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SirF protocol

Posted by Harry on April 14, 2009 at 1:03pm
Hi, I am waiting for the new Arduino Board and am trying to read up on everything. I've looked at the code some and trying to understand what I can. I have a EM401, not the 406. The 401 speaks Sirf, but I know there could be a difference with the 406. What I've been looking at is the parts of the ardupilot code that pertain to SirF, like this:void configure_gps(void){const byte gps_header[]={0xA0,0xA2,0x00,0x08,0xA6,0x00 };//Used to configure Sirf GPSconst byte gps_payload[]={0x02,0x04,0x07,0x09,0x1B };//Used to configure Sirf GPSconst byte gps_checksum[]={0xA8,0xAA,0xAD,0xAF,0xC1 };//Used to configure Sirf GPSconst byte cero=0x00;//Used to configure Sirf GPSI know these are HEX, but I dont really understand it. I know the SirF manual should explain, but I'm not a programmer(yet:). So, first question is about the format of HEX. They all start with 0x and then a letter or number, but the SirF manual doesnt show same format. It's very confusing to me. So, next question is about the ardupilot code example above. You have 3 const bytes and then the HEX numbers. Are these 3 const the layers of the SirF Protocol? Are the HEX numbers message ID's?Thanks for any explanations.Harry

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  • Harry April 14, 2009 at 8:54pm
    Here is a snippet of some output from the SirF Demo:

    GeoNav PC Time=1239765913.090
    41,0,516,1527,271531868,2009,4,15,3,25,16868,4456612,392970517,-773026245,10844,14183,21,6,10328,0,5,0,317,481,0,0,2147483647,0,1878731,0,0,0,0,5,11
    4,503,27153186,12,13,234,50,0,0,0,0,0,0,0,0,0,0,0,8,309,15,191,37,37,37,37,37,37,37,37,37,37,11,175,7,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,61,62,191,34,34,34,35,34,34,35,35,34,34,6,54,47,191,31,32,32,31,31,31,31,31,31,31,25,321,77,0,0,0,0,0,0,0,0,0,0,0,23,196,30,191,34,35,35,34,34,34,35,34,36,34,19,151,71,191,38,37,37,37,37,38,37,38,37,37,16,66,22,0,0,0,0,0,0,0,0,0,0,0,125,0,0,0,0,0,0,0,0,0,0,0,0,0
    2,1086389,-4821718,4017961,0.000,-0.125,0.000,4,2.2,2,503,27153186,5,8,3,6,23,19,0,0,0,0,0,0,0
    ThrPut(186=1ms): Latency:000 SegStatMax:000 AveTrkTime:186 Nav Complete:0080 ms
    27,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
    52,3,25,17,15,4,2009,14,999999996,7
    GeoNav PC Time=1239765914.091
    41,0,516,1527,271532868,2009,4,15,3,25,17868,4456612,392970442,-773026389,10959,14297,21,5,10328,0,10,0,318,481,0,0,2147483647,0,1878750,0,0,0,0,5,11
    4,503,27153286,12,13,234,50,0,0,0,0,0,0,0,0,0,0,0,8,309,15,191,37,36,37,38,37,37,37,37,37,37,11,175,7,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,61,62,191,33,34,34,35,34,34,34,35,34,35,6,54,47,191,32,31,32,32,30,31,31,31,30,31,25,321,77,0,0,0,0,0,0,0,0,0,0,0,23,196,30,191,34,33,34,34,34,34,34,35,34,34,19,151,71,191,37,38,37,38,38,38,38,38,38,38,16,66,22,0,0,0,0,0,0,0,0,0,0,0,125,0,0,0,0,0,0,0,0,0,0,0,0,0
    2,1086388,-4821720,4017961,0.000,-0.125,0.000,4,2.2,2,503,27153286,5,8,3,6,23,19,0,0,0,0,0,0,0
    ThrPut(186=1ms): Latency:000 SegStatMax:000 AveTrkTime:186 Nav Complete:0067 ms
    27,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
    52,3,25,18,15,4,2009,14,999999996,7
    GeoNav PC Time=1239765915.093
    41,0,516,1527,271533868,2009,4,15,3,25,18868,4456612,392970375,-773026531,11070,14409,21,5,10328,0,13,0,318,481,0,0,2147483647,0,1878750,0,0,0,0,5,11
    4,503,27153386,12,13,234,50,0,0,0,0,0,0,0,0,0,0,0,8,309,15,191,37,37,37,37,37,37,37,37,37,37,11,175,7,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,61,62,191,34,35,35,34,34,34,33,33,33,34,6,54,47,191,30,30,30,31,31,32,30,31,31,30,25,321,77,0,0,0,0,0,0,0,0,0,0,0,23,196,30,191,34,34,34,35,35,35,34,34,34,34,19,151,71,191,37,37,38,38,37,37,37,37,37,38,16,66,22,0,0,0,0,0,0,0,0,0,0,0,127,0,0,0,0,0,0,0,0,0,0,0,0,0
    2,1086387,-4821721,4017961,0.000,-0.125,0.000,4,2.2,2,503,27153386,5,8,3,6,23,19,0,0,0,0,0,0,0
    ThrPut(186=1ms): Latency:000 SegStatMax:000 AveTrkTime:186 Nav Complete:0071 ms
    27,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
    52,3,25,19,15,4,2009,14,999999996,7

    How does this compare to the output from a 406? How does it relate to the code used in ardupilot 2.0.1? So many questions. Can anyone point out what is in this output?

    Thanks,
    Harry
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