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Lexus LS 400/LS 430

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Comments

  • darbhdarbh Posts: 51
    The thing I find frustrating is that although the car "knows" when there is a person in the front passenger seat, it still won't let the NAV be programmed unless the car is stopped.

    The situation on the phone is ridiculous. And, they choose SPRINT, which, at least in LA, has incredibly bad service and they have not been truthful about it.

    This is not to downgrade the LS430, its a great car. It is just that these points are out of character for such as great vehicle.
  • nealm1nealm1 Posts: 154
    My antipathy to the NAV/Arcade-game phenomenon is well known to this group, and probably well-worn-out. I won't repeat prior rants about its lack of ergonomics, threats to safety etc. Besides, I won't need NAV on my Segway. Can you get a Mark Levinson on one of those?
  • jamesfletcher2, The GPS/NAV designer & manufacturer is Nippon-Denso of Japan for the 98-2000 LS400 as well as for the current LS430. Don't have any contact info. though.
  • wwestwwest Posts: 10,706
    Does business in the US under the name Denso USA.

    If you really want I have a contact name in the US that I can find if I go searching.

    But...

    Denso is an OEM supplier to any and all (mostly Japanese) automotive manufacturer's (primarily), as such they do not (have to) deal with individual customers, end users, and haven't a clue as to where to start.
  • Hi:
    I'm contemplating putting a NAV system (pulled from a LS 99 - screen, audio controls and all) into my 95 LS. Will it fit ? Can a car audio mechanic do it ? Thanks for your reply.
  • What about the GPS antenna? I'm not sure where it was located. Maybe printed on the rear window?
  • lenscaplenscap Posts: 854
    I don't think you can just put a nav system into a 1995 LS 400. The system was not even offered that year. Therefore, I'm sure the car is not wired to have it.
  • I live north of Atlanta, GA. and do not require snow tires. However sometimes we get an ice storm. The county I live in has many hill. Our home is down a long hill. When we have an ice storm every one must wait or walk out and sometimes rent a car for a day.
    Some one told me about these chains. I own a 2001 LS430 standard wheels.
    I purchased a set of chains from: tirechains.com.
    I installed the chains without removing the wheels or using a jack. See the site for a description.
    The work very well for me. Please post any comments.
  • wwestwwest Posts: 10,706
    you are absolutely on the right track.

    I run on summer tires year round and keep a set of chains in the trunk in the wintertime. Worked for all the time I was out in Montana too.
  • The navigation system is very complex. I doubt just changing the stereo, climate control, and adding the Nav system is possible. From what I remember the dealer telling me, there is part of the GPS system located behind the rear seat-I believe the gyroscope is there-as well as hard drive in the trunk area. But beyond that, I believe the GPS system in the 1998-2000 LS400 caused the need to change alot of other electronics in the car that work with the GPS.

    I would bet on it, that you won't be able to retrofit a 1998-2000 LS400 Nav system into a 1995 LS400. Best bet would be to go with a aftermarket Navigation system.
  • lenscaplenscap Posts: 854
    That's actually one of the reasons Lexus switched from Nakamichi stereos to Mark Levenson. Nakamichi could not get their system to work with the nav -- you could only have one or the other. The ML, however, can be ordered with the nav.
  • I thaught a gyro was for boat steering? In a boat the gps and gyroscope are hooked together to keep boat on track with currents working against it, I thaught. Tony
  • anthony1, It may not be a gyroscope-I can't remember the proper term the dealer told me-but the GPS system has a transmitter-tracking device of some sort located behind the rear seat and above the rear axle.
  • Yaw sensor would be for the Vehicle Skid Control sensor.
  • wwestwwest Posts: 10,706
    used a gyroscope as the basis for sensing yaw. Today's Lexii use a lateral and a longitudinal "accelerometer". Lateral for yaw detection and longitudinal for acceleration/deceleration.
  • That has nothing to do with the GPS Navi system though. That is strictly a Vehicle Skid Control/Traction system hardware unit.
  • wwestwwest Posts: 10,706
    I was just correcting what is under the rear seat, not a gyroscope but a yaw sensor and an accelerometer. And yes I can't imagine how those could be used with the GPS/Nav.
  • wwest you sure know your stuff. I`v enjoyed your posts over the months Tony
  • lateralglateralg Posts: 929
    Could it be used by the nav system when it is doing dead-reckoning? Steering position could also be used, but tire slippage that varies with speed may make it less accurate than sensing yaw that is induced by steering.
  • wwestwwest Posts: 10,706
    would be that the yaw sensor is good, okay, for detecting short term lateral "excursions" but not accurate enough over the long term to be used for "inertial guidance".

    The yaw sensor and the steering wheel position sensor and speed are used in combination to react and possibly correct oversteer, lateral yaw beyond that "commanded" by the steering wheel position, and understeer, insufficient yaw for the command input.
  • lateralglateralg Posts: 929
    Seems to make sense, but I'm unclear on your second paragraph.
  • flint350flint350 Posts: 250
    What he is saying is, the yaw sensor compares the amount of turn indicated by steering wheel input (e.g. gentle off-ramp vs. full 90 degree turn, etc) with the amount of turn (skid, spin, over/understeer) the car is actually making. If the steering wheel input doesn't match what the car is doing, corrective action is taken by the computers (braking, wheel spin, etc).

    Hope that's not more confusing yet. It's clear in my mind, but not as easy to explain.
  • lateralglateralg Posts: 929
    Oh!

    What you say makes perfect sense to me. Thanks.

    OTOH, doesn't that suggest that the yaw sensor would be a more accurate nav. system info. source for dead-reckoning navigation?
  • wwestwwest Posts: 10,706
    Only if you travel like a certain crab, SIDEWAYS!
  • flint350flint350 Posts: 250
    gschwartz, in theory, yes. But it is not that simple. The yaw sensor in the car is much less sophisticated than the several used in inertial nav. systems. You would need several and they have to be calibrated precisely and fully integrated gyroscopically with all nav inputs, including wheel size/spin rate and other such inputs that would be far too expensive to consider in a consumer product.

    In theory also, you wouldn't even need the GPS satellites since inertial nav doesn't need them - only a very precise knowledge of it's starting point. It then calculates position by measuring (thru those many and expensive sensors) the actual movement of the vehicle (inertia). These types of systems, used in airliners for years, can detect movement as small as a "push-back" from the gate at the airport.

    The car's GPS, on the other hand, uses satellite triangulation to arrive at a map coordinate which it then compares to the stored map in your database and, thereby, "finds" your position on the map. That is one reason why it occasionally gets "lost" or off position - if the roads change slightly since the database was made, a mismatch occurs. Of course, there are other reasons also, but this is getting long - sorry.
  • wwestwwest Posts: 10,706
    Only detects/senses "sideways" movements, "lack of" for understeer and "excessive" for oversteer. There is a decelerometer included in some lexus vehicles but I'm sure it isn't accurate enough in the long term.
  • lateralglateralg Posts: 929
    I'm getting smarter. Thanks Flint & West. I still have a knowledge gap:

    When in dead reckoning mode, (no GPS signal) which provides better information, steering sensor or yaw sensor?

    It seems that the steering sensor reads what the driver asks for, and the yaw sensor reads what the driver gets.

    The difference would be slippage, (slip angle) which varys with speed, road & tire coefficient of friction (which in turn vary with weather & temperarure), road camber, and maybe other stuff.

    Or, am I demonstrating profound ignorance of a yaw sensor's capabilities?

    Is there just one yaw sensor in the car? Is it (them) truly a yaw sensor, or as you suggest, a lateral accelerometer?
    Yaw: (Aeronautics) "To turn or deviate from the line of flight by angular motion about the normal, or vertical, axis"
  • flint350flint350 Posts: 250
    To the best of my knowledge, the yaw sensor in the LS is only for use in the vsc and associated systems and has nothing whatever to do with the nav. I was just trying to answer/explain how inertial nav works in response to your question and that, in theory (but not real world, economic reality) it could be applied in a car. But again, the yaw sensing is for loss of control - as you correctly state, it is sideways deviation from straight line and that is what is being monitored, not geographic position. Sorry for any confusion.
  • flint350flint350 Posts: 250
    Of course, if the yaw is sufficiently horrendous, it can, after all, result in a change in geographic position that might be detectable by the gps nav. ;) (requiring a tow truck)
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