Explorer Physics 101

[grrtrainman]

:scratch::scratch:

A few questions to Cory and/or fellow forum members about the “Collision Warning System” , (CWS), installed in some of our Explorers. The owner’s manual, pg 269 , states “Due to the nature of radar technology, there may be certain instances where vehicles do not provide a collision warning. These include :

-STATIONARY VEHICLES or vehicles moving below 6 mph (10 km/h). “

Okay, we know radar works by bouncing microwaves off of solid objects in front of it and a tiny part of that energy is returned to the transmitting antenna. In our case that antenna is behind the left front bottom fascia of the Explorer.

Question: why does that “target” have to be moving ??? I may be incorrect, but doesn’t the military use radar on both stationary and moving targets??? I know my CWS is working because the red “heads up display” and audible chime will go off when going around sharp corners with a guardrail in front of you. From that statement above, it appears that the warning system will NOT WORK if you come up on a STOPPED car in your lane. If that’s true, how unfortunate - it could prevent quite a few rear enders. No, I am not about to “test” the system !!! What have forum owners with the CWS experienced ??? BTW, the things the Explorer will do, (i.e.: “Driving Aids” ), are unbelievable. GM and Chrysler aren’t even close. Yet.

Thanks in advance,

David

 

[peterk9]

:scratch::scratch:

A few questions to Cory and/or fellow forum members about the “Collision Warning System” , (CWS), installed in some of our Explorers. The owner’s manual, pg 269 , states “Due to the nature of radar technology, there may be certain instances where vehicles do not provide a collision warning. These include :

-STATIONARY VEHICLES or vehicles moving below 6 mph (10 km/h). “

Okay, we know radar works by bouncing microwaves off of solid objects in front of it and a tiny part of that energy is returned to the transmitting antenna. In our case that antenna is behind the left front bottom fascia of the Explorer.

Question: why does that “target” have to be moving ??? I may be incorrect, but doesn’t the military use radar on both stationary and moving targets??? I know my CWS is working because the red “heads up display” and audible chime will go off when going around sharp corners with a guardrail in front of you. From that statement above, it appears that the warning system will NOT WORK if you come up on a STOPPED car in your lane. If that’s true, how unfortunate - it could prevent quite a few rear enders. No, I am not about to “test” the system !!! What have forum owners with the CWS experienced ??? BTW, the things the Explorer will do, (i.e.: “Driving Aids” ), are unbelievable. GM and Chrysler aren’t even close. Yet.

Thanks in advance,

David

"No, I am not about to “test” the system !!!" David, where is your sense of adventure??
Perhaps our system works on calculation the moving distance between our vehicle and the one ahead. That would not however, explain why the warning sounded due to the guardrail. The manual also states it will not detect a vehicle coming at you in your lane. Mine has only ever triggered when approaching a vehicle that is slowing to make a right hand turn and I don't brake because I know the vehicle will be gone by the time I arrive at that spot.
Very interesting question.:scratch:

Peter

 

[KlausJ]

I think this has not a technical but a functional reason.

If the system would detect stationary vehicles or other things not moving, it would give you one false alarm after another. Because it would not only detect cars but also traffic signals or signs or every other damm thing which is temporarily in your way or just nearby.
Think of driving down a highway with a lot of curves. Your car has no idea that you will follow the cuve and detects a traffic sign which is a second right in front of you, or the car which is just driving the opposite direction and is just in front of you for a second during the curve. It would alarm you all the time.
So there is a software checking if the recognized obstacle is moving relatively to the "ground" and coming close no faster than you are driving at this moment.

Because of the same reason the ACC does not work for stationary vehicles or obstacles or if the the car is below 15 mph. Imagine it would apply full brakes every time you are approaching something stationary or a car driving the opposite direction. So also the ACC is restricted to vehicles driving in more or less your direction and does not approach you faster than you are driving.

In Europe some cars are equipped with traffic jam Cruise control. It recognizes also stationary verhicles. It accelerates up to 25mph and stops to zero and holds you behind the car in front of you automatically.
But this system disables itself when you are faster than 25 mph because it would fully brake if (even only temporary) approaching something stationary.
You as the driver know what you will do and where you will turn in a few seconds. The Software doesn´t have a clue about that.

 

[grrtrainman]

Klaus:

Now THAT makes sense. In fact, as in my original note, my forward scanning radar does, in fact, set off the red HUD and the audible warning when it sees a guardrail, etc. I’ve even had it go off while backing up out of my garage! The sensitivity is set at the highest value, so that probably explains it. Has anyone else out here in ‘Explorer Land’ experienced this ?

BTW, your English is absolutely fine !

Thanks-

David

 

[harlenm]

The largest obstacle that the radar sees is the road itself. That is how police radar is able to work while moving. It measures the speed of the car based on the reflection off the road, and subtracts it from the speed of the oncoming vehicle.

 

[Justyman87]

I feel as if I had times when the CWS went off randomly with no car insight. I figured it must read something on the floor or turn but it shouldn’t. It happens once in a while but should I get it checked?

 

[FordService]

Hey guys,

My tech adviser got back to me stating the main intention of the Collision Warning System is to pick up slower moving vehicles or vehicles that slow down rapidly in front of you. Most rear end accidents involve a slower moving vehicle being hit by a vehicle moving at higher speeds, not a stopped vehicle. Because of this the software is looking for slower moving vehicles, not stopped vehicles. It will, in most cases, pick up a vehicle at a standstill, but that’s not what the primary intention of the CWS is for.

See page 274 of the 2013MY Explorer Owner Guide 3rd Printing for more on the system. Grab a free copy of the Owner Guide here:

http://Owner.Ford.com/servlet/ContentServer?pagename=Owner/Page/OwnerGuidePage

Pick your ride from the drop-down menus and download away!

I feel as if I had times when the CWS went off randomly with no car insight...

I recommend having your dealer check the system next time you’re in, Justyman87. I’m confident they’ll get to the bottom of it.

Cory

 

[grrtrainman]

Very informative answer there, Cory - fine job. Thanks for getting to the tech guys so fast! Just another reason why I’m back with Ford…

David

 

[Justyman87]

Thanks Cory. I’ll sure get it checked.

 

[FordService]

Very informative answer there, Cory - fine job. Thanks for getting to the tech guys so fast! Just another reason why I’m back with Ford…

David

Thanks a bunch, David; I appreciate it!

Thanks Cory. I’ll sure get it checked.

You got it, Justyman87; I’m looking forward to seeing an update.

Cory