Can someone please explain why the head units (Kenwood, Eclipse, Pioneer) all have a speed pulse sensor to hook up yet the portable units work great without? Is the speed pulse sensor really needed? On the Corvette forum most don't even hook it up, they say all it does is keep the car from floating on the screen when standing still. Seems like this is the hardest part of the install (wiring) which could be skipped.
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- Thread starter ltnate3
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Dartastic
Dedicated LVC Member
ltnate3 said:
How do you know it doesnt have a speed sensing unit? I cant look at my system and tell but can tell you my Eclipse avn5495 is very accurate. I can only guess that it gives me info on how long it would take to reach my destination based on distance and speed.
the way the portables work without is they just plain lose the signal near real tall buildings and in tunnels (I've had several). additionally there is a bit of "lag" constantly (1 second behind). the satellite triangulation and processing is a little slow. the speed signal gets the car moving on the map pretty much in realtime. the way the portables calculate MPH (and accurately) is simply by measuring how fast you are moving according to the satellite data. I'd hook up the speed sensor.
Dartastic said:
I'm talking about the Garmins, Tom Tom, etc...If they have a speed sensing unit it's internal and I have no idea how that would work. However that is my question, how do the portable units get away with not having something hooked up to the wheels and the indash units (Eclipse) require it?
kudisbetta
Well-Known LVC Member
ltnate3 said:
dam, you have navi too.
You have the mobile video deparment on lock.
Nice
Dartastic
Dedicated LVC Member
ltnate3 said:
The guys that installed my Eclipse said the speed sensor was the easiest part of the install.
beaups said:
Yeah I was just being lazy and the Nav is the only thing that I can't do without help. Just thought someone might know of a place other than the wheels. I put one in my vette and it was a pain.
Dartastic
Dedicated LVC Member
ltnate3 said:
Uhhh hooked up to to the speed sensor on the vehicle? LOL I dont know. I know where the antenna is. I knew it was an install beyond my capabilities and I used to install head units for fun. Crutchfield says it doesnt fit the LS and it DOESNT without some major modification. I watched them grind away here and there. I have some tools but dont own a machine shop.
SilverLS
Dedicated LVC Member
OK I have tom tom on my dell and its very accurate....speed is right on(check again a radar gun) and it also has turn buy turn.....so it works great....IIRC there was a guy with the eclipse unit and he was trying to find where he could get the signal from all four wheels....they all were wired indepnt. and he could not find where they averaged out....he had all data too IIRC or Lou (quickLS) helped him.... I dont remember
The speed sensor is normally mounted in the transmission, because it reads the tail shaft RPM and send it to the PCM for calculation of the vehicle's speed.
Any decent GPS-based nav system will have an accurate speed reading when moving; even though portable GPS units aren't necessarily precise when it comes to positioning (+/- 10m, IIRC), their velocity readings are very precise (+/-0.11mph on my old Garmin). The more GPS satellites they can lock onto, the more accurate the readings will be.
The portables will lose signal in tunnels, when surrounded by tall building, etc. I don't know, but I'd bet that they use some sort of inertial guidance system, probably using an accelerometer setup, ala the G-Tech--then again, it could also be a software strategy...
Any decent GPS-based nav system will have an accurate speed reading when moving; even though portable GPS units aren't necessarily precise when it comes to positioning (+/- 10m, IIRC), their velocity readings are very precise (+/-0.11mph on my old Garmin). The more GPS satellites they can lock onto, the more accurate the readings will be.
The portables will lose signal in tunnels, when surrounded by tall building, etc. I don't know, but I'd bet that they use some sort of inertial guidance system, probably using an accelerometer setup, ala the G-Tech--then again, it could also be a software strategy...