[teqc] Converting Android GPS data to Rinex file format

rocken rocken at ucar.edu
Wed Oct 13 14:54:12 MDT 2010


Why not use you gpss email for this?
Lots of visibility.


On Oct 13, 2010, at 11:44 AM, James Johnson wrote:

> Hi Lalitha,
>
> It is not possible to generate RINEX from an android phone.  This is  
> because the raw data required for RINEX is not exposed by the  
> Android API.  You can get some information about the SVs tracked and  
> a position, but you can not get the raw Pseudo range data.  The NMEA  
> strings are not useful for generating RINEX as well, simply because  
> the data is not there.
>
> Sorry for the sad news.
>
> Best Regards,
> Jim Johnson
> On Oct 13, 2010, at 11:40 AM, Lalitha wrote:
>
>> Hi Homan,
>>
>> Tons of thanks for the detailed reply. I've been searching the net  
>> and posting in all the android, gps forums for the past 10 days and  
>> didn't get any response till now. Thanks to teqc mailing list.
>>
>> Q1. I checked the android api for the gps data. It provides GPS  
>> Satellite info from which we can get elevation, PRN (pseudo-random  
>> number), snr, Almanac, ephemeris data etc.
>>     Ref : http://developer.android.com/reference/android/location/GpsStatus.html
>> With these data, will it be possible to generate Rinex file  
>> directly from android app?.
>>
>> Q2. Also, there is a nmealistener provided in the android api using  
>> which we can capture gps nmea strings. Will this data be useful by  
>> anyway to translate to rinex format? (Though, I coudnt succeed  
>> capturing nmea string using my htc magic phone, I can try with some  
>> other phones if this data will be  useful for post processing).
>>
>> Thanks,
>> Lalitha.
>>
>> On Wed, Oct 13, 2010 at 9:58 AM, Homan, Thomas  
>> <thoman at co.gila.az.us> wrote:
>> Lalitha,
>>
>>
>> .gpx files cannot be converted to Rinex as they don’t contain the  
>> necessary data elements. If I remember correctly, the api only  
>> outputs the final latitude and longitude values. I don’t believe  
>> the underlying raw gps data is accessible but I’m just getting  
>> started on Exclipse.
>>
>>
>> To generate a Rinex file you need to have access to underlying  
>> information such as pseudorange, carrier phase and other data from  
>> each satellite in the GPS constellation. As an example, below are  
>> a .gpx file compared to a Rinex file that I collected in 2005. Each  
>> of the 7 satellites visible has a set of 7 data elements logged out  
>> of my $$$ survey grade receiver and this happens each logging period.
>>
>>
>> Peruse the api docs and see if there is access to the underlying  
>> data and not the final coordinates. If not, then you might be out  
>> of luck. One thing you might explore is if the android OS supports  
>> inserting DGPS correctors so you could get real time sub-meter  
>> accuracies.
>>
>>
>> Hope this helps some.
>>
>>
>> Tom
>>
>>
>> GPX
>>
>> <?xml version="1.0" encoding="ISO-8859-1"?>
>>
>> <gpx xmlns="http://www.topografix.com/GPX/1/1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance 
>> " version="1.1" creator="Doug Forster's map viewer"  
>> xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd 
>> ">
>>
>> <wpt lat="-42.48781" lon="172.29404">
>>
>> <ele>1273</ele>
>>
>> <name>NwDvls</name>
>>
>> <cmt> 30/01/10 19:14</cmt>
>>
>> <desc>New Devils Den Biv</desc>
>>
>> <sym>Anchor</sym>
>>
>> <extensions>
>>
>> <type xmlns="Freshmap">Place</type>
>>
>> <TrackColor xmlns="Freshmap">0</TrackColor>
>>
>> <FontSize xmlns="Freshmap">90</FontSize>
>>
>> <GPSColor xmlns="Freshmap">14</GPSColor>
>>
>> <Layout xmlns="Freshmap">5</Layout>
>>
>> </extensions>
>>
>> </wpt>
>>
>> </gpx>
>>
>>
>> Rinex
>>
>> 05 10 12 14 44 45.0000000  0  7G 1G24G23G20G16G25G11
>>
>>  18540407.76711  14441990.35651  22140106.912    22140108.9425    
>> 22140103.6715
>>
>>     -1502.342       -1170.656
>>
>>  18405511.80411  14342294.04151  23619878.513    23619880.7005    
>> 23619875.3565
>>
>>       382.895         298.360
>>
>>  18279304.44211  14260112.94351  22317896.240    22317897.3485    
>> 22317888.9405
>>
>>      2122.449        1653.856
>>
>>  18331079.75811  14289623.90551  20672596.529    20672597.6675    
>> 20672590.3895
>>
>>      1386.704        1080.549
>>
>>  18282886.39611  14256935.72751  21779940.978    21779941.1535    
>> 21779934.4995
>>
>>      2177.108        1696.448
>>
>>  18595837.79911  14470056.42251  21824971.770    21824972.4395    
>> 21824966.6485
>>
>>     -2263.324       -1763.629
>>
>>  18612482.40511  14492926.57751  23828871.571    23828874.4325    
>> 23828869.0685
>>
>>     -2470.753       -1925.262
>>
>>
>> From: teqc-bounces at ls.unavco.org [mailto:teqc- 
>> bounces at ls.unavco.org] On Behalf Of Lalitha
>> Sent: Wednesday, October 13, 2010 9:03 AM
>> To: teqc at ls.unavco.org; gpstech at ls.unavco.org
>> Subject: [teqc] Converting Android GPS data to Rinex file format
>>
>>
>> Hi,
>>
>> How do i convert the gps data I get from Android GPS Receiver into  
>> Rinex file format in order to do Post processing corrections.
>> I can write the gps data into .gpx format using the android api  
>> provided. I use HTC Magic phone with 2.2 api version.
>> I cudnt find option for android in the teqc toolkit. Can anyone  
>> help how do I convert to Rinex?
>> Also I'm looking for the post processing softwares or service  
>> available for evaluation. I could find only one free evaluation  
>> software 'PPro2' from Kinematic GPS.
>> Is there any other free post processing software present?
>>
>> Thanks,
>> Lalitha.
>>
>>
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