A car position measurement method, device and system

Abstract

The application discloses a kind of car position measurement method, device and system. First radar signal is obtained by the first echo signal of the reflection of reference object, and the second echo signal of the reflection of reference object by second radar signal, calculate first intermediate frequency signal based on first radar signal and first echo signal, and calculate second intermediate frequency signal based on second radar signal and second echo signal, respectively on first intermediate frequency signal and second intermediate frequency signal are carried out fast fourier transform, obtain the frequency-signal intensity relationship corresponding to first intermediate frequency signal and the frequency-signal intensity relationship corresponding to second intermediate frequency signal, find the peak point representing reference object from it, calculate the distance of car and reference object based on the frequency of peak point. Relative to the prior art, the reference object of the present application does not need special material, and also does not need to learn the distance characteristics of several sub-reference objects, and the cost is lower.

Description

Technical Field

[0001] This invention relates to distance detection technology, and more particularly to a method, apparatus and system for measuring the position of a car. Background Technology

[0002] Radar ranging is a non-contact measurement method. Compared with other elevator car absolute position measurement solutions such as scales, radar solutions have the advantages of simple installation and maintenance and low cost, and have the potential to be applied to elevator car position measurement.

[0003] The basic principle of radar ranging is that a radar installed on the top of the elevator car transmits radar signals to a signal reflector installed on the top of the elevator shaft. The radar signal is reflected back to the radar, which receives and processes the echo signal to achieve distance measurement. Currently, millimeter-wave radar is used as a sensor for elevator car positioning. Theoretically, only one radar is needed, along with a reference object (such as a corner reflector) set up inside the shaft, to achieve positioning. However, due to the large number of other reflective objects (hereinafter referred to as interference objects) inside the elevator shaft, the radar needs to find the reference object from among the many reflective objects to perform distance measurement. This requires assigning some radio frequency (RF) characteristics to the reference object to distinguish it from other objects in the shaft. Currently, the following two methods are commonly used to assign RF characteristics to the reference object: 1. The reference object has special RF characteristics, such as being able to reverse the polarization direction of the radar signal, so that the electromagnetic waves reflected by the reference object can be received by a receiving antenna with the same polarization direction, while interference objects are blocked; 2. Several objects are combined to form a reference object, and the distance between the objects is used as a characteristic.

[0004] For the first approach, the materials used for the reference object that can reverse the polarization direction of the radar signal are currently not ideal. For example, passive Van atta reflector antennas have low conversion efficiency, while active Van atta reflector antennas are expensive and require sophisticated design of both the transmitting and receiving antennas. Installation also necessitates careful consideration of the antenna's polarization direction and the reference object's orientation. For the second approach, the range characteristics of several sub-reference objects must be input into the radar through input or on-site debugging and learning, requiring additional learning time. Summary of the Invention

[0005] This invention provides a method, device, and system for measuring the position of a car, which does not require a reference object made of special materials, nor does it require learning the distance characteristics of several sub-reference objects, resulting in lower costs.

[0006] In a first aspect, the present invention provides a method for measuring the position of a car, comprising:

[0007] Acquire a first echo signal of a first radar signal reflected by a reference object, and a second echo signal of a second radar signal reflected by the reference object. The distances from the first millimeter-wave radar antenna corresponding to the first radar signal and the second millimeter-wave radar antenna corresponding to the second radar signal to the reference object are equal. The first millimeter-wave radar antenna and the second millimeter-wave radar antenna are mounted on the car, and the reference object is mounted at the hoistway terminal where the car is running. Alternatively, the first millimeter-wave radar antenna and the second millimeter-wave radar antenna are mounted at the hoistway terminal, and the reference object is mounted on the car.

[0008] The first intermediate frequency signal is calculated based on the first radar signal and the first echo signal, and the second intermediate frequency signal is calculated based on the second radar signal and the second echo signal;

[0009] Perform Fast Fourier Transform on the first intermediate frequency signal and the second intermediate frequency signal respectively to obtain the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal;

[0010] Find the peak point characterizing the reference object from the frequency-signal intensity relationship corresponding to the first intermediate frequency signal and the frequency-signal intensity relationship corresponding to the second intermediate frequency signal;

[0011] The distance between the car and the reference object is calculated based on the frequency of the peak point.

[0012] Optionally, calculating a first intermediate frequency (IF) signal based on the first radar signal and the first echo signal, and calculating a second IF signal based on the second radar signal and the second echo signal, includes:

[0013] The first radar signal and the first echo signal are mixed to obtain a first mixed signal;

[0014] The first mixing signal is low-pass filtered and amplified to obtain the first intermediate frequency signal;

[0015] The second radar signal and the second echo signal are mixed to obtain a second mixed signal;

[0016] The second mixing signal is low-pass filtered and amplified to obtain the second intermediate frequency signal.

[0017] Optionally, the peak point characterizing the reference object is found from the frequency-signal intensity relationship corresponding to the first intermediate frequency signal and the frequency-signal intensity relationship corresponding to the second intermediate frequency signal, including:

[0018] Find the first target peak point with the same frequency value from the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal;

[0019] The phase of the first target peak point is determined based on the real and imaginary parts of the first target peak point in the fast Fourier transform result;

[0020] Find the second target peak point with the same phase from multiple first target peak points;

[0021] The peak points representing the top of the wellbore are excluded from the second target peak points to obtain the peak points representing the reference object.

[0022] Optionally, before searching for a first target peak point with the same frequency value from the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal, the method further includes:

[0023] The peak points with signal strength greater than the threshold are searched from the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal.

[0024] Optionally, excluding the peak points representing the top of the wellbore from the second target peak points to obtain the peak points representing the reference object includes:

[0025] The peak point with higher frequency from the two second target peak points is determined as the peak point characterizing the top of the wellbore;

[0026] By excluding the peak points representing the top of the wellbore, the peak points representing the reference object are obtained.

[0027] Optionally, calculating the distance between the car and the reference object based on the frequency of the peak point includes:

[0028] The first value is obtained by multiplying the propagation speed of the radar signal by the frequency of the peak point;

[0029] The second value is obtained by calculating the quotient of the slope of the linear change in the frequency of the first radar signal and the first value.

[0030] Calculate half of the second value as the distance between the car and the reference object.

[0031] Optionally, the first radar signal and the second radar signal operate in different frequency bands.

[0032] Optionally, the first radar signal and the second radar signal operate at different time periods.

[0033] Secondly, the present invention also provides a car distance measuring device, comprising:

[0034] The signal acquisition module is used to acquire a first echo signal of a first radar signal reflected by a reference object, and a second echo signal of a second radar signal reflected by the reference object. The distances from the first millimeter-wave radar antenna corresponding to the first radar signal and the second millimeter-wave radar antenna corresponding to the second radar signal to the reference object are equal. The first millimeter-wave radar antenna and the second millimeter-wave radar antenna are disposed on the car, and the reference object is disposed at the hoistway terminal where the car is running. Alternatively, the first millimeter-wave radar antenna and the second millimeter-wave radar antenna are disposed at the hoistway terminal, and the reference object is disposed on the car.

[0035] An intermediate frequency signal calculation module is used to calculate a first intermediate frequency signal based on the first radar signal and the first echo signal, and to calculate a second intermediate frequency signal based on the second radar signal and the second echo signal;

[0036] The Fourier transform module is used to perform fast Fourier transform on the first intermediate frequency signal and the second intermediate frequency signal respectively to obtain the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal.

[0037] The peak point lookup module is used to find the peak point characterizing the reference object from the frequency-signal intensity relationship corresponding to the first intermediate frequency signal and the frequency-signal intensity relationship corresponding to the second intermediate frequency signal;

[0038] The distance calculation module is used to calculate the distance between the car and the reference object based on the frequency of the peak point.

[0039] Thirdly, the present invention also provides a car distance measurement system, comprising:

[0040] The first millimeter-wave radar is used to transmit a first radar signal and receive a first echo signal reflected by a reference object from the first radar signal.

[0041] The second millimeter-wave radar is used to transmit a second radar signal and receive a second echo signal reflected by the reference object from the second radar signal.

[0042] A controller, which is connected to the first millimeter-wave radar and the second millimeter-wave radar respectively, is used to execute the car position measurement method provided in the first aspect of the present invention;

[0043] Wherein, the first millimeter-wave radar and the second millimeter-wave radar are at the same distance from the reference object, the first millimeter-wave radar and the second millimeter-wave radar are installed on the car, and the reference object is installed at the hoistway terminal where the car is running, or the first millimeter-wave radar and the second millimeter-wave radar are installed at the hoistway terminal, and the reference object is installed on the car.

[0044] The car position measurement method provided by this invention acquires a first echo signal of a first radar signal reflected by a reference object and a second echo signal of a second radar signal reflected by a reference object. The distances from the reference object to the first millimeter-wave radar antenna corresponding to the first radar signal and the second millimeter-wave radar antenna corresponding to the second radar signal are equal. The first and second millimeter-wave radar antennas are mounted on the car, and the reference object is mounted at the hoistway terminal where the car is running, or the first and second millimeter-wave radar antennas are mounted at the hoistway terminal, and the reference object is mounted on the car. A first intermediate frequency signal is calculated based on the first radar signal and the first echo signal, and a second intermediate frequency signal is calculated based on the second radar signal and the second echo signal. Fast Fourier transforms are performed on the first and second intermediate frequency signals respectively to obtain the frequency-signal strength relationship corresponding to the first and second intermediate frequency signals. The peak point representing the reference object is found from the frequency-signal strength relationship corresponding to the first and second intermediate frequency signals, and the distance between the car and the reference object is calculated based on the frequency of the peak point. Compared to existing solutions, this invention does not require a reference object made of special materials, nor does it require learning the distance characteristics of several sub-reference objects, resulting in lower costs.

[0045] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 A flowchart of a car position measurement method provided in an embodiment of the present invention;

[0048] Figure 2 This is a waveform diagram of a frequency-modulated continuous wave radar signal;

[0049] Figure 3The graph shows the frequency variation of the frequency-modulated continuous wave radar signal over time.

[0050] Figure 4 Waveform diagrams of millimeter-wave radar signals, echo signals, and mixed signals;

[0051] Figure 5 The graph shows the frequency variations of the millimeter-wave radar signal, echo signal, and mixing signal over time.

[0052] Figure 6 The frequency-signal strength curves for the first intermediate frequency signal and the second intermediate frequency signal are shown.

[0053] Figure 7 A schematic diagram for searching for peak points where the signal strength is greater than a threshold;

[0054] Figure 8 A schematic diagram showing peak points with the same frequency value;

[0055] Figure 9 A schematic diagram of the peak points of the second target with the same phase;

[0056] Figure 10 A schematic diagram representing the peak points of the reference material;

[0057] Figure 11 This is a schematic diagram of the structure of a car distance measuring device provided in an embodiment of the present invention;

[0058] Figure 12 This is a three-dimensional structural diagram of a car distance measurement system provided in an embodiment of the present invention;

[0059] Figure 13 for Figure 12 Side view along the y-direction;

[0060] Figure 14 for Figure 12 Side view along the x-direction;

[0061] Figure 15 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0062] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0063] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0064] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0065] Figure 1 This is a flowchart illustrating a car position measurement method provided in an embodiment of the present invention. This embodiment is applicable to situations where frequency-modulated radar wave signals are used to measure the car position. The method can be executed by the car position measurement device provided in this embodiment of the present invention. This device can be implemented in software and / or hardware, and is typically configured in an electronic device, such as... Figure 1 As shown, the method for measuring the car position includes the following steps:

[0066] S101. Acquire the first echo signal of the first radar signal reflected by the reference object, and the second echo signal of the second radar signal reflected by the reference object.

[0067] In this embodiment of the invention, the first radar signal is transmitted by a first millimeter-wave radar antenna, and the second radar signal is transmitted by a second millimeter-wave radar antenna. The distances from the first and second millimeter-wave radar antennas to the reference object are equal. The first and second millimeter-wave radar antennas are mounted on the car, and the reference object is mounted at the end of the hoistway where the car travels; alternatively, the first and second millimeter-wave radar antennas are mounted at the end of the hoistway, and the reference object is mounted on the car. For example, the first and second millimeter-wave radar antennas are mounted on the top of the car, and the reference object is mounted on the top of the hoistway; or, the first and second millimeter-wave radar antennas are mounted on the bottom of the car, and the reference object is mounted on the bottom of the hoistway; or, the first and second millimeter-wave radar antennas are mounted on the top of the hoistway, and the reference object is mounted on the top of the car; or, the first and second millimeter-wave radar antennas are mounted on the bottom of the hoistway, and the reference object is mounted on the bottom of the car. Of course, the millimeter-wave radar antennas or the reference object can also be mounted on the side wall of the car; this embodiment of the invention does not limit this.

[0068] For example, in this embodiment of the invention, taking a millimeter-wave radar installed on the top of the elevator car and a reference object installed on the top of the hoistway as an example, the two radar antennas should be on the same horizontal plane, and there should be no objects between the radar antennas and the reference object. The distances between the two radar antennas and the reference object should be equal. Both radar antennas are narrow-beam antennas, using lenses to achieve beam focusing. The main lobe half-power angle should be as small as possible to improve signal strength, but it should not be too small; it should be greater than the angular deviation during actual radar operation, such as assembly error, installation error, and car offset. The detection direction of the millimeter-wave radar should be vertical, i.e., consistent with the direction of elevator car operation. To avoid mutual interference between the radar signals, the operating frequencies of the two radar signals can be staggered. For example, one radar signal operates in the frequency range of 61GHz-62GHz, and the other radar signal operates in the frequency range of 63GHz-64GHz. Alternatively, the transmission times of the two radar signals can be staggered, such as with a period of 500μs, one radar signal operating from 0 to 200μs, and the other radar signal operating from 250 to 450μs. The reference object is a reflective object that can reflect the radar signal back along its original path, such as a corner reflector.

[0069] For example, in this embodiment of the invention, the radar signal is a frequency-modulated continuous wave radar signal. Figure 2 This is a waveform diagram of a frequency-modulated continuous wave radar signal. Figure 3 The graph shows the frequency variation of a frequency-modulated continuous wave radar signal over time, as shown below. Figure 2 and Figure 3 As shown, the frequency of the frequency-modulated continuous wave radar signal increases linearly with time, with an increase rate (slope) of S and a frequency increase period (sweep period) of T. c .

[0070] S102. Calculate the first intermediate frequency signal based on the first radar signal and the first echo signal, and calculate the second intermediate frequency signal based on the second radar signal and the second echo signal.

[0071] In this embodiment of the invention, an intermediate frequency signal is calculated based on a first radar signal and a first echo signal, and is denoted as the first intermediate frequency signal; and an intermediate frequency signal is calculated based on a second radar signal and a second echo signal, and is denoted as the second intermediate frequency signal.

[0072] For example, in some embodiments of the present invention, a first radar signal and a first echo signal are mixed to obtain a first mixed signal; the first mixed signal is low-pass filtered and amplified to obtain a first intermediate frequency signal. A second radar signal and a second echo signal are mixed to obtain a second mixed signal; the second mixed signal is low-pass filtered and amplified to obtain a second intermediate frequency signal.

[0073] For example, suppose the transmitted millimeter-wave radar signal is:

[0074]

[0075] The received echo signal is:

[0076]

[0077] Design a mixer whose function is to subtract the frequencies and phases of the TX and RX signals respectively to obtain the frequency and phase of the intermediate frequency (IF) signal. The mixer design is as follows:

[0078]

[0079] Inputting x1 and x2 into the mixer yields the following mixed signal:

[0080]

[0081] Therefore, if the initial phase of the transmitted signal is... The initial phase of the feedback signal is The initial signal of the output signal of the signal mixer is

[0082] Figure 4 The waveforms of the millimeter-wave radar signal, echo signal, and mixed signal are shown. Figure 5 This is a graph showing the frequency variations of the millimeter-wave radar signal, echo signal, and mixer signal over time. Figure 4 The three curves, from top to bottom, represent the millimeter-wave radar signal TX, the echo signal RX, and the mixer signal IF, as shown below. Figure 4 and Figure 5As shown, there is a phase difference τ between the transmitted millimeter-wave radar signal TX and the received echo signal RX. The frequencies of the millimeter-wave radar signal and the echo signal change linearly, but the mixing signal IF has a constant frequency Sτ, which is the frequency difference between the millimeter-wave radar signal TX and the received echo signal RX, satisfying the following relationship:

[0083] Sτ=S2d / c

[0084] Where S is the slope of the frequency change of the millimeter-wave radar signal, d is the distance of the radar to the object being detected, and c is the transmission speed of the radar signal, i.e., the speed of light.

[0085] S103. Perform Fast Fourier Transform on the first intermediate frequency signal and the second intermediate frequency signal respectively to obtain the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal.

[0086] For example, in order to reduce the amount of data processed and improve processing efficiency, the first intermediate frequency signal and the second intermediate frequency signal are sampled respectively, and then the sampled first intermediate frequency signal and the second intermediate frequency signal are subjected to fast Fourier transform to obtain the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal.

[0087] Figure 6 The graphs show the frequency-signal strength curves for the first and second intermediate frequency (IF) signals. The upper graph represents the frequency-signal strength curve for the first IF signal, and the lower graph represents the frequency-signal strength curve for the second IF signal. Each peak point corresponds to the frequency of the IF signal generated by mixing the echo signal from a reflector with the transmitted millimeter-wave radar signal. In other words, the frequency corresponding to each peak point can characterize a reflector. Our goal is to find the frequency of the peak point corresponding to a reference object.

[0088] S104. Find the peak point characterizing the reference object from the frequency-signal intensity relationship corresponding to the first intermediate frequency signal and the frequency-signal intensity relationship corresponding to the second intermediate frequency signal.

[0089] Since the two signal sources are equidistant from the reference object, the frequency of the peak point corresponding to the reference object is the same as the frequency of the peak point in the frequency-signal intensity curve corresponding to the first intermediate frequency signal and the frequency-signal intensity curve corresponding to the second intermediate frequency signal. Therefore, the peak point characterizing the reference object can be found based on this from the frequency-signal intensity relationship corresponding to the first intermediate frequency signal and the frequency-signal intensity relationship corresponding to the second intermediate frequency signal.

[0090] For example, in this embodiment of the invention, in order to remove background noise in the signal, reduce data processing volume, and improve processing efficiency, peak points with signal strength greater than a threshold are searched from the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal. Figure 7 A schematic diagram for searching for peak points where the signal strength is greater than a threshold, as shown below. Figure 7 As shown, peak points with signal strength less than a threshold are deleted (i.e., deleted). Figure 7 Peak points below the horizontal line are retained, and peak points with signal strength greater than the threshold are preserved.

[0091] Next, the first target peak point with the same frequency value is found from the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal. That is, the peak point with the same frequency value is found from the peak points retained in the previous steps. Figure 8 A schematic diagram showing peak points with the same frequency value, such as... Figure 8 As shown, the five peak points with the same frequency value in the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal are retained, which are the first target peak points.

[0092] Next, the phase of the first target peak point is determined based on the real and imaginary parts of the first target peak point in the Fast Fourier Transform (FFT) result. For example, after the FFT, each first target peak point can be represented as a complex number. The quotient of the imaginary and real parts of this complex number is calculated to obtain the tangent of the phase angle, thus yielding the phase of the first target peak point. Figure 8 As shown, the phases of the first target peak points with the same frequency value in the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal are respectively as follows: Figure 8 As indicated by the label.

[0093] Next, find the second target peak point with the same phase from multiple first target peak points. Figure 9 A schematic diagram of the second target peak point with the same phase, as shown below. Figure 8 and Figure 9 As shown, among the five first target peak points with the same frequency value in the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal, only the peak points with phases of 1.4π and 1.33π have the same phase in the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal. Therefore, only these two peak points are retained as the second target peak points. These two second target peak points represent the reference object and the top of the wellbore, respectively.

[0094] Next, the peak point representing the top of the well passage is excluded from the second target peak point to obtain the peak point representing the reference object. For example, since the distance from the signal source to the reference object is less than the distance from the signal source to the top of the well passage, the peak point with the higher frequency among the two target peak points can be determined as the peak point representing the top of the well passage, thereby excluding the peak point representing the top of the well passage and obtaining the peak point representing the reference object. Figure 10 A schematic diagram characterizing the peak points of the reference material, from Figure 10 The frequency of the peak point can be determined from this.

[0095] S105. Calculate the distance between the car and the reference object based on the frequency of the peak point.

[0096] For example, after determining the peak point of the reference object, the distance between the car and the reference object is calculated based on the frequency of that peak point. For example, the product of the radar signal propagation speed and the frequency of the peak point is calculated to obtain a first value; the quotient of the first value and the slope of the linear change in the frequency of the first radar signal is calculated to obtain a second value; half of the second value is calculated as the distance between the car and the reference object. For example, the calculation formula is as follows:

[0097]

[0098] Where c is the propagation speed of the radar signal, i.e. the speed of light, Sτ is the frequency of the peak point of the reference object, i.e. the frequency of the intermediate frequency signal, and S is the slope of the linear change of the frequency of the millimeter-wave radar signal.

[0099] The car position measurement method provided in this embodiment of the invention acquires a first echo signal of a first radar signal reflected by a reference object and a second echo signal of a second radar signal reflected by a reference object. The distances from the reference object to the first millimeter-wave radar antenna corresponding to the first radar signal and the second millimeter-wave radar antenna corresponding to the second radar signal are equal. The first and second millimeter-wave radar antennas are mounted on the car, and the reference object is mounted at the hoistway terminal where the car is running, or the first and second millimeter-wave radar antennas are mounted at the hoistway terminal, and the reference object is mounted on the car. A first intermediate frequency signal is calculated based on the first radar signal and the first echo signal, and a second intermediate frequency signal is calculated based on the second radar signal and the second echo signal. Fast Fourier transforms are performed on the first and second intermediate frequency signals respectively to obtain the frequency-signal strength relationship corresponding to the first and second intermediate frequency signals. The peak point representing the reference object is found from the frequency-signal strength relationship corresponding to the first and second intermediate frequency signals, and the distance between the car and the reference object is calculated based on the frequency of the peak point. Compared to existing solutions, this invention does not require a reference object made of special materials, nor does it require learning the distance characteristics of several sub-reference objects, resulting in lower costs.

[0100] This invention also provides a car distance measuring device. Figure 11 This is a schematic diagram of the structure of a car distance measuring device provided in an embodiment of the present invention, as shown below. Figure 11 As shown, the car distance measuring device includes:

[0101] The signal acquisition module 201 is used to acquire a first echo signal of a first radar signal reflected by a reference object, and a second echo signal of a second radar signal reflected by the reference object. The distances from the first millimeter-wave radar antenna corresponding to the first radar signal and the second millimeter-wave radar antenna corresponding to the second radar signal to the reference object are equal. The first millimeter-wave radar antenna and the second millimeter-wave radar antenna are disposed on the car, and the reference object is disposed at the hoistway terminal where the car is running. Alternatively, the first millimeter-wave radar antenna and the second millimeter-wave radar antenna are disposed at the hoistway terminal, and the reference object is disposed on the car.

[0102] The intermediate frequency signal calculation module 202 is used to calculate a first intermediate frequency signal based on the first radar signal and the first echo signal, and to calculate a second intermediate frequency signal based on the second radar signal and the second echo signal;

[0103] The Fourier transform module 203 is used to perform fast Fourier transform on the first intermediate frequency signal and the second intermediate frequency signal respectively to obtain the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal.

[0104] Peak point lookup module 204 is used to find the peak point characterizing the reference object from the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal;

[0105] The distance calculation module 205 is used to calculate the distance between the car and the reference object based on the frequency of the peak point.

[0106] In some embodiments of the present invention, the intermediate frequency signal calculation module 202 includes:

[0107] The first mixing submodule is used to mix the first radar signal and the first echo signal to obtain a first mixed signal;

[0108] The first filtering and amplification submodule is used to perform low-pass filtering on the first mixing signal and amplify it to obtain the first intermediate frequency signal;

[0109] The second mixing submodule is used to mix the second radar signal and the second echo signal to obtain a second mixed signal;

[0110] The second filtering and amplification submodule is used to perform low-pass filtering on the second mixing signal and amplify it to obtain the second intermediate frequency signal.

[0111] In some embodiments of the present invention, the peak point finding module 204 includes:

[0112] The first peak point search submodule is used to search for a first target peak point with the same frequency value from the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal.

[0113] The phase calculation submodule is used to determine the phase of the first target peak point based on the real and imaginary parts of the first target peak point in the fast Fourier transform result;

[0114] The second peak point search submodule is used to search for a second target peak point with the same phase from multiple first target peak points;

[0115] The peak point determination submodule is used to exclude the peak points representing the top of the wellbore from the second target peak points to obtain the peak points representing the reference object.

[0116] In some embodiments of the present invention, the peak point finding module 204 further includes:

[0117] The elimination submodule is used to search for peak points with signal strength greater than a threshold from the frequency-signal strength relationships corresponding to the first intermediate frequency signal and the second intermediate frequency signal, before searching for the first target peak point with the same frequency value from the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal.

[0118] In some embodiments of the present invention, the peak point determination submodule includes:

[0119] The peak point determination unit at the top of the well is used to determine the peak point with a higher frequency from the two second target peak points as the peak point characterizing the top of the well.

[0120] The peak point determination unit is used to exclude peak points that characterize the top of the wellbore and obtain peak points that characterize the reference object.

[0121] In some embodiments of the present invention, the distance calculation module 205 includes:

[0122] The first calculation submodule is used to calculate the product of the radar signal propagation speed and the frequency of the peak point to obtain a first value;

[0123] The second calculation submodule is used to calculate the quotient of the slope of the linear change of the first value and the frequency of the first radar signal to obtain the second value.

[0124] The third calculation submodule is used to calculate half of the second value as the distance between the car and the reference object.

[0125] In some embodiments of the present invention, the first radar signal and the second radar signal operate in different frequency bands.

[0126] In some embodiments of the present invention, the first radar signal and the second radar signal operate at different time periods.

[0127] The aforementioned car distance measuring device can execute the car distance measuring method provided in the foregoing embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the car distance measuring method.

[0128] This invention also provides a car distance measurement system. Figure 12 This is a three-dimensional structural diagram of a car distance measurement system provided in an embodiment of the present invention. Figure 13 for Figure 12 Side view along the y-direction, Figure 14 for Figure 12 Side view along the x-direction, such as Figures 12-14 As shown, the car distance measurement system includes:

[0129] The first millimeter-wave radar 301 is used to transmit a first radar signal and receive a first echo signal reflected by the reference object 303.

[0130] The second millimeter-wave radar 302 is used to transmit a second radar signal and receive a second echo signal reflected by the reference object 303.

[0131] A controller (not shown in the figure) is connected to the first millimeter-wave radar 301 and the second millimeter-wave radar 302 respectively, and is used to execute the car position measurement method described in any of the foregoing embodiments of the present invention.

[0132] In this configuration, the distances from the first millimeter-wave radar 301 and the second millimeter-wave radar 302 to the reference object 303 are equal. The first millimeter-wave radar 301 and the second millimeter-wave radar 302 are positioned on the top of the car 400, and the reference object 303 is positioned on the top of the hoistway 500 through which the car 400 operates. Alternatively, the first millimeter-wave radar 301 and the second millimeter-wave radar 302 are positioned on the top of the hoistway 500, and the reference object 303 is positioned on the top of the car 400. For example... Figure 11 , 12The following example illustrates the application of a first millimeter-wave radar 301 and a second millimeter-wave radar 302 mounted on the top of the elevator car 400, with a reference object 303 mounted on the top of the hoistway 500 through which the elevator car 400 operates. For example, the two radar antennas should be on the same horizontal plane, and there should be no objects between the radar antennas and the reference object. The distances between the two radar antennas and the reference object should be equal. For example, if the radar antenna arrangement direction is x, the radar antenna detection direction (elevator car running direction) is z, and the direction perpendicular to x and z is y, then on the horizontal plane where the reference object is located, no objects that would cause radar signal reflection should be placed in the y-direction. The two radar antennas are equidistantly distributed on both sides of the vertical line of the corner reflector along the x-axis, i.e., d1 = d2. Both radar antennas are narrow-beam antennas, using lenses to achieve beam focusing. The main lobe half-power angle should be as small as possible to improve signal strength, but it should not be too small; it should be greater than the angular deviation during actual radar operation, such as assembly errors, installation errors, and elevator car offset. The detection direction of the millimeter-wave radar should be vertical, i.e., consistent with the elevator car running direction. To avoid interference between radar signals, the operating frequencies of the two radar signals can be staggered. For example, one radar signal operates in the frequency range of 61GHz-62GHz, and the other operates in the frequency range of 63GHz-64GHz. Alternatively, the transmission times of the two radar signals can be staggered, such as with a period of 500μs, one radar signal operating from 0 to 200μs, and the other radar signal operating from 250 to 450μs. The reference object 303 is a reflective object that can reflect the radar signal back along its original path, such as a corner reflector.

[0133] In other embodiments of the present invention, the first millimeter-wave radar and the second millimeter-wave radar are disposed at the bottom of the car and the reference object is disposed at the bottom of the hoistway; or the first millimeter-wave radar and the second millimeter-wave radar are disposed at the top of the hoistway and the reference object is disposed at the top of the car; or the first millimeter-wave radar and the second millimeter-wave radar are disposed at the bottom of the hoistway and the reference object is disposed at the bottom of the car. Of course, the millimeter-wave radar antenna or the reference object can also be disposed on the side wall of the car. The embodiments of the present invention are not limited here.

[0134] Figure 15 This is a schematic diagram of an electronic device provided for an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0135] like Figure 15 As shown, the electronic device includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded into the RAM 13 from storage unit 18. The RAM 13 can also store various programs and data required for the operation of the electronic device. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0136] Multiple components in the electronic device are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, optical disk, etc.; and a communication unit 19, such as a network card, modem, wireless transceiver, etc. The communication unit 19 allows the electronic device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0137] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the car position measurement method.

[0138] In some embodiments, the car position measurement method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on an electronic device via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the car position measurement method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the car position measurement method by any other suitable means (e.g., by means of firmware).

[0139] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0140] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0141] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0142] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0143] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0144] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0145] This invention also provides a computer program product, including a computer program that, when executed by a processor, implements the car position measurement method as provided in any embodiment of this application.

[0146] In implementing the computer program product, computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof. Programming languages ​​include object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0147] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0148] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for measuring the position of a car, characterized in that, include: Acquire a first echo signal of a first radar signal reflected by a reference object, and a second echo signal of a second radar signal reflected by the reference object. The distances from the first millimeter-wave radar antenna corresponding to the first radar signal and the second millimeter-wave radar antenna corresponding to the second radar signal to the reference object are equal. The first millimeter-wave radar antenna and the second millimeter-wave radar antenna are mounted on the car, and the reference object is mounted at the hoistway terminal where the car is running. Alternatively, the first millimeter-wave radar antenna and the second millimeter-wave radar antenna are mounted at the hoistway terminal, and the reference object is mounted on the car. The first intermediate frequency signal is calculated based on the first radar signal and the first echo signal, and the second intermediate frequency signal is calculated based on the second radar signal and the second echo signal; Perform Fast Fourier Transform on the first intermediate frequency signal and the second intermediate frequency signal respectively to obtain the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal; Find the peak point characterizing the reference object from the frequency-signal intensity relationship corresponding to the first intermediate frequency signal and the frequency-signal intensity relationship corresponding to the second intermediate frequency signal; The distance between the car and the hoistway terminal is calculated based on the frequency of the peak point; Finding the peak point characterizing the reference object from the frequency-signal intensity relationship corresponding to the first intermediate frequency signal and the frequency-signal intensity relationship corresponding to the second intermediate frequency signal includes: Find the first target peak point with the same frequency value from the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal; The phase of the first target peak point is determined based on the real and imaginary parts of the first target peak point in the fast Fourier transform result; Find the second target peak point with the same phase from multiple first target peak points; The peak points representing the top of the wellbore are excluded from the second target peak points to obtain the peak points representing the reference object.

2. The car position measurement method according to claim 1, characterized in that, Calculating a first intermediate frequency (IF) signal based on the first radar signal and the first echo signal, and calculating a second IF signal based on the second radar signal and the second echo signal, includes: The first radar signal and the first echo signal are mixed to obtain a first mixed signal; The first mixing signal is low-pass filtered and amplified to obtain the first intermediate frequency signal; The second radar signal and the second echo signal are mixed to obtain a second mixed signal; The second mixing signal is low-pass filtered and amplified to obtain the second intermediate frequency signal.

3. The car position measurement method according to claim 1, characterized in that, Before searching for the first target peak point with the same frequency value from the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal, the method further includes: The peak points with signal strength greater than the threshold are searched from the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal.

4. The car position measurement method according to claim 1, characterized in that, The peak points representing the top of the wellbore are excluded from the second target peak points to obtain the peak points representing the reference object, including: The peak point with higher frequency from the two second target peak points is determined as the peak point characterizing the top of the wellbore; By excluding the peak points representing the top of the wellbore, the peak points representing the reference object are obtained.

5. The car position measurement method according to claim 1, characterized in that, Calculating the distance between the car and the reference object based on the frequency of the peak point includes: The first value is obtained by multiplying the propagation speed of the radar signal by the frequency of the peak point; The second value is obtained by calculating the quotient of the slope of the linear change in the frequency of the first radar signal and the first value. Calculate half of the second value as the distance between the car and the reference object.

6. The car position measurement method according to any one of claims 1-5, characterized in that, The first radar signal and the second radar signal operate in different frequency bands.

7. The car position measurement method according to any one of claims 1-5, characterized in that, The first radar signal and the second radar signal operate at different time periods.

8. A car distance measuring device, characterized in that, The method for performing the car position measurement method according to any one of claims 1-7 includes: The signal acquisition module is used to acquire a first echo signal of a first radar signal reflected by a reference object, and a second echo signal of a second radar signal reflected by the reference object. The distances from the first millimeter-wave radar antenna corresponding to the first radar signal and the second millimeter-wave radar antenna corresponding to the second radar signal to the reference object are equal. The first millimeter-wave radar antenna and the second millimeter-wave radar antenna are disposed on the car, and the reference object is disposed at the hoistway terminal where the car is running. Alternatively, the first millimeter-wave radar antenna and the second millimeter-wave radar antenna are disposed at the hoistway terminal, and the reference object is disposed on the car. An intermediate frequency signal calculation module is used to calculate a first intermediate frequency signal based on the first radar signal and the first echo signal, and to calculate a second intermediate frequency signal based on the second radar signal and the second echo signal; The Fourier transform module is used to perform fast Fourier transform on the first intermediate frequency signal and the second intermediate frequency signal respectively to obtain the frequency-signal strength relationship corresponding to the first intermediate frequency signal and the frequency-signal strength relationship corresponding to the second intermediate frequency signal. The peak point lookup module is used to find the peak point characterizing the reference object from the frequency-signal intensity relationship corresponding to the first intermediate frequency signal and the frequency-signal intensity relationship corresponding to the second intermediate frequency signal; The distance calculation module is used to calculate the distance between the car and the hoistway terminal based on the frequency of the peak point.

9. A car distance measurement system, characterized in that, include: The first millimeter-wave radar is used to transmit a first radar signal and receive a first echo signal reflected by a reference object from the first radar signal. The second millimeter-wave radar is used to transmit a second radar signal and receive a second echo signal reflected by the reference object from the second radar signal. A controller, which is connected to the first millimeter-wave radar and the second millimeter-wave radar respectively, is used to execute the car position measurement method according to any one of claims 1-7; Wherein, the first millimeter-wave radar and the second millimeter-wave radar are at the same distance from the reference object, the first millimeter-wave radar and the second millimeter-wave radar are installed on the car, and the reference object is installed at the hoistway terminal where the car is running, or the first millimeter-wave radar and the second millimeter-wave radar are installed at the hoistway terminal, and the reference object is installed on the car.

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