I can't get into VRS (not too mention I don't have the money for it). Maybe I'm a Luddite.
It seems like you lose the prime advantage of GPS which is it can measure vectors conveniently. So If I need some topo on the street behind my project I can use my receivers to do a couple of static sessions to directly transfer my control over there. I suppose I could do it with two long VRS vectors from the base 20 miles away but I just can't get into that.
I worked on a job near Portland a few years ago that required us to set the base up along a street. Being fearful of having the equipment tampered with we assigned one of the rodmen to watch it. We took an extra truck for him to sit in so he could stay out of the weather. This was old equipment and the battery would only last 3 hours or so. So I go back to change the battery, pull up behind the truck, switch out the batteries with a lot of opening/closing of truck doors etc.
And wake up the guardian of the company equipment on my way out.
Happened every day until he was re-assigned.
Who's watching the base indeed.
DJJ
Had the new GPS a week.
I was retracing some sections in a remote area and couldn't get a fix.
Rode the 4 wheeler back to the truck and setup (about 30 minutes) and some cattle had knocked over the tripod. I had asked the ranch if they had livestock in that pasture and they said no so I felt pretty safe. Turns out the cattle had another brand and were someone else's. So I sliced together the wire they had stomped, took my mag mount off the 4 wheeler and stuck it on top of the truck's roof with the radio antenna, located my control point, recalced a base calling it "truck" and started the survey over.
I do that a lot anymore; but learned it 15 years ago.
Works well for city surveys also, you can lock up everything except the antennas.
> Subscribe to a VRS net.
I second that. It's the way to go for control work.
If I was doing topo with GPS, however, I'd want a traditional base station. The cell phone modem isn't really reliable enough for high speed collection.
does anyone use a virtual base station
connected via cell phone as noted in the KARA network?
does anyone use a virtual base station
> connected via cell phone as noted in the KARA network?
We do not use the KARA network but we do use another privately run network on Long Island. We also use the publicly run NYS DOT network. The obvious advantage is not needing to baby sit an RTK base station. Both networks are however single baseline RTK networks with all the disadvantages of single baseline RTK. The baselines can be longer than one would ideally like. For control work you have to visit the sites twice with different satellite configurations or add some other type of redundancy to get reliable results especially for the vertical.
Peter Lazio
You hit on my greatest fear of leaving my equipment. LIVESTOCK
I know for a fact that livestock can be the worst problem. They will always tamper with anything in their domain and stomp on it.
When I have doubt about livestock being present in a field, I will not leave it there without being inside of a hay ring or other enclosure.
It is best to find another place for a control point.
W.C. Fields setting up the base...
About six minutes into the video you can get an idea what it would look like if W.C. Fields tried to setup a tripod...
[flash width=480 height=385] http://www.youtube.com/v/9oOvHnTiQcc?fs=1&hl=en_US [/flash]
We have a point set up on a high ridge near the interstate with easy access on the side of the fence of one of our longtime clients. I had asked about cattle and there weren't any so I set up for the day. Got back to the base after I quit hearing the radio. A horse was kicking everything around and had pulled the sholder strap from bag the base battery is in and was chewing on it. I jumped the fence and went up to him, scratched his head, calmed him a little and then grabbed the strap.
He threw his head back and looked at me, stood there and while I reached for the tripod, then he put his head down snached that strap out of my hand and took off with it. I figured it was his and set up the base again, set a cap across the fence, located it and moved the base. As I was leaving that horse came back and spit the strap at me just on his side of the fence, but I didn't take the bait.
for some reason cattle will never leave a lath standing in their field. and they'll eat the flagging off the spike or pipe or whatever is in the ground making it tough to find your control point the next time you are out there.
And if you leave pin flags around it can cost you plenty when a prised bull eats one and it kills him.
Perhaps a Mannequin in a Lime-Green Safety Vest
You'd think that some equipment manufacturer would realize that it might be smart to market camouflage versions of their equipment. Failing that, I've previously posted that one good way to protect a receiver/antenna setup by the side of the road would be to use a mannequin dressed up in a lime green safety vest, appearing to be leaning on a shovel (which is really a brace for stability) beside the receiver/antenna combo. Just put some "WORKERS IN R-O-W" signs out and who would ever notice that the mannikins weren't moving?
Perhaps a Mannequin in a Lime-Green Safety Vest
You could purchase a used police cruiser and park it next to the base with a mannequin inside dressed in a blue uniform.
Perhaps a Mannequin in a Lime-Green Safety Vest
Ive always thought that somekind of locking mechanism that would keep the tripod from folding in would be a good dterent to the grab and go thieves.
Perhaps a Mannequin in a Lime-Green Safety Vest
> You could purchase a used police cruiser and park it next to the base with a mannequin inside dressed in a blue uniform.
Better yet, just use the police cruiser as the base, with the antenna mounted to the light bar and tint the windows.
Perhaps a Mannequin in a Lime-Green Safety Vest
Just be sure to get the Police Cruiser at the Mount Pleasant Police Auction, I heard the practically give 'em away 🙂
There's better solutions if you're interested.
Remarkable what you can do with access to 1-second VRS data for post-processing.
Every tool has it's use. If I'm driving 2" iron pipes I'll use a 10lb hammer. If I'm removing a 1/2" long screw I think I'll back it out with a screwdriver.
If I'm putting flight crosses all over the County then I'll probably use a VRS system.
If I need to measure 500' from Street A to Street B without traverse half a mile around the block then I'll use L1 GPS.
Dave: In a true VRS system (Trimble) you do not have ties from a single base 20 miles away. You get a modeled solution calculated from a Virtual Base at your location.
