Hello, I use EMLID RS2 for the Base and ROVER. I want to make a topo survey but if I use AVERAGING SINGLE MODE for the BASE STATION can I have a accurate data?
I made time for the base to retrieve satellite data for 10 minutes and I use RTK method for this job with LoRA correction input.
Hello !
With this method, you can have good relative accuracy, because you can have a fix solution during the whole survey session. But the absolute accuracy will be at a meter level because of the base positioning mode.
You can check this thread to see how to correct things : How to correct collected points with a new base position? - Support tips - Emlid Community Forum
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okay noted. thank you, sir!
Hi there,
Agree with Florian. The accuracy of the Average Single mode is about several meters. But the accuracy of the rover, relative to the base, may still be of several centimeters if you have a Fix. So you can do the survey locally and then update it with the correct position of the base.
To get the correct position of the base, you can use a PPP Service. For example, NRCan CSRS-PPP. Here are the guides to learn more about how it works and how to record the logs for it.
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Can you set the Base input to NTRIP and the base output to Lora to achieve absolute accuracy?
Yes! As long as you have an in range CORS providing an NTRIP stream to your base can use it to achieve absolute accuracy. Notes:
- on your base you will choose āAVERAGE FIXā instead of āaverage singleā
- on your base choosing RTK mode as STATIC will probably be helpful if the CORS station is farther away. Off the top of my head I think you are limited to about 60km max from the CORS and will need ideal conditions to reach that range.
- Your base average fix position will be in the same datum as the CORS and this will be passed on to your rover.
- Even though we are talking absolute accuracy, you must still consider that there is an error budget for your measurements. You will have error from the CORS to your base and then error from your base to your rover. Depending on your project error requirements and the CORS setup (single site corrections vs network corrections), this setup might work really well for you. If your error requirements are tighter, you may need to establish your local base with a better method.
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Hi Josh,
Sure, I second @Africawaterdoc words here.
A small recommendation from me is to separate these 2 steps to avoid confusion. First, place the base using Average Fix with corrections from NTRIP. Once it is done, you can disconnect the unit from the NTRIP Service and configure base output via LoRa. Further survey can be carried out via LoRa locally.
Thank you!
Would this method - work with using NTRIP as the correction input. Does this work with Emlid Caster?
I using LoRa because in forest we cannot got the internet signal
Hi Josh,
Emlid Caster doesnāt provide corrections per se. It works more like a āpipelineā to pass the corrections between your own base and rover via the internet.
What you need to place the base via NTRIP is NTRIP Service (CORS). Such services place several receivers as bases and provide access to the data from them. Please note that they may take a fee.
Here is also an article to learn more about the difference between NTRIP Caster and NTRIP Service.
Hi @arsifalf,
In areas with no internet coverage, using LoRa to pass the corrections is indeed a good solution.
But please ensure that both your receivers have a good sky view. Itās vital for the GNSS receivers to calculate a solution. In a dense forest, where the sky view is fully covered, itās better to go with non-satellite-based ways to get the position.
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