Positioning speed measurement and vehicle-to-ground communication system and method using cross-induction loops

Abstract

The invention discloses a positioning speed measurement and vehicle-to-ground communication system and method using a cross induction loop line. The system comprises: a vehicle-mounted subsystem, a carrier signal generator of which is used to divide a crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generate a frequency modulation driving current according to the first and second frequency division coefficients, and an antenna unit of which is used to generate a frequency modulation electromagnetic field according to the frequency modulation driving current; a ground loop line subsystem, comprising an R line, an SG0 line and a G0-Gn line, wherein the R line, the SG0 line and the G0-Gn line generate a frequency modulation induced voltage according to the frequency modulation electromagnetic field; a ground station subsystem, comprising an address detection unit, which is used to process the frequency modulation induced voltage generated by the G0 line and the SG0 line to obtain the relative position information of the train, to process the frequency modulation induced voltage generated by the R line and the G0-Gn line to obtain the absolute position information of the train, and to process the frequency modulation induced voltage generated by the R line to obtain effective information and send the effective information to a zoning operation control system of the train through vehicle-to-ground communication.

Description

Technical Field

[0001] The invention relates to the technical field of ultra-high-speed maglev train positioning and speed measurement, and in particular to a positioning and speed measurement and vehicle-to-ground communication system and method utilizing a cross-induction loop. Background Art

[0002] The existing technology cannot use the same system to take into account both positioning and speed measurement and vehicle-to-ground communication. It often uses two sets of vehicle-mounted antennas and ground loops, which work at different frequencies to ensure that the two do not affect each other and independently complete the functions of positioning and speed measurement and vehicle-to-ground communication. For the positioning and speed measurement system, the H line and H' line are used for relative positioning, and the R line and n line are used for absolute positioning of the G line; and for the communication system, a pair of parallel cables are required for communication, and there is a problem of electromagnetic field interference between the two in space, so the working frequencies need to be staggered. In other words, the existing induction loops can be used for positioning and speed measurement or vehicle-to-ground communication, but the same set of equipment cannot be used to meet the needs of positioning and speed measurement and vehicle-to-ground communication at the same time. Summary of the invention

[0003] The present invention provides a positioning speed measurement and vehicle-to-ground communication system and method using a cross induction loop, which can solve the problems in the prior art.

[0004] The present invention provides a positioning speed measurement and vehicle-to-ground communication system using a cross induction loop, wherein the system comprises:

[0005] The vehicle-mounted subsystem includes a carrier signal generator and an antenna unit, wherein the carrier signal generator is used to divide a crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generate a frequency modulation driving current according to the first frequency division coefficient and the second frequency division coefficient, and the antenna unit is used to generate a frequency modulation electromagnetic field according to the frequency modulation driving current;

[0006] A ground loop subsystem, comprising an R line, an SG0 line and G0-Gn lines, wherein the R line, the SG0 line and the G0-Gn lines generate a frequency-modulated induced voltage according to the frequency-modulated electromagnetic field;

[0007] The ground station subsystem includes an address detection unit, which is used to process the frequency-modulated induced voltage generated by the G0 line and the SG0 line to obtain the relative position information of the train, to process the frequency-modulated induced voltage generated by the R line and the G0-Gn lines to obtain the absolute position information of the train, and to process the frequency-modulated induced voltage generated by the R line to obtain valid information and send the valid information to the zoning operation control system of the train through train-to-ground communication.

[0008] Preferably, the carrier signal generator includes a modulation module and a drive circuit, and the carrier signal generator is used to divide the crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generate a frequency modulation drive current according to the first frequency division coefficient and the second frequency division coefficient, including:

[0009] The modulation module is used to divide the frequency of the crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient, select the first frequency division coefficient or the second frequency division coefficient according to the current code element of the baseband signal, and perform a shift operation when the number of carrier cycles corresponding to the current code element reaches the target value N, and use the next code element as the frequency division coefficient corresponding to the current code element selection to obtain a frequency modulated carrier signal;

[0010] The driving circuit is used to process the frequency-modulated carrier signal to obtain a frequency-modulated driving current.

[0011] Preferably, the modulation module comprises a frequency divider, a first shifter, a two-choice electronic switch and a first counter, wherein:

[0012] The frequency divider is used to divide the frequency of the crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient;

[0013] The first shifter is used for controlling the two-to-one electronic switch to select the first frequency division coefficient or the second frequency division coefficient according to the current code element of the baseband signal;

[0014] The first counter is used to count the carrier period corresponding to the current code element;

[0015] The first shifter is also used to perform a shift operation when the number of carrier cycles corresponding to the current code element reaches the target value N, and use the next code element as the current code element to control the corresponding frequency division coefficient of the two-to-one electronic switch to obtain a frequency modulated carrier signal.

[0016] Preferably, the address detection unit includes a demodulation module, and the address detection unit is used to process the frequency modulation induced voltage generated by the R line to obtain effective information and send the effective information to the zoning control system of the train through the train-ground communication, including:

[0017] The demodulation module is used to generate a square wave according to the frequency-modulated induced voltage generated by the R line, determine the carrier frequency of the square wave by a pulse width counting method and generate corresponding binary code elements according to the determination result, perform shift processing on the generated binary code elements to generate a combination code, perform serial-to-parallel conversion on the generated combination code and perform verification, and obtain valid information if the verification is successful and send the valid information to the zoning control system of the train through train-to-ground communication, wherein the combination code includes valid information and a verification code.

[0018] Preferably, the demodulation module includes a comparator, a second counter, a judgment unit, a second shifter, a serial-to-parallel conversion unit and a verification unit, wherein:

[0019] The comparator is used to generate a square wave according to the frequency-modulated induced voltage generated by the R line;

[0020] The second counter is used to count the pulse width of the square wave to obtain a pulse width count value;

[0021] The judging unit is used to compare the pulse width count value with a threshold value, and if the pulse width count value is greater than or equal to the threshold value, it is judged that the carrier frequency corresponds to the frequency corresponding to the first frequency division coefficient and a corresponding binary symbol is generated according to the frequency corresponding to the first frequency division coefficient; otherwise, it is judged that the carrier frequency corresponds to the frequency corresponding to the second frequency division coefficient and a corresponding binary symbol is generated according to the frequency corresponding to the second frequency division coefficient;

[0022] The second shifter is used to perform shift processing on the generated binary code element to generate a combined code;

[0023] The serial-to-parallel conversion unit is used to perform serial-to-parallel conversion on the generated combined code;

[0024] The verification unit is used to verify the combined code after the serial-to-parallel conversion, and if the verification is successful, obtain valid information and send the valid information to the train's zoning control system through train-to-ground communication.

[0025] Preferably, the antenna unit comprises a series resonant circuit.

[0026] The present invention also provides a method for positioning, speed measurement and vehicle-to-ground communication using a cross-induction loop, wherein the method comprises:

[0027] The carrier signal generator divides a crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generates a frequency modulation driving current according to the first frequency division coefficient and the second frequency division coefficient;

[0028] The antenna unit generates a frequency modulated electromagnetic field according to the frequency modulated driving current;

[0029] The R line, the SG0 line and the G0-Gn lines generate a frequency-modulated induced voltage according to the frequency-modulated electromagnetic field;

[0030] The address detection unit processes the frequency-modulated induced voltage generated by the G0 line and the SG0 line to obtain the relative position information of the train, processes the frequency-modulated induced voltage generated by the R line and the G0-Gn lines to obtain the absolute position information of the train, and processes the frequency-modulated induced voltage generated by the R line to obtain valid information and sends the valid information to the sectional operation control system of the train through train-to-ground communication.

[0031] Preferably, the carrier signal generator divides a crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generates a frequency modulation driving current according to the first frequency division coefficient and the second frequency division coefficient, including:

[0032] The crystal oscillator is divided to obtain a first frequency division coefficient and a second frequency division coefficient, the first frequency division coefficient or the second frequency division coefficient is selected according to the current code element of the baseband signal, and a shift operation is performed when the number of carrier cycles corresponding to the current code element reaches a target value N, and the next code element is used as the frequency division coefficient corresponding to the current code element selection to obtain a frequency modulation carrier signal;

[0033] The frequency-modulated carrier signal is processed to obtain a frequency-modulated driving current.

[0034] Preferably, the address detection unit processes the frequency modulation induced voltage generated by the R line to obtain effective information and sends the effective information to the zoning control system of the train through the train-to-ground communication, including:

[0035] A square wave is generated according to the frequency-modulated induced voltage generated by the R line, the carrier frequency of the square wave is judged by the pulse width counting method and the corresponding binary code elements are generated according to the judgment result, the generated binary code elements are shifted to generate a combination code, the generated combination code is serial-to-parallel converted and verified, and when the verification is successful, valid information is obtained and sent to the sectional operation control system of the train through train-to-ground communication, wherein the combination code includes valid information and a check code.

[0036] Preferably, judging the carrier frequency of the square wave by a pulse width counting method and generating corresponding binary symbols according to the judgment result comprises:

[0037] Counting the pulse width of the square wave to obtain a pulse width count value;

[0038] The pulse width count value is compared with a threshold value. If the pulse width count value is greater than or equal to the threshold value, it is determined that the carrier frequency corresponds to the frequency corresponding to the first frequency division coefficient and a corresponding binary code element is generated according to the frequency corresponding to the first frequency division coefficient. Otherwise, it is determined that the carrier frequency corresponds to the frequency corresponding to the second frequency division coefficient and a corresponding binary code element is generated according to the frequency corresponding to the second frequency division coefficient.

[0039] Through the technical solution, a set of cross-induction loop equipment can be used to simultaneously realize the functions of positioning, speed measurement and vehicle-to-ground communication, effectively solving the problem of mutual electromagnetic field interference between two sets of equipment in the same space in the prior art, and realizing the functions of full-range absolute position measurement, high-precision relative position measurement, speed and running direction measurement, and vehicle-to-ground communication, effectively saving hardware costs and reducing the complexity of signal processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 A block diagram of a positioning, speed measurement and vehicle-to-ground communication system using a cross induction loop according to an embodiment of the present invention is shown;

[0042] Figure 2 A principle block diagram of a modulation module according to an embodiment of the present invention is shown;

[0043] Figure 3 A principle block diagram of a demodulation module according to an embodiment of the present invention is shown;

[0044] Figure 4 A schematic diagram of an RLC series resonant circuit according to an embodiment of the present invention is shown;

[0045] Figure 5 A schematic diagram of the Gray bus encoding principle according to an embodiment of the present invention is shown;

[0046] Figure 6 A schematic diagram of the relative positioning principle according to an embodiment of the present invention is shown;

[0047] Figure 7 A schematic diagram showing the modulation of the amplitude of a ground loop receiving signal according to an embodiment of the present invention;

[0048] Figure 8 A schematic diagram of relative positioning and speed detection according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0049] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in 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.

[0050] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0051] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0052] Figure 1 A block diagram of a positioning, speed measurement and vehicle-to-ground communication system using a cross-induction loop according to an embodiment of the present invention is shown.

[0053] Among others, the system can be applied to high-speed flying trains.

[0054] like Figure 1 As shown, an embodiment of the present invention provides a positioning speed measurement and vehicle-to-ground communication system using a cross induction loop, wherein the system includes:

[0055] The vehicle-mounted subsystem includes a carrier signal generator and an antenna unit, wherein the carrier signal generator is used to divide a crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generate a frequency modulation drive current (high-frequency drive current) according to the first frequency division coefficient and the second frequency division coefficient, and the antenna unit is used to generate a frequency modulation electromagnetic field (high-frequency alternating magnetic field signal) according to the frequency modulation drive current;

[0056] Ground Loop Subsystem( Figure 1 The ground loop line is referred to as the ground loop line in the figure, comprising an R line, an SG0 line and G0 to Gn lines, wherein the R line, the SG0 line and the G0 to Gn lines generate a frequency-modulated induced voltage according to the frequency-modulated electromagnetic field;

[0057] The ground station subsystem includes an address detection unit, which is used to process the frequency modulation induced voltage generated by the G0 line and the SG0 line to obtain the relative position information of the train, to process the frequency modulation induced voltage generated by the R line and the G0-Gn lines to obtain the absolute position information of the train, and to process the frequency modulation induced voltage generated by the R line to obtain effective information and send the effective information to the zoning operation control system of the train through the train-ground communication. Figure 1 (referred to as zone operation and control in Chinese).

[0058] That is, the G0 line and the SG0 line are used for relative positioning, the R line and the G0~Gn lines are used for absolute positioning, and the R line is also used for vehicle-ground communication.

[0059] Taking the high-speed flying train as an example, the G0-Gn line can be the G0-G11 line. The valid information can include the train ID number, train position, train speed and train running direction. In addition to being sent to the partition operation control system, the valid information can also be sent to the traction control system of the train.

[0060] Through the technical solution, a set of cross-induction loop equipment can be used to simultaneously realize the functions of positioning, speed measurement and vehicle-to-ground communication, effectively solving the problem of mutual electromagnetic field interference between two sets of equipment in the same space in the prior art, and realizing the functions of full-range absolute position measurement, high-precision relative position measurement, speed and running direction measurement, and vehicle-to-ground communication, effectively saving hardware costs and reducing the complexity of signal processing.

[0061] According to an embodiment of the present invention, the carrier signal generator includes a modulation module and a drive circuit, and the carrier signal generator is used to divide the crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generate a frequency modulation drive current according to the first frequency division coefficient and the second frequency division coefficient, including:

[0062] The modulation module is used to divide the frequency of the crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient, select the first frequency division coefficient or the second frequency division coefficient according to the current code element of the baseband signal, and perform a shift operation when the number of carrier cycles corresponding to the current code element reaches the target value N, and use the next code element as the frequency division coefficient corresponding to the current code element selection to obtain a frequency modulated carrier signal;

[0063] The driving circuit is used to process the frequency-modulated carrier signal to obtain a frequency-modulated driving current.

[0064] According to an embodiment of the present invention, Figure 2 As shown, the modulation module includes a frequency divider, a first shifter, a two-to-one electronic switch and a first counter, wherein:

[0065] The frequency divider is used to divide the frequency of the crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient;

[0066] The first shifter is used for controlling the two-to-one electronic switch to select the first frequency division coefficient or the second frequency division coefficient according to the current code element of the baseband signal;

[0067] The first counter is used to count the carrier period corresponding to the current code element;

[0068] The first shifter is also used to perform a shift operation when the number of carrier cycles corresponding to the current code element reaches the target value N, and use the next code element as the current code element to control the corresponding frequency division coefficient of the two-to-one electronic switch to obtain a frequency modulated carrier signal.

[0069] Below Figure 2 The following sections describe the various parts of the

[0070] CLK: represents the clock signal, providing standard clock information for the microcontroller;

[0071] RESET: reset signal, providing reset information for the microcontroller;

[0072] Baseband signal: The encoded information stream of "0" and "1" generated by the microcontroller according to the valid information + check code to be transmitted as needed is sent to the first shifter as a control signal;

[0073] The first shifter: performs a shift operation on the coded information stream in the baseband signal, and controls a two-choice electronic switch according to the value of the current bit symbol;

[0074] The frequency divider includes a first frequency division switch and a second frequency division switch, wherein the first frequency division switch divides the crystal oscillator to obtain a first frequency division coefficient to generate a frequency f1;

[0075] Second frequency division switch: divides the crystal oscillator to obtain a second frequency division coefficient, generating a frequency f2;

[0076] Two-choice electronic switch: the current code element of the baseband signal is used as the control signal. If the current code element is "0", the first frequency division coefficient is selected. If the current code element is "1", the second frequency division coefficient is selected.

[0077] The first counter is used to count the carrier cycle corresponding to a certain code element in the baseband signal. In order to reduce the bit error rate, it is preferred to select N (N≥10) carrier cycles to represent a code element in the baseband signal, and send the counting result to the shifter for controlling the shift operation.

[0078] In the present invention, only one crystal oscillator is needed, different code elements correspond to different frequency division coefficients, and a counter is used to accurately count the carrier cycle, so as to ensure that the frequency switching point is located at the zero crossing position, and there is no transition frequency, that is, the continuity of the phase is ensured. In this way, for the antenna unit (the series RLC circuit described below), the degree of detuning is very low, and the time to re-establish resonance can be ignored. If two independent crystal oscillators are used to generate two carrier frequency signals respectively, phase discontinuity will occur at the frequency switching point, resulting in an intermediate frequency far away from the resonance point. The system needs time to re-establish resonance, and this time is at the ms level, which will have a serious impact on the accuracy of positioning and speed measurement. That is, the present invention only uses one crystal oscillator, avoids the problems caused by two independent crystal oscillators, and improves the accuracy of positioning and speed measurement.

[0079] According to an embodiment of the present invention, the address detection unit includes a demodulation module, and the address detection unit is used to process the frequency modulation induced voltage generated by the R line to obtain effective information and send the effective information to the zoning control system of the train through the train-ground communication, including:

[0080] The demodulation module is used to generate a square wave according to the frequency-modulated induced voltage generated by the R line, determine the carrier frequency of the square wave by a pulse width counting method and generate corresponding binary code elements according to the determination result, perform shift processing on the generated binary code elements to generate a combination code, perform serial-to-parallel conversion on the generated combination code and perform verification, and obtain valid information if the verification is successful and send the valid information to the zoning control system of the train through train-to-ground communication, wherein the combination code includes valid information and a verification code.

[0081] According to an embodiment of the present invention, Figure 3 As shown, the demodulation module includes a comparator, a second counter, a judgment unit, a second shifter, a serial-to-parallel conversion unit and a verification unit, wherein:

[0082] The comparator is used to generate a square wave according to the frequency-modulated induced voltage generated by the R line;

[0083] The second counter is used to count the pulse width of the square wave to obtain a pulse width count value;

[0084] The judging unit is used to compare the pulse width count value with a threshold value (pulse width threshold value), and if the pulse width count value is greater than or equal to the threshold value, it is judged that the carrier frequency corresponds to the frequency corresponding to the first frequency division coefficient and a corresponding binary symbol is generated according to the frequency corresponding to the first frequency division coefficient; otherwise, it is judged that the carrier frequency corresponds to the frequency corresponding to the second frequency division coefficient and a corresponding binary symbol is generated according to the frequency corresponding to the second frequency division coefficient;

[0085] The second shifter is used to perform shift processing on the generated binary code element to generate a combined code;

[0086] The serial-parallel conversion unit is used to perform serial-parallel conversion on the generated combined code;

[0087] The verification unit is used to verify the combined code after serial-parallel conversion, and obtain valid information in the case of successful verification and send the valid information to the sub-area operation control system of the train through vehicle-ground communication.

[0088] That is, as Figure 3 shown, the induced voltage signal in the R line is sent into the comparator of the address detection unit, compared with the threshold voltage Ref, a square wave signal is generated, the pulse width of this square wave signal is counted by the second counter, and compared with the threshold value VAL through the judgment unit. If it is greater than or equal to the threshold value VAL, it is judged as frequency f1 (f1 < f2), if it is less than VAL, it is judged as frequency f2. After continuously judging N cycles, a one-bit symbol is obtained and sent into the second shifter, and finally the combined code of the valid information + check code is decoded, and then the valid information is obtained through verification.

[0089] The following will explain Figure 3 each part in

[0090] Carrier signal: The induced voltage signal generated in the ground loop R line;

[0091] Ref: Threshold voltage;

[0092] Comparator: Compares the carrier signal voltage with the reference voltage, and is used to convert the sine signal into a square wave signal;

[0093] Second counter: Fills the high-level part of the square wave signal with a high-frequency reference clock signal, records the number of filled high-frequency pulses, that is, the duration of the high-level part within one cycle can be calculated. For different frequencies f1 and f2, there are differences in the duration of their high-level parts.

[0094] VAL: Pulse width threshold, if it is greater than or equal to VAL, it is judged as f1, if it is less than VAL, it is judged as f2;

[0095] Second shifter: Shifts the judged several current-bit symbols to obtain a binary code stream;

[0096] Serial-parallel conversion unit: Reads to the single-chip microcomputer through the parallel port to improve the reading and writing efficiency;

[0097] Verification unit: Verifies the valid information + check code sequence, judges whether there is information loss during the communication process, and if there is no loss, it is judged as verification passed;

[0098] Valid information: The information that needs to be transmitted through vehicle-ground communication.

[0099] According to an embodiment of the present invention, the antenna unit may include a series resonant circuit.

[0100] like Figure 4 As shown, the series resonant circuit is, for example, an RLC series resonant circuit. Thus, the antenna unit can utilize the RLC series resonance principle to generate a high-frequency alternating magnetic field in the space around the coil of the antenna unit, and by reasonably selecting the values ​​of the inductor L and the capacitor C, ensure that the frequency of the excitation current is equal to the frequency of the circuit resonance point, so that the current in the antenna unit coil can reach the maximum when the input voltage amplitude is constant.

[0101] The present invention does not limit the values ​​of the inductance L and the capacitance C.

[0102] The absolute positioning in the present invention is described below by taking a high-speed flying train as an example.

[0103] The G0 to G11 lines in the ground loop are laid in the track according to the Gray code encoding principle, which is called Gray busbar. Take 3 pairs of Gray codes as an example. Figure 5 As shown in . Among them, the minimum cross spacing is as follows Figure 5 As shown, it is equal to the size of the antenna unit along the heading. The phase of all Gray busbars at the starting point is the same as that of the R line, and the phase is reversed at each intersection (the Gray busbars are inverted at adjacent intersections). Therefore, when the antenna unit moves from left to right, the absolute position changes according to the Gray code, which is: 000->001->011->010->110->111->101->100. The address detection unit parses each Gray busbar to obtain the corresponding Gray code, thereby determining in which "minimum intersection spacing" the antenna unit is located, thereby achieving absolute positioning.

[0104] The absolute positioning in the present invention is described below by taking a high-speed flying train as an example.

[0105] When the area directly facing the coil of the antenna unit and the single cross unit (minimum cross unit) of the ground loop is the largest ( Figure 6 When the center of the antenna unit is located directly above the intersection ( Figure 6 When the antenna unit is moving along with the train, the amplitude of the induced voltage signal in the ground loop also undergoes periodic changes, that is, the amplitude of the high-frequency carrier signal is modulated, and its envelope (modulated envelope) changes approximately according to the sine law, representing the relative position information of the train.

[0106] Among them, the induced voltage signal in the G0 line / SG0 line is as follows: Figure 7 shown.

[0107] Specifically, in the present invention, the envelope signal extraction can be completed by using a synchronous demodulation method based on a multiplier, wherein, Figure 8 As shown, the solid line (sinusoidal solid line) represents the envelope of the demodulated induced voltage signal of the G0 line, and the dotted line (sinusoidal dotted line) represents the envelope of the demodulated induced voltage signal of the SG0 line. Since the crossing length of the two loop lines (G0 / SG0) is the minimum crossing unit, the signal cycle length is also the minimum crossing unit, and they are laid with a difference of half a minimum crossing unit, so they are 90 degrees apart. The phase relationship of the induced voltages of the G0 and SG0 lines can be used to determine the running direction of the test vehicle (for example, if the solid line is 90 degrees ahead of the dotted line in phase, it is determined that the train is running in the forward direction; if the solid line is 90 degrees behind the dotted line in phase, it is determined that the train is running in the reverse direction). Furthermore, the amplitude of the G0 / SG0 envelope signal can be used to determine the relative position within a crossing interval. The relative position of the train can be obtained by using the table lookup method based on the amplitude after signal sampling (the amplitude of either the solid line or the dotted line). In order not to confuse the present invention, it will not be repeated here. The speed can be obtained by dividing the difference of relative positions within a predetermined time (for example, 50 ms) by the time, wherein the shorter the predetermined time is, the better and closer to the real speed.

[0108] For vehicle-to-ground communication, as mentioned above, 2FSK (binary frequency shift keying) can be used to use the change in carrier frequency to represent digital information. By changing the frequency division coefficient of the crystal oscillator in the carrier signal generator, a square wave signal with a frequency that changes with time is generated, and converted into a magnetic field in the antenna unit through an RLC series resonant circuit. The carrier frequency of the induced voltage in the ground loop also changes according to this coding rule, and then the address detection unit uses the demodulation module to complete information decoding.

[0109] The embodiment of the present invention further provides a method for positioning, speed measurement and vehicle-to-ground communication using a cross-induction loop, wherein the method comprises:

[0110] S100, the carrier signal generator divides a crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generates a frequency modulation driving current according to the first frequency division coefficient and the second frequency division coefficient;

[0111] S102, the antenna unit generates a frequency-modulated electromagnetic field according to the frequency-modulated driving current;

[0112] S104, the R line, the SG0 line and the G0-Gn lines generate a frequency-modulated induced voltage according to the frequency-modulated electromagnetic field;

[0113] S106, the address detection unit processes the frequency-modulated induced voltage generated by the G0 line and the SG0 line to obtain the relative position information of the train, processes the frequency-modulated induced voltage generated by the R line and the G0-Gn lines to obtain the absolute position information of the train, and processes the frequency-modulated induced voltage generated by the R line to obtain valid information and sends the valid information to the sectional operation control system of the train through train-to-ground communication.

[0114] Through the technical solution, a set of cross-induction loop equipment can be used to simultaneously realize the functions of positioning, speed measurement and vehicle-to-ground communication, effectively solving the problem of mutual electromagnetic field interference between two sets of equipment in the same space in the prior art, and realizing the functions of full-range absolute position measurement, high-precision relative position measurement, speed and running direction measurement, and vehicle-to-ground communication, effectively saving hardware costs and reducing the complexity of signal processing.

[0115] According to an embodiment of the present invention, the carrier signal generator divides a crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generates a frequency modulation driving current according to the first frequency division coefficient and the second frequency division coefficient, including:

[0116] The crystal oscillator is divided to obtain a first frequency division coefficient and a second frequency division coefficient, the first frequency division coefficient or the second frequency division coefficient is selected according to the current code element of the baseband signal, and a shift operation is performed when the number of carrier cycles corresponding to the current code element reaches a target value N, and the next code element is used as the frequency division coefficient corresponding to the current code element selection to obtain a frequency modulation carrier signal;

[0117] The frequency-modulated carrier signal is processed to obtain a frequency-modulated driving current.

[0118] According to an embodiment of the present invention, the address detection unit processes the frequency modulation induced voltage generated by the R line to obtain effective information and sends the effective information to the zoning control system of the train through the train-ground communication, including:

[0119] A square wave is generated according to the frequency-modulated induced voltage generated by the R line, the carrier frequency of the square wave is judged by the pulse width counting method and the corresponding binary code elements are generated according to the judgment result, the generated binary code elements are shifted to generate a combination code, the generated combination code is serial-to-parallel converted and verified, and when the verification is successful, valid information is obtained and sent to the sectional operation control system of the train through train-to-ground communication, wherein the combination code includes valid information and a check code.

[0120] According to an embodiment of the present invention, determining the carrier frequency of the square wave by a pulse width counting method and generating corresponding binary symbols according to the determination result includes:

[0121] Counting the pulse width of the square wave to obtain a pulse width count value;

[0122] The pulse width count value is compared with a threshold value. If the pulse width count value is greater than or equal to the threshold value, it is determined that the carrier frequency corresponds to the frequency corresponding to the first frequency division coefficient and a corresponding binary code element is generated according to the frequency corresponding to the first frequency division coefficient. Otherwise, it is determined that the carrier frequency corresponds to the frequency corresponding to the second frequency division coefficient and a corresponding binary code element is generated according to the frequency corresponding to the second frequency division coefficient.

[0123] The above method and Figure 1 The system described above corresponds to the system described above. For specific examples, please refer to the above Figure 1 The description of the system will not be repeated here.

[0124] Continue to refer to Figure 1 , the system and method of the present invention are described by taking the transmission of a train ID number (VID) as an example.

[0125] The zoned operation control system obtains information such as the train ID number through the positioning speed measurement system (induction loop) to complete registration before entering the section. If the registration is unsuccessful, the section is considered unavailable and the train cannot enter the section. For registered trains, control is performed according to the train ID number (VID), independent connections are established for different identifications, and corresponding information exchange is performed.

[0126] The specific process is as follows: the on-board operation control system transmits the train ID number to the induction loop carrier signal generator. The carrier signal generator generates a check code according to the VID, and uses the VID+check code as the baseband signal (control signal) and sends it to the first shifter. The first shifter obtains the current code element by shifting, controls the two-choice electronic switch to select, selects a frequency division coefficient, and obtains a carrier signal of N cycles. After the counter completes the counting of N cycles, it controls the shifter to shift, and takes the next bit as the current bit. Repeat the above process, and finally obtains a string of FM carrier signals used to represent VID. This FM carrier signal obtains FM drive current after passing through the drive circuit, which is used as the excitation power supply of the series resonant circuit to generate a FM electromagnetic field in the coil of the antenna unit. Based on the principle of electromagnetic induction, the R line of the ground loop generates a FM induced voltage, which is sent to the demodulation module of the address detection unit. After being converted into a square wave, the carrier frequency is judged by the pulse width counting method to obtain the binary code element corresponding to this frequency. The second shifter generates a code stream composed of VID+check code after shifting. After serial-to-parallel conversion, verification is completed in the microcontroller and finally the VID is sent to the partition operation and control system.

[0127] It can be seen from the above embodiments that compared with the traditional induction loop line that uses two sets of equipment and two non-interfering frequencies to achieve positioning, speed measurement and vehicle-to-ground communication, the above system and method of the present invention can use only one set of induction loop line system to meet the needs of positioning, speed measurement and vehicle-to-ground communication at the same time, and the positioning accuracy can reach ±2.5mm. The baud rate of vehicle-to-ground communication is related to the carrier frequency and the number of cycles of 1-bit code element repetition. The calculation formula is: baud=f / N, where f is the carrier frequency, and N is the number of carrier cycles corresponding to one code element. When f is 48kHz and N is 10, the baud rate is 4.8kHz. Using a counter to count the frequency conversion carrier cycle can ensure that the phase of the carrier signal is continuous, there will be no intermediate transition frequency, and there is basically no process of re-establishing resonance, which can ensure the accuracy of positioning and speed measurement. At the same time, using N consecutive (N≥10) carrier cycles to judge a code element can improve the reliability of the judgment result and reduce the bit error rate.

[0128] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0129] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0130] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0131] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A positioning speed measurement and vehicle-to-ground communication system using a cross-induction loop, characterized in that: The system includes: The vehicle-mounted subsystem includes a carrier signal generator and an antenna unit, wherein the carrier signal generator is used to divide a crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generate a frequency modulation driving current according to the first frequency division coefficient and the second frequency division coefficient, and the antenna unit is used to generate a frequency modulation electromagnetic field according to the frequency modulation driving current; A ground loop subsystem, comprising an R line, an SG0 line and G0-Gn lines, wherein the R line, the SG0 line and the G0-Gn lines generate a frequency-modulated induced voltage according to the frequency-modulated electromagnetic field; The ground station subsystem includes an address detection unit, which is used to process the frequency-modulated induced voltage generated by the G0 line and the SG0 line to obtain the relative position information of the train, to process the frequency-modulated induced voltage generated by the R line and the G0-Gn lines to obtain the absolute position information of the train, and to process the frequency-modulated induced voltage generated by the R line to obtain valid information and send the valid information to the zoning operation control system of the train through train-to-ground communication.

2. The system according to claim 1, characterized in that The carrier signal generator includes a modulation module and a driving circuit, and the carrier signal generator is used to divide the crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generate a frequency modulation driving current according to the first frequency division coefficient and the second frequency division coefficient, including: The modulation module is used to divide the frequency of the crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient, select the first frequency division coefficient or the second frequency division coefficient according to the current code element of the baseband signal, and perform a shift operation when the number of carrier cycles corresponding to the current code element reaches the target value N, and use the next code element as the frequency division coefficient corresponding to the current code element selection to obtain a frequency modulated carrier signal; The driving circuit is used to process the frequency-modulated carrier signal to obtain a frequency-modulated driving current.

3. The system according to claim 2, characterized in that The modulation module includes a frequency divider, a first shifter, a two-to-one electronic switch and a first counter, wherein: The frequency divider is used to divide the frequency of the crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient; The first shifter is used for controlling the two-to-one electronic switch to select the first frequency division coefficient or the second frequency division coefficient according to the current code element of the baseband signal; The first counter is used to count the carrier period corresponding to the current code element; The first shifter is also used to perform a shift operation when the number of carrier cycles corresponding to the current code element reaches the target value N, and use the next code element as the current code element to control the corresponding frequency division coefficient of the two-to-one electronic switch to obtain a frequency modulated carrier signal.

4. The system according to claim 3, characterized in that The address detection unit includes a demodulation module, and the address detection unit is used to process the frequency modulation induced voltage generated by the R line to obtain effective information and send the effective information to the zoning control system of the train through the train-ground communication, including: The demodulation module is used to generate a square wave according to the frequency-modulated induced voltage generated by the R line, determine the carrier frequency of the square wave by a pulse width counting method and generate corresponding binary code elements according to the determination result, perform shift processing on the generated binary code elements to generate a combination code, perform serial-to-parallel conversion on the generated combination code and perform verification, and obtain valid information if the verification is successful and send the valid information to the zoning control system of the train through train-to-ground communication, wherein the combination code includes valid information and a verification code.

5. The system according to claim 4, characterized in that The demodulation module includes a comparator, a second counter, a judgment unit, a second shifter, a serial-to-parallel conversion unit and a verification unit, wherein: The comparator is used to generate a square wave according to the frequency-modulated induced voltage generated by the R line; The second counter is used to count the pulse width of the square wave to obtain a pulse width count value; The judging unit is used to compare the pulse width count value with a threshold value, and if the pulse width count value is greater than or equal to the threshold value, it is judged that the carrier frequency corresponds to the frequency corresponding to the first frequency division coefficient and a corresponding binary symbol is generated according to the frequency corresponding to the first frequency division coefficient; otherwise, it is judged that the carrier frequency corresponds to the frequency corresponding to the second frequency division coefficient and a corresponding binary symbol is generated according to the frequency corresponding to the second frequency division coefficient; The second shifter is used to perform shift processing on the generated binary code element to generate a combined code; The serial-to-parallel conversion unit is used to perform serial-to-parallel conversion on the generated combined code; The verification unit is used to verify the combined code after the serial-to-parallel conversion, and if the verification is successful, obtain valid information and send the valid information to the train's zoning control system through train-to-ground communication.

6. The system according to any one of claims 1 to 5, characterized in that: The antenna unit comprises a series resonant circuit.

7. A method for positioning, speed measurement and vehicle-to-ground communication using a cross-induction loop, characterized in that: The method includes: The carrier signal generator divides a crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generates a frequency modulation driving current according to the first frequency division coefficient and the second frequency division coefficient; The antenna unit generates a frequency modulated electromagnetic field according to the frequency modulated driving current; The R line, the SG0 line and the G0-Gn lines generate a frequency-modulated induced voltage according to the frequency-modulated electromagnetic field; The address detection unit processes the frequency-modulated induced voltage generated by the G0 line and the SG0 line to obtain the relative position information of the train, processes the frequency-modulated induced voltage generated by the R line and the G0-Gn lines to obtain the absolute position information of the train, and processes the frequency-modulated induced voltage generated by the R line to obtain valid information and sends the valid information to the sectional operation control system of the train through train-to-ground communication.

8. The method according to claim 7, characterized in that The carrier signal generator divides a crystal oscillator to obtain a first frequency division coefficient and a second frequency division coefficient and generates a frequency modulation driving current according to the first frequency division coefficient and the second frequency division coefficient, including: The crystal oscillator is divided to obtain a first frequency division coefficient and a second frequency division coefficient, the first frequency division coefficient or the second frequency division coefficient is selected according to the current code element of the baseband signal, and a shift operation is performed when the number of carrier cycles corresponding to the current code element reaches a target value N, and the next code element is used as the frequency division coefficient corresponding to the current code element selection to obtain a frequency modulation carrier signal; The frequency-modulated carrier signal is processed to obtain a frequency-modulated driving current.

9. The method according to claim 8, characterized in that The address detection unit processes the frequency modulation induced voltage generated by the R line to obtain effective information and sends the effective information to the zoning control system of the train through the train-ground communication, including: A square wave is generated according to the frequency-modulated induced voltage generated by the R line, the carrier frequency of the square wave is judged by the pulse width counting method and the corresponding binary code elements are generated according to the judgment result, the generated binary code elements are shifted to generate a combination code, the generated combination code is serial-to-parallel converted and verified, and when the verification is successful, valid information is obtained and sent to the sectional operation control system of the train through train-to-ground communication, wherein the combination code includes valid information and a check code.

10. The method according to claim 9, characterized in that Determining the carrier frequency of the square wave by a pulse width counting method and generating corresponding binary symbols according to the determination result comprises: Counting the pulse width of the square wave to obtain a pulse width count value; The pulse width count value is compared with a threshold value. If the pulse width count value is greater than or equal to the threshold value, it is determined that the carrier frequency corresponds to the frequency corresponding to the first frequency division coefficient and a corresponding binary code element is generated according to the frequency corresponding to the first frequency division coefficient. Otherwise, it is determined that the carrier frequency corresponds to the frequency corresponding to the second frequency division coefficient and a corresponding binary code element is generated according to the frequency corresponding to the second frequency division coefficient.

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