Abstract:
Disclosed is a device and method for dynamically adjusting orientation of a satellite antenna carried in a movable carrier, including a satellite tracking system and an adjusting device. The satellite tracking system includes a position processor that receives a group of positioning signals comprising a current coordinate from a group of GPS satellites and retrieve a program signal comprised a preset coordinate among at least one of program satellites, a comparator comparing the current coordinate with a preset coordinate to generate an deviation, and a microprocessor processing the deviation to issue a control signal that is fed to the adjusting device for changing orientation of the antenna to match with that of the program satellite.

Description:
REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present invention is a Continuation-in-Part of patent application Ser. No. 11/062,871, filed Feb. 23, 2005. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to a control device for adjusting the orientation of a satellite disc antenna, and in particular to a control device that dynamically adjusts the orientation of a satellite disc antenna carried by a moving carrier, such as a vehicle, so as to make the constantly point at program satellites located at predetermined positions.  
       BACKGROUND OF THE INVENTION  
       [0003]     Global positioning system (GPS) is widely used in a variety of applications, such as automobile navigation, geographic survey, satellite television program, satellite broadcasting, satellite communication, and military applications. The general function of the global positioning system is detection of the position, namely coordinates, of an object, which may be moving or maintains fixed, and calculation of distance, time, velocity and altitude of the object. Such data are of importance use in a variety of applications, which means the global positioning system is getting broader applications.  
         [0004]     Development of the global positioning system has made a great progress in a number of applications. For example, U.S. Pat. No. 6,680,694 discloses a GPS based vehicle information system, comprising an in-vehicle system that communicates with a centralized server system via a wireless communication link. A user may specify a destination to the in-vehicle system, which transmits the specification of the destination to the centralized server system. The server system computes a route to the destination and transmits the computed route back to the in-vehicle system. The in-vehicle system may then guide the user to drive along the route.  
         [0005]     Another example is illustrated in U.S. Pat. No. 6,690,323, which discloses a GPS receiver having emergency communication channel. When a normal GPS communication channel is interfered with, the communication of the GPS receiver can be maintained by switching to the emergency channel.  
         [0006]     A further example is U.S. Pat. No. 6,633,814, which discloses a GPS system for navigating a vehicle, comprising vehicle carried receiver that receives a GPS signal to perform vehicle navigation based on pre-established maps and route information.  
         [0007]     One further example is shown in U.S. Pat. No. 6,671,587, which discloses a vehicle dynamic measuring apparatus and a method using multiple GPS antennas. To realize vehicle dynamic measurement and determination of velocity, two GPS receiving antennas are installed in a vehicle and a controller is employed to detect change in carrier frequency.  
         [0008]     When people watch TV programs or listen to radio programs in a moving vehicle, the electromagnetic waves that carry the programs are received by a frequency based receiver carried in the vehicle. In other words, the program can be correctly received once the receiver in tuned to the frequency of the electromagnetic waves that carry the program. Since the electromagnetic waves are generally omni-directional, an antenna can receives the waves without being set in a specific direction.  
         [0009]     However, an electromagnetic signal that carries a satellite program is directional, which can be received by an antenna oriented in a particular direction. This makes it difficult to receive the satellite program in a moving vehicle for the direction is constantly changed. Thus, generally speaking, a conventional satellite program receiving device that is generally designed for use on fixed location cannot effectively and clearly receive the satellite program in a moving vehicle.  
         [0010]     Past development of the GPS techniques, such as those discussed above, does not provide a solution for clearly receiving satellite program in a moving vehicle. The present invention is thus aimed to provide a solution for such a problem.  
       SUMMARY OF THE INVENTION  
       [0011]     An objective of the present invention is to provide a dynamic adjustment control device for a satellite antenna carried in a moving carrier, which tracks the current position of at least one program satellite with respect to the carrier, determines an deviation of the position of the satellite due to the movement of the carrier, and adjusting, based on the deviation, the orientation of the antenna to clearly receive program signals from the program satellite.  
         [0012]     To realize the objective, the present invention provides a device that is capable of dynamic adjustment of the orientation of an antenna carried by a moving vehicle to obtain an optimum reception of satellite programs. The control device comprises a satellite coordinate tracking device and an antenna adjusting mechanism. The satellite coordinate tracking device comprises a GPS position processor, which processes a positioning signal received from a group of GPS satellites to obtain current coordinate of the movable carrier currently with respect to the program satellite and compares the current satellite coordinate with a preset coordinate of the program satellite that is retrieved from a preset coordinate register. A deviation signal is generated, if the current coordinate is different from the preset one. The deviation signal is fed to a microprocessor, which provides a correction signal corresponding to the deviation signal. The correction signal is fed to an adjusting mechanism to reorient the antenna to match the preset coordinate of the program satellite.  
         [0013]     Three partial preset coordinates of the preset coordinate of the a program satellite, including preset longitude, preset latitude, and preset altitude of a program satellite, are used to adjust the antenna with respect to the program satellite. The dynamic adjusting device of the present invention allows for adjustment of the orientation of the antenna that is carried in a moving vehicle with a current coordinate including three partial preset coordinates, i.e., current longitude, current latitude and current altitude, with respect to the program satellite to match the preset longitude, preset latitude, and preset altitude of the preset coordinate of the program satellite, which in turn realizes an optimum reception of program signals sent from the program satellite by an program receiver within the moving vehicle and makes display of the programs clearer carried by the program signals, regardless the moving of the vehicle. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment thereof, with reference to the attached drawings, in which:  
         [0015]      FIG. 1  is a schematic view illustrating a dynamic adjusting device for satellite antenna carried in a vehicle in accordance with the present invention;  
         [0016]      FIG. 2  is a block diagram of a control circuit of the dynamic adjusting device in accordance with the present invention; and  
         [0017]      FIG. 3  is a flowchart illustrating orientation adjustment of a satellite antenna carried in a moving vehicle for tracking a satellite. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]     With reference to the drawings and in particular to  FIG. 1 , a dynamic adjustment control device constructed in accordance with the present invention is shown, which is provided for controlling the adjustment of orientation of a satellite antenna, generally designated with reference numeral  2 , mounted in/on a movable carrier, such as a moving vehicle  1 . A program satellite  3  located in a predetermined position with a preset coordinate sends a program signal  31  which can be received by a program receiver  4  via a satellite disc antenna  2 . A number of GPS satellites  3   a,    3   b,    3   c  that are located at differently predetermined positions send a series of positioning signals  32  which can be received by a GPS receiver  6   a.  The program receiver  4  and the GPS receiver  6   a  are installed in the vehicle  1 . The program signals  31  sent from the program satellite  3  carry audio/video programs that can be displayed on for example a TV set or can be broadcast through a radio or the likes.  
         [0019]     The program signal  31  sent from the program satellite  3  is received by the program receiver  4  via the antenna  2  and the receiver  4  generates a satellite program signal S 1  corresponding to the received program signal  31 . The satellite program signal S 1  generated by the program receiver  4  is comprised of a video component, and an audio component, all obtained by processing the program signal  31 . The satellite program signal S 1  is fed to a satellite program play device  5 , which may then play a satellite program composed of the video and audio components.  
         [0020]     In a preferred embodiment of the present invention, a satellite tracking device  6  is provided in the vehicle  1  and electrically coupled to the GPS receiver  6   a  to receive the positioning signals  32  and also electrically coupled to an antenna adjusting device  7 , which receives a control signal from the satellite tracking device for adjusting the orientation of the antenna  2  in order to dynamically track the program satellite  3  and cooperates with an antenna adjustment mechanism  7  and thus realizing the best reception of the program signal  31  from the satellite  3  by the antenna  2 .  
         [0021]     Also referring to  FIG. 2 , a circuit of the control device in accordance with the present invention is shown. The satellite tracking device  6  comprises a channel tracking logic circuit  60 , which receives the positioning signal  32  from the GPS receiver  6   a  and in turn provides a signal to a GPS position processor  61  in which the current coordinate is retrieved from the positioning signal  32  and processed to provide a current coordinate of the vehicle  1 . The current coordinate in this embodiment comprises a current longitude Sx, a current latitude component Sy, and a current altitude Sa.  
         [0022]     The current longitude Sx, current latitude Sy, and current altitude Sa are then fed to a first set of inputs of a GPS position comparator  62 . The GPS position comparator  62  has a second set of inputs that receive preset longitude Tx, preset latitude Ty, and preset altitude Ta from a preset coordinate register  65 . The preset longitude Tx, preset latitude Ty, and preset altitude Ta are stored in the preset coordinate register  65  and are preset by a user in advance via a satellite channel setting/selection unit  64 . The user may select a favorite channel received from the program satellite  3  via the satellite channel setting/selection unit  64 , which provides and stores the associated preset longitude Tx, preset latitude Ty, and preset altitude Ta in the register  65 .  
         [0023]     In addition, a number of satellite program channels P 1 , P 2 , P 3 , . . . , Pn may be preset in a channel memory  66  in the factory site when the device is manufactured or later by a user. This allows the user to readily select one of the program channels P 1 -Pn from the channel memory  66  via the satellite channel setting/selection unit  64 . Preset longitude Tx, preset latitude Ty, and preset altitude Ta associated with the selected channel P 1 -Pn can be retrieved from data stored in the channel memory  66  or obtained by processing the data from the channel memory  66 . Such longitude, latitude, and altitude are then transferred to the preset coordinate register  65  from which the preset longitude Tx, preset latitude Ty, and preset altitude Ta are conveyed to the GPS position comparator  62 .  
         [0024]     The memory  66  selectively comprises a user channel section  661  in which a user&#39;s personal favorite channel can be set and stored by the user via the satellite channel setting/selection unit  64 . Date stored in the user channel section  661  of the memory  66  may be quickly retrieved by the user and processed and transferred to the preset coordinate register  65 .  
         [0025]     The GPS position comparator  62  performs a comparison between the current longitude Sx, current latitude Sy, and current altitude components Sa received from the GPS satellites  3   a,    3   b,    3   c  and the preset longitude Ta, preset latitude Ty, and preset altitude Ta received from the preset coordinate register  65  and generates a longitude deviation signal Ex, a latitude deviation signal Ey, and an altitude deviation signal Ea, which are fed to a microprocessor  63 . Based on the longitude deviation signal Ex, latitude deviation signal Ey and altitude deviation signal Ea, a set of correct control signals S 2  comprising a longitude correction control signal Cx, a latitude correction control signal Cy, and an altitude correction control signal Ca are calculated by the microprocessor  63  and respectively applied to first, second, and third drive circuits  67 ,  68  and  69 , which in turn control the operation of a first, longitude-associated adjusting mechanism  71 , a second, latitude-associated adjusting mechanism  72 , and a third, altitude-associated adjusting mechanism  73 , which constitute the antenna adjusting device  7  and are mechanically coupled to the antenna  2  for re-orienting the antenna  2  toward the target program satellite  3 .  
         [0026]     The adjusting mechanisms  71 ,  72 ,  73  can be any known mechanism for moving the antenna  2 , such as that comprising a rotatable table rotated by gear train driven by a servo motor or stepping motor. This is well known and thus no further detail is necessary herein.  
         [0027]     Also referring to  FIG. 3 , the operation of the control device in accordance with the present invention will be briefly described. In step  101 , the control device of the present invention tracks and receives the positioning signals  32  sent from the GPS satellites  3   a,    3   b  and  3   c.  The positioning signals  32  are then processed to retrieve the current longitude Sx, the current latitude Sy, and the current altitude Sa (step  102 ). On the other hand, in step  103 , the user selects one of a number of preset program channels or simply sets a program channel of which the preset longitude Tx, the preset latitude Ty and the preset altitude Ta are retrieved (step  103 ).  
         [0028]     The current longitude Sx, the current latitude Sy and the current altitude Sa obtained in step  102  and the preset longitude Tx, the preset latitude Ty, and the preset altitude Ta obtained in step  103  are compared with each other (step  104 ). In step  105 , it is determined if any unacceptable deviation, i.e., any unacceptable deviation among anyone of the longitude deviation Ex, the latitude deviation Ey and the altitude deviation Ea, exists between the current coordinate and the preset coordinate. A negative answer of the judgment step  105  indicates that the antenna  2  is currently in correct orientation and no adjustment or re-orientation is necessary. The process goes back to step  101  again to start a new cycle for continuous and dynamic control of the orientation of the antenna in order to ensure the antenna  2  is always in the correct orientation.  
         [0029]     On the other hand, if the answer of the judgment step  105  is positive, then in step  106 , the longitude correction control signal Cx, the latitude correction control signal Cy and the altitude correction control signal Ca are generated and applied to the drive circuits  67 ,  68  and  69  respectively, which in step  107  control the adjusting mechanisms  71 ,  72 ,  73  to re-orient the antenna  2  in order to reduce the longitude deviation Ex, latitude deviation Ey and altitude deviation Ea to a desired level, such as approximately zero. In step  108 , it is determined if an operation stop instruction is received from for example a user. If positive, then the process stops, otherwise the process goes back to step  101  to start a new cycle of adjustment.  
         [0030]     The present invention allows a satellite disc antenna carried in a moving vehicle to make adjustment of the orientation of the antenna with respect to a selected commercial program satellite in order to obtain optimum reception of the program signals transmitted from the commercial program satellite. Thus, program quality shown in a play device can be maintained excellent regardless the moving of the vehicle. Apparently, the present invention can be of a great application in for example satellite program reception in fore example a long distance bus, a passenger marine vehicle and personal amusement.  
         [0031]     Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.