Industry is main to 3 kinds sensor (photograph like head, radar and LIDAR) the different motive in the car, and how are they satisfied severally advanced drive support system (ADAS) and the feeling that drive automatically measure demand to still be put in a few bewilderment.

 

Recently, I and my friend undertook interesting discussion, he knows I am considering to be used at ADAS system to mix drive automatically car (AVs) in the TI millimeter wave of radar (MmWave) sensor.

 

Every time he is read drive automatically the car is in different drive below the environment (for instance fraise detects) the metropolis when the article of moving circumstance makes fun of at once I. Among them dialog is as follows:

 

Matt: “ if that car carries the sentence that has LIDAR, can distinguish the object among path of dispatch a vehicle easily. ”

I: I still do not agree with “ such view. ”

Matt: “ what? ! Why don’t you agree? Sensor resembling a head and sensor of a radar are photographed of on that car, but ADAS system fails completely still to feel measure that vehicle among driveway. ”

I: When “ should read the event that produces recently to these, if photograph,you can notice often expose the Jiang Guanghe in dazzling like the head under other factor, can bring about its to cannot see the object on the road. Their low to the light of tall contrast and visibility circumstance is relatively sensitive, be like weather of snow of big mist, rain. Below this kind of circumstance, radar sensor may identify a target really. ”

Matt: “ nevertheless, we still can encounter the different situation that these ADAS and AV system answer very hard it seems that. So does the problem go after all where be? ”

I: The decision-making system of “ADAS is relied on it seems that make those who give priority to sensor photograph will judge a target to whether exist really like the head, whether be perhaps false alarm. ”

Matt: “ so, che Zailei is amounted to and photograph undeserved like the head trustful cough up. Can regard exclusive and reliable sensor as LIDAR only so. Is what I say right? ”

I: “ is completely not right. Although LIDAR is inferior to photographing to the susceptibility of visibility,resemble a head, but it waits for weather situation to mist, rain, snow sensitive. In addition, the cost of LIDAR is very high still, the likelihood brings about his to be able to be in only at first the 4 class of opposite high end drive automatically with 5 class use on car. ”

Matt: “ this is! Can make drive automatically without a kind of sensor car is truly reliable. We must this 3 person union is used, but this also is meant drive automatically the price of car will be very expensive. ”

I: You say “ only was opposite one part. 4 class drive automatically with 5 class car may need to photograph like head, LIDAR and radar these 3 kinds of sensors offer high reliability to mix full automatic drive experience. But, to more need the part drives automatically and for the 2 class that had begun massive amount to produce and 3 class economy car, of sensor of use TI millimeter wave into can come true like radar high-powered with cost effectiveness, can use ADAS function extensively. ”

 

So, what is to become resemble radar?

No less than I explain to Matt in that way, into a subclass that resembling radar is radar, because its are tall,horny resolution can provide clear picture and get a name.

 

Into enable by configuration of a sensor like radar, among them cascade of sensor of millimeter wave of TI of many low power is together, and as unit synchronism moves. It is had many receive and launch a channel, can improve horny resolution and radar distance performance significantly. When cascade of millimeter wave sensor is together, can use compositive phase shifter to establish beam ode look, reach 400 meters patulous range thereby. Graph 1 showed the sensor of cascade millimeter wave that evaluates module to go up and its antenna.

 

Graph 1: A kind have sensor of millimeter wave of 4 cascade TI into evaluate module like radar

 

Use at becoming the millimeter wave technology like radar

Typical radar sensor just is regarded as car till recently medium advocate sensor, its are main the reason depends on horny resolution function relatively finite.

 

Horny resolution is to point to the capacity that leaves divisional object with identical and relative speed inside same range.

 

One highlights the common use that resembles radar sensor advantage is can distinguish static object with high resolution. Typical millimeter wave sensor has the property that is apart from resolution high rate, high, can identify easily and divisional mobile, but to static object, its identify ability very finite however.

 

For example, the car that sees stop among ” driveway to let sensor “ distinguishs its and lamp lever or barrier come, sensor need is mixed in angle of elevation azimuthal the horny resolution with go up to have proper.

 

Pursue 2 showed one is stranded the car in channel, inside the car ceaseless fume. This car stops in about 100 meters of far, channel height is 3 meters.

 

Graph 2: Come of the car before radar need is enough high horny resolution will distinguish channel and stop car. Millimeter wave sensor can penetrate any visibility circumstances, for instance smoke.

 

Graph 3: How does millimeter wave sensor use much input to be outputted more (MIMO) radar implements resolution of tall angle of elevation.

 

To discern a plan 2 show the car in channel, sensor need distinguishs its and channel ceiling and wall come.

 

Classification of real spot scene needs to use these angle of elevation and azimuthal resolution:

? (Angle of elevation) = is cut anyway (2 M/100 M) = 1.14 is spent

? (Angle of elevation) = is cut anyway (3.5 M/100 M) = 2 is spent

 

Among them, 2 M is channel height the value of subtractive car height, 100 M is to take those who resemble radar to come car and the distance that stay between the car inside channel, 3.5 M is the distance between the car that parks inside channel and channel wall.

 

Below certain weather and visibility circumstance, rely on other optics sensor to may have challenge sex. Smoke, mist, soup and contrast of light and shade are the visibility case that has challenge sex, these circumstances can check optical passivity and active sensor, if photograph,resemble head and LIDAR, bring about these sensor to cannot identify a target possibly thereby. However, below harsh weather and visibility circumstance, sensor of TI millimeter wave still can hold driving property.

 

Current, into resembling radar sensor is exclusive the sensor that can hold driving property below all sorts of weather and visibility circumstance, its are in azimuthal the horny resolution that goes up to be able to achieve 1 degree with angle of elevation (use when exceeding numerical value of resolution algorithm computation lower even) .

 

Conclusion

Use sensor of TI millimeter wave into have very tall flexibility like radar, can be felt with very high resolution and classify the object in near field, can dog in 400 meters of far field beyond at the same time target. Efficient high resolution becomes this kind of cost to be able to make like radar system 4 class mix 2 class and application of 3 class ADAS and high end 5 class drive automatically car becomes a possibility, can use as in car advocate sensor.