DUAL GPS - RTK Here + & Here 2

Here GPS
1

Hi,

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.

2

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+.

3

@Mallikarjun_SE
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.

4

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

5

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 ?

A.

6

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?

7

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!

8

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.

Adrien

9

@Adrien_RunOI
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.

10

Hi,

Thanks.
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.