Hello Fellow Sparkfun members,
We are going to do some walk testing in a dense urban area to collect some wireless signals. I looked at a product which may work but not sure.
https://www.sparkfun.com/products/16329
Few Questions I have:
Can this be used while the person is walking and not in a car?
Can this be directly connected to laptop using USB port and collect GPS coordinates ?
Hello, and thanks for posting!
The answer to your first questions is yes. 
However, there is one caveat.
You do need to [calibrate the IMU inside the GPS module and to do that, you need to get it moving above 30km/h. Since it’s not very likely you can run that fast, you’d need a car to do the calibration.
After calibration, I believe you should be OK to use these on foot.
For the second question:
The USB port is only used for power and you need a microcontroller attached for the GPS to function. We recommend using a SparkFun RedBoard (Arduino Uno clone) and that does have USB and can be programmed to send data to a PC via USB. You just can’t use the USB port on the GPS itself for that. Please see the [hookup guide for more information on how this all works together.](SparkFun GPS Dead Reckoning NEO-M8U Hookup Guide - SparkFun Learn)](SparkFun GPS Dead Reckoning NEO-M8U Hookup Guide - SparkFun Learn)
I haven’t seen much posted on these new GPS with UDR. The hookup guide looks very promising. I have two additional questions, though.
First, is the dead reckoning feature part of the default setup for the board? I am hoping I would not need to change any of the configuration parameters initially.
My second question needs some explaining: I am running a small GPS guided machine on my farm, and I have always noticed the machine wanders quite erratically whenever it gets within 50 feet of some high tension power lines, which the course actually passes under and runs parallel to for about 100 feet. I had always suspected EMI from the power lines, but could never confirm. So the other day I took my RF signal tracer out their and just held it up over my head and it buzzed like crazy once I get anywhere near the power lines. Note that this is happening on the high-potential lines, not the feeders coming from the transformer on the pole. I was not sure if this amount of noise was normal for these lines, so I went to a neighbor’s house about a mile away and got the same result from his high voltage overhead lines.
So now I suspect that at the very least this noise is affecting the magnetic compass on my rig, and possibly degrading the GPS signal. (btw this vehicle orients its heading from the magnetic compass because it runs very slowly and the GPS heading only seems to be accurate over about 1 mph.)
So my second question is whether this new GPS should be able to recognize the EMI and seamlessly switch to dead reckoning as needed. My read of the product description has me thinking yes, but I wanted to confirm if anyone knows for sure.
Thanks for any help - Rob
As far as I was able to find in the datasheet: "With UDR, positioning starts as soon as power is applied to the module, before the first GNSS fix is available. " It seems that it may be enabled by default. However, I’m not sure about the second question. These questions would better be answered by Ublox on their forums: https://portal.u-blox.com/s/
TS-Chris:
For the second question:The USB port is only used for power and you need a microcontroller attached for the GPS to function.
Is that correct? The NEO-M8U datasheet states “A USB interface, which is compatible to USB version 2.0 FS (Full Speed, 12 Mbit/s), can be used for communication as an alternative to the UART.” It seems seems very limiting if you can’t log GPS data on a laptop with USB. Do all the uBlox GPS receivers operate this way?
Technically it is possible to receive data via the USB connector, but we don’t have a driver that allows for this. If you can locate a driver you should be able to see the GPS as a COM port on a computer and get data through a terminal program.
Currently we only support operation through I2C (Qwiic) but the other interfaces are available if you’re feeling adventurous.
Chris is right that we support the I2C functionality. However, Ublox does make a U-Center app: https://learn.sparkfun.com/tutorials/ge … for-u-blox. For information on how to pull data from that you’d have to contact Ublox.