GPS Module Comparison for LoRa Trackers

Asset trackers built on LoRa live or die on how efficiently they can get a GPS fix. A module that takes 30 extra seconds to lock isn't just slow — at 25-40mA during acquisition, those seconds are a meaningful chunk of your power budget.

What actually matters for tracker builds

1. Cold-start time-to-fix (TTFF) — how long the module burns acquisition current before you get a position.
2. Tracking current — draw once locked, if you're doing continuous logging rather than single fixes.
3. Backup power for ephemeris data — a small backup cap/battery can cut cold starts to warm starts, saving acquisition time on every wake cycle.

Modules I've tested

u-blox NEO-6M — cheap, widely available, solid documentation, ~26mA acquisition / ~19mA tracking. Cold TTFF around 26-32s in open sky. Good default choice for a first build.

u-blox NEO-M8N — better multi-constellation support (GPS + GLONASS + Galileo), faster fix in marginal conditions (under tree cover, urban canyon), slightly higher cost. Worth it if your trackers won't always have clear sky view.

Air530 / Air530Z — budget option seen on a lot of LoRa dev boards, works fine in open sky, noticeably weaker in obstructed environments compared to the u-blox parts.

Duty-cycling strategy

For a LoRa tracker reporting every 15 minutes, don't leave the GPS module powered continuously — that alone can dominate your entire power budget. Power it via a MOSFET load switch, wake it, wait for fix (or timeout), grab the position, and cut power again. Model this properly: a module drawing 25mA for 30 seconds every 15 minutes has a very different average current than one running continuously — plug the numbers into the power budget calculator with duty cycle set to reflect actual acquisition time, not just "on/off."

u-blox NEO-M8N GPS Module^[aff] is my default recommendation for anything that needs to work outside of perfectly open sky.

Disclosure: links marked [aff] are affiliate links. I only recommend parts I've actually used.