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Mapping GPS coordinates

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GS_TECH01:
Just a few more questions:

For every train trip, does it travel at the same time everytime?
Also, does it start and arrive to its destination the same time for every other trips?

Since the default output rate is every 1 second, the device continually outputs sentences every second whether the train is moving or not. You can possibly check the timestamp to confirm this.
Because we're not familiar with your app, perhaps, you can modify it or make some changes if there's any filtering scheme. Other than that, you can verify with GPSInfo (http://www.usglobalsat.com/store/downloads/GPSInfo.zip) and see that it's outputting data every one second.

zarkfoo:
First of all... thanks USG_TECH10 for hanging with me on this.

Every trip takes around 11 minutes... so the goal is to travel at the same time which means probably +- 20 seconds each trip.  Each trip starts and ends at the same spot every time.

In my app I capture not only just valid GPRMC data, but I also log all GPS data as well.  Below are examples from back to back runs which I'm only including the first 5 seconds from each run. You will notice each run begins with "**** 801 ****" which obviously does not come from the GPS receiver.  This comes from an RFID tag that is fix-mounted to the railroad tie and the RFID antenna is fix-mounted to the bottom of the train.  In my app I open a different Comm port so I can read both the GPS data and RFID data from their respective Comm ports as they are received. So my app will start logging GPS data whenver the "801" RFID tag is read... and that's how I know that logging GPS data starts at the same identical spot each time.

Run 1
*********************************** 801 ***********************************
21:12:37 - $GPGGA,031139.000,3623.1137,N,09508.4042,W,2,11,0.7,228.1,M,-28.1,M,2.8,0000*4E
21:12:37 - $GPGSA,A,3,31,22,14,32,25,11,18,30,20,12,01,,1.4,0.7,1.2*38
21:12:37 - $GPRMC,031139.000,A,3623.1137,N,09508.4042,W,4.75,282.33,241112,,*15
21:12:38 - $GPGGA,031140.000,3623.1140,N,09508.4058,W,2,11,0.7,228.1,M,-28.1,M,0.8,0000*49
21:12:38 - $GPGSA,A,3,31,22,14,32,25,11,18,30,20,12,01,,1.4,0.7,1.2*38
21:12:38 - $GPRMC,031140.000,A,3623.1140,N,09508.4058,W,4.70,284.04,241112,,*17
21:12:39 - $GPGGA,031141.000,3623.1143,N,09508.4074,W,2,11,0.7,228.1,M,-28.1,M,0.8,0000*45
21:12:39 - $GPGSA,A,3,31,22,14,32,25,11,18,30,20,12,01,,1.4,0.7,1.2*38
21:12:39 - $GPGSV,3,1,12,31,75,216,51,14,47,052,45,22,43,134,45,32,41,314,37*7F
21:12:39 - $GPGSV,3,2,12,25,31,074,39,01,30,289,38,11,21,265,42,30,13,174,42*7C
21:12:39 - $GPGSV,3,3,12,12,12,042,34,20,10,313,37,18,05,133,23,51,45,199,54*74
21:12:39 - $GPRMC,031141.000,A,3623.1143,N,09508.4074,W,4.69,284.39,241112,,*1D
21:12:40 - $GPGGA,031142.000,3623.1147,N,09508.4090,W,2,11,0.7,228.1,M,-28.1,M,0.8,0000*48
21:12:40 - $GPGSA,A,3,31,22,14,32,25,11,18,30,20,12,01,,1.4,0.7,1.2*38
21:12:40 - $GPRMC,031142.000,A,3623.1147,N,09508.4090,W,4.66,283.95,241112,,*1E
21:12:41 - $GPGGA,031143.000,3623.1150,N,09508.4106,W,2,11,0.7,228.1,M,-28.1,M,0.8,0000*41
21:12:41 - $GPGSA,A,3,31,22,14,32,25,11,18,30,20,12,01,,1.4,0.7,1.2*38
21:12:41 - $GPRMC,031143.000,A,3623.1150,N,09508.4106,W,4.69,283.78,241112,,*1B
21:12:42 - $GPGGA,031144.000,3623.1153,N,09508.4121,W,2,11,0.7,228.1,M,-28.1,M,1.8,0000*41
21:12:42 - $GPGSA,A,3,31,22,14,32,25,11,18,30,20,12,01,,1.4,0.7,1.2*38
21:12:42 - $GPRMC,031144.000,A,3623.1153,N,09508.4121,W,4.64,283.31,241112,,*1A
21:12:43 - $GPGGA,031145.000,3623.1157,N,09508.4137,W,2,11,0.7,228.1,M,-28.1,M,2.8,0000*40
21:12:43 - $GPGSA,A,3,31,22,14,32,25,11,18,30,20,12,01,,1.4,0.7,1.2*38
21:12:43 - $GPRMC,031145.000,A,3623.1157,N,09508.4137,W,4.67,283.34,241112,,*1E
21:12:44 - $GPGGA,031146.000,3623.1160,N,09508.4153,W,2,11,0.7,228.1,M,-28.1,M,3.8,0000*44
21:12:44 - $GPGSA,A,3,31,22,14,32,25,11,18,30,20,12,01,,1.4,0.7,1.2*38
21:12:44 - $GPGSV,3,1,12,31,76,218,51,14,47,053,46,32,42,314,40,22,42,134,45*72
21:12:44 - $GPGSV,3,2,12,25,31,073,40,01,30,288,38,11,21,264,42,30,14,174,42*72
21:12:44 - $GPGSV,3,3,12,12,11,041,30,20,11,313,37,18,05,133,32,51,45,199,54*71
21:12:44 - $GPRMC,031146.000,A,3623.1160,N,09508.4153,W,4.74,283.04,241112,,*1A
21:12:45 - $GPGGA,031147.000,3623.1163,N,09508.4169,W,2,11,0.7,228.2,M,-28.1,M,0.8,0000*4F
21:12:45 - $GPGSA,A,3,31,22,14,32,25,11,18,30,20,12,01,,1.4,0.7,1.2*38
21:12:45 - $GPRMC,031147.000,A,3623.1163,N,09508.4169,W,4.79,283.85,241112,,*15

Run 2
*********************************** 801 ***********************************
21:36:29 - $GPRMC,033531.000,A,3623.1141,N,09508.4050,W,4.50,284.06,241112,,*1E
21:36:30 - $GPGGA,033532.000,3623.1144,N,09508.4065,W,2,10,0.8,228.7,M,-28.1,M,0.8,0000*48
21:36:30 - $GPGSA,A,3,31,22,14,32,25,11,20,30,12,01,,,1.5,0.8,1.3*3E
21:36:30 - $GPRMC,033532.000,A,3623.1144,N,09508.4065,W,4.59,283.96,241112,,*19
21:36:31 - $GPGGA,033533.000,3623.1147,N,09508.4081,W,2,10,0.8,228.7,M,-28.1,M,1.8,0000*41
21:36:31 - $GPGSA,A,3,31,22,14,32,25,11,20,30,12,01,,,1.5,0.8,1.3*3E
21:36:31 - $GPRMC,033533.000,A,3623.1147,N,09508.4081,W,4.66,283.70,241112,,*15
21:36:32 - $GPGGA,033534.000,3623.1150,N,09508.4097,W,2,10,0.8,228.7,M,-28.1,M,2.8,0000*44
21:36:32 - $GPGSA,A,3,31,22,14,32,25,11,20,30,12,01,,,1.5,0.8,1.3*3E
21:36:32 - $GPRMC,033534.000,A,3623.1150,N,09508.4097,W,4.73,284.79,241112,,*19
21:36:33 - $GPGGA,033535.000,3623.1154,N,09508.4113,W,2,10,0.8,228.6,M,-28.1,M,0.8,0000*4F
21:36:33 - $GPGSA,A,3,31,22,14,32,25,11,20,30,12,01,,,1.5,0.8,1.3*3E
21:36:33 - $GPRMC,033535.000,A,3623.1154,N,09508.4113,W,4.80,284.78,241112,,*1C
21:36:34 - $GPGGA,033536.000,3623.1157,N,09508.4129,W,2,10,0.8,228.6,M,-28.1,M,0.8,0000*46
21:36:34 - $GPGSA,A,3,31,22,14,32,25,11,20,30,12,01,,,1.5,0.8,1.3*3E
21:36:34 - $GPGSV,3,1,12,31,85,278,52,32,52,313,48,14,40,064,45,22,32,140,39*7A
21:36:34 - $GPGSV,3,2,12,01,29,276,39,25,29,061,42,30,23,171,40,20,20,314,37*76
21:36:34 - $GPGSV,3,3,12,11,17,255,41,12,06,034,27,23,03,279,33,51,45,199,49*7B
21:36:34 - $GPRMC,033536.000,A,3623.1157,N,09508.4129,W,4.84,283.80,241112,,*11
21:36:35 - $GPGGA,033537.000,3623.1160,N,09508.4146,W,2,10,0.8,228.6,M,-28.1,M,0.8,0000*4A
21:36:35 - $GPGSA,A,3,31,22,14,32,25,11,20,30,12,01,,,1.5,0.8,1.3*3E
21:36:35 - $GPRMC,033537.000,A,3623.1160,N,09508.4146,W,4.88,284.25,241112,,*19

GS_TECH01:
Sorry for the late response.

Got it. Thanks for the answers. So, it doesn't travel at the same time everytime. That's why you're getting different number of coordinates for each trip.

After looking at the log you provided, it does outputs the RMC data every one second. I could not find anything alarming or strange as well.

Moreover, I would not consider this an issue since it outputs accurate data properly and the device is able to get a good GPS signal.  Thanks.

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