If lidar deceives you

在未来的某一天，自动驾驶仪已经普及，各种自动驾驶仪汽车在街上行驶，人们在车里睡觉。

One day in the future, autopilot has been popularized, and all kinds of autopilot cars are running on the streets, and people are sleeping in cars.

突然，一辆汽车上的激光雷达错误地接收到了不属于它的"信号"，导致了一系列的误判。一时间，路上快速移动的机器陷入混乱

Suddenly, the lidar on a car mistakenly received the "signal" that did not belong to it, resulting in a series of misjudgments. For a moment, the fast-moving machines on the road fell into chaos

这种有点赛博朋克的场景在今天似乎很难理解，但事实上，这种情况已经出现在一些自动驾驶车辆集中的试验区。

This somewhat cyberpunk scene seems difficult to empathize with today, but in fact, this situation has appeared in some test areas where autonomous vehicles are concentrated.

据一位研究自动驾驶的高管透露，他们在亦庄安排了很多自动驾驶考试团队。这些测试装载了激光雷达和毫米波雷达，在我们想象的单车智能中实现了足够的设备和安全冗余。然而，在一次实际测试过程中，我们从未遇到过激光雷达出现故障。后来发现，原因是测试环境中的设备太多，导致干扰，导致一些传感器直接躺下。

According to a senior executive who studies automatic driving, they arranged a lot of automatic driving test teams in Yizhuang. These tests were loaded with lidar and millimeter wave radar, which achieved enough equipment and safety redundancy in the single car intelligence we imagined. However, in one actual test process, a lidar failed that we had never encountered before. Later, it was found that the reason was that there were too many devices in the test environment, resulting in interference, resulting in some sensors lying down directly.

这些机器相互作用造成的隐患场景看起来非常科幻，但背后的问题非常现实：如果装有激光雷达的自动驾驶车辆大规模上路，它们会相互干扰吗？这种干扰是否会成为影响自动驾驶安全的隐患？

The scene of hidden dangers caused by the interaction of such machines seems very sci-fi, but the problem behind it is very realistic: if autonomous vehicles equipped with lidar go on the road on a large scale, will they interfere with each other? Will this interference become a hidden danger affecting the safety of automatic driving?

今年是使用激光雷达的第一年。包括威来、小鹏和长城在内的量产汽车已宣布，将上市配备激光雷达的量产汽车。

This year is the first year of lidar boarding. Mass production vehicles, including Weilai, Xiaopeng and great wall, have announced that mass production vehicles equipped with lidar will be listed.

威莱et7将配备innovusion超远程高精度激光雷达，小鹏汽车将配备livox激光雷达，长城将配备ibeonext激光雷达。

Weilai et7 will be equipped with innovusion ultra long-range high-precision lidar, Xiaopeng automobile will be equipped with livox lidar, and the Great Wall will be equipped with ibeonext lidar.

威莱et7 nad硬件配置表来源：威莱官网

Hardware configuration table of Weilai et7 nad source: Weilai official website

每个人都在争先恐后地寻找谁将率先登陆大规模生产的激光雷达模型，这似乎让我们感觉越来越接近L3和L4辅助驾驶的时代。

Everyone is scrambling for who will take the lead in landing mass-produced lidar models, which seems to make us feel closer and closer to the era of L3 and L4 assisted driving.

同时，我们不得不承认，汽车驾驶的时代已经不再是传统的握着方向盘、踩刹车、驾驶员掌握安全的时代。人机驾驶，或者换句话说，人类驾驶，除了汽车本身，还由代码行驱动，携带中央处理器，携带大量传感器和芯片，进行大量复杂的计算，机器正在悄悄地控制着人机驾驶的新驾驶时代。

At the same time, we have to admit that the era of automobile driving is no longer the traditional era of holding the steering wheel and stepping on the brake, and the driver mastering safety. Man-machine driving, or in other words, human driving, in addition to the car itself, is also driven by lines of code, carrying a central processor, carrying a large number of sensors and chips, and carrying out a large number of complex calculations, Machines are quietly controlling the new driving era of man-machine driving.

如果技术正在创造新的驾驶体验，那么技术是否也会带来新的问题？

If technology is creating a new driving experience, will technology also create new problems?

当pinplay/pindrive询问准备搭载激光雷达的主机制造商、原始设备制造商和一级供应商时，他们几乎无一例外地回答说会存在干扰。

When pinplay / pindrive inquired about the main engine manufacturers, OEMs and Tier1 suppliers preparing to carry lidar, almost without exception, they answered that interference would exist.

我们试图从几个角度回答：

We try to answer from several angles:

首先，从技术角度来看，激光雷达之间的干扰是如何产生的？

First, from a technical point of view, how is the interference between lidar generated?

其次，在什么样的环境下会形成激光雷达干扰问题，目前如何解决？

Secondly, under what kind of environment will the problem of lidar jamming be formed and how to solve it at present?

最后，在自动驾驶时代，安全应该如何定义？

Finally, in the era of automatic driving, how should safety be defined?

关于激光雷达的干扰，cepton激光雷达的创始人裴军以PinWan/Pinjia为例：毫米波雷达发射电磁波，然后接收电磁波，检测前方物体的距离和速度。这一过程将受到干扰。

With regard to the interference of lidar, Pei Jun, founder of cepton lidar, gave an example for PinWan / Pinjia: millimeter wave radar transmits electromagnetic waves and then receives electromagnetic waves to detect the distance and speed of objects in front. There will be interference in this process.

裴军说："如果前面的汽车也发射毫米波雷达，而且波段与你的相同，就会产生串扰。"。激光雷达和毫米波雷达的工作原理相似。

"If a car in front also emits millimeter wave radar, and the wave band is the same as yours, it will cause crosstalk." Pei Jun said. The working principle of lidar and millimeter wave radar is similar.

首先，我们需要普及激光雷达的工作原理。

First, we need to popularize the working principle of lidar.

目前，车载激光雷达主要有两条技术路线：调频连续波（FMCW）激光雷达和飞行时间（TOF）激光雷达。TOF激光雷达是目前的主流。例如，为宝马提供L3自动驾驶和量产激光雷达的innoviz采用了基于TOF的MEMS方案。

At present, there are two main technical routes for vehicle lidar: FMCW (frequency modulated continuous wave) lidar and TOF (time of flight) lidar. TOF lidar is currently the mainstream. For example, innoviz, which provides BMW with L3 automatic driving and mass production lidar, adopts the MEMS scheme based on TOF.

它也是能够产生干扰的TOF激光雷达。当接收来自其他激光雷达的脉冲时，它可能会产生干扰。虽然发生的概率很小，但仍然有可能：a的激光照射到物体上，然后辐射到B的接收器。激光在物体上的反射是漫反射。这种漫反射可能导致B无法识别它是否是自己的激光雷达发射的激光束。

It is also TOF lidar that can generate interference. It may generate interference when receiving pulses from other lidars. Although the probability of occurrence is small, it is still possible: the laser of a shines on the object and then radiates to the receiver of B. the reflection of the laser on the object is diffuse reflection. This diffuse reflection may cause B to be unable to identify whether it is the laser beam emitted by its own lidar.

目前的解决方案是引入编码技术，将传输信号分成多个脉冲，或者根据时间序列号进行识别，这与我们手机接收验证码的原理类似，这是一种常见的做法。

The current solution is to introduce coding technology to divide the transmission signal into multiple pulses, or identify according to the time series number, which is similar to the principle of our mobile phone receiving verification code, which is a common practice.

裴军说，FMCW激光雷达方法使用调制波方法分别进行调制，最终能够抵抗干扰。然而，尽管FMCW激光雷达技术在消除干扰和提高远程性能方面具有优势，但其成本较高，因此尚未得到广泛应用。

Pei Jun said that the FMCW lidar method uses the modulation wave method to modulate respectively, and finally can resist interference. However, although the FMCW lidar technology has advantages in eliminating interference and improving long-range performance, it has high cost, so it has not been widely used.

虽然解决方案是一致的，但当装有激光雷达的车辆未大规模上路时，干扰的情况和概率仍在预测中，工程师无法预见。当数百辆装有激光雷达的车辆在道路上行驶，而道路上有密集的激光雷达时，会发生什么？

Although the solutions are consistent, the situation and probability of interference when vehicles equipped with lidar are not on the road on a large scale are still in prediction, and engineers can't foresee it. What will happen when hundreds of vehicles equipped with lidar are on the road and there are dense lidars on the road?

技术的发展是随着场景的复杂性而逐渐发展起来的。

The development of technology is gradually developed with the complexity of the scene.

激光雷达之间的相互干扰有几种情况。

There are several situations about how mutual interference between lidar occurs.

威尔逊智能网应用中心总设计师朱大伟分析，存在两种情况：对同一品牌安装的激光雷达的干扰和不同品牌型号之间的干扰。

Zhu Dawei, chief designer of Wilson intelligent network application center, analyzed that there are two situations: interference with lidar installed by the same brand and interference between models of different brands.

不同品牌模式的干扰也可以分为两种类型：有意干扰和无意干扰。

The interference of different brand models can also be divided into two types: intentional interference and unintentional interference.

朱大伟说，上述问题在理论上是存在的，但在现实中并没有成为问题，因为在道路上没有大规模生产装有激光雷达的车辆。

Zhu Dawei said that the above problems exist in theory, but they have not become a problem in reality, because there are no mass-produced vehicles equipped with lidar on the road on a large scale.

这就是为什么在谈到干扰时，许多汽车公司承认干扰很普遍，并且认为可以很容易地解决。

This is why when talking about interference, many car companies admit that it is widespread and think it can be easily solved.

然而，自动驾驶仪将在不同的场景中逐渐着陆。

However, autopilot will gradually land in different scenarios.

目前，很多汽车公司都从独立停车功能开始，因为场景单一，行驶速度低，相对比较好实现。

At present, many car companies start with the independent parking function, because the scene is single and the driving speed is low, which is relatively better to achieve.

在自动停车功能下，车辆可以在封闭的停车场环境中找到自己的停车位置，而无需驾驶员控制车辆。那么封闭式停车场可能是最早的干扰环境之一。由于具备聚集大量装有激光雷达的自主车辆的条件，当自动停车被广泛使用时，车辆之间的激光束会形成干扰。

Under the autonomous parking function, the vehicle can find its own parking position in the closed parking lot environment without the driver's control in the vehicle. Then the closed parking lot may be one of the earliest interference environments. Because it has the conditions for gathering a large number of autonomous vehicles equipped with lidar, when automatic parking is widely used, the laser beam between vehicles forms interference.

Link：https://new.qq.com/omn/20210830/20210830A0BCKY00.html

update time：2021-08-31 18:10:10