DUAL GPS - RTK Here + & Here 2


What would you recommend when using dual GPS configuration using RTK ?

Maybe it is not relevent, i’d be happy, if so, that you explain me the reasons.

So far, i have built a 12s quad, 1400mm. I use with good result a Here2 CAN gps.

I’d like to set up a dual GPS setup for redundancy and very precise flight. The drone will drop biocid in national park so we want to give precise report to our client.

Should i use CAN 1 and 2 for both ? RTK primary ? Should i keep an I2c connection ?

Thanks for helping.

Best regards.

Lucky you! Here3 is released for almost Here2 price. Here3=Here+, Here+v2.
You can use Dual Here3 or Here3 with your existing RTK Here+.

I see there is a big price difference between the Here + and Here 3 now. They both are RTK ready and I think the Here 3 has some water resistance. What are the other differences between the two? Thank you.

Water resistance, No unsafe button, Same Ublox M8P as Here+ versions, better LEDs, CAN interface, cheaper price.

Thank you,

Our next mission starts in two weeks, no time to order and receive the Here3.

So i will work with Here+ and Here2.

would you use CAN ports for both ?


Would be interested in an answer to this question as well.

In my case, I have the Here3 and Here+ Base for RTK. For some reasons I have an additional Here2 as well. Is it possible to use both GPS (only for redundancy) in ArduPilot? Would it be better to use GPS_AUTO_SWITCH=1 or blend the two? Or is it imposible to use a “normal” Here2 and Here3 in RTK mode at the same time?

Hey there, found the answer in the Ardupilot forums. No blending should be used, so better use two same RTK GPSs or use the switch function which might be a little bit harsh in case of the RTK GPS failing.

Thank you @MadRC for asking it over there!

Hi samuel,

Thanks for the information and link to the discussion. It saves me a lot of time in research and tests.

Great job.

Best regards.


on a demo UAV we are building I have it outfitted with here+ and a here 2 on CAN.
I was able to use CAN1 and CAN2 for the two units.
If you have the same struggle getting the here+ flashed with the CAN firmware as I did be prepared to pull your hair out. I have seen some random posts the here+ is not ready or not compatible with CAN operation but never saw anything official.

If you run into the same flashing issues let me know and I will try and dredge up the posts that assisted in getting it flashed.


To be honest, as my knowledge is low, i swap to another issue on our build and try to fix the dual GPS later.

I received the Here+ with no CAN cable (or i did a mistake). And not sure it ismeant to work other than in I2C… But again, i’am not a specialist.

I will try to fly my test setup (X8 900mm) with only one GPS, the Here + and dig the RTK option.
Once its done, i will think again putting 2 GPS. (maybe to Here3)

Best regards.