Patent Publication Number: US-2020284875-A1

Title: Vehicle radar detection angle adjustment system and angularly adjustable radar thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to radar detection systems, and more particularly, to a vehicle radar detection angle adjustment system and angularly adjustable radar thereof. 
     2. Description of the Related Art 
     A conventional vehicle radar detection system is a radar transmitter disposed on the in-vehicle rearview mirror. Bye use of the radar transmitter launching out a radar beam, the status of the vehicle ahead is detected, such as the speed and distance of the vehicles ahead. However, the radar beam launched out by such radar transmitter will be refracted when passing through the windshield (especially those being attached with window films having a small amount of metal), such that the dip angle of the radar beam is varied, and the radar beam is unable to be launched out at an optimal angle (such as in parallel to the ground surface). As a result, the vehicle detection is sometimes not reliable. Therefore, the dip angle of the radar beam transmission needs to be calibrated. 
     Referring to U.S. Pat. No. 5,313,213A, a conventional vehicle radar detection system is disclosed, wherein a mechanical adjustment is applied (such as providing an adjustment screw) for adjusting the dip angle of the radar beam transmission. However, mechanical adjustment has to be repeatedly operated for acquiring the correct dip angle. Although the dip angle of the radar beam transmission is correctly adjusted, the calibration process is slow due to the repeatedly carried out adjustment, lowering the efficiency of the calibration process. Therefore, it is desirable to resolve such issue. 
     SUMMARY OF THE INVENTION 
     For improving the issues above, a vehicle radar detection angle adjustment system and the angularly adjustable radar thereof are disclosed. When the refraction of the radar beam occurs during the radar beam passing through a medium (such as the windshield), the operation frequencies are adjusted within a frequency range, and different feedback signals are received and compared, so as to select the operation frequency of a predetermined energy, whereby the dip angle of the radar beam is calibrated. 
     For achieving the aforementioned objectives, a vehicle radar detection angle adjustment system in accordance with an embodiment of the present invention comprises a processing unit, a transmission unit, and a receiving unit. The transmission unit is electrically connected with the processing unit. The transmission unit generates a radar beam according to an operation frequency. The processing unit adjusts the operation frequency within a frequency range, such that the transmission unit generates radar beams having different dip angles. The receiving unit is electrically connected with the processing unit. The radar beam, after being reflected, is received by the receiving unit, and a feedback signal is generated. The processing unit receives the feedback signal, and selects an operation frequency of a predetermined energy. Therefore, the dip angle of the radar beam generated by the transmission unit is calibrated. 
     In an embodiment of the present invention, an angularly adjustable radar is provided, comprising a processing unit, and a transmission unit electrically connected with the processing unit. The transmission unit generates a radar beam according to an operation frequency. The processing unit adjusts the operation frequency within a frequency range, such that the transmission unit generates radar beams having different dip angles. The transmission unit scans with the radar beams generated within the frequency range. 
     With such configuration, the processing unit adjusts the operation frequency of the transmission unit within the frequency range, such that the transmission unit scans with the radar beams generated according to different frequencies, and the feedback signals generated by the receiving unit are compared by the processing unit, so as to acquire the energies corresponding to each frequency within the frequency range. The frequency corresponding to the predetermined energy is deemed as optimal and therefore selected as the operation frequency according to which the transmission unit generates the radar beam. Therefore, when the radar beam generated by the transmission unit is reflected by a medium, by conducting the scanning process within the aforementioned frequency range, the dip angle at which the radar beam passes through the translucent body is efficiently calibrated to an optimal angle, achieving an efficiency angle calibration function. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view illustrating the detection operation in accordance with an embodiment of the present invention. 
         FIG. 2  is a structural block view of the system in accordance with an embodiment of the present invention. 
         FIG. 3  is a block view illustrating the radar beams having different dip angles being generated according to different frequencies. 
         FIG. 4  is a diagram illustrating the waveforms of the radar beams having different dip angles being generated according to different frequencies. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The aforementioned and further advantages and features of the present invention will be understood by reference to the description of the preferred embodiment in conjunction with the accompanying drawings where the components are illustrated based on a proportion for explanation but not subject to the actual component proportion. 
     Referring to  FIG. 1  to  FIG. 4 , a vehicle radar detection angle adjustment system  100  and the angularly adjustable radar thereof are provided, comprising a processing unit  10 , a transmission unit  20 , and a receiving unit  30 . 
     The transmission unit  20  is disposed on the vehicle  40  and electrically connected with the processing unit  10 . The transmission unit  20  generates and launches out a radar beam according to an operation frequency. In an embodiment of the present invention, the transmission unit  20  is a leaky-wave antenna, which is adhered to the inner side of the windshield  41  of the vehicle  40 . Therefore, when being disposed on the vehicle  40 , the transmission unit  20  in the embodiment is simply attached to the windshield  41 . Such installation method is relative easier compared to the conventional mechanical adjustment method, achieving an efficient installation function. 
     The processing unit  10  adjusts the operation frequency of the radar beam which is generated by the transmission unit  20  within a frequency range, so as to change the dip angle at which the radar beam passes through the windshield  41 . In a preferred embodiment, the processing unit  10  and the transmission unit  20  form an angularly adjustable radar. Therefore, the transmission unit  20  scans with the radar beam generated according to the frequency adjusted by the processing unit  10 . In an embodiment of the present invention, the frequency ranges between 77 GHz to 81 GHz. When the processing unit  10  adjusts the operation frequency of the radar beam generated by the transmission unit  20 , the adjustment is orderly carried out at a frequency of, for example, 77 GHz, 78 GHz, 79 GHz, 80 GHz, and 81 GHz, respectively. In other words, the transmission unit  20  generates radar beams corresponding to the operation frequencies of 77 GHz, 78 GHz, 79 GHz, 80 GHz, and 81 GHz, respectively. As shown by  FIG. 4 , the transmission unit  20  in the embodiment generates the radar beam  21  at the operation frequency of 77 GHz, generates the radar beam  22  at the operation frequency of 78 GHz, generates the radar beam  23  at the operation frequency of 79 GHz, generates the radar beam  24  at the operation frequency of 80 GHz, and generates the radar beam  25  at the operation frequency of 81 GHz, respectively. Also, it is clearly seen that the dip angles of the radar beam  21  to radar beam  25  orderly become larger than the previous one. 
     The receiving unit  30  is electrically connected with the processing unit  10 , so as to receive the reflected radar beam and accordingly generate a feedback signal  31 . In an embodiment of the present invention, a reflector  32  is further comprised, which is a corner reflector in the embodiment and disposed in front of the vehicle  40 . The reflector  32  faces the direction from which the transmission unit  20  launches out the radar beams  21  to  25 . When the radar beams  21  to  25  are launched out to pass through the windshield  41 , the radar beams  21  to  25  are reflected by the reflector  32  and received by the receiving unit  30 , whereby the feedback signals  31  are generated, respectively. 
     The processing unit  10  receives the feedback signals  31  and compares the energy of the radar beams  21  to  25 , and then select an operation frequency corresponding to the predetermined energy for calibrating the dip angle at which the radar beam is launched after passing through the windshield  41 . The operation frequency corresponding to the predetermined energy, in the embodiment, is the operation frequency corresponding to one of the radar beams  21  to  25 , received by the receiving unit  30 , which has the largest amount of energy. In the embodiment, the radar beam  23  has the largest energy. Therefore, the radar beam  23  at the operation frequency of 79 GHz is selected for calibrating the dip angle at which the radar beam is launched after passing through the windshield  41 . In the embodiment, the processing unit  10  is a digital signal processing (DSP), and the feedback signal  31  is mainly an analog signal. By use of the analog-digital signal conversion, the feedback signal  31  is converted into a digital signal to be received by the processing unit  10 . 
     In the embodiment, as shown by  FIG. 4 , based on the fact that the radar beams  21  to  25  are launched to pass through the windshield  41  toward the front side of the vehicle  40 , the transmission range is defined as a 180-degree range facing outward from the point where the transmission unit  20  is attached to the windshield  41 , so as to save unnecessary transmission range. In a preferred embodiment, the transmission range is defined as a 90-degree range toward the ground from a vertical line extending outward from the position at where the transmission unit  20  is attached to the windshield  41 . 
     With the foregoing configuration, the processing unit  10  adjusts the operation frequency of the transmission unit  20  within a given frequency range, and the transmission unit  20  conduct a scanning operation with the radar beams  21  to  25  generated according to different frequencies. Next, the receiving unit  30  generates feedback signals  31  that are compared by the processing unit  10 , such that the processing unit  10  selects the operation frequency corresponding to one of the radar beams  21  to  25  which has the predetermined energy amount (such as the operation frequency of 79 GHz having the largest energy), wherein the selected operation frequency is applied for the transmission unit  20  to generate the radar beam. Thus, when the radar beam generated by the transmission unit  20  passes through the windshield  41  and is refracted, through the efficiently carried out scanning operation of the processing unit  10  within the frequency range, one of the radar beams  21  to  25  having the most optimal dip angle at which the radar beam is launched after passing through the windshield  41  is acquired. Compared to the conventional mechanical adjustment method, the present invention enhances the calibration speed and achieves an improved calibration efficiency. 
     Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.