Hi Josh, Hoping you are doing good. Thank you for all the support. Over the past few days, I did some experiments. I would like to share and clear some doubts, if you do not mind.
So, basically, I kept of distance of 14-15m (approx) between the base and rover. Then I captured data in both "kinematic" and "moving base" modes and simultaneously I captured data from a third receiver using ublox u-center which I used for comparison. Now in both the cases, most of the time, the solution remains in "FLOAT" and there have been only 15%-20% of the time (in total) that the system remains holds a "FIX" position. What can go wrong here now? Secondly, what I am more concerned is the altitude difference between data from RTKLIB (using base-rover) and u-center (using single receiver). The altitude varies a lot in RTKLIB in both the modes i.e. Kinematic and Moving Base. It should remain nearly the same since both base and rover are at a fixed position as of now. Thirdly, the baseline too, varies a lot but the average is quite close i.e. I still get a difference of about 2 meters. The difference between high and low is quite large, similarly with altitude. Can you know as to what else can I try? Also, what what is the difference between moving base and kinematic modes? Difference between "continuous" and "fix and hold" integer ambiguity resolution? Which one would be more preferable? Also I noticed that cycle slip occurs a lot, infact most of the time there is a cycle slip (as I mentioned above that the solution remains as "FLOAT" mostly). I have done all my experiments on the terrace under the open sky. I cannot conclude as what could be the reason? Hoping to receive a reply from you and taking the discussion forward. Thank you once again. Cheers, Max On Fri, Feb 7, 2014 at 12:48 AM, Josh Leighton <[email protected]>wrote: > a) Those look like fairly standard patch antennas, so I wouldn't be > surprised if you are unable to achieve a consistent fix. > > b) The longer the better. The accuracy of a proper fix can be on the > order of cm's, so the accuracy of your base station should probably be at > least that good. > > c) If you're seeing an intermittent fix with low AR ratio, I believe it's > possibly an incorrect fix. > > d) If you don't have a good fix, I suspect changing the base station > values by a small amount won't do much. I'm not sure how important the > accuracy of your base's altitude is, nor do I know what the expected > accuracy of a good fix's altitude is. Perhaps others here know more. > > > On Wed, Feb 5, 2014 at 11:45 PM, mazahirp <[email protected]>wrote: > >> Hi Josh, >> >> Thank you for the reply. So basically I need longer distance between the >> base and rover. >> I am using - ABRACON APAE1575R2540AADBE-T & ABRACON APAE1575R2540BBDB1-T >> as >> my 2 antennas. >> So, few more doubts: >> a). Will these antennas do as far as RTK GPS is concerned? >> b). Will I have to take base readings for so long? Assuming, though base >> would be at a constant location, but base position could change on a day >> to >> day basis. Also, if I log (lat,long and altitude) these values, the data >> will be very large to average out. Should i use MATLAB for averaging? >> c). I was getting a "fix" status at certain intervals in static and >> kinematic mode, but the baseline in the graph was always beyond 5 to 6 >> meters (in both fix and float status). >> d). If I change the base values in options by a very minimal margin and >> change its altitude by 10m, still there is no change in the output rover >> position. The baseline still shows beyond 6m. Also the height/altitude is >> wrong (when I compare it with a ublox 5t running in u-center placed at >> same >> location). >> >> Would be really helpful. Thank you once again. >> >> Cheers, >> Max >> >> >> >> -- >> View this message in context: >> http://open-source-gps-related-discussion-and-support.1099874.n2.nabble.com/RTKLIB-errors-and-warnings-tp7572812p7572815.html >> >> Sent from the Open Source GPS-related discussion and support mailing list >> archive at Nabble.com. >> _______________________________________________ >> This message is sent to you from [email protected] mailing list. >> Visit http://lists.osgeo.org/mailman/listinfo/foss-gps to manage your >> subscription >> For more information, check http://wiki.osgeo.org/wiki/FOSS-GPS >> > > > _______________________________________________ > This message is sent to you from [email protected] mailing list. > Visit http://lists.osgeo.org/mailman/listinfo/foss-gps to manage your > subscription > For more information, check http://wiki.osgeo.org/wiki/FOSS-GPS >
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