Event38 now offers Emlid Reach upgrade to its vast fleet of UAVs aimed on providing ready-to-go PPK mapping solution. Reach PPK enabled system is able to deliver centimeter-level accurate 3D models without use of ground control points.
Emlid and Event38 products are a natural fit as both offer professional performance at an affordable price. Emlid will provide Reach and Reach RS receivers, while Event38 will bring its leading expertise into upgrading the E384/6 aircrafts with PPK mapping bundles. Integration of the Reach system enables map collection at centimeter level precision. Check out the case study conducted by Event38 to learn more about the system’s real world accuracy tests.
Both E384 and E386 may be now upgraded with a mapping kit which includes Reach installation, precise timing integration and utility for post-processing and image tagging. Recently released Reach RS receiver is used as the PPK base station. Existing Event38 users can send their aircraft and camera for an upgrade, recalibration and test flight.
If you were thinking of starting drone mapping - it’s never been easier to get survey grade results so don’t miss the opportunity. PPK mapping bundles are now available on Event38 website with discounts.
Comments
From my experience, to establish a position for an L1 base station using PPP, one needs to collect at least 2-3 hours of 1 second data (longer collects are better). Anything under 2 hours is useless.
To get a corrected position the raw data must be converted to RINEX and uploaded to the PPP site. In my experience corrected positions generally vary from 20-40cm. With an L1/L2 unit a couple hour collect will give accuracy of a few centimeters. In the northern Canada we use PPP all the time.
I'm very curious how accurate of a PPP position these little units will deliver. Too bad they don't have an L1/L2 option. A good way to check how good a gps unit is to do a 24 collect and then submit it to PPP
https://webapp.geod.nrcan.gc.ca/geod/tools-outils/ppp.php
Ok so it's an hardware modification !
Interesting, may be on shutter motor ...
We pull out a feedback wire from inside the QX1 for shutter syncing.
How the QX1 and reach are sync ? Is it a pre calculated shutter lag ?
@Dmitriy, I'm not sure I understand your comments on dual frequency GPS systems having a faster initialisation times, or comparable accuracy to single frequency systems for PPP solutions.
For dual frequency commercial units (L1/L2) from other manufacturers (Trimble etc.), they typically have a longer PPP initialisation times (at least 20 to 40 minutes), and while the RTK and PPK accuracy is comparable to single frequency units, the PPP solution is objectively more accurate.
The Reach RS still appears to be amazing value for money, but the reduction in cost necessarily comes with compromises. I imagine relying on existing geodetic points, or VRS for initial positioning for the base station is an acceptable compromise for most users.
In order to get not just precise, but as well accurate results it is important that the base is either setup over a known point or its position is calculated from CORS in RTK, or post-processed. The will be no shift in that case.
@GuyMcCaldin You are correct that Reach is a single frequency receiver. Dual frequency systems have advantage that they can work on longer baselines and faster initialization time. However, there is no fundamental reason for L1/L2 to be more accurate, only on long baselines when iono effect start to kick in. If you stay under 10km or work with VRS the results will be very close.
@keeyen you can use Reach or Reach RS in RTK mode from NTRIP to determine base station location.
We found there was definitely an offset of some size without the survey grade GPS, but didn't make comparisons day over day to see how much it moved. We haven't tried anything with PPP yet either.
Keeyen, you should be able to use PPP mode (Precise Point Positioning) of the Reach RS to find the base station location with accuracy in the decimetre range. This doesn't require an external correction signal. Instead, it uses the known positions of satellites from IGS data, and collects observations over an extended period of time. Statistical analysis is then performed on this data to calculate a more precise position.
Because the Reach RS is only a single frequency receiver (which substantially reduces cost), accuracy is typically reduced compared to the typical dual frequency systems used in commercial surveys. Dual frequency receivers are capable of providing centimetre level accuracy by comparing measurements from each frequency to correct for variance in the ionosphere.
I haven't worked with the Reach RS, so I might have it wrong. These comments are based on a general understanding of GPS technology.
Very impressive. From the study case, if we want cm accuracy, we still need to know the correct GPS location of the base station. Therefore a survey grade GPS receiver and correction service is needed. But I think it is far better than set up many ground control points. Do you know the expected accuracy without ground station coordinates ? Or can we use the Emlid system in RTK mode to obtain an accurate point then just put the ground station there ?
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