Quantcast

Highest Altitude GPS?

The Rocketry Forum

Help Support The Rocketry Forum:

gtg738w

FlightSketch - flightsketch.com
TRF Sponsor
Joined
Dec 27, 2018
Messages
230
Reaction score
171
I sent an email to Ublox a while back asking for SAM and CAM M9 modules...still waiting for a response.
SAM and CAM are going straight to M10. Will be available later next year. Max is available now for samples in M10.
 

cerving

Owner, Eggtimer Rocketry
TRF Sponsor
TRF Supporter
Joined
Feb 3, 2012
Messages
4,085
Reaction score
1,333
I had one such flight. We were getting packets and then they suddenly stopped. We weren't watching the altitudes in real time though (tracking 3 gps transmitters), and for a few minutes, I essentially lost situational awareness on the flight. It was confusing when the packets stopped and then confusing again when they started a minute or so later.

Jim
Did you have real-time IMU telemetry so you could at least tell what it might be doing?
 

JimJarvis50

Well-Known Member
Joined
Jan 18, 2009
Messages
2,462
Reaction score
701
Did you have real-time IMU telemetry so you could at least tell what it might be doing?
No, I didn't have anything other than the gps. There were a lot of things going on with four pieces coming down. The radio I was using was tracking 3 gps transmitters and 2 RF beepers simultaneously, and we had another Marshall tracker running two transmitters as well. I was trying to move volunteer humans around in a circle permimeter to mark the directions to the various pieces as they fell. It was quite exciting. By the time I got to looking at the sustainer, which I thought has crashed or shreaded, it was still pretty high up. I sent Kip out to pick up what I thought would be pieces and I was surprised he came back with a complete rocket. That 50km limit was a big part of the confusion, and it would have been nice to know about it.

Jim
 

GrouchoDuke

Well-Known Member
Joined
Oct 18, 2016
Messages
987
Reaction score
383
SAM and CAM are going straight to M10. Will be available later next year. Max is available now for samples in M10.
Oh cool, good to know. I'm good with that...assuming 10 is better than 9. :)
 

cerving

Owner, Eggtimer Rocketry
TRF Sponsor
TRF Supporter
Joined
Feb 3, 2012
Messages
4,085
Reaction score
1,333
The uBlox site currently only shows the MAX modules in M10... no SAM or CAM listed.
 

gtg738w

FlightSketch - flightsketch.com
TRF Sponsor
Joined
Dec 27, 2018
Messages
230
Reaction score
171
M10 has been optimized for ultra low power designs, not so much for performance. It is a nice upgrade over M8 though. M9 will continue to be the “power” receiver. Seems like they are really introducing two families that will alternate upgrades with each other. Both will continue to have pros & cons for our applications.
 

GrouchoDuke

Well-Known Member
Joined
Oct 18, 2016
Messages
987
Reaction score
383
M10 has been optimized for ultra low power designs, not so much for performance. It is a nice upgrade over M8 though. M9 will continue to be the “power” receiver. Seems like they are really introducing two families that will alternate upgrades with each other. Both will continue to have pros & cons for our applications.
Good to know, thanks guys. Well, so much for that hope of awesomeness. I guess our hobby will take what we get & be happy with it. :)
 

AllDigital

Well-Known Member
Joined
Jun 14, 2013
Messages
236
Reaction score
128
Location
SoCal
A quick update on the Ublox M9N. I haven't been able to test its upper limits (that will be a long ways off), but I did swap out my Ublox M8N for the M9N on a flight this weekend. To keep it "apples to apples" I used the same patch antenna I have been using with the M8N and I am logging locally to SD card every two seconds. Overall, the M9N performed slightly better, but it didn't blow my socks off. Here is a summary of the comparison between two flights with the same profile:

Flight: A 4" rocket launched to about 15K feet with a 4 second motor burn time (7700 N-sec), max speed of 1,250 Mph (1833 fps), max gee force of 23 G's, and 30 seconds to apogee.

Both GPS units consistently track a solid 12 satellites, while waiting on the pad, but both lose GPS shortly after take-off.

M8N: The M8N loses GPS immediately after launch and regains it about 28 seconds later with 4 satellites, two seconds before apogee. It takes a full 42 seconds of descent (avg 75 fps) to get back to a full 12 satellites.

M9N: The M9N held on to reception longer following launch (about 6 seconds) and reported 2D coordinates with only 3 satellites, but then also lost reception. It came back online 10 seconds before apogee (with 4 satellites), a full 8 seconds earlier than the M8N. Following apogee, it only took 10 seconds for the M9N to regain the full 12 satellites.

So, with the sample of one, the M9N seemed to perform better than its predecessor, but it still drops out during the high speed portion of the flight. I'll keep flying with the M9N and see if the trend continues.
 
Top