[OSGeo Africa] Some technical questions relating to GPS field data collection devices

Chris chris at airphotoafrica.co.za
Sat Jan 9 00:15:38 PST 2016

    Happy New Year to all
    Getting 2016 off to a good GPS start

    I am not sure if there is anyone on the list that is conversant with the 
    electronics of GPS chips and the development of GPS receiver firmware / 
    software ?

    ie .  Could you make this


    ( Yes there are people out there for which this is not strange )

    My old Trimble JUNO-ST is getting  towards being a museum piece and I 
    have been looking at alternatives. As we all know Trimble is an American 
    company and with the current exchange rate an expensive device is now 
    prohibitively expensive.

    New current smartphones can be acquired in "ruggedised" versions with all 
    the latest functionality including GPS receiver. Most of these run a 
    version of ANDROID ( Google associated ? ). Now there are a number of 
    "Geo-Apps" for these phones which are compiled to run under Android. 
    However as far as I understand the GPS / Satellite protocol used for 
    these devices / apps is NMEA ?  The problem with NMEA is that form in 
    which the GPS information is delivered does not lend itself to post 
    processing differential correction ? ( please correct me if I am wrong )

    Seems Trimble have a US patent to do this


    I do not know if any smartphone manufacturers utilise this capability ?

    The big advantage of Trimble ( and other brands ) is the ability to post 
    process collected data ( Trignet ) or -- real time correction ( RTK ) -- 
    NO WAAS in SA.  Now Trimble have their own way / format / protocol for 
    collecting and processing the GPS satellite signals -- TSIP. As far as I 
    know Trimble devices use [ONLY] Windows mobile as their OS.

    My question / s ....
    I assume that the hardware GPS chip is programmed ( device driver ) using 
    a low level language like C or assembler or one of the other micro-device 
    languages ( PIC ? ) so that these routines could be worked into any major 
    OS -- [this programming and these routines are normally done by the GPS 
    chip manufacturer who will supply an SDK] ie. Trimble could develop their 
    software to run on Android.  In which case one could have all the 
    advanced capability of a "survey" grade device on a smartphone / device 
    -- which in a ruggedised version ( US$300 )  could do all that the fancy 
    branded and expensive devices currently do ( and probably more in terms 
    of -- field--> office workflows ). As Android is an open platform any and 
    all apps could be developed to take advantage of this.

    As I am  not employed in a GPS industry postion I do not know what the 
    latest developments are ? or how much red tape , copyright . patents , 
    industry NDA's , military concerns there are as far as such development 
    is concerned.

    I would be most interested to hear what someone who IS involved in the 
    industry has to say ?


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