Quantcast

Which GPS Modules Save Settings?

The Rocketry Forum

Help Support The Rocketry Forum:

Bruce

Well-Known Member
Joined
Feb 21, 2019
Messages
130
Reaction score
17
I am interested in sending GPS data from a rocket to the ground.

I have noticed that some GPS modules will save settings and some won't. I use u-center to change things like the sample rate and which sentences to output. My M9N GPS saves the settings just fine. After a power cycle or even after a couple of days, the settings remain. But an M8Q GPS does not save the settings even though it looks like it is.

Is there a list somewhere that tells which GPS modules save the configuration and which don't?
 

Reinhard

Well-Known Member
TRF Supporter
Joined
Jan 18, 2009
Messages
1,067
Reaction score
246
Location
Austria
Is there a battery or supercap on the M9N module that you're using? This would explain why it keeps its settings.
How long does it take for those systems to get their first fix after powering them up? If the M9N is much faster (typ. seconds instead of minutes) then there is some energy storage involved.
You can also check the u-blox documentation wether your modules are flash or ROM based.

Reinhard
 

ksaves2

Lifetime Supporter
TRF Lifetime Supporter
Joined
Nov 25, 2009
Messages
6,002
Reaction score
312
I discovered the cheaper versions of a GPS chipset usually don't allow one to change many of the settings through the manufacturer's setup program. They are "hobbled" versions of their pricier counterparts. As I recalled back when I was doing a lot of this, a $20.00 version of a GPS chip was limited as opposed to the "full range" $125.00 version which might just differ by one designated letter or number. This was some time ago mind you and prices for full featured chipsets have probably dropped somewhat.
Holee guacamole. Just did a search and found this: https://www.beyondlogic.org/fsa03/
Specs are pretty good, tiny unit and that antenna is for GPS reception. Just the module so would have to be wired into an Rf module to transmit the data.
Incidentally, I dorked an Eggfinder tracker by dropping it and the GPS receiver snapped clean off the base. For fun I took it out of the junk door as I acquired a fancy dancy desoldering station. I have a quadrifilar GPS chipset that runs off the same power as the EggFinder and I just had to solder 3 wires. Two for "+" and "-" (power) and one wire for the signal "out" of the GPS to the signal "in" of the broken EggFinder. Eureka, it works! Still does last time I tried it.
Oh the reason I was trying to get into a particular GPS chipset's setup program was I wanted to make a comment statement that would go out over the transmitted NMEA sentences that would have my Ham callsign, KC9LDH, which would make it perfectly legal for me to use the unit on the ham bands. The GPS stat sheet said it was totally doable but I found out I couldn't program the "cheaper" version of the chipset to do it. That area was grayed out in the setup program. Tried a couple of other cheap GPS chipsets and same issue. They were not full featured.
I was trying to come up with a cheap disposable tracker and having to buy a $125.00 full featured GPS chipset spoiled that quest.
Launch a rocket high enough or far enough and even though one has a GPS tracker, it's no guarantee you'll get it back. Yes the odds are much greater especially if one can track on a live map but everyone knows that "shoot" happens. I can attest to as one of my early Beeline GPS trackers died in a core sampled rocket. Didn't need the tracker to find it. Ouch!
Kurt
 

gtg738w

FlightSketch - flightsketch.com
TRF Sponsor
Joined
Dec 27, 2018
Messages
230
Reaction score
171
Are you actually saving the config after you send the new settings? That is a separate step in uCenter. As Reinhard said, the M9 module you have may have a battery backup. If that’s the case, removing power won’t actually cause a restart to clear the config.
 
Top