GPS memory

Martin Y

Well-Known Member
Alex
I have the new gps and upgrade board. My question is how long does the memory keep in the gps with out power to the osd? Mine lasts about an hour then the gps does a stupidly long cold start (20+ minutes). Which is a real PIA. My old 5hz starts up a whole lot faster then the new.

Martin
 

martinv

Well-Known Member
I found some info on the datasheet for the "GPTA010".
http://www.propox.com/download/docs/GPS_GMM_U1LP.pdf

VBACKUP, Pin4
This is the power for GPS chipset to keep RTC running when main power is removed. The voltage
should be kept between 2.0V~4.3V, Typical 3.0V. If Vbackup is no supplied with power, GPS
module will revert back to default setting and perform cold start when re-started.
Backup Power Consumption@ 3V 25°C 10 uA
It looks like the battery backup pin is connected and the RVOSD5 has a battery. Not sure if it's used for the GPS though.
 
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man2000me

Well-Known Member
I put my plane away from me and any transmitting devices. The hop goes almost instantly from 1.52 to 1 - 1.20. Quick start up.
 

martinv

Well-Known Member
If the issue is based on powered off time I would guess it is an issue with the GPS losing memory.
 

Martin Y

Well-Known Member
Thanks guys, I've just finished a test from my last post(12:50pm). I reinstalled my old G2 board connected the new gps and powered up. It got it's first sat in under 1 min (as todays date showed up at that time). Then took another 5 minutes to receive all information thats needed to fly. Disconnected the battery and went out till now(4:10pm). Tested backup battery at gps and it had 2.93 volts(perfect). Powered up and less than 3 minutes ready to go. So this tells me that BT1 in the upgrade board or one of the components related to it is leaking or faulty. I dont want to wait to send back to Vova for a repair/replacement so I will change out BT1 and see what happens. Alex what else can I check in the curcuit before I do this? As requesting a schematic is a no-brainer in asking.

Martin
 

rcmike

Well-Known Member
Hmm.. wonder if mine is too then. I waited a long time the other night for a GPS lock and finally gave up.
 

Alex Villa

Super Moderator
The GPS backup batteries used on the G5 were not that great. However with or without charged battery I always get lock in less than 5 minutes. So I suggest to check for other GPS interference sources on board. The first lock always require a better signal.
 

Martin Y

Well-Known Member
View attachment 1437View attachment 1438
The GPS backup batteries used on the G5 were not that great. However with or without charged battery I always get lock in less than 5 minutes. So I suggest to check for other GPS interference sources on board. The first lock always require a better signal.
Like I said before. Nothing is connected(no power applied), No Vtx, No rx. The gps sits in the same spot as my original 5 hz one. When using the upgrade board it takes 10+(cold start), when using the old G2 board it takes 5+(cold start). After gps lock is done, new board no memory, old board works like a charm. This happens inside or outside.
 

Alex Villa

Super Moderator
Ok you could ask vova for a board exchange. But I don't think a new board will be that much different. On old boards we used a supercapacitor, G5 board does use a battery, but it didn't worked like we expected. Still the Battery backup circuit does provide immediate power to the GPS. So even if the battery is dead the worst that will happen is that your GPS will always do a cold start. Battery status does not affect the start up time when GPS has to do a cold start.
Anyways I have to repeat that I get locks usually on less than 2-3 minutes from cold start, with G5 board and the new GPS module.
 

Martin Y

Well-Known Member
If thats the case then the GPS is faulty or the programming is wrong in the gps. I will change the battery and see what happens.
 
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