GPS tracker over mach 2

Anyone out there used gps in rockets over mach2? I hear they they might not be able to handle G's over 25. I figure someone out there has tried gps in a minimum diameter screamer.

Cheers

I don't think it's g-forces at the component level-it's data acqusition. Most guys I know reacquire signal after it slows down.

It will lose lock, but will reacquire once it slows down.

Based on comments from electronics manufacturers, hardware is available which will maintain lock at higher velocities....but you likely don't want to pay for it.

-Kevin

I'm worried about the GPS coming apart. I have read that this can happen and was wondering if anyone has been able to figure out how to keep it all together. I would like to use it in 38mm MD and 54mm MD birds. I'm guessing the 38mm will be a problem with limited space.

Cheers

They're not going to fall apart just from the speed; they fall apart from crashes.

That was a bigger issue with Lassen IQ based devices, because the Lassen IQ is a huge chip that's weakly anchored down, but most nowadays use ublox chips which are small and very securely soldered down.

powderskierman said:

Anyone out there used gps in rockets over mach2? I hear they they might not be able to handle G's over 25. I figure someone out there has tried gps in a minimum diameter screamer.

Cheers

Click to expand...

A GPS is no more or less rugged than any other piece of electronics. Almost any board level ones should withstand 100 Gs or more just like a rocket computer.

You should be aware that any inexpensive GPS will loose lock around 4-6 G and will not provide a location during high acceleration. Check the spec sheet for the level. This has nothing to do with the strength of the unit, but is a limitation of the processors in the chip. Once the acceleration drops back down below 4 G, most relock in a second or 2 and start providing accurate positonal data.

Bob

It took me quite a while to figure out how to properly reinforce the Lassen IQ, but then the weak point became the board itself. The u-blox is indeed much more robust. Some GPS modules have the patch antenna integrated into the device, which makes them big and heavy -- not good for those high G flights, either.

Yeah, you will lose lock. troj did the GPS on my Mach 3 attempt (since I don't know a ton about GPS) and we lost lock after about 100 feet, and it never regained lock...

For sub sonic to mach one model rocketry flights, what would be a good recommendation for a device that could track the location, altitude, velocity and acceleration of my rocket throughout its flight? I'm curious to know, and also how expensive would it be? I have limited resources when it comes to funds at the moment, however I'd rather pay for a quality and reliable part.

Flown my garmin Astro to Mach 2+ on three different occasions.

Once lock the whole flight.

Once lock till landing.

Once lost it 100ft off the pad (project 60k) Mach 3 and 80+G takeoff. Oh and then shred. But still works great.

bandman444 said:

Oh and then shred. But still works great.

Click to expand...

A testament to the durability of modern electronics.

I have had a Big Red Bee 70cm to Mach 1.5 mounted on a small piece of basswood, wrapped in small bubble wrap, and stuffed into the nosecone. On this flight the main never deployed (apogee separation did work) so it hit harder than I'd like. (It is a Neo Blox not a Lassen based chip set) Everything is fine with it. Using a Yaesu 8-GR HT to track it (worked well too). Yeah, I lost lock quickly, but it reacquired shortly after apogee (around 15K) and was sending packets until it disappeared behind some low hills several miles away.

I got the BRB to put into a 38mm two stage which my dog collar will not fit into without significant modification. The BRB 70cm easily fits into a 38mm nosecone. The biggest g-shock I see in my rockets is at separation, often reaching 15-20g's according to my Raven. I don't think Mach has much effect on it, unless it shreds (duh). Of note, the price of the Garmin dog collars is approaching that of the BRB 70cm transmitter, $210 vs. $259.00. The receivers are the same price, but the Yaesu does a lot more. The Astro is extremely user friendly and does not require a license. Getting the dog collars repaired by Garmin isn't trivial and is costly once you exceed 12 months. Big Red Bee is customer friendly. I like and use both systems.