Abstract:
A handheld radio signal tracker is provided. The handheld tracker includes a plurality of directional antennas to receive radio signal, whereby a microprocessor will identify the direction and distance of the target which sends the signal. In particular, two directional antennas receive a signal from the same target, the indicating light will show the right direction when the target is positioned in the overlapping area between two directional antennas&#39; detection area.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a radio signal tracker, particularly to a handheld radio signal tracker to search the handheld radio signal transmitters. 
         [0003]    2. Description of the Prior Art 
         [0004]    After the IEEE proposes 802.15 protocols, the proposal standard of WPAN (Wireless Personal Area Network), the standard of next generation of wireless communication is assured. Besides the Bluetooth (802.15.1), the wireless sensor network and the UWB (Ultra Wireless Broadband) will come into the market with their own characteristics, such as speed, price and so on. The wireless sensor network, Bluetooth and UWB will respectively construct their applications at low, medium and high speed on the classification of short-distance wireless communication for themselves. 
         [0005]    Because of low power consumption and cost, the wireless sensor network is popular for the home automation from lighting control, curtain control, to water or power meters reading wirelessly, and for medical uses from the medical nursing to the body information collection. The other applications, like air and water inspection, wireless toy, door security, all of these may use wireless sensor network to implement all functions without any wire connection problem. 
         [0006]    A conventional wireless tracking system has some transmitters for the children and a sensor for their parent, when the children walking beyond the signal covering area the parent&#39;s sensor will alarm, so as the parent won&#39;t let the children go too far, some sensor even may show the children&#39;s direction or position. There is one conventional wireless tracking system utilizing a unidirectional antenna to detect the direction and distance of a tracked device (transmitter). However, due to the environmental influence, the error is usually too great to tell the correct direction of the tracked device. There is another conventional wireless tracking system utilizing double unidirectional antennas to detect the direction and distance of a tracked device. Although the double directional antennas will detect the direction of the signal, the end-points of two antennas often miss the signal&#39;s direction.  FIG. 1  shows the missing area A and A′ for the structure of double unidirectional antennas  01  and  02 . 
       SUMMARY OF THE INVENTION 
       [0007]    To realize the direction identification capability of multiple antennas, one embodiment of the present invention provides an handheld radio signal tracker for identifying signal&#39;s direction, wherein utilizing the directional antenna to detect the signal from specified area may provide better capability of direction identifying. 
         [0008]    To avoid the problem of the dead space occurred in double directional antennas for radio signal tracker, one embodiment of the present invention provides an antenna structure for identifying signal&#39;s direction, wherein each directional antenna may receive the wireless signal transmitted from a specified region, and the wireless tracking system using the multiple directional antennas&#39; structure of the present invention may precisely determine the direction and distance of a tracked target. 
         [0009]    To achieve the abovementioned objectives, one embodiment of the present invention provides a handheld radio signal tracker, which uses a wireless network to detect at least one handheld radio signal transmitter. The handheld radio signal tracker includes: a first micro-processor executing the programs and computing the data; a wireless transceiver module coupled to the first micro-processor and having at least three directional antennas, the wireless transceiver module receiving a signal using the directional antennas and transforming the signal into digital data, then the digital data being sent to the first micro-processor, wherein the directional antennas are equally assigned detecting sectors for covering a whole 360-degrees zone, and each of the detecting sectors overlaps with the adjacent ones; and a display unit receiving instruction from the first micro-processor for displaying a status of communicating with the handheld radio signal transmitter, and an information of distance and direction. 
         [0010]    Other advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of the present invention. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The foregoing aspects and many of the accompanying advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
           [0012]      FIG. 1  is a conventional antenna structure for identifying signal&#39;s direction; 
           [0013]      FIG. 2  is a functional diagram of the handheld radio signal tracker according to one embodiment of the present invention; 
           [0014]      FIG. 3  is a functional diagram of the handheld radio signal transmitter according to one embodiment of the present invention; 
           [0015]      FIG. 4  is the description of the directional antennas&#39; structure for identifying signal&#39;s direction according to one embodiment of the present invention; and 
           [0016]      FIG. 5  is a display unit of the handheld radio signal tracker for identifying signal&#39;s direction according to one embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]    Refer to  FIG. 2  for the functional diagram of the handheld radio signal tracker according to one embodiment of the present invention. In this embodiment, the handheld radio signal tracker  10  uses a wireless network to detect at least one handheld radio signal transmitter (not shown), the handheld radio signal tracker  10  includes: a micro-processor  11  executing the programs and computing the data; a wireless transceiver module  12  coupled to the micro-processor  11  and having three directional antennas  121 ,  122 ,  123 ; the adaptor  120  assigning every directional antennas  121 ,  122 ,  123  to receive the signals sent from specific detection area; the wireless transceiver  12  module receiving the signals from any directional antennas  121 ,  122 ,  123  and transforming the signals into digital data, then the digital data being sent to the micro-processor  11 , wherein the directional antennas are equally assigned detection sectors for covering a whole 360-degree zone, and each of the detection sectors overlaps wthe the adjacent ones; and a display unit receiving instruction from the micro-processor  11  for displaying a status of communicating with the handheld radio signal transmitters, and the information of distance and direction thereof. 
         [0018]      FIG. 3  illustrates the functional diagram of the handheld radio signal transmitter according to one embodiment of the present invention. The handheld radio signal transmitter  20  includes: a micro-processor  21  executing the programs and computing the data; a wireless transceiver module  22  coupled to the micro-processor  21  and having a omni-directional antenna  221 , the wireless transceiver module  22  receiving a signal from the omni-directional antenna  221  and transforming the signal into digital data, then the digital data being sent to the micro-processor  21 , or the wireless transceiver module  22  receiving the digital data from the micro-processor  21  and transforming the digital data into a signal, then the signal being sent to the omni-directional antenna  221 ; and a calling unit  23  transmitting an instruction to the micro-processor  21  for enabling the wireless transceiver module  22  to send a specific signal to the air via the omni-directional antenna  221 . 
         [0019]    Accordingly, the handheld radio signal tracker  10  communicates with the handheld radio signal transmitters  20  via a wireless sensor network, like Zigbee, which assigns every device in the network a unique ID number for conveniently identifying the target device, wherein the device may be the handheld radio signal tracker  10  or the handheld radio signal transmitter  20 . 
         [0020]      FIG. 4  is the description of the antenna structure for identifying signal&#39;s direction according to one embodiment of the present invention. In this embodiment, the antenna structure has three directional antennas  321 ,  322  and  333  to receive the signals; wherein three directional antennas  321 ,  322  and  333  are arranged in a triangle shape and the boundaries between those antennas&#39; detecting sectors are OP 1 , OP 2  and OP 3 , each directional antenna cover 120 degrees. In real implementation, each of directional antennas  321 ,  322  and  333  covers 140 degrees, thus directional antennas  321 ,  322  and  333  detect area A, B and C respectively, and each of the overlapping areas is 20-degree sector. When a handheld radio signal transmitter  40  transmits a signal, the directional antenna  321  is controlled by an adaptor to receive the signal, which is then sent to the micro-processor by the wireless transceiver module. The micro-processor processes the signal and output the direction and distance of the handheld radio signal transmitter  40  on the display unit, wherein the display unit is a FPT (Flat Panel Display). 
         [0021]    Refer to  FIG. 5  for a display unit of the handheld radio signal tracker for identifying signal&#39;s direction according to one embodiment of the present invention. In this embodiment, a handheld radio signal tracker  50  utilizes a wireless sensor network to track at least one handheld radio signal transmitter  60 . The display unit of the handheld radio signal tracker has six directional lights  51 ,  52 ,  53 ,  54 ,  55  and  56  to indicate six directions. When a handheld radio signal transmitter  60  positions at the A, B or C sector, the directional light  52 ,  56  or  54  is on respectively. If the handheld radio signal transmitter  60  positions at the A and C overlapping area the directional light  53  is on. At this event the two directional antennas may receive a same signal, thus the structure of three directional antennas may avoid the dead area to improve the accuracy of detection. In addition, the directional lights  51 ,  52 ,  53 ,  54 ,  55  and  56  are the LEDs. 
         [0022]    Accordingly the handheld radio signal tracker has a “tracking” button, which may send an instruction to the micro-processor. The micro-processor controls the directional antenna that detects the handheld radio signal transmitter to send a signal to that handheld radio signal transmitter for alarming the carrier. In addition, handheld radio signal tracker has some channel indicators to show the direction, distance and status of the handheld radio signal transmitters. Thereby, the handheld radio signal tracker can perform the omni bearing detection of wireless signals and obtain the direction and distance of the tracked device. 
         [0023]    The tracked device should have a wireless transceiver module with an antenna to transmit signals to the handheld radio signal tracker  50 . The wireless communication network used by the tracked device and the handheld radio signal tracker  50  is a wireless sensor network. In the wireless sensor network, each hardware device should have a unique hardware address so that the hardware device can be recognized in wireless way. 
         [0024]    In summary, the present invention utilizes the directional antennas to confine to different sectors respectively. Via allocating different sectors to several antennas, the signal&#39;s direction can be identified. The present invention further utilizes the intensity of the received signal to determine the distance between the handheld radio signal tracker and the handheld radio signal transmitters. 
         [0025]    Although the Embodiments Abovementioned are described with three directional antennas, some embodiments may use more directional antennas to implement the spirit of the present invention. However, the whole 360 degrees are not necessarily covered by three directional antennas. In the present invention, 360 degrees may also be covered by four directional antennas, and each of them covers a 90-degree sector. 
         [0026]    While the invention is susceptible to various modifications and alternative forms, a specific example thereof has been shown in the drawings and is herein described in detail. It should be understood, however, that the invention is not to be limited to the particular form disclosed, but to the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the appended claims.