Forward Sensing Camera VS Radar Sensor?

[theplayer11]

Wife stated today there was a big orange circle warning error message this morning on the dash. Windshield had a layer of ice. I'm just trying to figure out if the message was because of the windshield camera(most likely) or because of the camera behind the Mazda emblem.
Manual states the FSC and the RS are both used by cruise control and smart brake support.
Can someone please explain the differences between the camera and the radar and how they might work together?

 

[Ronzuki]

Your suspicion is correct. When the camera in windshield is compromised, many things won't fully function, if at all. Becomes very hit-or-miss. RACC and auto hi-beam control are two I know of for certain, by experience. I get a warning that says radar cruise won't operate below 20mph when the windshield is frosted, iced, or too wet. 'Too wet' as in it's raining more than the wipers can clear with a single swipe. The radar cruise won't operate under that condition reliably either I've experienced. The windshield issue alone combined w/ the 20mph warning indicate the camera is integrated into the "radar assisted cruise control" Rather misleading (no surprise there) for close quarters distance control by the "Radar Cruise". The device behind the Mazda emblem is the radar detector, not a camera. When it's snowing out and this device becomes covered in winter road slush, it renders the RACC totally non-functional and will throw a warning message that Radar Cruise is disabled. All these nifty, so-called driver assist, safety systems don't function when drivers would really benefit the most from the concept...during foul weather. Knowing there isn't enough money on the planet to properly automate these functions for guaranteed reliably in an automotive application, this is no surprise to me. I consider these 'features' a me-too marketing ploy and waste of vehiclular dollars. Vision systems are among the most difficult, and expensive, automation projects to implement reliably.

 

[Avoidin Deer]

From my manual:

Pg. 4-208 Front Radar

Your vehicle is equipped with a radar sensor (front). The following systems also use the radar sensor (front).
* Distance Recognition Support System (DRSS)
* Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function)
* Smart Brake Support (SBS) The radar sensor (front) functions by detecting the radio waves reflected off a vehicle ahead or an obstruction sent from the radar sensor.

One interesting note:

When driving on roads with little traffic and few vehicles ahead or obstructions for the radar sensor (front) to detect, *Front Radar Sensor Blocked* may be temporarily displayed, however, this does not indicate a problem.

I live in a very rural area with extended distances of no traffic at times, and have never had a lack of surrounding objects trigger this warning.

Pg. 4-203 Forward Sensing Camera

Your vehicle is equipped with a Forward Sensing Camera (FSC). The Forward Sensing Camera (FSC) is positioned near the rearview mirror and used by the following systems.
* High Beam Control System (HBC)
* Lane-keep Assist System (LAS) & Lane Departure Warning System (LDWS)
* Traffic Sign Recognition System (TSR)
* Advanced Smart City Brake Support (Advanced SCBS)
* Smart City Brake Support (SCBS)
* Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function)
* Smart Brake Support (SBS)

There are also rear radar sensors for Blind Spot Monitoring and Rear Cross Traffic Alert System.

Only Smart Brake Support uses both the front radar and the camera, according to this list. I believe the camera works at lower speeds and the radar works at higher speeds, but that's conjecture.

I had a system failure warning once when the car was parked for a couple of days during huge rainstorms followed by drastic temperature changes. I use a windshield sunscreen, and when I took it off, the inside of the windshield was soaked from condensation. I've never seen anything like it. It was so bad I started looking for leaks, but I could tell it was from general condensation and not localized intrusion. After driving for a while, things dried out and the systems returned to normal (in other words, they self-reset once the condition cleared, and did not require a restart.)

 

[Ronzuki]

From my manual:

One interesting note:

I live in a very rural area with extended distances of no traffic at times, and have never had a lack of surrounding objects trigger this warning.

There are also rear radar sensors for Blind Spot Monitoring and Rear Cross Traffic Alert System.

I too live in a rural area and have had that random BS warning appear, twice that I can recall, and wondered wtf now? Chalked it up to the fact that this 'stuff' simply is no where near ready for prime-time deployment. We're just afforded the luxury of paying to be beta testers. And as far as the Blind spot monitoring, another non-functional piece of garbage when it's really needed... In bad weather...ice covered vehicle, radar detector/sensors no worky, just like the forward unit.

As far as your conjecture is concerned, that's a very relavent key statement. It's all operational conjecture and the real problem is there will be operational assumptions made by owners/operators that are simply not reliable. Therefore, I don't pay any attention to it, disable it all, and continue operating the machine as I always have before all of the wonderfully over-priced innovations were shoved down my throat.

 

[Avoidin Deer]

Dude, you sound like me.

I was angry when I could no longer find a car with manual roll-up windows.
I never used the a/c in the car because driving with the windows up isolated me from my surroundings.
Back in the days of landlines, friends would be at my house and get angry I had yet to upgrade to a touch-tone phone.
I love analog anything...music media, watches, meters, etc. Life is not binary.

Regarding these modern features: I have only experienced one false alarm, and that was from the braking system that saw something that either I did not or that was not there (I was headed into a sharp curve, and that's a condition where those things happen). Been down that road many times, it's only happened once. Maybe there was a dog I did not see in the yard in front of me behind the fence.

I'm retired so am not forced to drive in whatever weather condition might exist on any given day...I've yet to have any real problems with the systems. That being said, this stuff merely augments my own awareness as I drive (knock on wood), but I've grown to like the support (even though given a choice I would not have paid for any of it). Being a habitual turn signal user, I really like the Blind Spot Monitor warning me when I prepare to change lanes.

The only thing that is a true addition to real functionality for me is the Radar Cruise Control. Now that I've had it, I would not want to live without it.

Perhaps after I've lived through an entire year's worth of weather conditions I'll feel different about my car. But being here in Central Virginia, snow of any amount is an every-4th-year event, punctuated every two decades with a 4 foot event.

 

[Ronzuki]

No doubt RACC is the bomb. I wouldn't go back to std cruise either. I use it quite a bit to simply drive in lobotomy mode on the relatively straight and mundane two lane road portion of my daily commute. The RACC consistently achieves better overall fuel economy on those stretches of road than I than I do. However, there are instances on the 2-lane roads where the radar's/camera's short comings become quite apparent, accelerating when it really shouldn't, usually requiring a tap of the brakes to disable it. Much like you have noted above, some weirdness. The beauty is I can chose to not use the feature by not turning it on. All the other crap, I must disable. I'm certain the braking algos that are utilized by the RACC is/are the same as the so-called Smart Braking System, which has it's issues, and which I've gotten in the habit of disabling, every, bloody, time, I start the car. Truly a huge PITA. The RACC can be fairly annoying on the highway when you get cut off (gradually or otherwise), resulting in the heavy application of the brakes...not good. My 2010 Kizashi has almost 92,000 miles on it... still has the original brake pads and rotors. I'd wager heavily that will not be the case w/ this CX-5.

As far as the blind spot monitoring goes, it's extremely annoying and unreliable to me, and is therefore totally disabled. Simply don't trust it. I rode cycles for many many years in my younger days, so I never make a move w/o visual verification first (quick flick of the head in conjunction w/ the mirrors). It's an ingrained habit, served me very well, kept me out of wrecks and alive, will never cease, and is why I am utterly pissed about a mid-grade AWD model car not having heated side mirrors as standard safety equipment. Especially in the NE. Frozen rain, ice and heavy frost is a constant winter-time reality. But hey, I have a gov mandated back-up camera...for safety (like I drive down the road backwards). The tech can not function and now I can't see either, perfect 'blind-spot' safety system aye? Fail. One must think of the car's systems in concert and that was clearly not the case in the Touring model.

 

[Ronzuki]

No more 'assistance' anything. Annoying lights cluttering up the dash, but better than the beeps and BS. No more 'nearly rear-ended' events because of that middle one, which, is the real PITA if I don't remember to disable it at every single start.

 

[Anchorman]

They don’t actually work in conjunction, they work separately as shown in the attached tech info sheets.

 

[Avoidin Deer]

They don’t actually work in conjunction, they work separately as shown in the attached tech info sheets.

That's right. I may have implied otherwise. The two do not work in conjunction, but the braking system is driven by the radar under one set of circumstances (SBS) and by the camera in another (SCBS). I believe that SCBS is a sub-component of SBS.

See this note at the bottom of Page 11 on SCBS.pdf:

If the Smart Brake Support (SBS) system operation is turned off, the Smart City Brake Support (SCBS) system operation is turned off simultaneously.

 

[Anchorman]

My comment was for the benefit of the OP, not correcting you AD