PPK Using Station Logs?

If using log files (RINEX format) from a nearby GPS reference network station in the post process, a base and rover (drone based in this case) would still be required, correct? The logs from the station and logs from the drone receiver are not enough? I read this https://docs.emlid.com/reachrs/common/tutorials/gps-post-processing/
but I’m foggy on understanding how the base would be needed in this scenario.

Thanks.

If within 10km of the reference station then the base data from the reference network station may be used for PPK with the drone log file.

Thanks Simon. I also see that here I have the option to select a Virtual Reference Station logs which I’m guessing extrapolates from those close. If there is a station about 10km in 2 directions, would it be best to select one of those or the Virtual option?

Virtual Reference Stations are great and have been shown to work with L1 GNSS (like the reach) to a distance of 40-50km so select the VRS. You will end up with a solid position, unless there is some file format or observation format incompatibility, but until you try, you will never know.
Let us know how it goes.
Simon

some reading:

When using station logs to correct for error in a ppk workflow, could a number of Reach RTK kits (https://emlid.com/shop/reach-rtk-kit/) without need for radios connected be set out with targets for an hour during a uas flight like a poor-man’s Aeropoints solution? The station logs would be applied to each unit’s logs?

BTW, I apologize for all these unsophisticated questions. :blush:

Would the goal of this to be getting accurate positions of those placed Reach`s ?
If so, then yes. But really a expensive way.
It would be easier to just PPK those points ahead with only two units.

Yes. To be able to show up at a remote location and set them out and then collect images and then recover. If it were a location that was close or would be repeated then I suppose even one unit could be moved around but would take a lot of time, correct?

The RTK alternative would be to use an RS as base and let it sit for an hour and then use another as a rover and mark locations like typical GCP placement. But this would take more time over all to record I think?

I’m just trying to get an understanding of the options available using this gear. If I only wanted to be at a location for a couple of hours and didn’t have a ppk equiped uas, then do you think that this would be a decent approach?

If only relative accuracy was needed, then just the logs of the static units for the same time period could be used without need to correct them using station logs, correct?

I’m also following this:

Dave,
You are right! Thanks for pointing that option out. for a mere $295m per target plus a large laminated computer readable reference mark like the ones printable within Photoscan you could easily litter the area with a series of these, do your aerial work then go collect them. It would save you one or two round trips per survey and the processing would be very easy. For big area surveys this could pay for itself in just a couple of projects.

Yes, in fact there are commercially made GCP pads with the GPS built in for this exact purpose, but you can save yourself a lot of money by just buying Reach and ‘doing it yourself’.

@Luke_Wijnberg had some fun with the propeller version i reckon

Gosh, that was ages ago! That airframe has been retired since.

Yeah, that brings me to something. How long does your airplane last ?
i saw the new “beliver” (is that the name?).

50 hours is acceptable. But we land in rough areas. No manicured grass strips for us. We moved on to twin engines now and are much heavier. Time will tell what we will get in terms of lifespan but currently 3 of our new airframe are over the 50 hour mark and are looking very good.

We moving away from the Lipo batteries now and want to explore ic generators. Air travel in Africa is getting tough with restrictions on lithium products, so petrol is maybe the answer.

AeroPoints look like nice units and have L1 and L2, solar panels, radios for connecting to networks and generally a very nice looking product. But they are very expensive.

Coming at this from a non-surveyor perspective, I am finding that the new polished products aimed a uas surveying are very expensive. But I understand that surveyors generally charge a high price and so the idea that the margin on hardware is so high doesn’t bother them in the least. I suspect that is going to change a little. Emlid’s products are a sign of that beginning. It’s generally true that you get what you pay for. But in cases where the markup is incredibly high leaves a lot of room for other companies to eat away at market share unless there is some magic element that can’t be figured out by the competition. Time will tell. But I’ll wager that in 2 years time, Propeller (for example) is going to have to choose to live with more reasonable margins or come up with something that can’t be built just as easily by someone else.

Welcome to the maker world, where is is possible to consider small batch production, without having to tool up a production line, which costs millions to do and either needs high volumes or high recovery per unit. It is not that the propellor unit has a high margin (on the overall cost of setup of production + production costs) just that they are seeking to recover the money from a realistic number of sales. and then make a profit.

Simon, makes sense to me. I know of one particular company in Canada that has a great solution for setting GCPs and after full investigation of what it would realistically take to to manufacture stepped back. A “cobbled together” solution is definitely different than a polished product.

@Luke_Wijnberg

I don’t have any fixed wing experience but am thinking about starting up the learning hill.
I’ve been reading recent info on the Believer and when you mentioned the heavier weight which in turn requires faster speed, I was wondering how fast is too fast for capturing images from no greater than 120m height? I fly multis at only about 5 meters per second on average, so fixed wing speeds seem really fast. No problem with smearing if shutter speeds are fast?

If in fact you are using that airplane I would welcome your thoughts there too. If I went down this path, I would happily pay for autopilot parameters already worked out by an experienced crew. Being in the NW US and not traveling internationally, I doubt I would be your competition if that was a concern.

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