GPS fix but MP "no GPS"

Hi,

i have strange situation on my APM2.6 with LEA-6 GPS. The GPS have solid blu led and red one on APM is blinking, i have checked with terminal session on MP the GPS, i see right position value and good number of satellite, also inside home.

In these conditions MP continue to show “no GPS” , but comunication it’s OK, other parameters like horizontal work fine, no change with USB connection or 3DR radio telemetry.

I try to erase eeprom, upload different version of firmware, until 2.9b, i try also latest 3.01 but in this case the MP hang-up on during mavlink parameter download, typically on RC5 parameter, this my be onther problem, i don’t know…, i’m not strongly interested to use latest firmware, but i need to have GPS online…, any idea / suggestion ?

@roberto_buti
The uBlox GPS should have a blinking blue led, not a solid blue led, when it is receiving at least a 3 satellite 2D lock. The APM blue led will go from blinking to solid when there is a GPS 3D lock.
The MediaTek V2.0 GPS blue led will be blinking and then go solid when it has a 2D lock.
Regards,
TCIII Developer

Yes,
ok i have a uBlox GPS, no compass version. (i get it few month ago with APM 2.6)
I see solid led on GPS and i see regular data on terminal > test > gps, so why the MP still "no gps " ?
Honestly seem a MP problem more then a APM or firmware problem, but i don’t have idea why.

thanks

@roberto_buti,
Are you seeing a flashing blue led on the uBlox GPS. If not, then there is not enough satellite data for a 3D fix.
In the CLI, how many satellites is it indicating?
Is your GPS module a 3DR product or a clone?
Regards,
TCIII Developer

Yes the blu led is solid, 5/6 satellite in indoor , that’s good. The product it’s original from 3DR.
I think have found the problem, cheking more other functions in terminal > test i found problem on compass “no healty” and “no data flash inserted” at terminal session begin , strange things…(i remember compass was working…), searching on web i found this is a relatively common issue, do to U3 (3v3 regulator) not working anymore. I check it and really is not working , just 1 V output, hard to understand the cause, probably spike or electrical events on main power suppy. I have just ordered some of them on Farnell, i will change it and check again.

Update soon.

Yes, after i changed 3V3 regulator U3 on APM all come to work again, compass OK, GPS now sign “fix” and also FW update to 3.01 is working .
Great !!
I hope this issue can help other users.

Bye

Hi Roberto and TCIII

I’m having a similar problem. MP is showing “bad compas health” and “GPS:NO GPS”. CLI shows “compass initialisation failed!” (terminal>test>compass)

I have an original 3dr apm 2.6 with ublox gps+compass module, runnig arducopter v. 3.1 (5c6503e2), MP v. 1.2.90.

on the ublox I have a solid red light (seems dimmer than before) and no blue light. On APM the red ABC led is blinking and the blue and yellow leds are of (all three leds blink at startup)

Roberto, would you mind posting a picture of the U3 3V3 regulator and the method you used to test the voltage? all your help is greatly appreciated!

Thanks!
Jorge

@jgutierrez101,
The compass on the GPS/Compass module is powered by the 5vdc supplied to the GPS and is regulated to 3.3vdc for the compass so you may not have a 3.3vdc regulator problem.

Since the APM 3.3vdc regulator supplies the gyro/accels , if you had a 3.3vdc problem then the gyro/accels would not initialize.

I suspect that your problem might be that your computer USB port cannot supply enough current for a full up APM and the voltage to the APM is dropping below 5vdc. I have found the voltage on the GPS using a stock USB cable to be less than 5vdc. I suggest trying a powered USB port to help the computer power the APM. The GPS having a dim power led is typical of less than 5vdc being supplied to the GPS.
Regards,
TCIII Developer

Hi TCIII,

Thank you for your quick reply! I’ve tried powering the apm using the 3dr power module and a fully charged 3s lipo, still no dice… :frowning:

The red lightn on ublox is still dim, the blue ABC led on apm is off and the MP still reads “bad compass health” in the HUD…

How can I test if the ublox is getting enough power?

Hello TCII,

Thank you for your help and I apologize for taking so long to get back to you. I tested the U3 voltage as
Per this pages:

diydrones.com/forum/topics/ac3-1 … ed-problem
rcgroups.com/forums/showpost … tcount=614

In both cases the voltage was 3.29 while connected directly to my MacBook Pro through USB. So this confirms you were right in the first place, how can I check if the gps+compass module is getting enough voltage.

Please let me know what else can I do

Thanks again!

Hello everybody;

I have a problem with my Pixhawk, it is flashing blue (disarmed, searching for GPS. Autonomous, loiter, and return-to-launch modes require GPS lock) so i have a message appears in mission planner “GPS NO FIX”

can you help me please

Thank you very much

@Yassine,
Did you buy your GPS module with the Pixhawk from 3DR or a 3DR distributor? If it is a clone GPS or not a uBlox LEA-6, it may not be flashed with the 3DR GPS configuration file and will not work with the Pixhawk.

Is the GPS module a combination GPS/Compass module and if so do you have the Compass cable attached to the Pixhawk I2C port as well as the GPS cable attached to the Pixhawk GPS port?

After the Pixhawk has booted up does the GPS display the solid red led? If not it is not getting any power>

After a while does the GPS display a blinking blue led? If so, the GPS has a 3D lock, if not you may have to go outside to get a 3D lock.

The Pixhawk indicator led will remain solid blue until a 3D lock is obtained at which time it will turn green.

Regards,
TCIII GM

Trying to narrow down my GPS problem. I’ve got the HKPilot32 (Pixhawk clone?) and a the HK Ublox LEA 6H.

Long story short. It used to work, now it doesn’t. Mission Planner says “No GPS”, however as soon as I plug the GPS into a USB cable it starts working.

So I’m assuming it’s some kind of power issue. I have two of the same GPS units and they both do the same thing. So not sure if something happened on both GPSs or something on the HKPilot.

Both GPSs work great in the Ublox u-connect software.

How do I track it down?

Thanks.

Just got this issue. I’m using a HKPilot Mega 2.7 with LEA-6H GPS on my tricopter and flown with it several times.

I was flying my tricopter today, it had good satellite reading (10). During my last flight, I noticed the satellite reading went to zero, and also the home arrow was no longer pointing to the correct direction.

When I noticed this, I hurriedly flew back and landed. I examined the tricopter and observed the blue LED light on the GPS was not lit.

I’m completely dumbfounded as I have no idea why would the GPS would stop working all of sudden. It had not crashed or had a bad, hard landings. All landings thus far have been soft and gentle.

Anyone here, might have an idea what went wrong or have the know-how to troubleshoot.

Could it be the battery in the GPS is dead? I think not because the GPS being powered by the board.

LG

[quote=“littleg”]Just got this issue. I’m using a HKPilot Mega 2.7 with LEA-6H GPS on my tricopter and flown with it several times.

I was flying my tricopter today, it had good satellite reading (10). During my last flight, I noticed the satellite reading went to zero, and also the home arrow was no longer pointing to the correct direction.

When I noticed this, I hurriedly flew back and landed. I examined the tricopter and observed the blue LED light on the GPS was not lit.

I’m completely dumbfounded as I have no idea why would the GPS would stop working all of sudden. It had not crashed or had a bad, hard landings. All landings thus far have been soft and gentle.

Anyone here, might have an idea what went wrong or have the know-how to troubleshoot.

Could it be the battery in the GPS is dead? I think not because the GPS being powered by the board.

LG[/quote]

I finally discovered what was wrong with my GPS. I opened the enclosure that the GPS came in and found that the connector where the GPS cable plug into was loose and was no longer soldered to the board.

For anyone following this issue, I found a resolution:

Post:

Only 1 GPS on SERIAL4/5 - No position telemetry. [SOLVED]

viewtopic.php?f=21&t=13846&p=38938#p38938

Hello,

I am trying to get GPS readings in MP. I have Pixhawk connected to the 3DR GPS (blue light blinking), but MP always shows “No GPS”. When I write “GPS status” in the terminal, it shows:

gps: protocol: MTK
gps: port: /dev/ttyS3, baudrate: 38400, status: NOT OK
gps: sat info: disabled, noise: 0, jamming detected: NO

Could anyone suggest a way to fix it?

Thanks.