Problem getting fix status on Rover

[caspuk]

I have 2 Reach RS, one base and one Rover.
I set the base up to take on average single position over 30 mins.
With both Reach RS having clear, unobstructed views of the sky,I sometimes have difficulty achieving a Fix status on the Rover. The rover receives corrections over LoRa. Does anyone have any tips?

[igor.vereninov]

Satellite reception is quite poor. Can you provide a picture of how everything is installed?

[caspuk]

Hi Igor, I have attached pics of how I use the equipment. The location is different to the previous post. The tripod is 1.6M high and the pole I use at 2M. I hope this helps.

[caspuk]

@igor.vereninov the work carried out was quite near a mobile telephone transmission mast, would this have any effect on the performance of the Reach RS

[TB_RTK]

Yes, i would think it hade some effect, how much its not clear. I belive its nota good idea todo survey close interference like this. At least be aware that it might not be a solid fix. I think @Luke_Wijnberg has a post or two about it.

[caspuk]

thanks @TB_RTK

[caspuk]

Even with good gps coverage I find it hard to keep Fix status

[TB_RTK]

Could you share log for this?

[caspuk]

Google Drive: Sign-in

You can find the logs here @TB_RTK

[TB_RTK]

Looking right?

[RickJ (Richard Johnson)]

Same results as TB_RTK. Follows is Time Edit for Kinematic Point. Looks Good to me…

[RickJ (Richard Johnson)]

I think interference is ruled out. Maybe data link throughput ? Lora setup?

[caspuk]

Hi @RickJ I have attached a couple of screen shots of the LoRa setup, does it look ok to you? Thanks for your help

[TB_RTK]

Looks allright. If your doing long range, lowering bit rate might help. Also set Hz to 0,1 has given me a more stable age of differential

[caspuk]

@TB_RTK Do you mean lower all RTCM3 messages to 0.1HZ? I will reduce the the air data rate to 9.11kb/s as thatis the only other option I have. Thanks for your help

[TB_RTK]

Correct, but you dont need to do this for all messages, you can start of with SBAS and then GLONASS etc… Things get slower but at long range you need to do this to keep rover from choking. Its also easier to transmit low amount of data at long range.
If you do some test you`ll see this soon enough

By choking, i mean Age Of Differential is going through the roof

[caspuk]

@TB_RTK I reduced the Air data rate from 18 to 9. Initial tests show it is very stable in Fix status and Age of Differential is between 1.6 and 2.8. Thanks again for your help.

[RickJ (Richard Johnson)]

Glad to hear you got it going. I think I read that Igor said Emlid is going to add some checks for Lora data link. Main point is to slow down data that is only needed infrequently and use less satellites if you have good fix. But, keep in mind that I have no experience with Lora, just communications engineering.