I'm using the LS20031 GPS module https://www.sparkfun.com/products/8975.
Everything seems to be working OK, except that I've noticed that when I check the validation codes (the last two characters at the end of each sentence) about 4-6% of the sentences fail validation.
Does this seem about right? I'm using one of the standard arduino libraries, and the module itself is straight out of the box - I've not changed the configuration. The module is mounted very close to the Arduino (a mega) so I don't think there's a problem with wire-length or anything like that, and because over 90% of the records DO pass validation, I'm assuming the checksum processing is going ok.
I've looked at the records that have failed, and they look ok (no weird characters, nothing out of the ordinary).
It's not really a big deal, now that I know I need to check I'm sure enough valid records will get through to meet my needs, but I'm a bit surprised that either the module is generating dodgy data, or it's somehow getting corrupted on the 5mm of copper track between the module and the arduino.