Nmea data sharegps-laptop

[raz222]

Hello Everyone!
I am trying to develop a map application using dotspatial. Despite the fact that i have completed the task of passing nmea data to my application, longitute and latitude values that i see in my application are wrong in relationship with the coordinates in my smartphone.
I use sharegps application in my smartphone and this application connects to my laptop via bluetooth.
Why i have a big deviation in coordinates between smartphone application and laptop application?

 

[Nuvi-Nebie]

How big is the error?, i,e, how many metres (or kilometres), is there between your smartphone application and laptop application?

You can enter the latitude / longitude from your application into say Google Earth and then compare the position with your real location

 

[raz222]

We talk about 1 km error. For example, i get my position in the $GPRMC message (38,060736N, 23,78391E) but my real position is (38.067936N, 23.782917E) . Do you know why is this happen? I use sharegps application downloaded from playstore and the position that gives is correct but from the side of laptop in my application the nmea data that i receive , are wrong.

 

[Nuvi-Nebie]

There are two possibilities I can think of :-
1) The GPRMC sentence is being miss-interpreted, the Latitude and Longitude is not in Degrees, they are in Degrees and minutes e.g. not N38.067936 (Degrees) but N38 06.7936 (Degrees and minutes)

so you would have to convert the the figures to get Degrees such as 38,060736N, 23,78391E

2) there is some data corruption in the Latitude and Longitude digits :-

real . N38.067936
error N38.060736

real . E23.782917
error E23.78391?

Where does the laptop get it's NMEA sentences from? is e.g. USB dongle etc.

 

[raz222]

Yeap, i found it! As you said, coordinates are in Degrees and minutes format and i was thinking that they are in Decimal Format. I made changes to my code and the result is correct! Thanks a lot!!