Method for estimating distance of element relative to vehicle
Through the reflection mode and channel impulse response of ultra-wideband technology, combined with filtering technology, the accuracy and safety problems of vehicle-user distance detection are solved, fast and reliable distance detection is achieved, and the shortcomings of traditional technology are overcome.
Patent Information
- Application Number
- CN202410791964.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-06-19
- Filing Date
- 2024-06-19
- Publication Date
- 2024-12-20
AI Technical Summary
Existing distance detection technologies between vehicles and users have accuracy and safety issues, especially capacitive sensor technologies are susceptible to moisture, icing and electrical interference, and the accuracy of RF and low-frequency communications is not sufficient to support positioning relatedness. Function.
The reflection mode adopts ultra-wideband (UWB) technology, by sending signals on the ultra-wideband channel, receiving reflected signals, determining phase and standard deviation, estimating the distance of the user relative to the vehicle based on the index whose standard deviation is lower than a predetermined threshold, using the channel Impulse response and filtering techniques improve detection accuracy and reliability.
It realizes fast, simple, reliable and effective distance detection, reduces computer processing needs, improves the accuracy and security of distance detection, and avoids the shortcomings of traditional technology.
Smart Images
Figure CN119165474A_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to the automotive field, and more particularly to a method for estimating a distance of an element relative to a vehicle and a detection module implementing the method. [Background Technology]
[0002] In motor vehicles it is known to provide functionality based on a user's proximity to the vehicle, such as unlocking a door (the term refers here to any openable door leaf, such as a door of a passenger compartment, a lid / door of a trunk / luggage compartment and possibly also a hood) using a key, a key card or a smartphone.
[0003] Historically, the technologies used have been based either on radio frequency (RF) and low frequency (LF) communications between the vehicle and the key or fob, or on capacitive sensors located in the door handle.
[0004] However, these technologies currently do not allow the provision of new functionalities related to positioning, particularly due to their lack of accuracy. In addition, capacitive sensor technology may malfunction due to moisture, ice or electrical interference.
[0005] To overcome some of these shortcomings, Technology is already used for communication between the vehicle and the user's smartphone.
[0006] However, Technology has shortcomings in terms of security and accuracy.
[0007] Therefore, a simple, reliable and effective solution allowing to at least partially remedy these drawbacks would be advantageous. [Summary of the invention]
[0008] To this end, a first subject of the invention is a method for estimating the distance of an element relative to a vehicle based on a detection module, said method comprising the following steps implemented by said detection module:
[0009] - sending at least one signal over an ultra-wideband channel in the direction of said element,
[0010] - receiving at least one signal reflected from said element,
[0011] - determining the phase of at least one received reflected signal for different distance indices in a series of distance indices, each index corresponding to a predetermined distance relative to the detection module or a predetermined range of distances relative to the detection module,
[0012] - determining the standard deviation of the phase for each range index in the series of range indices,
[0013] - determining, in the order of the series, the first index for which the standard deviation is below a predetermined threshold for at least a predetermined length of time,
[0014] - estimating a distance of the feature relative to the detection module based on the determined index, the estimated distance corresponding to a predetermined distance associated with the determined index.
[0015] In the present application, "ultra-wideband" refers to the per se known ultra-wideband (UWB) technology. The method according to the invention uses the "reflection mode" or "radar mode" of said UWB technology.
[0016] The use of the phase of the reflected signal makes it possible to detect the characteristics of a user or of his movements. However, the use of the phase alone is not sufficient, since the phase is measured using a phase-locked loop which may generate so-called "phase" noise due to variations in the frequency oscillator of said loop. When the standard deviation decreases below a predetermined threshold during a change in the phase of the signal representative of the user or of his movements at a given distance associated with one of the indices, it is confirmed that the user is actually present at the distance corresponding to said index. The use of phase and standard deviation does not require very high computer processing power for the detection module, making the method fast, simple, reliable and effective, while limiting costs.
[0017] Preferably, the method comprises the step of filtering the phase signal to obtain a rectangular signal, thereby improving the calculation of the standard deviation.
[0018] Preferably, the method comprises the step of filtering the standard deviation signal to obtain a rectangular signal, thereby facilitating determining, in order of the series, a first index at which the standard deviation is below a predetermined threshold for at least a predetermined length of time.
[0019] Advantageously, the method comprises the step of determining a channel impulse response, the phase being determined based on said channel impulse response.Using the channel impulse response (CIR) allows to easily determine the amplitude and phase of at least one received reflected signal.
[0020] The invention also relates to a computer program product, characterized in that the computer program product comprises a set of program code instructions which, when executed by one or more processors, configure the one or more processors to implement the method as described above.
[0021] The invention also relates to a detection module for estimating the distance of an element relative to a motor vehicle, the detection module being configured to be installed in the vehicle and to send and receive ultra-wideband signals, the detection module being configured to:
[0022] - sending at least one signal over an ultra-wideband channel in the direction of said element,
[0023] - receiving at least one signal reflected from said element,
[0024] - determining the phase of at least one received reflected signal for different distance indices in a series of distance indices, each index corresponding to a predetermined distance relative to the detection module,
[0025] - determining the standard deviation of the phase for each range index in the series of range indices,
[0026] - determining, in the order of the series, the first index for which the standard deviation is below a predetermined threshold for at least a predetermined length of time,
[0027] - estimating a distance of the feature relative to the detection module based on the determined index, the estimated distance corresponding to a predetermined distance associated with the determined index.
[0028] Preferably, the detection module is configured to filter the phase signal to obtain a rectangular signal, and / or to filter the standard deviation signal to obtain a rectangular signal.
[0029] Preferably, the detection module is configured to determine a channel impulse response and to determine the phase based on said channel impulse response.
[0030] The invention also relates to a motor vehicle comprising at least one detection module as described above.
[0031] In one embodiment, the vehicle comprises an electronic control unit and a plurality of detection modules as described above, each detection module being configured to send a determined index or an estimated distance to the electronic control unit at a given time, and the electronic control unit being configured to locate the feature based on the received index or the received distance. [Drawings]
[0032] Further features and advantages of the present invention will become more clearly apparent when reading the following description. The description is purely illustrative and should be read with reference to the accompanying drawings, in which:
[0033] [ Figure 1 ] Figure 1 An embodiment of the system according to the invention is schematically illustrated.
[0034] [ Figure 2 ] Figure 2 An embodiment of the method according to the invention is schematically illustrated.
[0035] [ Figure 3 ] Figure 3Contains six graphs showing phases with indices 1, 7, 9, 10, 11 and 13, a predetermined threshold value S of the standard deviation σ of 0.8 and a predetermined time length Δt of, for example, 200 ms and standard deviation σ, as well as the envelope of the reflected signal in each graph. [Specific implementation method]
[0036] Figure 1 An example of a vehicle 1 according to the invention is shown.
[0037] Vehicle 1
[0038] In this example, the vehicle 1 includes six detection modules 10 and one electronic control unit 20 .
[0039] Detection module 10
[0040] Each detection module 10 makes it possible to estimate the distance of an element relative to the vehicle 1. The element may be a person or an object. Figure 1 In the example of , the element is user 5 of vehicle 1 .
[0041] The detection modules 10 are installed at various locations on the vehicle 1 , so that each detection module 10 can measure the distance between itself and the user 5 according to its location around or in the vehicle 1 .
[0042] Each detection module 10 is configured to transmit and receive ultra-wideband signals. Specifically, each detection module 10 is configured to transmit at least one signal in the direction of the user 5 on the ultra-wideband channel, and receive one or more signals reflected from the user 5 by the transmitted signal.
[0043] Each detection module 10 is configured to determine the phase of at least one received reflection signal for different distance indices in a series of distance indices, wherein each index corresponds to a predetermined distance or a predetermined distance range relative to the detection module 10 .
[0044] The number of distance indices (for each of which the phase and standard deviation are determined) is preferably selected in order to limit the number of calculations performed by each detection module 10. For example, the calculations may be performed for less than 64 indices, such as 16 or 32 indices. For example, each index may correspond to a "tap" of the UWB standard, which corresponds to a distance increment of 15 cm (index 1 = 15 cm, index 2 = 30 cm, index 3 = 45 cm, ..., index 10 = 150 cm, etc.).
[0045] Preferably, each detection module 10 is configured to determine a channel impulse response and to determine a phase based on the channel impulse response.
[0046] Each detection module 10 is configured to determine a standard deviation of the phase for each range index in a series of range indices.
[0047] Preferably, each detection module 10 is configured to filter the phase signal to obtain a rectangular signal, and / or to filter the standard deviation signal to obtain a rectangular signal.
[0048] Each detection module 10 is configured to determine, in the order of the series, the first index for which the standard deviation is below a predetermined threshold for at least a predetermined length of time. For example, the threshold can be preset to a portion of the standard deviation range measured in the absence of the user 5, for example between 0% and 50%. For example, in order to locate the position of a mobile user 5, the predetermined length of time is advantageously greater than 50 or 100 ms, and in the case of movement detection (e.g., leg movement for opening the trunk), the predetermined length of time is advantageously greater than 1 second.
[0049] Each detection module 10 is configured to estimate, based on the determined index, the distance of the user 5 relative to the detection module 10. The estimated distance then corresponds to a predetermined distance or a predetermined distance range (eg its median or average value) associated with the determined index.
[0050] Preferably, each detection module 10 is configured to send an index determined at a given time or a distance estimated at a given time to the electronic control unit 20 .
[0051] Each detection module 10 comprises a processor or microcontroller capable of implementing a set of instructions allowing these functions to be performed.
[0052] Electronic control unit 20
[0053] The electronic control unit 20 is configured to locate the user 5 based on the received indexes or the received distances sent by the plurality of detection modules 10 .
[0054] Example of Implementation
[0055] In this example, reference Figure 1 , the user 5 is located near the vehicle 1 and within the signal range of the three detection modules 10. Still in this non-limiting example, reference Figure 3 , the number of distance indices I1, . . . , I16 (for each distance index the phase and the standard deviation are determined) is chosen to be equal to 16.
[0056] Reference now Figure 2In step E1, each detection module 10 transmits a signal on the ultra-wideband channel around itself, in particular in the direction of the user 5. Preferably, the channels of all detection modules 10 are the same and the signals are transmitted sequentially (in sequence). When transmitting in UWB reflection mode, the frequency is the same but the format of the frame (e.g. preamble) is different. In UWB reflection mode, the detection module 10 immediately switches to reception mode and uses the signal it transmits as a filter (mask).
[0057] Some of the signals sent by the receiving module are reflected from the user 5 and then return directly or indirectly to the detection module 10 that sent them.
[0058] In this example, in step E2 , three receiving modules 10 receive signals reflected from the user 5 .
[0059] Then, in step E3, each receiving module 10 determines the phase of at least one received reflected signal for different distance indices I1, ..., I16 in a series of distance indices I1, ..., I16 (i.e., 16 index values I1, ..., I16 in this example) after receiving at least one signal reflected from the user 5.
[0060] Then, in step E4, each receiving module 10 determines the phase The standard deviation σ of the phase of each index I1, ..., I16 of the series is then determined. An optional filtering step may be performed on the phase signal and / or the standard deviation signal in order to improve the index determination in the subsequent step E5.
[0061] Then, in step E5 , each receiving module 10 , after determining the standard deviation σ, determines, in the order of the series, a first index ISD in which the standard deviation σ is smaller than a predetermined threshold value for at least a predetermined time length Δt.
[0062] Figure 3 Phases with indices 1, 7, 9, 10, 11 and 13, a predetermined threshold value S of the standard deviation σ of 0.8 and a predetermined time length Δt of, for example, 200 ms are shown. Six graphs of σ and standard deviation σ. Each graph also contains the envelope of the reflection signal. For reasons of clarity of the drawing, it is not possible to show every reflection signal.
[0063] In this example, for the first index I1, the phase It appears that user 5 or the movement of user 5 is detected (a series of peaks); however, the standard deviation σ does not drop below the predetermined threshold S of 0.8. The same is true for indices I2 to I6 (not shown).
[0064] However, for index I7, the phase It appears that the user 5 or the movement of the user 5 is detected (a series of peaks) and the standard deviation σ drops below a predetermined threshold value S of 0.8 for a time length dt greater than a predetermined time length Δt of 200 ms.
[0065] Index I7 is therefore the first index ISD in the series that satisfies the detection condition for user 5. It should be noted that for indices I9 and I10, the detection is confirmed, thus making it possible to determine the thickness of user 5. On the contrary, for the indices following index I11, the detection condition is no longer satisfied (the standard deviation σ falls below a predetermined threshold value S of 0.8 for a time length dt greater than a predetermined time length Δt of 200 ms).
[0066] Then, in step E6, each receiving module 10 estimates the distance D of the user 5 relative to said detection module 10 based on the index ISD determined by said detection module 10, the estimated distance D corresponding to the predetermined distance associated with the determined index ISD. Figure 3 In the example of , since the difference between each index is 15 cm, index I7 corresponds to a distance of 105 cm, and thus corresponds to the estimated distance D.
[0067] Next, in this example of embodiment, each receiving module 10 then sends the determined index ISD or the estimated distance D to the electronic control unit 20 in a step E7. Figure 1 In the example of , three detection modules 10 have received signals reflected from the user 5 , which means estimates of three distances D1 , D2 , D3 relative to each of these three detection modules.
[0068] More generally, when the electronic control unit 20 receives the indices I1 , . . . , I16 , it is able to estimate the distance D between each detection module 10 and the user 5 itself, for example using a look-up table.
[0069] When the electronic control unit 20 knows the distance (determined or received) between each detection module 10 (sent index or distance) and the user 5 , it determines the position L of the user 5 by intersecting the estimated distances D, in step E8 .
[0070] In other words, each distance D estimated by each detection module 10 defines a circle around the detection module 10, and the user 5 is located at the intersection of the circles (when there are at least three detection modules 10, such as Figure 1 example) or at one of the two intersection points of the circle (when there are two detection modules 10).
[0071] Using the standard deviation σ to determine the indices I1 , ..., I16 is cheap in terms of computer processing resources. Thus, the present invention makes it possible to accurately, quickly, efficiently and reliably locate elements around or inside the vehicle 1 .
Claims
1. A method for estimating a distance (D) of an element (5) relative to a vehicle (1) based on a detection module (10), the method comprising the following steps implemented by the detection module (10): - sending (E1) at least one signal in the direction of said element (5) over an ultra-wideband channel, - receiving (E2) at least one signal reflected from said element (5), - determining (E3) a phase (φ) of at least one received reflection signal for different distance indices (I1, ..., I16) of a series of distance indices (I1, ..., I16), each index (I1, ..., I16) corresponding to a predetermined distance relative to the detection module (10), - determining (E4) for each distance index (I1, ..., I16) of the series of distance indices (I1, ..., I16) a standard deviation (σ) of the phase (φ), - determining (E5) in the order of the series the first index (ISD) of the standard deviation (σ) below a predetermined threshold (S) for at least a predetermined length of time (Δt), - estimating (E6) the distance (D) of the element (5) relative to the detection module (10) based on the determined index (ISD), the estimated distance (D) corresponding to a predetermined distance associated with the determined index (ISD).
2. The method as claimed in claim 1, comprising the step of filtering the phase signal (φ) to obtain a rectangular signal.
3. The method as claimed in any one of the preceding claims, comprising the step of filtering the standard deviation signal (σ) to obtain a rectangular signal.
4. A method as claimed in any one of the preceding claims, further comprising the step of determining a channel impulse response, the phase (φ) being determined based on the channel impulse response.
5. A computer program product, characterized in that The method comprises a set of program code instructions which, when executed by one or more processors, configure the one or more processors to implement the method as claimed in any one of the preceding claims.
6. A detection module (10) for estimating a distance (D) of an element (5) relative to a motor vehicle (1), the detection module (10) being configured to be installed in the vehicle (1) and to send and receive ultra-wideband signals, the detection module (10) being configured to: - sending at least one signal in the direction of said element (5) over an ultra-wideband channel, - receiving at least one signal reflected from said element (5), - determining a phase (φ) of at least one received reflected signal for different distance indices (I1, ..., I16) of a series of distance indices (I1, ..., I16), each index (I1, ..., I16) corresponding to a predetermined distance relative to the detection module (10), - determining for each distance index (I1, ..., I16) of the series of distance indices (I1, ..., I16) a standard deviation (σ) of the phase (φ), - determining, in the order of the series, a first index (ISD) for which the standard deviation (σ) is below a predetermined threshold (S) for at least a predetermined length of time (Δt), - estimating the distance (D) of the element (5) relative to the detection module (10) based on the determined index (ISD), the estimated distance (D) corresponding to a predetermined distance associated with the determined index (ISD).
7. The detection module (10) according to the preceding claim, the detection module (10) being configured to filter the phase signal (φ) to obtain a rectangular signal and / or to filter the standard deviation signal (σ) to obtain a rectangular signal.
8. The detection module (10) according to any one of claims 6 and 7, the detection module (10) being configured to determine a channel impulse response and to determine the phase (φ) based on the channel impulse response.
9. A motor vehicle (1) comprising at least one detection module (10) according to the preceding claim.
10. A vehicle (1) according to the preceding claim, comprising an electronic control unit (20) and a plurality of detection modules (10) according to any one of claims 6 to 8, each detection module (10) being configured to send a determined index (ISD) or an estimated distance (D) to the electronic control unit (20) at a given time, the electronic control unit (20) being configured to locate the element (5) based on the received index (I1, ..., I16) or the received distance (D).