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Thread: GPS receiver with external antenna?

  1. #21
    Raw Wave Laidback's Avatar
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    Quote Originally Posted by bes51659 View Post
    Thanks for links newb77!
    So I will probably buy the Epson gyro and the rev 5 u-blox unless any of you see any incompatibility.

    I will design hw around it and publish (sell maybe) if successful.
    You're going to design the hw to do the DR??

  2. #22
    Maximum Bitrate bes51659's Avatar
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    Yes, whatever interface that is needed. Hopfully it does not mean AD converters and such.

    From what I understand the DR algoritms and such are integrated in the receiver and all I have to do is to provide gyro signal in accurate format. Similar to your system that only needed an RS232 adapter (correct?)

    But I am new to this and have not looked into specs in detail so please tell me if you see any hurdles.

  3. #23
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    Quote Originally Posted by bes51659 View Post
    Yes, whatever interface that is needed. Hopfully it does not mean AD converters and such.

    From what I understand the DR algoritms and such are integrated in the receiver and all I have to do is to provide gyro signal in accurate format. Similar to your system that only needed an RS232 adapter (correct?)

    But I am new to this and have not looked into specs in detail so please tell me if you see any hurdles.
    Yes, they're integrated into a DR module but I didn't see any u-blox 5 modules with DR. You can't just tack a gyro on to any GPS module. They don't even seem to sell the u-blox 4 DR receiver board seperately, just in the evaluation kit.

  4. #24
    Maximum Bitrate bes51659's Avatar
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    Learnings something new every day :-)

    So you've bought the $500 kit including DR module? What about the Murata gyro in your thread? Is that the part included in the kit? Getting confused on a higher level...

    One way forward would be to get a EVK-5H-0 kit and build a small cpu system that takes the NMEA info from it and together with a gyro signal, tacho and direction and a clever algoritm generates standard NMEA traffic when there is no signal.

    If there was such a thing as a USB gyro that algoritm could even run on the carputer.

    Maybe its that USB device I should build? Algoritms available? Thread at franson

  5. #25
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    Yes, the 500 kit has the gyro within.

    Quote Originally Posted by U-blox website
    Features:
    Small and lightweight evaluation unit. Ideally suited for laboratory, vehicle and outdoor use
    LEA-4R module inside
    Built-in Epson gyroscope
    No, I didn't buy a kit. They used to supply the older DR module on it's own but I got mine second hand anyway.

    Algorithms? Look for Kalman Filter algorithm, That's what u-blox use.

  6. #26
    Maximum Bitrate bes51659's Avatar
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    Kalman

    I see... I guess the Kalman filter adjusts for signal strength from gyro and tacho gain etc. so that calibration is unnessessary. Below a picture that says nothing to me, but a picture always increase interest :-)



    I have googled "dead reckoning" and "kalman" and read wikipedia and realize that there is a lot of development spent in these algoritms and that it is not given away for free.

    So I need a DR module and a receiver, but I still think €500 is to much.

    So then there is the LEA-4R (USB) and the TIM-4R (UART). Unfortunately they do not contain the newest technology in the receiving department (? confirm?)

    These module are €145 and require a gyro with ADC (SPI interface), some kind of dc/dc converter, battery battery-backup and temperature sensor, also SPI (what is temp used for?!). and everything has to go on a pcb with antenna connector, usb connector etc.

    No Problem (why is the AEK-4R €350 extra?)

    Is there again a mayor part I've forgotten about?

    ----

    The €500 kit also contains an Epson gyro, maybe the very same one I saw on ebay that was $60 including p&p from Malaysia!

  7. #27
    Maximum Bitrate bes51659's Avatar
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    decition made

    I've just ordered the Lassen DR+GPS at 50 + p&p and the Epson XV-8100CB gyro at $50 + p&p. (notice currency) The gyro is listed in list of compatible devices, so I do not expect any surprices there.

    The Lassen DR+GPS kit was too expensive for me at 500. But "Diamond Point" is kind enough to enclude some electronics in their documentation that will save me quite some time. If I had enough money not to care, I would buy the kit.

    Thanks for all help so far.

    I will post result when done, which will probably be in 2 months or so.

  8. #28
    ptk
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    I am using a Sparkfun's Sirf III based GPS USB evaluation board ET301
    http://www.sparkfun.com/commerce/pro...roducts_id=780
    in conjunction with a rooftop mounted triplex antennae
    http://store.mp3car.com/Roof_top_GPS..._p/com-008.htm
    ***
    CarPC Ver 4 completed. Aopen i45GMT-HD, C2D mobile 2GHz. Photofast 64GB SSD. Novatel EU-850D

  9. #29
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    Quote Originally Posted by ptk View Post
    I am using a Sparkfun's Sirf III based GPS USB evaluation board ET301
    http://www.sparkfun.com/commerce/pro...roducts_id=780
    in conjunction with a rooftop mounted triplex antennae
    http://store.mp3car.com/Roof_top_GPS..._p/com-008.htm
    And?

    a, It sucks
    b, It's fantastic
    c, Can't answer now, I'm lost

  10. #30
    ptk
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    my apologies.

    it's working rather well. lock is quite reliable and consistant. bias voltage is applied on the module itself, removing the need to build one's own circuit. lock is near immediate coming out of standby. do remember that the connectors are different, so u need to custom make a inter connecting cable.

    kao
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    CarPC Ver 4 completed. Aopen i45GMT-HD, C2D mobile 2GHz. Photofast 64GB SSD. Novatel EU-850D

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