John's search area is roughly 60 miles by 40 miles, pretty big by surveying standards.
The given point is on Mission Island. NGS lists three points somewhat less than 30 miles south. They are SZ0022, SZ0023, and SZ0024.
I only looked at the NGS map, not the data sheets, so I don't know what's really there, but they're kinda far away.
Dang! These 3 all have photos with the data sheets. Take a look at this one, SZ0022:
Not much help with the current problem, but pretty cool. Online geography lesson. 😎
@mathteacher+
Everybody knows that the US/Canada Border runs east-west. You have shown it going north-south.
Hmmmmm..... unless we are talking about the Alaska/Yukon Territory border.
????
cf.67 I had some more time and found 5 stations for you to look up. Station MCKAY is on a noll 200+ metre higher in elevation
than the boat so you might be able to see it IF nothing is on line. Just a little hike; looks like fun.
MCKAY?ÿ ?ÿ12316?ÿ ?ÿN48 20 40.7 , W89 17 10.8 (in dms for plotting). Its like 4700 metre from boat.
Look at?ÿ 353341?ÿ Watermains -89.23075?ÿ 48.36650?ÿ in Deg.decimal deg
35344?ÿ IRWIN?ÿ ?ÿ-89.23501?ÿ ?ÿ48.35811
35339?ÿ ?ÿDunphy?ÿ -89.20900?ÿ 48.38142
35356?ÿ ?ÿNorthwestern?ÿ -89.30373?ÿ 48.35603
Let me know what you think. As you can tell all points are GSC points.
?ÿ
JOHN NOLTON
Yeah, I probably don't want to check into that point after telling the boat which way is north 😮
@mathteacher small area by Geodetic standards (do I get a laugh out of that?).
I do think my model 8 geodimeter (after I get a new Laser in it) will reach out to 60 miles
JOHN NOLTON
Wowsers - Irwin and Dunphy are right there!
McKay would be an awesome backsight - but that is quite the hike - that's a steep hill!
Thanks for the sleuthing - I will definitely check these out.
GNSS Solutions shouldn’t be broken. I use it with win10 Just fine.
gnss solutions baseline is best/easy idea. Lots people here use it with win10
Yeah, I was confused, too, because I had always heard 54 40 or fight and this is way too far south. The mark is on a bridge; maybe this screenshot from the NGS site will help:
I had great success with it in the past. But I remember having to convert rinex into ashtech format (I was using Leica gear) - which didn't bother me at all because it worked. (I think it was maybe Ashtech Solutions I was using.)
Now, with GNSS Solutions it accepts rinex directly and the old 2 way converter is gone - but it always says "raw file is invalid" when ever I try.
If you can get me past that roadblock I would be good to go!
I'm sure it will. Of course, I said surveying standards, not geodetic standards, but I get your point.
i get rinex online, from others, I’ve had zero issues. My Ashtechs are weekrollover glitched. So I generate rinex, fix the date and leave it in rinex, and GNSS likes it fine.
And in your task L1 only will still yield best az
maybe it’s the version of rinex that you’re generating. Most can select 2.11, and think that’s the most recognized. (I’ve not tested rinex 3) If GNSS won’t take your rinex, does opus like it?
you might post this on the GNSS page
The system looks to be controlled by GPS.
How do you calibrate GPS?
If GNSS won??t take your rinex, does opus like it?
We had a thread recently where a file wasn't being accepted and it turned out the way it was generated under Win10 it used 16-bit characters. Changing the process to get 8-bit characters worked.
https://surveyorconnect.com/community/software-cad-mapping/rinex-file-will-not-import-to-tbc-5-20/
The system looks to be controlled by GPS.
How do you calibrate GPS?
It is likely the heading sensor mentioned is in addition to GPS and at a minimum needs to be rotated into agreement with the boat heading, and possibly also corrected at various azimuths.
GNSS could perhaps be used to get heading while in straight-line motion, but probably not to the precision mentioned.
Correct me if I'm wrong, but this system appears to use multiple GNSS receivers, pulse and IMU, to determine azimuth.?ÿ The GNSS derived baseline azimuth will be very precise at 1 mm error over the 4 m baseline.?ÿ The IMU appears to me mostly used for pith and roll, notice the drift in azimuth when GNSS is down.?ÿ In theory, you could add more receivers and do away with the IMU all together.?ÿ I think it is more critical to obtain the relationship of the sensors baseline to the axis of the vessel.?ÿ Just like surveying in an aerial mapping plane for offsets from the sensors to the camera.
I'm not sure how to do this analytically, so I tried a Monte Carlo approach. I interpreted cf.67's post to mean the distance from the true point to the measurement was normally distributed, with 2-sigma being 10 mm, so 1 sigma is 5 mm. The angle?ÿ is random and uniformly distributed from 0 to 2 pi radians. I'm using the Cartesian coordinate system where 0 degrees is the positive x axis. Let there be two points, the first at (100 m, 100 m) and the second at (100 m, 200 m).
For each trial, I generate a random offset from the first point, and a different random offset from the second point. The I find the azimuth from the first to second point, which is nominally 0 degrees.
In Excel, I created 1000 trials. The angle was +- 20 arcseconds (2 standard deviations)
In an earlier post it was stated the sideways 2-standard-deviation would be 14 mm. Applying this to a 100 m distance, the angle would be +- 29 arcseconds.