GPS suggestions

igage.com

Have you used any RTK GPS before? Are you looking for network rover or base and rover?

I have been using a Javad LS rover with a Javad Triumph 2 base with 4 watt UHF radio for almost 2 years now. I have used Trimble R8 model 3, Topcon hiper, Topcon Gr3, Topcon GRS1, Leica 1200 and 500 and the Javad equipment out preforms all of the above. Lifetime free updates to firmware. 3 year warranty. Customer service is provided by licensed surveyors that currently use the equipment in their practice. Send me a message and I can put together a quote for you.

www.SatLabgeosolutions.com
Take a look at the SL600 RTK Rover, data controller (SL55) uses Carlson SurvCE. Network RTK Rover with internal GSM modem. RTK Base and RTK Rover kit with both UHF radio and GSM modem. Static data collection in Rinex format. GNSS activations including GPS, Glonass, Beidou, Compass, QZSS and SBAS. Free Firmware updates for life.

Correction for the SatLab web page > www.satlabgps.com
Supported RTK Formats: sCMRx, CMR+, CMR, RTCM 2.X, 3.x

Mark Silver at Igage has several options for you. I can attest that his customer support is second to none. I have been extremely happy with my (2) OPUS X90 static receivers, and I am sure his RTK units perform just as well.

I know Mark and he does offer very good customer service.

I just bought a Spectra SP-80 network rover. So far so good, very user friendly. I got mine at Allen Precison, great support

Bob LeMoine, post: 332405, member: 10375 wrote: www.SatLabgeosolutions.com
Take a look at the SL600 RTK Rover, data controller (SL55) uses Carlson SurvCE. Network RTK Rover with internal GSM modem. RTK Base and RTK Rover kit with both UHF radio and GSM modem. Static data collection in Rinex format. GNSS activations including GPS, Glonass, Beidou, Compass, QZSS and SBAS. Free Firmware updates for life.

Where have you been Bob, and what have you been up to? Definitely need an update.

Paul in PA

John Giles, post: 332379, member: 57 wrote: First should I stick with Trimble to make sure I get compatibility?
And second, what is out there right now new/used (prefer used) that is good under canopy? Or is there such a beast.

Trimble is a great choice for really good unit with a broad user base. R8s are still really good units. Better "performance" under canopy comes at the expense of reliability of the positions. Don't be fooled.

I work in mostly wooded hilly terrain. With a small field here and there on the property. Generally I can find open spots with no tree cover but most all corners are under canopy or are the canopy (tree as corner). I would need to be able to locate fences around the property and most are under canopy.

Can you get good reliable data under canopy consistently? My plan was to locate what I could with GPS and traverse the completely covered areas. But if I can't go back and hit the same point twice, there wouldn't be much point.

I'm looking for GPS that will get me accurate data under canopy. At most when I look towards the sky I can see 'holes' with sky in them.

Is there a place that would let you try it out before you buy?
Maybe that is what I need to do to get an idea of the capability.

I would second Mark Mayer in being skeptical of claims under canopy... we do not spend a lot of time under trees, but in my experience one needs to be extremely wary of the reliability of GPS in multipath situations such as canopy, buildings, chain link fences, etc., sometimes it's good and orther times... not so much.

Newer equipment offers improvements in this area and having the ability to track muliple constellations with the additional satellites this provides probably accounts for the bulk of this improvement along with better algorythms and software... we currently run Trimble R10s and I will certainly admit to being a BIT more confident in adverse areas. At the end of the day, redundancy is the only way to have confidence in these tough areas and you have to be careful that you are not replicating the previous constellation/mulipath condition when you revisit the position

As many people on this board whom I consider much wiser than myself have said - gotta use the proper tool for the job.

John,
Good to see you posting! Hope your doing well. Please please don't believe any fool that tells you GPS works under canopy! A company near here uses GPS for everything. What a mess!

gschrock, post: 332419, member: 556 wrote: Hi John,

There are many good options - very many. The flavor of network does not matter, any rover that can utilize standard RTCM3.1 will be fine and only if a network is restricted to proprietary formats would it matter - that network does offer standard formats so you have a lot of choices.

The fans (and sales people, and semi-salespeople) can duke it out as to what you should buy... I'll stay out of that fray... In my experience there are no magical advantages of one over another....

I disagree with the flavor makes no difference. I shot some set rods with both the trimble network and Lieca's network. My solutions were better with the Leica over the Trimble. I had a closure of 1:100,342 with the Trimble and 1:100,500 with the Lieca. So obviously the Lieca network is so much better.

John Giles, post: 332444, member: 57 wrote: I work in mostly wooded hilly terrain. With a small field here and there on the property. Generally I can find open spots with no tree cover but most all corners are under canopy or are the canopy (tree as corner). I would need to be able to locate fences around the property and most are under canopy.

Can you get good reliable data under canopy consistently? My plan was to locate what I could with GPS and traverse the completely covered areas. But if I can't go back and hit the same point twice, there wouldn't be much point.

I'm looking for GPS that will get me accurate data under canopy. At most when I look towards the sky I can see 'holes' with sky in them.

Is there a place that would let you try it out before you buy?
Maybe that is what I need to do to get an idea of the capability.

John,

Yes, most dealers around here will give you a demo to try for a few days. Ask you dealer. I suggest you get a base and rover setup for the conditions you describe. In hilly, wooded terrain I suggest setting the base in a wide open area so you can log static data and broadcast RTK corrections at same time. Then use OPUS to correct for SPC. For a network ROVER you will need 100% cell service, and long baselines may degrade accuracy along with the addition of trees and hills. Also when you get it an area where your RTK is subject to high multipath, you can collect a 1-2hr static data to double check, and process with your BASE.

I find too many short comings when depending on someone else's GPS base.

When depending on a local RTN, where you DON'T set your own base up, you are good, up to 7-10 miles. But, the RMS grows too much after that. Keep a base close to your project, and you have better data, and faster fixes.

John Giles, post: 332379, member: 57 wrote: ... good under canopy? Or is there such a beast..

In pine forests where we operate there is no such beast. Perios. No matter what the sales folks tell us, it just doesn't work reliably...

gschrock, post: 332514, member: 556 wrote: I had a closure of 1:100,342 with the Trimble and 1:100,500 with the Lieca. So obviously the Lieca network is so much better.

Gavin,

I think Steven meant to use the sarcasm font. As there is virtual no difference between a closure of 1:100,342 and 1:100,500.

Jim in AZ, post: 332520, member: 249 wrote: In pine forests where we operate there is no such beast. Perios. No matter what the sales folks tell us, it just doesn't work reliably...

I agree. GPS does like like conifers.

Only a chain saw can make GPS work in dense pine forest.

Just for the record, if you buy a single topcon hyper, (not the short range lite one) it will work with this network.

Just has to match the corrections protocol.

N