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Taking the GPS for a walk in the bush

The next day I set out to map some of the roads and tracks around a patch of Bush that I have been frequenting for a few years - recording native Orchid growth etc.

Here is the voltage recordings of the battery:

11:30 13.25V (No load)

11:32 12.63V (PC On)

14:45 strong electrical burning smell noted!

14:50 9.8V (No Load)

 

I knew I was pushing it, but I am lucky that the damage wasn't perminant. As it was, I managed to scp the NMEA data file off the corrupted flash drive. Looks like I should really work on building a power monitoring device before I go on my next extended walk!

Here is a plot of satellite error on my walk around the area:

I have manually included a colour legend this time. I drove in on the lower left hand side (widly spaced points), and drove out at the top. Interestingly, when I walked down the left hand side track the satellite error was low (blueish), but it wavered around all over the place, whereas, when I walked back an hour later or so, I was getting a higher error rate, but the track was much straighter and was how the track runs I can't explain that one! The blue walk was on the south side of the track, giving the GPS better access to the satellites, whereas the browny walk was next to a pine plantation, walking North.

At the lower right hand corner, I tried keeping to one side of the track heading down, and coming back on the other side, therefore hopeing to pick up the width of the track etc. This sort of worked, of course the larger 5m road (bottom) showed up better than a 1.5-2m track:

This shows me walking south (from the top) on the left hand side of the track, continuing anti-clockwise around the road (bottom) and back up the right hand side of the track heading North. Note that even though I an walking on either side of a 1.5-2m wide track, the GPS looks like I was wandering around. The above image is showing my true heading. That way it makes it easier to see the GPS error and therefore crossing over at the top.

Below is an excel graph of the height data of the walk along the track (something I haven't figured out how to get JUMP or MapWindow to produce:

The data above is from the profile 'A' to 'B' (see blow), from the end of the track, to where I had parked my car at 'B'. You can see how I traced out a section of the road at the bottom. Interestingly there was only a 17.8m difference in height from the lowest point to the highest point. Once again, the colours are displaying my heading I am walking:

You can also see some of the side tracks and small clearings that I traced out in my walk. It was a lovely day with just a bit of light drizzel to keep me from over heating. Below is a photo of me in the typical Mari/Jarrah bush land found in the area walking back to the car along the track:

and here is the total height profile for the drive out and back. Yes, I did drive out and back on different roads, so I drove up a different hill than I drove down. Also you will not the difference in the start and end heights. This is because I decided to drive down to the beach and place the GPS antenna down at sea level, so I could pick up the actual difference in how heigh the GPS thought I was. I turned out it thought the sea level was 7.8m high:

It turns out that due to the low voltage, the PC shutdown at the beach, so I never got to collect the data for the 500m trip home. I will have to have a look at the data from the two times where I left the GPS to record a static fixed point and see how much the height fluctuated over a 20 minute period. I will also look over other data I have collected from around the home to see how much each run has fluctuated.