[Diy_efi] Fast updating (20Hz) GPS receivers for track

Hugh Keir hugh
Fri Aug 5 06:33:06 UTC 2011


Hi Guy?s,

This has been done rather well by one of our radio controlled aeroplane
enthusiasts.

The board comes with a dsPIC30F4011 CPU, an MMA7260 three axis
accelerometer, and two dual axis IXZ500 gyros which have enough vibration
tolerance to be used in Radio Controlled helicopter applications

Various GPS units can be connected to create an ?IMU?

The designer talking about his ?dead reckoning? calculations
http://diydrones.com/profiles/blogs/a-simple-deadreckoning

Google ?Bill Premerlani? and ?dead reckoning? and you will find loads.

Purchase and board spec http://www.sparkfun.com/products/9980

Main development page http://code.google.com/p/gentlenav/wiki/Home

Discussion forum http://groups.google.com/group/uavdevboard

Cheers

Hugh







> Ah the wonderful Kalman filter, its a ncie algorithm for extracting signal
> from
> noise that has a bell shaped distribution or other variations depending
> upon
> signal history depth ie No of samples etc...
>
> ie. We used a software Kalman filter to extract scintillation counter
> pulses
> generated by Cobalt 60 ie. Two horizontal streams of beta particles one
> above
> the other and a sheet of iron ore falling due to gravity, the difference
> in counts
> gave us a virtually instantaneous reading of mass flow rate - the maths
> wasnt that
> hard but relied on a filter process which kept a history, step changes
> were essential
> to be monitored otherwise the mesh screens for the iron ore would get
> clogged from
> too much flow - the workers would hate this as they had to manual dig out
> the
> iron ore to clear the screens, so we often got dirty looks as we were
> programming
> the microcode - on a Pace 16 but cpu by NS, the assembler was written in
> forth like
> stack operations, worked well - quite easy to code as we both were HP rpn
> weaned,
> the HP-41C did wonders, no equals sign to be found :-)
>
> PC emulator for 41C uploaded to my dir for diy_efi users only:-
> http://niche.ii.net/HP-41V
>
>
> The mass flow rate was output as an analog 4-20mA signal and fed to a
> Foxboro controller,
> all old hat now - this maintained a control systems perspective and saved
> a heap of
> wear on alternative conveyor based weighing systems prevalent at the
> time...
>
> Like to see someone use one, thanks for the link, more reading it seems
> which will keep
> me from dinner - geesh I've lost so much weight from all the stuff on the
> net recently <sigh>
>
> Cheers
>
> Mike
>
> At 10:47 PM 8/3/2011, Hugh Keir wrote:
>>Seems like the best way to link the GPS is with an IMU ( solid state
>> gyros
>>+ accelerometer).
>>
>>Here is racelogic's explanation of why this is so
>>
>>http://www.racelogic.co.uk/_downloads/vbox/Application_Notes/IMU_Integration_Flyer.pdf
>>
>>The model robot, helicopter and aeroplane guy's use these extensively,
>>there are quite a few projects on the NET showing the outputs and code
>>from IMU's
>>
>>Really would love this for my race car.
>>
>>> Found this 20Hz GPS module, it appears to be mass market so should be
>>> cheap.
>>>
>>> http://www.skytraq.com.tw/products/Venus638LPx_PB_v3.pdf
>>>
>>>
>>> ----- Original Message -----
>>> From: <steve at donegan.org>
>>> To: <diy_efi at diy-efi.org>; "Mike" <niche at iinet.net.au>
>>> Sent: Monday, July 25, 2011 7:29 PM
>>> Subject: Re: [Diy_efi] Fast updating (20Hz) GPS receivers for track
>>>
>>>
>>> Well, if you lived in Germany it would be like 15 Euro's out the door.
>>> However with shipping to the US that becomes 70+ Euro's. But still far
>>> cheaper than the original poster's 1000$+ for a 10 Hz GPS :-)
>>>
>>> I bought one anyway as I want to check it out with my navigation/rally
>>> software which needs more than 1 Hz updates.
>>>
>>> The URL for the place in Germany is:
>>> http://shop.trenz-electronic.de/catalog/product_info.php?cPath=105_139&products_id=744
>>> ____________
>>> Steven Donegan
>>> SSCC/NORC Car #86
>>> www.sscc.us
>>>
>>>
>>>
>>> --- On Mon, 7/25/11, Mike <niche at iinet.net.au> wrote:
>>>
>>>> From: Mike <niche at iinet.net.au>
>>>> Subject: Re: [Diy_efi] Fast updating (20Hz) GPS receivers for track
>>>> To: steve at donegan.org, diy_efi at diy-efi.org
>>>> Date: Monday, July 25, 2011, 6:10 PM
>>>> Gee its small, amazing what can be
>>>> done with fractal antennas,
>>>> I'm tempted to hang one off a cheapie netbook when I next
>>>> go country
>>>> as the gps in my son's HTC is a bit flakey and geotagging
>>>> doesnt work that well,
>>>> also give him a chance to maybe read from it in C++
>>>>
>>>> If you get one, let us know the overall price and how well
>>>> it works,
>>>>
>>>> Thanks
>>>>
>>>>
>>>> At 10:26 PM 7/25/2011, you wrote:
>>>> >I found this:
>>> http://www.gtop-tech.com/jsf/moduleproduct.jsf?muid=5a50acc3cd4f20749b345fe86e442ed78a6d204d&suid=d2aafd64c93952bb33c7ee066e322e597947063d&puid=881a56b7500af0dc8b4fe87bba293ff898b039d6
>>>> >
>>>> >It's a 10 Hz, non-interpolation, USB module. Seems
>>>> perfect for the original gentleman's uses although the only
>>>> place I find it available at present is a EU electronics
>>>> outfit.
>>>> >____________
>>>> >Steven Donegan
>>>> >SSCC/NORC Car #86
>>>> >www.sscc.us
>>>> >
>>>> >
>>>> >
>>>> >--- On Mon, 7/18/11, Avery Nisbet <anisbet at gmail.com>
>>>> wrote:
>>>> >
>>>> >> From: Avery Nisbet <anisbet at gmail.com>
>>>> >> Subject: Re: [Diy_efi] Fast updating (20Hz) GPS
>>>> receivers for track
>>>> >> To: steve at donegan.org
>>>> >> Cc: "Jay Rabe" <jayrabe at gmail.com>,
>>>> diy_efi at diy-efi.org
>>>> >> Date: Monday, July 18, 2011, 6:24 PM
>>>> >> Yup a max232 chip and antenna with an
>>>> >> SMA connector and it should be
>>>> >> good to go. LM7805 like 3.3v
>>>> regulator
>>>> >> would be needed too but those
>>>> >> are cheap.
>>>> >>
>>>> >>
>>>> >> It has configurable baud and sample speed so it
>>>> should hook
>>>> >> right up
>>>> >> to the motec after using a Max232 chip. It also
>>>> has two
>>>> >> serial ports I
>>>> >> assume they can both be configured as outputs so
>>>> you could
>>>> >> hook it up
>>>> >> to to DAQ's if you wanted to.
>>>> >>
>>>> >>
>>>> >> -Avery
>>>> >>
>>>> >> On Mon, Jul 18, 2011 at 11:17 AM, <steve at donegan.org>
>>>> >> wrote:
>>>> >> > That item looks good - mate it with a
>>>> USB/Serial
>>>> >> interface and it makes the acquisition side of a
>>>> system. Or
>>>> >> simply a level shifter serial interface as it
>>>> appears a 3.3V
>>>> >> interface is on that module.
>>>> >> > ____________
>>>> >> > Steven Donegan
>>>> >> > SSCC/NORC Car #86
>>>> >> > www.sscc.us
>>>> >> >
>>>> >> >
>>>> >> >
>>>> >> > --- On Mon, 7/18/11, Avery Nisbet <anisbet at gmail.com>
>>>> >> wrote:
>>>> >> >
>>>> >> >> From: Avery Nisbet <anisbet at gmail.com>
>>>> >> >> Subject: Re: [Diy_efi] Fast updating
>>>> (20Hz) GPS
>>>> >> receivers for track
>>>> >> >> To: "Jay Rabe" <jayrabe at gmail.com>
>>>> >> >> Cc: diy_efi at diy-efi.org
>>>> >> >> Date: Monday, July 18, 2011, 6:07 PM
>>>> >> >> I highly doubt its doing any
>>>> >> >> interpolation. It would be more
>>>> work
>>>> >> >> than actually doing the real thing.
>>>> >> >> If anything they may not truly giving 10
>>>> NMEA
>>>> >> sentences a
>>>> >> >> second.
>>>> >> >> Maybe 9.3 or 9.75 a second.
>>>> >> >>
>>>> >> >>
>>>> >> >> http://www.sparkfun.com/products/9133
>>>> >> >>
>>>> >> >> Sparkfun also did a good right up on what
>>>> to look
>>>> >> for and
>>>> >> >> what chips
>>>> >> >> they carry and how it all works.
>>>> >> >>
>>>> >> >> Look into what the chip in the module can
>>>> do.
>>>> >> Find
>>>> >> >> the data sheet
>>>> >> >> most are reconfigureable with some
>>>> resistors or by
>>>> >> sending
>>>> >> >> them some
>>>> >> >> commands.
>>>> >> >>
>>>> >> >>
>>>> >> >> -Avery
>>>> >> >>
>>>> >> >> 2011/7/16 Jay Rabe <jayrabe at gmail.com>:
>>>> >> >> > Im not sure if this is exactly what
>>>> you are
>>>> >> looking
>>>> >> >> for but it has some info
>>>> >> >> > on 5hz vs 10hz gps receivers.
>>>> >> >> > http://trackmaster.trackaroo.com/forums/-/message_boards/message/43468
>>>> >> >> > theres one post that says a bunch of
>>>> the
>>>> >> 10hz
>>>> >> >> receivers are really 5hz and
>>>> >> >> > interpolate to make them 10hz, no
>>>> idea the
>>>> >> validity of
>>>> >> >> that claim but might
>>>> >> >> > want to check it out quick before
>>>> you go nuts
>>>> >> hunting
>>>> >> >> a 20hz down. (maybe
>>>> >> >> > more interpolation bs or something
>>>> to look
>>>> >> out for.)
>>>> >> >> > The GPS receiver is
>>>> bluetooth that they're
>>>> >> talking
>>>> >> >> about,
>>>> >> >> > http://www.qstarz.com/GPS_products.htm
>>>> >> >> you might find some more info there.
>>>> >> >> >
>>>> >> >> > On Sat, Jul 16, 2011 at 1:20 PM,
>>>> Brian Koontz
>>>> >> <brian at pongonova.net>
>>>> >> >> wrote:
>>>> >> >> >>
>>>> >> >> >> On Sat, Jul 16, 2011 at
>>>> 11:08:03AM -0700,
>>>> >> steve at donegan.org
>>>> >> >> wrote:
>>>> >> >> >> > Been googling for GPS
>>>> modules this
>>>> >> morning
>>>> >> >> and the fastest I've
>>>> >> >> >> > found so far is a 5Hz
>>>> refresh. If
>>>> >> anyone else
>>>> >> >> finds something better
>>>> >> >> >> > (module, not system) let me
>>>> know.
>>>> >> >> >>
>>>> >> >> >> 10Hz, $40:
>>>> >> >> >>
>>>> >> >> >>
>>>> >> >> >> http://www.thaieasyelec.net/index.php/GPS/65-Channel-SUP500F-10Hz-GPS-Receiver-with-Smart-Antenna/p_145.html
>>>> >> >> >>
>>>> >> _______________________________________________
>>>> >> >> >> Diy_efi mailing list
>>>> >> >> >> Diy_efi at diy-efi.org
>>>> >> >> >> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>>> >> >> >
>>>> >> >> >
>>>> >> >> >
>>>> >> _______________________________________________
>>>> >> >> > Diy_efi mailing list
>>>> >> >> > Diy_efi at diy-efi.org
>>>> >> >> > http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>>> >> >> >
>>>> >> >> >
>>>> >> >>
>>>> _______________________________________________
>>>> >> >> Diy_efi mailing list
>>>> >> >> Diy_efi at diy-efi.org
>>>> >> >> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>>> >> >>
>>>> >> >
>>>> >>
>>>> >_______________________________________________
>>>> >Diy_efi mailing list
>>>> >Diy_efi at diy-efi.org
>>>> >http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>>>
>>>>
>>> _______________________________________________
>>> Diy_efi mailing list
>>> Diy_efi at diy-efi.org
>>> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>>
>>> _______________________________________________
>>> Diy_efi mailing list
>>> Diy_efi at diy-efi.org
>>> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>>
>>
>>
>>_______________________________________________
>>Diy_efi mailing list
>>Diy_efi at diy-efi.org
>>http://lists.diy-efi.org/mailman/listinfo/diy_efi
>
>





More information about the Diy_efi mailing list