Finally Spilling the Beans on RTK GNSS

Howdy Roby,
Glad to hear a new angle on RTK.

When Kris sees this he will want one for his Bobcat..........

A Harris, post: 424986, member: 81 wrote: Howdy Roby,
Glad to hear a new angle on RTK.

When Kris sees this he will want one for his Bobcat..........

Hi Mr. Harris, We've had a fair amount of excitement with self-driving Scag mowers, but a self-driving Bobcat sounds like a fun project 🙂

Here‰Ûªs a challenge: find 1 URL where either Trimble or Novatel or Leica lists the price ANY L1/L2 GPS/GLONASS receiver or antenna and allows you to purchase said component for said price.

You left out one very important player in the high-precision GNSS world: Javad GNSS. You can customize, price and buy any of their receivers (the link is to the OEM receiver page) right from the Javad website.

Jim Frame, post: 425004, member: 10 wrote: You left out one very important player in the high-precision GNSS world: Javad GNSS. You can customize, price and buy any of their receivers (the link is to the OEM receiver page) right from the Javad website.

Jim -- Thanks for taking the time to read the article. Can you advise the price of an L1/L2 GPS/GLONASS RTK receiver from Javad? Are they in the $450-$900 range of ComNav/Unicore? For those of us in Robotics, $500 for a solid L1/L2 GPS/GLONASS RTK (@ 10HZ output) is a huge game changer.

Roby_, post: 425006, member: 12678 wrote: Jim -- Thanks for taking the time to read the article. Can you advise the price of an L1/L2 GPS/GLONASS RTK receiver from Javad? Are they in the $450-$900 range of ComNav/Unicore? For those of us in Robotics, $500 for a solid L1/L2 GPS/GLONASS RTK (@ 10HZ output) is a huge game changer.

I'm not familiar with the Javad OEM line, but it looks like theTR-G2T is the lowest-cost board they have that offers GPS L1 and L2. (It also has L2C and L5.) It sells for $2,850.

Jim Frame, post: 425008, member: 10 wrote: I'm not familiar with the Javad OEM line, but it looks like theTR-G2T is the lowest-cost board they have that offers GPS L1 and L2. (It also has L2C and L5.) It sells for $2,850.

Jim -- Can you advise if there's a reason why you guys pay that much? Please don't read that as being sarcastic -- being totally sincere -- I realize I'm playing a game here where you are the expert -- it's just hard for me (as a programmer/robotic builder) to understand what benefit you guys get by paying so much for equipment.

I also bought the piksi system only to be disappointed in the proprietary data format they used. Then bought the ublox rtk system and used rtklib and that has been a good L1 rtk system. But when you jump up to a major manufacturer system (I use Trimble) it does cost more than it should but it's a polished system that works and for the most part works the same every time you need it. I play with the cheap systems but I use the expensive systems. Good article!

Bryce, post: 425012, member: 11791 wrote: I also bought the piksi system only to be disappointed in the proprietary data format they used. Then bought the ublox rtk system and used rtklib and that has been a good L1 rtk system. But when you jump up to a major manufacturer system (I use Trimble) it does cost more than it should but it's a polished system that works and for the most part works the same every time you need it. I play with the cheap systems but I use the expensive systems. Good article!

Bryce -- thanks for taking the time to read that long article! Two questions:

1. Do you have experience with the ComNav / Unicore L1/L2 GPS/GLONASS systems? Specifically have you ever heard (either in print or word-of-mouth in the Surveying community) anyone claim that Trimble/Novatel/Javad/etc are superior in any technical way to Comnav/Unicore? Again, I'm pushing to understand why you guys pay 5x for what I've concluded is basically the same product. I've got another theory that the reason is that many folks haven't yet heard much about ComNav/Unicore, and they haven't seen their performance first-hand.

2. Have you contacted the folks at Swift Navigation for a refund? You should -- I think you may be surprised that you'll be $1000 richer without much headache.

Thanks again for taking the time to weigh in.

--Roby

Roby_, post: 425009, member: 12678 wrote: Jim -- Can you advise if there's a reason why you guys pay that much?

Because this isn't a hobby for us. We make a living using these tools, and we need them to deliver the accuracy, dependability and efficiency that we need to do our work.

Roby_, post: 425009, member: 12678 wrote: Jim -- Can you advise if there's a reason why you guys pay that much? Please don't read that as being sarcastic -- being totally sincere -- I realize I'm playing a game here where you are the expert -- it's just hard for me (as a programmer/robotic builder) to understand what benefit you guys get by paying so much for equipment.

I paid about $60,000 for my Leica 1200 with the GLONASS option about ten years ago. Why did I spend that kind of money? Because it was a great working gold mine that repaid itself many, many times over. Worth every penny. I have zero regrets on that investment.

Don't take Roby's questions personally. I am not saying that anyone has yet, I just appreciate this thread. {luker mode back on}

Roby, useful info here, in this thread on this forum, from February:

https://surveyorconnect.com/community/threads/rtk-for-699-a-piece-reach-rs.329621/

Jim Frame, post: 425017, member: 10 wrote: Because this isn't a hobby for us. We make a living using these tools, and we need them to deliver the accuracy, dependability and efficiency that we need to do our work.

Jim, Totally understand. RTK GNSS is not a hobby for me, either -- We build precision path-following large-scale outdoor robots for a living. Previously I spent 10 years writing software at NASA.

At NASA we have a motto to always find the SMEs in any field. In RTK GNSS, Surveyors (and Precision Ag farmers) are the unquestioned experts. When I was learning RTK, it was PEOPLE LIKE YOU who actually had the answers (rather than marketing hype). Specifically, for instance, if I make the statement:

L1 GNSS is a joke next to L1/L2

Everyone in this community knows exactly what that means. If you look at the robotics community -- we've only recently started to figure out how good RTK is (when you get it right), and how frustrating it is if you don't know what you're doing. In the robotics community, many folks (who have no experience with a good L1/L2 GPS/GLONASS system), have NO IDEA why you guys rave about how awesome RTK is. Part of the problem is, of course, the marketing arms of crummy L1 RTK systems (no need to name names, my blog has already drawn enough fire) have sold snake oil to robot builders.

Surveyors demand robust L1/L2 multi-constellation systems. Many of you guys are independent, and so, of course, you know EXACTLY how much your time is worth, and how much $$$ a bad RTK system would cost you.

Back to my work (deepsouthengineering/deepsouthrobotics) -- we can source an amazing L1/L2 GPS/GLONASS base/rover system (with receivers and antennas) from ComNav for $2000. Same system from Novatel is $10,000. I'm not going to lie -- robot building has nice margins -- but I can't leave $8000 on the table and buy a system that's not technically superior in any way.

Have any of you guys ever heard anyone claim that ComNav was in any way technically inferior (in performance) to Novatel/Trimble/Leica?

I'm a Mopar guy -- my Dad's a Mopar guy -- he's got a 1970 GTX that he spent 2 years restoring (best-of-show many times). His last mopar was a 1980s Dodge Colt.

Now we both own Honda Civics.

Is it possible that ComNav is the new Honda?

Thanks again for taking the time to critique this. Seriously, I don't think you guys realize how much nuanced knowledge you have of RTK GNSS systems that the average guy just doesn't know.

--Roby

Research and development cost a lot of money. I bet a modern GPS system doesn't cost more than the grand in the hardware alone. All the rest goes for R&D. If you want cutting-edge equipment you're going to pay for R&D.

Nate The Surveyor, post: 425045, member: 291 wrote: Research and development cost a lot of money. I bet a modern GPS system doesn't cost more than the grand in the hardware alone. All the rest goes for R&D. If you want cutting-edge equipment you're going to pay for R&D.

Nate, you're absolutely right! Even at $500 for a board, much of the cost is R&D. It's much better to pay $500 than $5,000 🙂 Hey, have you reviewed the ComNav k501g's (L1/L2 GPS/GLONASS) performance personally?

I think mobile RTK needs are different from surveying RTK needs. We both need position solutions that are fast and accurate; however, you're probably willing to trade some accuracy for speed, while I'm willing to trade some speed for accuracy. (In fact, I'm willing to trade a lot of speed for accuracy. While I like to get a reliable cm-level (or less) solution with a 3-minute observation, if I have to spend 15 minutes on a point to get that, most of the time that's still faster than getting the shot using a different technology.) So the signal acquisition hardware, signal processing engine, and user interface that I want are going to be markedly different from the ones that you want. And I'm willing to pay a hefty price premium for the ones that deliver the results I need.

I fully expect outfits like ComNav to see a burgeoning mobile market as an incentive to develop hardware, firmware and software to address mobile RTK needs at a very competitive price point. The size of the market is going to be large, so they should be able to recoup development costs even though their products aren't exorbitantly expensive. The surveying market, by contrast, is small, and getting back the R&D expense means costly products. As long as the surveying community can make money with those products, they'll continue to sell at those elevated levels.

Very interesting. My brother was looking for an inexpensive way of providing ground control for his drone. He bought a pair of the emlid receivers. I was/am extremely sceptical; but, so far he has matched my total station measurements within 0.02'.
It's very early in our testing, but...

Jim Frame, post: 425050, member: 10 wrote: I think mobile RTK needs are different from surveying RTK needs. We both need position solutions that are fast and accurate; however, you're probably willing to trade some accuracy for speed, while I'm willing to trade some speed for accuracy. (In fact, I'm willing to trade a lot of speed for accuracy. While I like to get a reliable cm-level (or less) solution with a 3-minute observation, if I have to spend 15 minutes on a point to get that, most of the time that's still faster than getting the shot using a different technology.) So the signal acquisition hardware, signal processing engine, and user interface that I want are going to be markedly different from the ones that you want. And I'm willing to pay a hefty price premium for the ones that deliver the results I need.

I fully expect outfits like ComNav to see a burgeoning mobile market as an incentive to develop hardware, firmware and software to address mobile RTK needs at a very competitive price point. The size of the market is going to be large, so they should be able to recoup development costs even though their products aren't exorbitantly expensive. The surveying market, by contrast, is small, and getting back the R&D expense means costly products. As long as the surveying community can make money with those products, they'll continue to sell at those elevated levels.

Jim, I see where you're going. A big consideration too is user interface -- I.E. if the ComNav's interface is a headache, and it costs you time then it's game over. Since I only buy the OEM cards, I have no experience at all with ComNav's UI on their surveyor products.

Back to RTK performance, let me ask this, specifically:

My ComNav k501g holds a +-1cm lock (horizonally) in my backyard testing ground (pictures here). Day after day, rock solid 1cm lock in those tough conditions. From a cold start, you'll get a lock within 50 seconds or so. Are you guys looking for more performance than that?

Again, I'm pushing on you guys to find out what the experts think.

Thanks,

Roby

Roby_, post: 425054, member: 12678 wrote: Jim, I see where you're going. A big consideration too is user interface -- I.E. if the ComNav's interface is a headache, and it costs you time then it's game over. Since I only buy the OEM cards, I have no experience at all with ComNav's UI on their surveyor products.

Back to RTK performance, let me ask this, specifically:

My ComNav k501g holds a +-1cm lock (horizonally) in my backyard testing ground (pictures here). Day after day, rock solid 1cm lock in those tough conditions. From a cold start, you'll get a lock within 50 seconds or so. Are you guys looking for more performance than that?

Again, I'm pushing on you guys to find out what the experts think.

Thanks,

Roby

What exactly do you mean by a 1cm "lock"?