SparkFun Forums

[jconradt]

Hi GPS guys,

I am planing to design a small GPS board for a mobile robot that will also (but not exclusively) operate indoors (top level apartment, unknown ceiling construction).
I was wondering if anyone has experience comparing the following (or additional) small GPS modules that I found? I have tried to find similar modul specs; i.e. all of them have on-board antenna and a "recent" chip as far as I know...

EB-15A (Sirf III, 20Channels, http://tinyurl.com/2gctah)
EM-406A (Sirf III, 20Channels, http://tinyurl.com/youxjc, SparkFun SKU#: GPS-08234)
EB-85A (MTK, 32 Channels, http://tinyurl.com/267b6m, SparkFun SKU#: GPS-08266)
4125Y (Skytraq?, 42 Channels, http://tinyurl.com/2d2fh5)

Any other suggestions? Any experience? Especially the skytraq I can can not find information about... is 42 channels reasonable?

Thanks a lot! J

[jconradt]

... or this one... (ok, it is without antenna, but tiny):

EB-230 (MTK, 32 Channels, http://tinyurl.com/2fepge)

Any experience, compared to the other modules listed above?

[axmanjr]

I am currently testing the EM-406A GPS module. It is really easy to implement. I was able to read the raw data via the hyperterminal. I also wrote a simple parsing code to display certain data and go it to display on my LCD screen (longitude, latitude and time).

HOWEVER, just yesterday I decided to fire up the module one more time (for demonstrating purposes) and it wouldn't work. All the connections were the same as previous. The LED indicator was faintly on. After minutes of frustration, I started changing the connections around (I was actually really annoyed at this point), and it worked again, spitting out correct data.

I'm not sure what happened. All I did was change the GND connection to the PPS connection (pin6). It doesnt make sense, but I'm gonna mess with it some more today. Keep in mind that the online manual is kinda messed up (pinouts are indicated incorrectly a bit)