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How to Disable GPS?

Discussion in 'Gen 4 Prius Audio and Electronics' started by sfblue, Dec 22, 2018.

  1. sfblue

    sfblue New Member

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    I would like to disconnect/disable GPS at the hardware level. That is, not just switch off the display, but disconnect the actual GPS hardware system.
    (Odd as it might sound, GPS systems inc. "Location" on my iPhone, trigger a mild ache in my groin (!))
    Any pointers much appreciated!
     
  2. fuzzy1

    fuzzy1 Senior Member

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    Is this likely to be integrated within the Safety Connect system, i.e. within the cellular communication system hardware? If so, you might need to disable / de-power / destroy that whole module.
     
  3. Elektroingenieur

    Elektroingenieur Senior Member

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    I assume by “GPS” you mean the GPS receiver in your car. I’m not a physician, but I’d consider it extremely unlikely that any such receiver is responsible for the physiological symptom you describe. I would encourage you, rather than modifying your car, to seek medical attention to diagnose and treat the actual cause.

    That said, fourth-generation Prius and Prius Prime cars have one or two GPS receiving antennas: the Navigation Antenna Assembly under the dashboard, used by the Navigation Receiver Assembly (the radio head unit in the instrument panel) and, on some models, the Telephone and GPS Antenna Assembly on the roof, used by the Telematics Transceiver (the data communication module for the Safety Connect system).

    Disconnecting or removing the antenna assemblies would probably keep the car from determining its location using GPS and might also disable other radio functions. The GPS receiver circuits in the Navigation Receiver Assembly and Telematics Transceiver (if equipped) would still be present and attempting to operate, so diagnostic trouble codes, such as B15C0 or B15C1, would be stored to indicate an antenna problem.

    The Navigation Antenna Assembly is shown in parts catalog Figure 86-03, Navigation & Front Monitor Display, with part name code 86860. The Telephone and GPS Antenna Assembly is shown in Figure 86-04, Antenna, with part name code 86300J. Details on parts removal and installation are in the Repair Manual (more info). It’s not trivial to do, and any resulting damage would not be covered by Toyota’s warranties.

    There could also be GPS antennas or receivers in dealer-installed or aftermarket accessories, of course.
     
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  4. sfblue

    sfblue New Member

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    Thanks for the detailed pointers. Sounds like quite an undertaking and I wonder if the system would continue hunting for a signal.

    On my iPhone, I avoid this issue by limiting the use of "Location Services" which can be switched off in the standard interface under Privacy settings. I can't see anything similar in the Entune interface. Is there is a way to turn off the maps function?

    btw - I first noticed this physiological issue in 2004 after many weeks of using a cellular modem in my laptop. An ultrasound showed no anomalies. I've mentioned it to a few docs but its not something they've seen.
     
  5. bisco

    bisco cookie crumbler

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  6. Elektroingenieur

    Elektroingenieur Senior Member

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    No, not without completely removing or disconnecting the Navigation Receiver Assembly.
     
  7. sam spade 2

    sam spade 2 Senior Member

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    The "real" GPS in the car works ENTIRELY differently than the "location" function in a cell phone.
    The GPS only calculates your position and does not transmit that out to anything......including your groin.

    Or are you saying that you have this groin pain show up every time you are in the car ???

    Side note: I've been fighting a bad case of heat rash all summer. Maybe it's caused by my cell phone. ;)
     
  8. ChapmanF

    ChapmanF Senior Member

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    At first, I read the thread title as "I don't want stuff in my car to track my location." That would be a question I could understand. I don't understand how a GPS signal receiver would give anyone an ache, but there are lots of things I don't understand.

    If you want to stop the car from knowing where you are, it's pretty helpless with the GPS antenna unplugged, which is easy. If you have nav and Safety Connect, remember there are two independent GPS antennas to unplug.
     
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  9. mitcheli

    mitcheli Junior Member

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    So, GPS is a broadcast signal emminating from satellites in space. They broadcast a low wattage signal that is encoded using spread spectrum. The algorithm for which is well known by receivers, which in turn look for the very weak signal space. Each satellite has its own transponder and is in geosynchronous orbit. If you wanted to actually block the GPS signal, you would need to live in a faraday cage. All the receivers do is listen for all the different signals, find which ones they can, and calculate signal strength they receive to triangulate your location.

    Now, cell phones use something called GPS-A, this “assisted” GPS. What means is that the same technique is used against other “fixed” radio sources, mainly Cell Towers and WiFi hotspots. (Convientently mapped by Google when they did their street view runs). It is possible that getting a fix may initiate a brief transmission with a tower, but more than likely, the transmission coming from your phone is likely downloading map data, or checking email, etc.

    There are other technologies in this mix as well like GLASNOSS and Galileo and Beidou. These are similar to GPS, but ran by countries outside the US. Also, there is a military version of GPS as well.
     
  10. sfblue

    sfblue New Member

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    It seems to be an issue only while navigating. When I drove the car home I had navigation on screen. This afternoon I drove from SF to San Jose without issue. 67mpg - wheeee! I have 13 miles of battery left so I'll do even better on way home. Loving this car!
     
  11. alanclarkeau

    alanclarkeau Senior Member

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    I don't understand how it could be causing a physiological problem, any more than any radio or TV or Wi-Fi gadget. My understanding is that there is no signal from the GPS/Car at all - all the car does is receive the signals from the various satellites in the GPS network. If it locates a signal from 3 or more GPS Satellites, it uses it's "brain" to locate your position on a map. If it locates 4 or more, it can also calculate altitude.

    They're there in the air, invisible, like TV and radio signals - and there's nothing we can do about them.

    Totally different from the situation you mention with a laptop modem - which I presume you're meaning Bluetooth or Wi-Fi.

    My concern with removing the antennae is that the GPS unit might use more and more power to try to find the Satellites it's trained to look for. But there's also a possibility that it might detect that the antennae are missing and give you a series of fault codes, (or even a failure of the Entertainment system).
     
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  12. alanclarkeau

    alanclarkeau Senior Member

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    The other thing you would have to keep in mind is that removing those antenna would almost certainly mean that you couldn't make phone calls by Bluetooth from your phone - it's referred to as a "Telephone and GPS Antenna Assembly" as mentioned by @Elektroingenieur in post #3.

    TOYOTA advises (referring to it only "receiving"):
    upload_2018-12-26_17-33-39.png

    AND (again advising that it only "receives"):
    upload_2018-12-26_17-34-52.png

    Reading this - you would probably have a non-working AM & FM radio (and Satellite radio if it's fitted) if you were to disconnect the antenna.
     
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  13. sam spade 2

    sam spade 2 Senior Member

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    The key part of that sentence is "Seems to be".
    Maybe you sit differently in the seat when you are watching the GPS screen.
     
  14. ChapmanF

    ChapmanF Senior Member

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    It's an 'assembly' with distinct antennas in it. They plug in to distinct ports at the back of the head unit. It's possible to unplug just one.

    At least, that's how it is in my Gen 3. Perhaps Gen 4 brings them all on one combined connector, but it's hard to see why they would want to.
     
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