Ultimate Gps breakout V3

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AnTieViL5
 
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Ultimate Gps breakout V3

Post by AnTieViL5 »

Hi

so I've run into a problem with my Gps, the latitude is incorrect for some odd reason and giving me the wrong info.

so here is what I've got, I've got the GPS with a small antenna connected. and I've just loaded a blank sketch to my Arduino to connect directly to the GPS.
I have also tested my location using another GPS module from another company and here is my data for my latitude as the longitude is correct.

Ultimate breakout GPS: -37.452209 (incorrect) and the raw data (3745.2231,S)
Google maps latitude: -37.753739 (correct)
Other Gps module I used: -37.753704 (correct)

do I have a faulty GPS?, is there something I might be missing or need to do?

Thanks

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ChliHug
 
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Re: Ultimate Gps breakout V3

Post by ChliHug »

Looks like the conversion from degrees/minutes to decimal went wrong. The correct value should be -37.753718. Here's a quote from the FAQ:

https://learn.adafruit.com/adafruit-ult ... aq-3024809
My GPS is giving me data but the location is wrong!

People often get confused because the GPS is working but is "5 miles off" - this is because they are not parsing the lat/long data correctly. Despite appearances, the geolocation data is NOT in decimal degrees. It is in degrees and minutes in the following format: Latitude: DDMM.MMMM (The first two characters are the degrees.) Longitude: DDDMM.MMMM (The first three characters are the degrees.)

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adafruit_support_carter
 
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Re: Ultimate Gps breakout V3

Post by adafruit_support_carter »

Generally agree with above. What software is doing the conversion from raw to computed?

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AnTieViL5
 
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Re: Ultimate Gps breakout V3

Post by AnTieViL5 »

I was manually trying to change the raw data into data to view in google maps, how come I got the longitude correct but the latitude is wrong?
could you show me how you process the data from raw to google map material?
thanks and do question further if you not sure.

Thanks

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adafruit_support_carter
 
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Re: Ultimate Gps breakout V3

Post by adafruit_support_carter »

Not sure, but you can compare to the source code for the GPS library:
https://github.com/adafruit/Adafruit_GP ... e.cpp#L679

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AnTieViL5
 
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Re: Ultimate Gps breakout V3

Post by AnTieViL5 »

I was not using any library, if the arduino is loaded with a blank scetch, then it will get the raw data from the GPS, so above i have posted the raw data, which is (3745.2231,S) this is meant to be my latitude.

if i take that raw data 3745.2231,S, and use DDMM.MMMM from the https://learn.adafruit.com/adafruit-ult ... aq-3024809

so google maps needs the following info:
In the search box at the top, type your coordinates. Here are examples of formats that work:
Degrees, minutes, and seconds (DMS): 41°24'12.2"N 2°10'26.5"E
Degrees and decimal minutes (DMM): 41 24.2028, 2 10.4418
Decimal degrees (DD): 41.40338, 2.17403

according to google -37.753739 is my correct latitude

also, i believe that the following then has the same format
DD. MM MM MM
-37 . 75 37 39
DD. MM MM MM
37 . 45 22 31,S - and south indicates that it is -

the decimal line up, but the minutes are all different values?
i dont think this is a conversion issue like i said ive tryed another gps board and the raw coordinates are correct.
am i missing something cause i dont see where the minutes 45 come from when my minutes are 75?
there is no library involved this is the data coming from the GPS.

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ChliHug
 
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Re: Ultimate Gps breakout V3

Post by ChliHug »

AnTieViL5 wrote:also, i believe that the following then has the same format
DD. MM MM MM
-37 . 75 37 39
DD. MM MM MM
37 . 45 22 31,S - and south indicates that it is -

the decimal line up, but the minutes are all different values?
i dont think this is a conversion issue like i said ive tryed another gps board and the raw coordinates are correct.
am i missing something cause i dont see where the minutes 45 come from when my minutes are 75?
there is no library involved this is the data coming from the GPS.
It would be weird to use 75 minutes because that would be 1.25 decimal degrees. Google gave you decimal degrees. To convert the minutes just divide them by 60 and add them to the degrees. And the S makes it negative, correct. -37 + 45.2231 / 60 = -37.7537183... Wikipedia has an interesting article on that.

https://en.wikipedia.org/wiki/Geographi ... conversion

I'm guessing the other board spits out decimal degrees directly.

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