Just came across this thread. I, too, have problems with getting GPS fixes with a GPS sensor attached to an Electron.
The sensor I’m using is a GP-20U7 module (I’ve also tried a U-BLOX UBX-G7020-KT).
The GP-20U7 module has been rock-solid when used with an ESP-8266 platform or an ESP-32 platform. Rock Solid! But in converting the project to the Electron, the module has problems getting a fix. When I monitor the serial data stream, the data seems incomplete (dropped characters or bad characters). Even when I try to just use the GPS module with sample code, same issue.
This thread seems to point to one of two problems - either RF interference from the electron, or noisy power. During testing, the GPS module is on pigtails about a foot from the electron. No help. As far as power, GPS power is coming from the electron’s 3.3V pin, with the Lipo battery attached and USB power coming from a laptop (or 120V wall wart).
One other bit of information. The UBX-G7020-KT has an onboard LED that lights up when it gets a fix. I assume that happens independently from any communications to the electron, so even if the serial data stream is getting corrupted, I would think that the LED would still show good status - and it doesn’t indicate a fix. So I’m inclined to eliminate an issue related to serial transmission.
Any insight would be appreciated. I have the entire project converted to run on the electron (temp sensing, Bluetooth communication to a remote module, OLED display, etc) and the only thing holding this up is getting the GPS piece to work reliably. NOTE: during testing, all of this other stuff isn’t there - just the TinyGPS example code.