Laser signature method and device resistant to multi-laser radar signal interference
By performing pseudo-random delay on the LASER and SPAD clock cycles in the lidar system, the problem of signal interference in multiple lidar systems is solved, and hardware resource saving and design simplification are achieved.
Patent Information
- Application Number
- CN202110533341.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-05-17
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2041-05-17
AI Technical Summary
In multi-lidar systems, the prior art is difficult to effectively eliminate signal interference between different user systems, and the hardware overhead is large and the design is complex.
By performing different pseudo-random delays on the rising edge of each clock cycle that drives LASER and SPAD, the pseudo-random number generator and counter generate and control the delay under the fast clock, the interference cancellation of fixed frequency signals is achieved, saving Hardware resources.
It effectively eliminates signal interference from multi-lidar systems, reduces hardware resource overhead, and simplifies design.
Smart Images
Figure CN113325387B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of laser radar ranging, and more specifically, relates to a laser signature method and device that are resistant to interference from multiple laser radar signals. Background Art
[0002] In a multi-laser radar system based on direct time-of-flight (DTOF) technology, multiple laser radar systems from different users may run simultaneously, which will cause mutual interference between signals. AugustoRonchini Ximenes et al. proposed a laser signature solution, in which only the clock driving the LASER uses a digitally controlled delay chain to delay the rising edge, and the delay information is stored at the same time. The time recorded by the time-to-digital converter (TDC) is subtracted from the delay information to obtain the true light flight time. In addition, the solution is based on a phase-locked loop (PLL) or a delay-locked loop (DLL) to realize a digitally controlled delay chain, which has a large hardware overhead and a complex design. Summary of the invention
[0003] In response to the above defects or improvement needs of the prior art, the present invention provides a laser signature solution that is resistant to interference from multiple laser radar signals. By simultaneously delaying the rising edge of each clock cycle that drives the LASER and SPAD differently, hardware resources are saved while eliminating interference from fixed-frequency signals.
[0004] To achieve the above objectives, according to one aspect of the present invention, a laser signature method that is resistant to interference from multiple laser radar signals is provided, which eliminates interference from fixed frequency signals by performing different delays on the rising edge of each clock cycle that drives the LASER and SPAD.
[0005] In one embodiment of the present invention, the method comprises:
[0006] Under fast clock, the pseudo-random number generator generates a pseudo-random number and stores it when the rising edge of the LASER and SPAD driving clock arrives;
[0007] When the upper edge of the LASER and SPAD driving clock arrives, the counter starts counting from 0 under the fast clock. Only when the counter counts the stored pseudo-random number and the driving clock is at a high level, it outputs a high level and the counter is cleared, otherwise it outputs a low level.
[0008] In one embodiment of the present invention, the delay is equal to a pseudo-random number×a fast clock period.
[0009] In one embodiment of the present invention, the high level or low level of the output is used as a driving clock for a LASER and a SPAD whose rising edge undergoes a pseudo-random delay, and this driving clock is used to achieve resistance to interference from multiple laser radar systems.
[0010] In one embodiment of the present invention, the pseudo-random number generator is implemented based on a linear feedback shift register.
[0011] According to another aspect of the present invention, a laser signature device that is resistant to interference from multiple laser radar signals is also provided, including a pseudo-random number generator, a counter, and a judgment control module. The counter and the pseudo-random number generator are driven by the fast clock domain, and different delays are performed on the rising edges of the driving clocks of the LASER and SPAD. The judgment control module outputs the corresponding level, thereby achieving the effect of resisting interference from multiple laser radar systems.
[0012] In one embodiment of the present invention, the pseudo-random number generator is used to generate a pseudo-random number under a fast clock and store it when the rising edge of the driving clock of the LASER and SPAD arrives; the counter is used to count from 0 under the fast clock when the rising edge of the driving clock of the LASER and SPAD arrives; the judgment control module is used to output a high level and clear the counter when the counter counts the stored pseudo-random number and the driving clock is at a high level, otherwise it outputs a low level.
[0013] In one embodiment of the present invention, the delay is equal to a pseudo-random number×a fast clock period.
[0014] In one embodiment of the present invention, the high level or low level of the output is used as a driving clock for a LASER and a SPAD whose rising edge undergoes a pseudo-random delay, and this driving clock is used to achieve resistance to interference from multiple laser radar systems.
[0015] In one embodiment of the present invention, the pseudo-random number generator is implemented based on a linear feedback shift register.
[0016] In general, the above technical solution conceived by the present invention has the following beneficial effects compared with the prior art:
[0017] The laser signature method and hardware architecture provided by the present invention save hardware resources while eliminating interference from fixed frequency signals by performing different delays on the rising edges of each clock cycle that drives the LASER and the SPAD. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a flow chart of the laser signature method for resisting interference from multiple laser radar signals provided by the present invention;
[0019] Figure 2 This is a diagram showing an implementation example of the laser signature method for resisting multi-laser radar signal interference provided by the present invention;
[0020] Figure 3 This is a rendering of the laser signature method for resisting multi-laser radar signal interference provided by the present invention;
[0021] Figure 4 It is a schematic diagram of the laser signature hardware architecture that is resistant to multi-laser radar signal interference provided by the present invention. DETAILED DESCRIPTION
[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0023] The present invention designs a laser signature method that resists interference from multiple laser radar signals, and eliminates interference from fixed frequency signals by performing different delays on the rising edge of each clock cycle that drives the LASER and SPAD. Specifically:
[0024] First, under a fast clock, a pseudo-random number generator (which can be implemented based on a linear feedback shift register (LFSR) and the pseudo-random number generator can also be replaced with a given code) generates a pseudo-random number and stores it when the rising edge of the driving clock (slow clock) of the LASER and the single photon avalanche diode (SPAD) arrives.
[0025] When the upper edge of the LASER and SPAD driving clock (slow clock) arrives, the counter starts counting from 0 under the fast clock. Only when the counter counts the stored pseudo-random number (pseudo-random number × fast clock cycle = required delay) and the driving clock is at a high level, it outputs a high level and the counter is cleared, otherwise it outputs a low level.
[0026] The output level (i.e. the high level or low level output above) is the driving clock of the LASER and SPAD with a pseudo-random delay on the rising edge. Using this driving clock can achieve resistance to interference from multiple laser radar systems.
[0027] like Figure 1 As shown, the present invention provides a laser signature method for resisting interference from multiple laser radar signals, the method comprising the following steps:
[0028] In the first step, the pseudo-random number generator generates a pseudo-random number under the fast clock, and Figure 2 The storage is performed when the rising edge of the driving clock of the LASER and SPAD without delay arrives.
[0029] In the second step, when the upper edge of the LASER and SPAD driving clock arrives, the counter starts counting from 0 under the fast clock. Only when the counter counts the stored pseudo-random number (pseudo-random number × fast clock cycle = required delay) and the driving clock is at a high level, it outputs a high level and the counter is cleared, otherwise it outputs a low level.
[0030] like Figure 2 As shown, the output level is the driving clock of the LASER and SPAD with the rising edge delayed by pseudo-random time.
[0031] like Figure 3 As shown in the figure, the use of this driving clock can achieve resistance to interference from multiple laser radar systems. That is, the rising edge of the driving clock of the LASER and its corresponding SPAD has the same pseudo-random delay, and other radar systems do not have this delay. Therefore, when the time from the LASER emitting light to the corresponding SPAD receiving light is statistically recorded, the signals of other radar systems will be dispersed in the frequency domain, which greatly reduces the interference of the signals of other radar systems to the radar system composed of the LASER and its corresponding SPAD.
[0032] like Figure 4 As shown, the present invention provides a laser signature device that is resistant to interference from multiple laser radar signals, including: a pseudo-random number generator (which can be implemented based on a linear feedback shift register (LFSR) and the pseudo-random number generator can also be replaced with a given code), a counter, and a judgment control module. By driving the counter and the pseudo-random number generator in the fast clock domain, the rising edge of the driving clock of the LASER and the SPAD is delayed to a certain extent, thereby achieving the effect of resisting interference from multiple laser radar systems. Specifically:
[0033] The pseudo-random number generator is used to generate a pseudo-random number under a fast clock and store it when the rising edge of the driving clock of the LASER and the SPAD arrives;
[0034] The counter is used to start counting from 0 under the fast clock when the upper edge of the driving clock of the LASER and the SPAD arrives;
[0035] The judgment control module is used to output a high level and clear the counter when the counter counts the stored pseudo-random number ((pseudo-random number×fast clock cycle=required delay)) and the driving clock is at a high level, otherwise output a low level.
[0036] The high level or low level of the output is used as the driving clock of the LASER and SPAD with a pseudo-random delay on the rising edge, and this driving clock is used to achieve resistance to interference from multiple laser radar systems.
[0037] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A laser signature method that resists interference from multiple laser radar signals, characterized in that: By delaying the rising edge of each clock cycle that drives the LASER and SPAD differently, the interference of fixed frequency signals can be eliminated; including: Under fast clock, the pseudo-random number generator generates a pseudo-random number and stores it when the rising edge of the LASER and SPAD driving clock arrives; When the rising edge of the LASER and SPAD driving clock arrives, the counter starts counting from 0 under the fast clock. Only when the counter counts the stored pseudo-random number and the driving clock is at a high level, it outputs a high level and the counter is cleared at the same time, otherwise it outputs a low level; The output high level or low level is used as the driving clock of the LASER and SPAD with a pseudo-random delay on the rising edge, and this driving clock is used to achieve resistance to interference from multiple laser radar systems.
2. The laser signature method for resisting interference from multiple laser radar signals as claimed in claim 1, characterized in that: The delay is equal to the pseudo-random number×fast clock period.
3. The laser signature method for resisting interference from multiple laser radar signals as claimed in claim 1, characterized in that: The pseudo-random number generator is implemented based on a linear feedback shift register.
4. A laser signature device resistant to multi-laser radar signal interference, characterized in that: It includes a pseudo-random number generator, a counter and a judgment control module. The counter and the pseudo-random number generator are driven by the fast clock domain to delay the rising edge of the LASER and SPAD driving clocks differently, and the judgment control module outputs the corresponding level to achieve the effect of resisting interference from multiple laser radar systems, where: The pseudo-random number generator is used to generate a pseudo-random number under a fast clock and store it when the rising edge of the driving clock of the LASER and the SPAD arrives; The counter is used to start counting from 0 under the fast clock when the rising edge of the LASER and SPAD driving clock arrives; The judgment control module is used to output a high level and clear the counter when the counter counts the stored pseudo-random number and the driving clock is at a high level, and to output a low level otherwise; The output high level or low level is used as the driving clock of the LASER and SPAD with a pseudo-random delay on the rising edge, and this driving clock is used to achieve resistance to interference from multiple laser radar systems.
5. The laser signature device resistant to multi-laser radar signal interference as claimed in claim 4, characterized in that: The delay is equal to the pseudo-random number×fast clock period.
6. The laser signature device resistant to multi-laser radar signal interference as claimed in claim 4, characterized in that: The pseudo-random number generator is implemented based on a linear feedback shift register.