<div dir="ltr">Hi Josh,<div><br></div><div>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. </div><div>
<br></div><div>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?</div>
<div><br></div><div>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. </div>
<div><br></div><div>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. </div>
<div><br></div><div>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? </div>
<div><br></div><div>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?</div>
<div><br></div><div>Hoping to receive a reply from you and taking the discussion forward. Thank you once again.</div><div><br></div><div>Cheers,</div><div>Max</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">
On Fri, Feb 7, 2014 at 12:48 AM, Josh Leighton <span dir="ltr"><<a href="mailto:leighton.josh@gmail.com" target="_blank">leighton.josh@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class=""><div dir="ltr">a) Those look like fairly standard patch antennas, so I wouldn't be surprised if you are unable to achieve a consistent fix. <div><br></div><div>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. </div>
<div><br></div><div>c) If you're seeing an intermittent fix with low AR ratio, I believe it's possibly an incorrect fix. </div><div><br></div><div>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. </div>
</div></div><div class="gmail_extra"><br><br><div class="gmail_quote"><div class="">On Wed, Feb 5, 2014 at 11:45 PM, mazahirp <span dir="ltr"><<a href="mailto:mazahir.poonawalla@gmail.com" target="_blank">mazahir.poonawalla@gmail.com</a>></span> wrote:<br>
</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="">Hi Josh,<br>
<br>
Thank you for the reply. So basically I need longer distance between the<br>
base and rover.<br>
I am using - ABRACON APAE1575R2540AADBE-T & ABRACON APAE1575R2540BBDB1-T as<br>
my 2 antennas.<br>
So, few more doubts:<br>
a). Will these antennas do as far as RTK GPS is concerned?<br>
b). Will I have to take base readings for so long? Assuming, though base<br>
would be at a constant location, but base position could change on a day to<br>
day basis. Also, if I log (lat,long and altitude) these values, the data<br>
will be very large to average out. Should i use MATLAB for averaging?<br>
c). I was getting a "fix" status at certain intervals in static and<br>
kinematic mode, but the baseline in the graph was always beyond 5 to 6<br>
meters (in both fix and float status).<br>
d). If I change the base values in options by a very minimal margin and<br>
change its altitude by 10m, still there is no change in the output rover<br>
position. The baseline still shows beyond 6m. Also the height/altitude is<br>
wrong (when I compare it with a ublox 5t running in u-center placed at same<br>
location).<br>
<br>
Would be really helpful. Thank you once again.<br>
<br>
Cheers,<br>
Max<br>
<br>
<br>
<br></div><span class="HOEnZb"><font color="#888888">
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