Emlid

Community Forum

PPK after Base Died


(Michael Lambert) #1

My base died 25% into an M+ drone mission. Is there any way to post-process in RTKLIB without a complete base file? I just ran it and went from Q1 to Q5 immediately. I do have a reference position in the report. I also have my Topcon base coordinate.


(Michael Lambert) #2

I also have the RINEX files from a nearby TXDOT VRS, but do not recognize their file types even though they do load into RTKLIB. I have never tried to use their data before.

image


(Hunter) #4

Can you provide rover file?


(Michael Lambert) #5

Here’s what I have. Includes the original UBX, post-rtkconv RTKPOST Outpout and the TXDOT (TXAU) CORS RINEX. Thank you!

GAP PPK 031119.zip (6.4 MB)


#6

The timeframe is not the same. The TXDOT is 1,5 hour to early


(Hunter) #7

Yes, time was off. Pulling different files.


(Michael Lambert) #8

Ok, I download the version by their naming, but wasn’t sure what time they used or how daylight savings affected it. I will get 2h later.


(Michael Lambert) #9

Here is the next hour. Still too early?

txau070Q.zip (432.5 KB)


#10

Sorry yes, this one is from 1600-1700. You need the next hour


(Hunter) #11

I just pulled from CORS site and ran through RTKPost and got a decent solution. Can be improved but little time fiddle.

image

Just run rover against CORS base. Baseline was 18-21 km. You will have to adjust base station coordinate accordingly though as I did not spend too much time here. Here is .coord file txau_08.coord.zip (1.5 KB)

All files from CORS site for the day: txau070.zip (4.5 MB)

You have topcon base coordinate, was that logging? Can use that if you think baseline is too much.


(Hunter) #12

I’ll let TB_RTK give it the proper polish :sunglasses:


#13

Haha, i can add som paintwork :sweat_smile:


(Michael Lambert) #14

I appreciate it and it is good to know that they might be a possible Plan B. The Topcon base coord is just the averaged from 1hr so may not be much good. No logging.


(Michael Lambert) #15

@RTK_Hunter, did you use 70R?


(Hunter) #16

You can use CORS on rover (M) if baseline is sufficient. All your base is doing is giving observations on shorter baseline, its not giving you more constellations over a CORS site as you generally log GPS only at 14hz on rover and 1hz for base.

No, I went to User-friendly CORS site and pulled it myself. https://www.ngs.noaa.gov/UFCORS/


(Michael Lambert) #17

Very good. As my actual plan B, I shot GCP’s so it’s not a catastrophe, but I was more interested in knowing if there was a way out. Imagine if I had been flying the P4P RTK and the base died. On RTK it wouldn’t have been doing any logging on either side… Thanks my friend.


#18

You guys are blessed with high density of station over there.

You

Me :joy:


(Michael Lambert) #19

Well, I guess it is a matter of perspective. We have no public service. Everything is paid for except for the TXDOT after-the-fact download. Is this normal? I find it fishy that I pay taxes to run that facility, but only have this access to it. I guess, at least they shared…


#20

We have expensive fees too, giving access to more stations. Other then that it is only those 3 ish visible and free you see on the map and known monuments, if your own base is used.
VRS is the common tool but expensive.

Maybe the SSR will be a game changer when operative.


(Hunter) #21

It’s a shame and we will lose more free ones here in the states.

We should build an open-source Emlid based global network when they introduce L1/L2 :thinking: