EggTimer GPS-TX/OpenLog/Proton and Google Earth Flight Track

[atestani]

My ebay includes an EggTime GPS-TX with an OpenLog breakout and uSD card installed. I am using single electronic deployment at apogee with a JLCR chute release. I am hoping to get some advice on how to get a Goggle Earth Flight Track. I have renamed the TXT file to *.nmea which I can open directly in Google Earth. I also tried converting to a *.kml file with the same results.

I open the file in Google Earth Pro and uncheck everything especially “Adjust altitudes to ground height”


The issue I have is the track seems to stop when the apogee ejection charge is fired and all of the ground movements are showing. What is missing is the GPS track of the descent. Like this:




I assume I can get rid of the ground tracks by deleting the sentences from the *.nmea file, but the descent data is missing. I am expecting a track like these but it isn’t working:


I am attaching the *.nmea file (rename it back with a nmea extension since I can only upload it as a TXT file.)

What am I doing wrong to not see the descent track?

 

[waltr]

I loaded your.nmea into google earth and got the same.

I then ran a Python code to extract the time, Lat, Long, Alt & number Sats from the NMEA $GPGGA sequence into a .CSV file. Loaded to Excel and graph the Alt & #sats verse time (minutes).

The highest Altitude is at the very beginning of the recorded data. This is due to a low number of sats (3). Alt improves after 4 sats are obtained and settles after 8 sats. Also a long period of time to refine the altitude values.
How long was the GPS turned on before the launch? Long times allows a refined fix on location and Altitude. I like at least 10 minutes.
How high do you estimate the rocket went? 180 meters? or 55 meters?

The Alt changes starting at 1070 minutes look like they could be 'real' altitude changes but do not look like a typical altitude profile.

 

[Charles_McG]

Two of those plots are from my software, and I think one of them is a flight of mine.

I find that a lot of the descent is often missing. It can take a long time to re-establish lock.

I’ve also seen Eggfinder-Eggfinder differences. The newer chipset (that comes remounted) seems faster.

 

[atestani]

Waltr:
Thanks for doing this. Would you post your Python code?

Answers to your questions:

• GPS was on for 30-45 minutes at my prep table but may have been shadowed by the open liftgate of my SUV but I don't know which direction the GPS antenna was facing. The rocket was vertical on the launch rail for maybe 15 minutes. Unfortunately, my JL chute release slipped off so the main chute opened at apogee and I had a long like to recover the rocket.
  
  
• The Proton and both JL Alts's recorded an altitude of ~1200 ft. (365 meters). Here is the Proton data plot:
  
  
• 

 

[waltr]

Best guess is at that time the Altitude data was not good. With the number of sats and length of time running it should have been better.
Attached is the Python code.
And NMEA Reference Manual:
https://www.sparkfun.com/datasheets/GPS/NMEA Reference Manual-Rev2.1-Dec07.pdf

 

[atestani]

Two of those plots are from my software, and I think one of them is a flight of mine.

When you said "my software", I went off the find it and what I found was absolutely fantastic! Your Eggstation is an awesome piece of work. I want one immediately! I've DM'ed you for access to the GitHub repo.

Some questions about hardware requirements: In your post on requirements you say: "1 or 2 eggFinder or eggFinder Minis". Why would I need 2? Also, you say: "1-3 receivers". I assume that one receiver is required for GPS data and another for telemetry but why would you want 3?

Another question is whether you have logfile playback implemented?

Thank you for doing the eggStation and making it available to us

 

[Charles_McG]

I built eggStation for a three stage flight I attempted last LDRS. I had Eggfinders in stages 2 and 3, and an Eggtimer telemetry module connected to the Proton in stage 3. Three transmitters means three receivers.

And no, I haven’t got back to working on playback.

 

[atestani]

Impressive!

I am looking to build an eggStation "box" to use with my laptop. I have questions. Should I use your main eggStation thread or continue the discussion here?

Thanks

 

[Charles_McG]

At least one, if not two, others have made fixtures to hold laptop and receivers in the field. So, if you ask in the other thread, they may see it, too.

 

[Desfossr]

My ebay includes an EggTime GPS-TX with an OpenLog breakout and uSD card installed. I am using single electronic deployment at apogee with a JLCR chute release. I am hoping to get some advice on how to get a Goggle Earth Flight Track. I have renamed the TXT file to *.nmea which I can open directly in Google Earth. I also tried converting to a *.kml file with the same results.

I open the file in Google Earth Pro and uncheck everything especially “Adjust altitudes to ground height”
View attachment 628073

The issue I have is the track seems to stop when the apogee ejection charge is fired and all of the ground movements are showing. What is missing is the GPS track of the descent. Like this:

View attachment 628074


I assume I can get rid of the ground tracks by deleting the sentences from the *.nmea file, but the descent data is missing. I am expecting a track like these but it isn’t working:
View attachment 628075View attachment 628076

I am attaching the *.nmea file (rename it back with a nmea extension since I can only upload it as a TXT file.)

What am I doing wrong to not see the descent track?

I too have a similar setup. Unlike you, I cannot get the file to open in Google Earth Pro. I renamed the TXT file with ".NMEA", but still no luck. This is all new to me so any help is appreciated. I searched TRF and this seems to be the closest thread to my issue. If I'm in the wrong place, I'll take that guidance.

 

[atestani]

I find the dragging the NMEA file and dropping on Google Earth Pro doesn't work. When the Open dialog is visible, make sure you select the GPS file type as that is the only way to see the file in the dialog. Also make sure you are opening not importing the file. If those things don't work, post your NMEA file and we'll look it over.

 

[BigDeal4]

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