A method and system for judging overspeed of electric bicycle based on radio frequency positioning speed measurement

Abstract

The invention relates to the technical field of radio frequency identification of non-motor vehicle speeding, and discloses a method for distinguishing speeding of an electric bicycle based on radio frequency positioning and speed measurement, comprising: S1, obtaining tag information, first phase information and first time information; S2, obtaining tag information, second phase information and second time information; S3, determining an initial speed value by using the first phase information, first time information, second phase information and second time information; S4, multiplying the initial speed value by a correction coefficient k to obtain a speed correction value, 0.7≤k≤1; S5, reporting a speed correction value exceeding a threshold and its tag information; the method can obtain a relative distance from a tag to an antenna and an instantaneous speed of a vehicle by calculating a phase difference, and a radio frequency antenna can continuously count all tags in a field at a microsecond period, so as to monitor the driving speed of electric bicycles in real time without losing the vehicle and in a traceable manner, so that speeding violations have nowhere to escape.

Description

Technical Field

[0001] The invention relates to the technical field of radio frequency identification of non-motor vehicle speeding, and in particular to a method and system for distinguishing overspeed of an electric bicycle based on radio frequency positioning and speed measurement. Background Art

[0002] Non-motor vehicles, especially electric bicycles, are small in size and have flexible routes. However, due to their increasing numbers, the potential traffic safety hazards they may cause are becoming increasingly prominent. Most traffic accidents involving electric bicycles are caused by excessive speed and the driver's lack of concentration.

[0003] The more mature speed measurement methods at present are interval speed measurement, radar speed measurement, and video speed measurement. Among them, interval speed measurement and radar speed measurement are more suitable for places with low vehicle density such as highways and urban peripheral areas. They cannot accurately meet the supervision needs when there are many roads, many vehicles, and many pedestrians, and the speed measurement objects are mainly motor vehicles. Video speed measurement has higher requirements for the environment and road conditions. In extreme weather or when electric bicycles are crowded and blocked, the effect will be poor. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method and system for determining speeding of electric bicycles based on radio frequency positioning speed measurement. The method and system can determine speeding violations of electric bicycles under complex road conditions through radio frequency positioning speed measurement.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for distinguishing overspeed of an electric bicycle based on radio frequency positioning speed measurement, comprising: S1, obtaining tag information, first phase information and first time information; S2, obtaining tag information, second phase information and second time information; S3, determining an initial speed value by using the first phase information, first time information, second phase information and second time information; S4, multiplying the initial speed value by a correction coefficient k to obtain a speed correction value, 0.7≤k≤1; S5, reporting a speed correction value exceeding a threshold and its tag information.

[0007] In the present invention, preferably, the correction coefficient k used in calculating the speed correction value for the Nth time is negatively correlated with the speed correction value obtained by the N-1th calculation.

[0008] In the present invention, preferably, S1 includes: S11, RF-enabled tag inventory; S12, after reading any tag in the field, receiving its tag information and first phase information; S13, CRC check to confirm the legitimacy of the tag information; S14, saving the tag information and the first phase information, and recording the timestamp as the first time information.

[0009] In the present invention, preferably, S2 includes: S21, performing a secondary visit to the corresponding tag to receive its tag information and second phase information; S22, saving the second phase information and recording the timestamp as the second time information.

[0010] In the present invention, preferably, receiving the tag information in S21 is to read Y bytes of the area corresponding to the tag, where Y is less than the total number of bytes included in the tag information.

[0011] In the present invention, preferably, S3 includes: S31, calculating the phase difference between the first phase information and the second phase information; S32, calculating the time difference between the first time information and the second time information; S33, calculating the initial value of the speed using the phase difference and the time difference.

[0012] In the present invention, preferably, between S4 and S5, it also includes: S4a, judging whether the speed correction value is within the normal speed range, if so, retaining the speed correction value; if not, deleting the speed correction value.

[0013] In the present invention, preferably, it also includes: S4b, eliminating the jump value in the speed correction value.

[0014] In the present invention, preferably, S4b includes: S4b1, establishing the N speed correction values ​​of the X label as a speed array v_list; S4b2, calculating the average value v_mean and variance v_stdev of the N+1th speed correction value V of the X label and each speed correction value in v_list; S4b3, judging whether v_stdev is greater than the jump threshold, if so, updating v_list with v_mean instead of V; if not, updating v_list with the V value; S4b4, taking each speed correction value in v_list as a valid speed correction value.

[0015] An electric bicycle overspeed discrimination system based on radio frequency positioning speed measurement, comprising: a radio frequency unit, used to obtain tag information, first phase information, first time information, second phase information and second time information; the radio frequency unit comprises: an inventory subunit, used to open the tag inventory by radio frequency; a reading subunit, used to read the tag information, the first phase information, the first time information, the second phase information and the second time information; a verification subunit, used for CRC verification to confirm the legitimacy of the tag information; a storage subunit, used to save the tag information, the first phase information, the first time information, the second phase information and the second time information; an information processing unit, connected to the radio frequency unit, used to determine the initial speed value by using the first phase information, the first time information, the second phase information and the second time information, correct the initial speed value and obtain the speed correction value; an abnormal elimination unit connected to the information processing unit and used to eliminate abnormal values ​​in the speed correction value; a jump elimination unit connected to the abnormal elimination unit and used to eliminate jump values ​​in the speed correction value; the jump elimination unit includes: an array subunit, used to establish the N speed correction values ​​of the X label as a speed array v_list; an average subunit, used to calculate the average value v_mean and variance v_stdev of the N+1th speed correction value V of the X label and each speed correction value in v_list; an update subunit, used to determine whether v_stdev is greater than the jump threshold, if so, then update v_list with v_mean instead of V; if not, then update v_list with V value; a communication unit, connected to the jump elimination unit, used to report the speed correction value exceeding the threshold.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The method and system of the present invention can obtain the relative distance from the tag to the antenna and the instantaneous speed of the vehicle by calculating the phase difference. The radio frequency antenna can continuously count all tags in the field at a microsecond period. Even in the case of poor road conditions such as a large number of non-motor vehicles, the distance and speed can be accurately calibrated. It is applicable to scenes with dense vehicles, can accurately meet regulatory requirements, and can adapt to a variety of complex and harsh environments and road conditions. It can also update the speed of electric bicycles in the scene in real time, so as to avoid losing the vehicle and traceably monitor the driving speed of electric bicycles in real time, leaving speeding violations nowhere to escape. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a flowchart of a method for determining overspeed of an electric bicycle based on radio frequency positioning and speed measurement in one embodiment of the present invention.

[0019] Figure 2 This is a flow chart of S1 in a method for determining overspeed of an electric bicycle based on radio frequency positioning and speed measurement in one embodiment of the present invention.

[0020] Figure 3 This is a flow chart of S2 in a method for determining overspeed of an electric bicycle based on radio frequency positioning and speed measurement in one embodiment of the present invention.

[0021] Figure 4 This is a flow chart of S3 in a method for determining overspeed of an electric bicycle based on radio frequency positioning speed measurement in one embodiment of the present invention.

[0022] Figure 5 The present invention is a flowchart of a method for determining overspeed of an electric bicycle based on radio frequency positioning and speed measurement in one embodiment of the present invention.

[0023] Figure 6 This is a flow chart of S4b in a method for determining overspeed of an electric bicycle based on radio frequency positioning speed measurement in one embodiment of the present invention.

[0024] Figure 7 The figure is a schematic diagram of the structure of an electric bicycle overspeed determination system based on radio frequency positioning and speed measurement in one embodiment of the present invention.

[0025] In the accompanying drawings: 1-RF unit, 101-inventory subunit, 102-reading subunit, 103-verification subunit, 104-storage subunit, 2-information processing unit, 3-abnormal elimination unit, 4-transition elimination unit, 401-array subunit, 402-average subunit, 403-update subunit, 5-communication unit. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0029] Please also see Figures 1 to 4 A preferred embodiment of the present invention provides a method for determining overspeed of an electric bicycle based on radio frequency positioning speed measurement, comprising:

[0030] S1, acquiring tag information, first phase information and first time information.

[0031] In this step, the radio frequency starts the electronic tag inventory operation. When a tag in the field is read, the tag information and phase information are received according to the corresponding air interface protocol. The legitimacy of the tag information is confirmed by CRC (cyclic redundancy check code), and the tag information and the first phase value are saved respectively, and the timestamp is recorded. The timestamp contains the first time information. S1 can be divided into several sub-steps, including:

[0032] S11, RF enabled tag inventory;

[0033] S12, after reading any tag in the field, receiving its tag information and first phase information;

[0034] S13, CRC check to confirm the legitimacy of the label information;

[0035] S14, save the tag information and the first phase information, and record the timestamp as the first time information.

[0036] S2, obtaining tag information, second phase information and second time information.

[0037] Then, perform a second access operation on the tag and wait for the result. Obtain the handle of the tag according to the RF air interface protocol. Since the handle and the tag are bound, it is possible to quickly confirm that the tag is the tag accessed for the first time. Since this method does not care about the tag information returned by the second air interface access, it is possible to choose operations that take less time, such as reading 1 byte, 2 bytes or part of the bytes in the corresponding area of ​​the tag, which can be expressed as reading Y bytes in the corresponding area of ​​the tag, where Y is less than the total number of bytes contained in the tag information. After the tag returns the data, save the phase data of the second access operation, that is, the second phase information, and record the timestamp as the second time information. At this point, the RF device's access to this tag ends. S2 can be divided into several sub-steps, including:

[0038] S21, perform a second visit to the corresponding tag to receive its tag information and second phase information;

[0039] S22, save the second phase information, and record the timestamp as the second time information.

[0040] S3, determining an initial speed value using the first phase information, the first time information, the second phase information, and the second time information.

[0041] The phase difference is calculated using the first phase information and the second phase information, and the time difference obtained by combining the first time information and the second time information, and then the relative distance and speed between the corresponding tag and the RF antenna can be calculated using the phase distance measurement and speed measurement method. Since the time interval between the two access operations is in microseconds, the result calculated based on this time difference can be approximately equal to the instantaneous value of the distance and speed, and the instantaneous value of the speed is the initial value of the speed. S3 can be decomposed into:

[0042] S31, calculating a phase difference between first phase information and second phase information;

[0043] S32, calculating the time difference between the first time information and the second time information;

[0044] S33, calculating the initial speed value using the phase difference and the time difference.

[0045] S4, multiplying the initial speed value by the correction coefficient k to obtain a speed correction value, 0.7≤k≤1.

[0046] Since the tag is moving and there is a time difference between the two acquisitions, this time difference will bring about an absolute error of the phase difference, which in turn affects the accuracy of the tag distance value and speed value. The actual performance is that all calculated initial speed values ​​have an offset based on the speed. The faster the tag moves, the greater the deviation of its initial speed value from the true value. In order to correct this deviation, after calculating the initial speed value of a tag each time, it is necessary to refer to the previous speed correction value (the initial speed value of this time can be used as a reference for the first measurement) to compensate the initial speed value of this time with a certain attenuation property. The specific way of compensation is to multiply the initial speed value of this time by a coefficient k ranging from 0.7 to 1 according to the size of the previous speed correction value. As for the corresponding relationship between the previous speed correction value and the k value, it is generally an empirical value. The general rule is that the faster the speed, the smaller the k value, or it can be expressed as the correction coefficient k used in the Nth calculation of the speed correction value is negatively correlated with the speed correction value obtained by the N-1th calculation. The corresponding value of k and different speeds can be determined experimentally.

[0047] S5, reporting the speed correction value exceeding the threshold and its label information.

[0048] After obtaining the speed correction value, it can be compared with the preset threshold. If it does not exceed the threshold, it does not need to be reported. If it exceeds the threshold, the speed correction value and its tag information can be reported to punish it. In this way, the speed correction value of electric vehicles entering the measurement scene is continuously measured. For electric vehicles that leave the measurement scene, the radio frequency will not detect its tag, and the speed measurement will stop.

[0049] In another embodiment of the present invention, Figure 5 , Figure 6 As shown, the electric bicycle overspeed determination method based on radio frequency positioning speed measurement also includes between S4 and S5:

[0050] S4a, determining whether the speed correction value is within the normal speed range, if so, retaining the speed correction value; if not, deleting the speed correction value.

[0051] S4b, removes the jump value in the speed correction value.

[0052] When the electronic identification of electric bicycles moves in the field covered by the RF antenna, the vehicle speed data obtained in each round of inventory will fluctuate. In order to obtain the accurate speed of the vehicle, it is necessary to remove abnormal points and smooth the data in real time (eliminate jump values). Every time the tag data is read, it enters the smoothing filter process for processing. After the processing is completed, an accurate vehicle speed is output and filled in the speed array contained in the RF node. The definition of an abnormal point is a value where the speed correction value exceeds 0-50km / h, and the processing method is that the abnormal value is directly discarded. Non-abnormal values ​​can continue to enter the jump point judgment, and the average value v_mean and variance v_stdev are calculated together using the input speed correction value V and the speed values ​​in the existing speed array v_list, a total of N+1. If the variance v_stdev exceeds the limit, it is determined to be a jump point, and the calculated average value v_mean is replaced by V and updated into the speed array v_list. If it is a non-jump point, the original V value is updated to the speed array v_list. The process ends here, waiting for the next speed correction value V to be input. Therefore, S4b includes:

[0053] S4b1, establish the N speed correction values ​​of the X label as the speed array v_list;

[0054] S4b2, calculating the mean value v_mean and variance v_stdev of the N+1th speed correction value V of label X and each speed correction value in v_list;

[0055] S4b3, determine whether v_stdev is greater than the jump threshold, if so, update v_mean instead of V into v_list; if not, update v_list with the V value;

[0056] S4b4, taking each speed correction value in v_list as a valid speed correction value.

[0057] like Figure 7 As shown, the present invention also provides an electric bicycle overspeed determination system based on radio frequency positioning speed measurement, comprising:

[0058] The radio frequency unit is used to obtain the tag information, the first phase information, the first time information, the second phase information and the second time information. The radio frequency unit includes: an inventory subunit, which is used to open the tag inventory by radio frequency; a reading subunit, which is used to read the tag information, the first phase information, the first time information, the second phase information and the second time information; a check subunit, which is used to check the legitimacy of the tag information by CRC check; and a storage subunit, which is used to save the tag information, the first phase information, the first time information, the second phase information and the second time information.

[0059] The information processing unit is used to determine the initial speed value by using the first phase information, the first time information, the second phase information and the second time information, and to correct the initial speed value to obtain the speed correction value.

[0060] The abnormality elimination unit is used to eliminate abnormal values ​​in the speed correction value.

[0061] The jump elimination unit is used to eliminate the jump values ​​in the speed correction value. The jump elimination unit includes: an array subunit, which is used to establish the N speed correction values ​​of the X label as a speed array v_list; an average subunit, which is used to calculate the average value v_mean and variance v_stdev of the N+1th speed correction value V of the X label and each speed correction value in v_list; an update subunit, which is used to determine whether v_stdev is greater than the jump threshold, if so, then update v_list with v_mean instead of V, if not, then update v_list with V value.

[0062] The communication unit is used to report the speed correction value exceeding the threshold.

[0063] Working principle:

[0064] After starting work, the host computer sends down the RFID rules. After receiving the rule data stream, the communication module forwards it to the RF unit. The unit extracts the information in the rules, determines the start and stop time of the tag inventory, the tag polling cycle, the tag operation type, etc., exchanges data with the RF electronic tag, and uses the tag's response data to update the RF node list. The information processing unit polls this list. When there is an RF node update, the node is extracted for RF positioning and speed measurement calculation. After the abnormal point removal and smoothing filtering (jump point removal) are performed by the abnormal removal unit and the jump removal unit, the speed data of the RF node is updated. If the speed reaches the specified trigger threshold, the information processing unit extracts all vehicle information and speed data of the RF node, frames it and sends it to the communication unit. The communication unit sends the vehicle speeding message to the data link connected to the host computer. If the tag is no longer read after a period of time after leaving the site, the information processing unit is responsible for clearing this node.

[0065] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for determining overspeed of an electric bicycle based on radio frequency positioning speed measurement, characterized in that: include: S1, obtaining tag information, first phase information and first time information; S2, obtaining tag information, second phase information and second time information; S3, determining an initial speed value using the first phase information, the first time information, the second phase information, and the second time information; S4, multiplying the initial speed value by the correction coefficient k to obtain a speed correction value, 0.7≤k≤1; S5, reporting the speed correction value exceeding the threshold and its label information; The S1 includes: S11, RF enabled tag inventory; S12, after reading any tag in the field, receiving its tag information and first phase information; S13, CRC check to confirm the legitimacy of the label information; S14, saving the tag information and the first phase information, and recording the timestamp as the first time information; The S2 includes: S21, perform a second visit to the corresponding tag to receive its tag information and second phase information; S22, saving the second phase information and recording the timestamp as the second time information; The S3 includes: S31, calculating a phase difference between first phase information and second phase information; S32, calculating the time difference between the first time information and the second time information; S33, calculating the initial speed value using the phase difference and the time difference; Also included between S4 and S5: S4a, determining whether the speed correction value is within the normal speed range, if so, retaining the speed correction value; if not, deleting the speed correction value; Also includes: S4b, removes the jump value in the speed correction value; The S4b comprises: S4b1, establish the N speed correction values ​​of the X label as the speed array v_list; S4b2, calculating the mean value v_mean and variance v_stdev of the N+1th speed correction value V of label X and each speed correction value in v_list; S4b3, determine whether v_stdev is greater than the jump threshold, if so, update v_mean instead of V into v_list; if not, update v_list with the V value; S4b4, taking each speed correction value in v_list as a valid speed correction value.

2. The method for determining overspeed of an electric bicycle based on radio frequency positioning speed measurement according to claim 1 is characterized in that: The correction coefficient k used in calculating the speed correction value for the Nth time is negatively correlated with the speed correction value obtained by the N-1th calculation.

3. The method for determining overspeed of an electric bicycle based on radio frequency positioning speed measurement according to claim 1, characterized in that: The receiving of the tag information in S21 is to read Y bytes of the corresponding area of ​​the tag, where Y is less than the total number of bytes included in the tag information.

4. An electric bicycle overspeed determination system based on radio frequency positioning speed measurement, characterized in that: include: A radio frequency unit, used to obtain tag information, first phase information, first time information, second phase information and second time information; The radio frequency unit comprises: Inventory subunit, used for RF-enabled tag inventory; A reading subunit, used for reading tag information, first phase information, first time information, second phase information, and second time information; The check subunit is used for CRC check to confirm the legitimacy of the tag information; A storage subunit, used to store tag information, first phase information, first time information, second phase information, and second time information; an information processing unit connected to the radio frequency unit, and configured to determine an initial speed value by using the first phase information, the first time information, the second phase information, and the second time information, and to correct the initial speed value to obtain a corrected speed value; an abnormality elimination unit, connected to the information processing unit, for eliminating abnormal values ​​in the speed correction value; A jump elimination unit, connected to the abnormal elimination unit, is used to eliminate the jump value in the speed correction value; The transition elimination unit comprises: The array subunit is used to create the N speed correction values ​​of the X label as the speed array v_list; The average subunit is used to calculate the average value v_mean and variance v_stdev of the N+1th speed correction value V of the X label and each speed correction value in v_list; The update subunit is used to determine whether v_stdev is greater than the jump threshold. If so, v_mean is updated to v_list instead of V; if not, v_list is updated with the V value; The communication unit is connected to the jump elimination unit and is used to report the speed correction value exceeding the threshold.

Images