On my travels to work the past couple of days I’ve noticed this guy walking along side of the highway. He’s wearing a reflective vest and he’s carrying a pole a little shorter than 2 meters tall with an oblonged-spherical shaped device on top. At first i thought he was some sort of surveyor, but he didn’t have a partner, he is by himself. His truck is not marked in any particular fashion.
I continued to think he was some sort of surveyor, and my instincts appear to be right when I found this website for engineering equipment. This GPS rod in the link is similar to what the man was carrying.
Link goes to an EngineerSupply.com listing.
Is this just a newer form of surveying as opposed to the two man teams that I’m used to seeing?
Probably. You carry a GPS receiver to a spot you wish to check and wait there until your receiver says, in effect “Okay, I’ve got this one accurate within a foot [or other chosen tolerance].” You then move to the next position.
He could just be taking GPS points for another purpose. A true survey has to be pretty accurate. If he is just putting a bid together for a project, or needs to make a map of the drainage structures or just about anything else, he could do it by himself to a lesser accuracy. I’m not a surveyor and I walk around taking GPS points all the time.
That is a surveyor with an RTK GPS. The Pole is so that he can measure a point on the ground while maintaining a good horizon. (The more satellites he can see, the better his accuracy.) Somewhere within a few miles., he will have a base station set up. The idea is that the base station will stay still, tracking the paths of the satellites as they orbit, and send corrections to the reciever the guy is using, letting him get accuracy down to about 1/2". Its all real time, your reciever is tracked as you walk around.
A recent development is a system where you pay a subscription to use a network of base stations set up throughout the country instead of setting up your own base station.
Sadly, the GPS isn’t very good at small talk or carrying round a big bundle of marker pegs, so sometimes you take a friend with you.
Lemme see if I can amplify on this a bit. I don’t know jack-sh*t about this stuff, but a friend was recently showing me some software he developed that gets into this.
GPS readings tend to “wander” over time, due to atmospheric factors and what-not. But the amount of “wander” will tend to be the same distance and same direction at the same time, everywhere within some relatively small radius (large number of feet, or small number of miles, or thereabouts).
So your base station takes readings regularly, and your roving station (like the guy with the pole) is taking readings. Since the base station is stationary, the wandering changes in its “location” actually tell you what the GPS “wander” is. You can thus adjust your roving readings accordingly (since they are wandering the same), to obtain their actual locations with much greater precision.
More or less. I think the ‘wobble’ you mentioned is more about the geometry of the satellites; sats in every direction but down is good, six sats, all to the north of you is pretty much useless. GPS broadcasts on two frequencies to minimise atmospheric disturbance, and usually satellites less than 10° above the horizon are filtered out because of the amount of atmosphere they send through.
Physically, not that hard, unless you get roped into doing boundary pegs on a 400 lot subdivision in the summer, when the ground turns hard. Quite a lot of walking. Mentally, once you’ve learned the ropes (Lots of maths), it’s not too bad until a problem comes up. You can sometimes get into situations where the is lots of pressure to deliver in a short time.
Stick Monkeys don’t make more than other labourers because they aren’t very trained they are usually students or semi-retired people. Operating instruments only takes a few days to learn. More Experienced field hands learn how to setup a good survey and do calculations as well, usually get a diploma. Probably similar to a plumber or electrician, or carpenter.
Qualified surveyors who have a Bachelors or better and are licenced (Virtually every jurisdiction has liscencing) will make a professional salary, and often get high positions in related fields
Finding out more? If you are a student or non-fulltimer, see if you can get a holiday job or a few days work experience at a survey, engineering or contracting firm. Be aware that the business is very much dependent on the economy of its customers - land prices and the availability of construction work, highway projects, etc.
