. According to this embodiment of the present invention, the antenna110is composed of a flat-type waveguide slot arrangement antenna.

The azimuth-angle gyro-sensor400is used to track the variation of the satellite azimuth-angle caused by the movement of a vehicle. The azimuth angle gyro-sensor detects an azimuth-angle angular-velocity caused by the vehicle movement, and transmits the detected angular velocity to the control board200.

The GPS receiver500is used to capture/track the elevation angle of the satellite. This GPS receiver500receives the GPS signal from the GPS satellite, and transmits the received GPS signal to the control board200.

The control board200includes a main controller210, an elevation-angle controller220, an azimuth-angle motor driver230, and an elevation-angle motor driver240. The main controller210analyzes the strength of the received satellite signal, captures the azimuth angle of the satellite, analyzes the movement information of the vehicle's azimuth-angle detected by the azimuth angle gyro-sensor400, and continuously tracks the azimuth angle of the satellite. The elevation-angle controller220analyzes the GPS signal received from the GP receiver500, and calculates/captures/tracks the elevation angle of the satellite according to the analyzed result. The azimuth-angle motor driver230drives the azimuth angle motor310of the motor300upon receiving a control signal from the main controller210. The elevation-angle motor driver240drives the elevation angle motor320of the motor unit300upon receiving a control signal from the elevation-angle controller220.

The main controller210includes a memory212and a controller211. The memory212stores an azimuth-angle tracking program, which captures the initial azimuth angle of the satellite and continuously tracks the satellite azimuth-angle according to the movement of the vehicle. The controller211executes the azimuth angle tracking program stored in the memory212to capture/track the azimuth angle of the satellite, controls the azimuth-angle motor driver230so as to allow the antenna unit100to face the azimuth angle of the satellite, and drives the azimuth-angle motor310.

The elevation-angle controller220includes a memory222and a controller221. The memory222stores an elevation-angle tracking program, which captures/tracks the elevation angle of the satellite. The controller221executes the elevation-angle tracking program stored in the memory222to capture/track the elevation angle of the satellite, controls the elevation-angle motor driver240so as to allow the antenna unit100to face the elevation angle of the satellite, and drives the elevation-angle motor320.

The memory222includes the satellite elevation-angle information which has been calculated/captured by the controller221. The main controller210and the elevation-angle controller220are driven independent of each other, so that they can control the azimuth angle and the elevation angle of the antenna unit100.

The motor unit300includes an azimuth-angle motor310and an elevation-angle motor320. The azimuth-angle motor310is driven by the azimuth-angle motor driver230of the control board200, and rotates the antenna unit100toward the azimuth angle. The elevation-angle motor320is driven by the elevation-angle motor driver240, and rotates the antenna unit100toward the elevation angle. According to this embodiment of the present invention, the above-mentioned elevation-angle motor320is composed of a linear motor.

The main controller210of the control board200transmits the satellite signal received via the antenna unit100to the rotary joint600. The rotary joint600transmits the satellite signal received from the control board200to the satellite broadcast receiver700. The satellite signal transmitted to the satellite broadcast receiver700is displayed on the monitor800. Also, the above-mentioned rotary joint600receives a power-supply signal from an external part, and transmits the power-supply signal to the above-mentioned components.

Operations of the above-mentioned satellite tracking antenna system will hereinafter be described with reference toFIGS. 4 and 5.

It should be noted that the satellite tracking antenna system controls the elevation angle and the azimuth angle of the antenna independent of each other.FIG. 4is a flow chart illustrating a method for controlling an elevation angle of an antenna according to the present invention.FIG. 5is a flow chart illustrating a method for controlling an azimuth angle of an antenna according to the present invention.

A method for controlling a directional elevation angle of the antenna unit100will hereinafter be described with reference toFIG. 4.

If the satellite tracking antenna system is turned on so that a power-supply signal is applied to the satellite tracking antenna system at step S100, the elevation-angle controller220of the control board200controls the elevation-angle motor320using the elevation-angle motor driver240, so that it moves the directional elevation angle of the antenna unit110to an initial location at step S110.

If the elevation angle of the antenna unit100is initialized, the GPS receiver500receives the GPS signal from the GPS satellite, and transmits the received GPS signal to the elevation-angle controller220.

The elevation-angle controller220analyzes the GPS signal of the GPS receiver500, and calculates the elevation angle of the satellite at step S130. Since the elevation angle of the satellite which desires to receive the signal is fixed, the elevation-angle controller220can calculate the elevation angle of the satellite on the condition that the current location of the vehicle is recognized via the GPS signal. If the GPS receiver500does not normally receive the GPS signal, the elevation-angle controller220extracts conventional setup elevation angle information stored in the memory222at step S121.

The elevation-angle controller220controls the elevation-angle motor320so that it rotates the elevation angle of the antenna unit100toward the elevation-angle location having been calculated or extracted at step S140, and stores the established elevation-angle information in the memory222at step S150.

If the elevation angle of the antenna unit100is established, the elevation-angle controller220transmits an elevation-angle change signal, indicating that the elevation angle of the antenna unit100has been changed to another angle, to the main controller210.

If the system operation is not terminated at step S170, the GPS receiver500receives the GPS signal, and transmits the received GPS signal to the elevation-angle controller220. The elevation-angle controller220analyzes the GPS signal, and calculates the elevation angle of the azimuth angle at step S180.

The elevation-angle controller220controls the calculated elevation angle and a variation of the elevation angle currently aimed by the antenna unit100, and determines whether a variation value of the elevation angle is higher than a reference value. If the variation value of the elevation-angle is higher than the reference value, the elevation-angle controller220controls the elevation-angle motor320at step S140, and stores the elevation angle information in the memory222at step S150.

According to the embodiment of the present invention, the elevation-angle controller220has been designed to change a current elevation angle to another elevation angle only when the variation value of the elevation angle is higher than the reference value, because the reception of the satellite signal is less affected by a minute or little variation of the elevation angle. If the elevation angle of the antenna unit100is continuously changed to another angle according to the minute variation of the elevation angle, this continuously-changing operation has a negative influence upon the system processing speed, etc. According to the embodiment of the present invention, the reference value associated with the elevation-angle variation may be set to about 4° in consideration of the reception rate and the processing speed of the satellite signal, etc.

In the meantime, a method for controlling the azimuth angle of the antenna unit100will hereinafter be described with reference toFIG. 5.

If the system is turned on, the main controller210receives an elevation-angle change signal, indicating that the elevation angle of the antenna unit100has been changed to another angle, from the elevation-angle controller220.

If the elevation-angle change signal is received from the elevation-angle controller220, the main controller210performs calibration to establish an output reference value of the azimuth-angle gyro-sensor400.

After the correction of the azimuth angle gyro-sensor400is performed, the main controller210drives the azimuth angle motor310to rotate the antenna unit100, and searches for an initial location of the satellite.

If the satellite signal is not received while the antenna unit100rotates by 360° at step S230, the main controller210determines that the vehicle is in a blind area in which the vehicle is unable to receive the satellite signal, so that it switches the satellite tracking mode to the sleep mode and maintains a standby status in the sleep mode at step S231. If a predetermined period of time has elapsed, the main controller210returns to step S220.

If a specific location, at which the satellite signal is received, is detected, the main controller210analyzes the strength of the received satellite signal, and captures the initial azimuth-angle location of the satellite.

If the initial azimuth-angle location of the satellite is captured, the main controller210analyzes the azimuth-angle movement information of the vehicle detected by the azimuth angle gyro-sensor400, and tracks the satellite azimuth-angle changed according to the movement of the vehicle, so that it can control the directional azimuth angle of the antenna unit100using the azimuth-angle motor310. The above-mentioned satellite azimuth-angle tracking process of the main controller210is performed separately from the satellite elevation-angle control process of the elevation-angle controller220.

The above-mentioned process for capturing/tracking the azimuth angle of the satellite is repeatedly performed until the system operation is terminated.

Although the present invention has disclosed that the main controller210captures/tracks the azimuth angle after receiving the initial elevation-angle variation signal from the elevation-angle controller220, it should be noted that this main controller210can also capture/track the azimuth angle on the condition that the system is turned on, irrespective of the reception of the elevation-angle variation signal.

As described above, the elevation-angle controller220according to the present invention analyzes the GPS signal to calculate the elevation angle of the satellite. The elevation-angle controller220drives the elevation-angle motor320so that it allows the antenna unit100to face the elevation angle of the satellite. The main controller210analyzes the strength of the received satellite signal, captures an initial azimuth-angle location of the satellite, analyzes the output value of the azimuth-angle gyro-sensor400, and continuously tracks the azimuth angle of the satellite according to the analyzed result. The elevation-angle controller220drives the azimuth-angle motor310, and allows the antenna unit100to face the azimuth angle of the satellite.

According to at least one embodiment, as apparent from the above description, the satellite tracking antenna system according to the present invention allows the main controller and the elevation-angle controller of the control board to control the elevation angle and the azimuth angle of the antenna independent of each other, so that it can quickly and stably track the satellite.

The elevation-angle controller according to the present invention analyzes the GPS signal, calculates the elevation angle of the satellite, controls the elevation angle of the antenna only when the variation of the satellite elevation-angle is equal to or higher than a reference value, and prevents the elevation angle from being frequently controlled by the minute variation of the elevation angle, so that it increases the satellite tracking speed and prevents the occurrence of unnecessary power consumption. Also, the elevation-angle controller stores the changed elevation angle of the satellite in the memory, and quickly controls the elevation angle of the antenna using previous satellite elevation-angle information stored in the memory even when it cannot receive the GPS signal.