SparkFun GPS Breakout - NEO-M9N Very Slow FIX Acquisition

GPS/GNSS Development Boards
1

I have a number of the SparkFun GPS Breakout - NEO-M9N units that I have purchased recently. Only one has the U.FL antenna connection while the rest have integrated chip antennas.

The time to first fix (TTFF) should be 24 seconds for a cold fix and 2 seconds for a hot fix.

The TTFF are inconsistent, sometimes they are within specifications and other times they are really long (up to 5 minutes).

Do you have any suggestions on how to go about troubleshooting the units when they are not performing to specifications?

I am not super concerned about positional accuracy as these are integrated into a magnetometer data logger and I have a very accurate RTK GNSS receiver located a fixed offset from the sensor. I just need them to get a fix quickly so that I can start collecting data with a correct time stamp on each magnetometer measurement.

I am curious if one possibility is that they are not getting the required current from the battery and this might cause a slow fix.

2

I doubt it’s your battery. I suspect it is your antenna. Chip antennas are notorious for their good, but marginal reception. If you can manage it, use a big antenna with a good amplifier (probably too big for your application but it’s excellent: https://www.sparkfun.com/products/21801). Alternatively, you can use u-blox AssistNow Offline service. We’ve had success getting u-blox receivers to lock within a few seconds by using this service. See here for more info: https://github.com/sparkfun/SparkFun_u- … /AssistNow

3

Oh, and ‘Hi’ from down the canyon!