ZemaLupin Posted February 2, 2016 Share Posted February 2, 2016 Hi, The company I work for has given me the job of investigating GPS tools. The current requirements are that it needs to be within 5cm accurate, works all over England, measures X, Y and Z coordinates, and somehow someway can be converted into a DWG format (for AutoCad). The price of the device most likely won't be a problem as what we are currently looking at is Leica ATX1230GG Smart Rover. Any suggestions and advice would be great. If you need any more information please do say and I will find out ASAP. Thanks. Quote Link to comment
+Cardinal Red Posted February 2, 2016 Share Posted February 2, 2016 Hi, The company I work for has given me the job of investigating GPS tools. The current requirements are that it needs to be within 5cm accurate, works all over England, measures X, Y and Z coordinates, and somehow someway can be converted into a DWG format (for AutoCad). The price of the device most likely won't be a problem as what we are currently looking at is Leica ATX1230GG Smart Rover. Any suggestions and advice would be great. If you need any more information please do say and I will find out ASAP. Thanks. You are most certainly looking for a very expensive Professional Grade work tool. Not the Consumer Grade "toys" we use for Geocaching. I think you have a better shot of reaching out to a Professional Surveyor that might use this type of tool at the Benchmarking Forum link below. Benchmarking Forum Also research an AutoCad product designed to use the data that will then be acquired (also going to be expensive, most likely comes with a steep learning curve as well). That product is not going to be Vanilla AutoCad. Since money is no object, hire a Civil Engineer type with the necessary software experience. There might me some information of interest to you at the AUGI Civil Engineering Forum link below. I would say you have not been given an easy task. Good Luck. AUGI Civil Engineering Forum Quote Link to comment
+ecanderson Posted February 2, 2016 Share Posted February 2, 2016 Though you've tried, your specific application isn't quite clear enough to make a firm recommendation. If you will be doing static surveying, check out the Trimble R10. It's high precision mode is capable of providing ~3mm horizontal and ~3.5mm vertical precision. http://www.trimble.com/Survey/TrimbleR10.aspx?tab=Overview and grab the data sheet. Quote Link to comment
Bill93 Posted February 3, 2016 Share Posted February 3, 2016 It appears I answered the wrong one of your duplicate posts, so will copy my response over here. You've already gotten some good advice. You are definitely looking for professional equipment, as any recreational or car GPS unit will be a couple orders of magnitude poorer than your requirement. If your company needs only a moderate amount of data, it will be advantageous to contract a professional surveyor to perform the service for you. If you have an ongoing need for a lot of data, then you or someone in the company may want to get educated on it, but it will be a big commitment. Depending on what the data is used for (e.g., land boundaries and perhaps some kinds of construction), there may also be regulations governing who is licensed to perform the work. You might try registering (free) on www.surveyorconnect.com and asking for advice from the professionals there. The 5 cm specification is not quite complete, since any measurement has statistical error. Are you looking for a standard deviation of 5 cm, or 95% confidence (i.e. 19 times out of 20) within 5 cm, or what? Is the requirement to find positions relative to a national or world coordinate system, or is the primary need to have accurate relative positions among certain points? How long are you willing to have the equipment on a point to get a reading? With a professional receiver operating by itself, "static autonomous" measurements of 15 minutes to a few hours may be needed to get that accuracy, depending on satellite positions at the time, and how clear the view of the sky is. Some people use a base and rover setup with a radio link. If the base is placed on a known point (Ordinance Survey trig point?) the rover can get positions relative to the base with very short occupation times. Of course, it is advisable to make the rounds of your unknown points twice to confirm that there was no anomalous reading. There are Real Time Kinetic networks (RTK or RTN) in some areas that you can subscribe to, which eliminate the need for you to have a base unit. I don't know anything about RTN coverage in England. Leica certainly sells equipment that will meet your needs, as do other manufacturers as well (Trimble, Javad, etc.) Besides equipment capability and price, pay a lot of attention to software compatibility with your CAD system and how easy it is to get training and service support from the company. Professional equipment will require some training to get good results. And there is a lot to understand about what you are really measuring at the cm level. Are you familiar with horizontal datums and vertical datums? Map projections? Map grid versus ground scaling? If you use the native GPS coordinate system, do you know how to account for continental drift that will be significant over a few years? And many other issues. Quote Link to comment
+ecanderson Posted February 5, 2016 Share Posted February 5, 2016 Yup. Depending upon the results he's after, 5cm doesn't sound like a lot until you take drift into account. The U.S. and Europe are slowly drifting apart at about 2.5cm / year. Still wondering about a LOT of details about the OP's use model. Quote Link to comment
astrodanco Posted February 6, 2016 Share Posted February 6, 2016 (edited) In the area where I live the velocity is about 39mm/year to the Northwest. Because of that, whenever specifying a location one must also specify a reference frame (datum and epoch). For example, "NAD83(2011) (Epoch 2010.0)" and "NAD83(NSRS2007) (Epoch 2011.0)" and "IGS08 (Epoch 20nn.nnnnn)" are reference frames I frequently deal with. One can use NGS's HTDP tool to convert between them. One thing I find to be unsettling is that even when using the same reference frame, different processing tools give different results. For instance I can collect 24 hours of static data and post process it using NGS OPUS-S, NASA APPS, CSRS-PPP and RTKLIB. Each one gives a different result both for the position and for the estimated accuracy of that position. And while NGS OPUS-S may appear to be optimistic (sub centimeter), NASA APPS appears to be wildly optimistic (sub millimeter). Edited February 6, 2016 by astrodanco Quote Link to comment
+ecanderson Posted February 6, 2016 Share Posted February 6, 2016 (edited) Where the heck ARE you out there, astrodanco? California? You be flyin' there! Hard to know the underlying assumptions of some of the tools out there. You would think they'd be using the same JPL data set since that holds the most promise as a reference. The JPL data for my area (TMGO set) indicates we're only moving at about -0.6cm latitude and -1.5cm longitude every year. Edited February 6, 2016 by ecanderson Quote Link to comment
RamblinBear Posted February 10, 2016 Share Posted February 10, 2016 Hi, The company I work for has given me the job of investigating GPS tools. The current requirements are that it needs to be within 5cm accurate, works all over England, measures X, Y and Z coordinates, and somehow someway can be converted into a DWG format (for AutoCad). The price of the device most likely won't be a problem as what we are currently looking at is Leica ATX1230GG Smart Rover. Any suggestions and advice would be great. If you need any more information please do say and I will find out ASAP. Thanks. In the UK, you're probably best off talking to a company like Positioning Resources (www.posres.co.uk), Korec (www.korecgroup.com), or Surveying Equipment (www.sccssurvey.co.uk) who would be able to advise you as to what kind of kit would best meet your requirements. Quote Link to comment
+GrateBear Posted February 11, 2016 Share Posted February 11, 2016 Yup. Depending upon the results he's after, 5cm doesn't sound like a lot until you take drift into account. The U.S. and Europe are slowly drifting apart at about 2.5cm / year. Does that mean we are drifting TOWARDS Asia at the same pace? Quote Link to comment
+ecanderson Posted February 11, 2016 Share Posted February 11, 2016 Unless it's drifting away from you! Haven't had reason to look at Asia motion for a long time. It's all relative since everything is in motion at the same time. Saw a site a while back that provided relative motion indicators (arrows). Not sure where it was. Cool stuff. My grandson loves looking at the old models of the continents and drift over the eons. Still trying to wrap his head around it. Quote Link to comment
+Team CowboyPapa Posted February 11, 2016 Share Posted February 11, 2016 I'm on the Newport Inglewood Fault, my front yard is going north while my backyard is going south. I have two GPSrs, front and back, to record this. Quote Link to comment
+Team CowboyPapa Posted February 11, 2016 Share Posted February 11, 2016 (edited) deleted Edited February 11, 2016 by Team CowboyPapa Quote Link to comment
+ecanderson Posted February 12, 2016 Share Posted February 12, 2016 I'm on the Newport Inglewood Fault, my front yard is going north while my backyard is going south. Which way is the house going? Or is a bit of it going SW and another bit going NE? At 0.6mm per year, at least the cracks won't grow very quickly. Quote Link to comment
+Team CowboyPapa Posted February 12, 2016 Share Posted February 12, 2016 ....Which way is the house going? .... Counterclockwise according to the swirls in my morning coffee. Quote Link to comment
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