Mounting a Surveying Antenna to a Bulldozer Blade

GPS/GNSS
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We are using ScreenStream to monitor the dozer operators screen remotely.

The dozer operator is connected on Discord, and we can provide audible communication about elevations, plans, and ensuring we’re all on the same page. Plus I have cameras where the Dozer is operating to monitor remotely.

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Here are the step by step instructions we use. Through this method, we can essentially level the LASER itself to the exact elevation we need.

SUPPLIES TO TAKE OUT WITH YOU

  • Yellow Tripod GPS (with phone)
  • Black Monopod GPS (with phone)
  • Dual-Slope Milwaukee Laser
  • Torpedo level
  • Chest Harness or Headset for hands-free communication
  • Gloves (as needed)

CALIBRATING YELLOW TRIPOD GPS

  1. Make sure you got the green dot in SW Maps and Wi-Fi is OFF.
  2. Verify Yellow Tripod GPS Antenna is fully contracted
  3. Take Yellow Tripod GPS to the blue, center line on the Edge of Pavement
  4. SW Maps: “Bluetooth GNSS” should have a height of 2.02 meters, and make sure to hit the small check mark and see the verification “Instrument Height Updated.”
  5. The Elevation should be “2683.821.” If the number is off, verify that the black, upper pole is firmly inserted in the Yellow Tripod. (“Within .083 is the error”)

SETUP LASER

  1. Calculate the 100 foot section that you will be focused on, and note the Station numbers
  2. Use the Yellow Tripod GPS to mark approximately 2’ feet past the 100 foot Station (each station is 50 feet) FACING the dozer blade
  3. Place the laser over the mark that is 2’ past the station line
  4. Ensure laser legs are fully extended and firmly pressed into the ground. Ensure that the telescoping head is in its lowest position
  5. TORPEDO LEVEL: Verify that the laser head is level
  6. Ensure the X arrow on the top of the Laser is pointing toward the front of the bulldozer blade either directly NORTH or directly SOUTH
  7. The X-Axis MAINFALL is dependent on the road plans. Review road plans.
  8. The Y-Axis is the CROSS-SLOPE.
  • X-AXIS POINTING NORTH (NORTH FACING): Set the Y-Axis to +2%
  • X-AXIS POINTING SOUTH (SOUTH FACING): Set the Y-Axis to -2%

ALIGN LASER

  1. Verify Black Monopod GPS with laser receiver has a green dot with RTK Fix. Wi-Fi should be OFF.
  2. Have another person at the laser to make adjustments & make sure Bulldozer is parked so it’s not in the way
  3. Use Black Monopod GPS with Laser Receiver to measure elevation of the laser at the closest station line (“BASELINE”) and blue centerline. Record this elevation. ________
  4. Now measure the laser 100 feet away (2 station lines)
  5. Err on the side of laser too high than too low
  • 1% Slope = The laser elevation should be 1 Foot different from BASELINE (within 0.10 error) _________
  • 2% Slope = The laser elevation should be 2 Feet different from BASELINE (within 0.10 error)
  1. Adjust head left or right to change the height of the laser at 100 feet as needed:
  • NORTH FACING LASER: To LOWER the laser, rotate RIGHT or CLOCKWISE. To RAISE the laser, rotate LEFT or COUNTER-CLOCKWISE.
  • SOUTH FACING LASER: To LOWER the laser, rotate LEFT or COUNTER-CLOCKWISE. To RAISE the laser, rotate RIGHT or CLOCKWISE.
  1. Once height is set, confirm the height at 1 station closer to the laser (50 feet) to double check. Adjust height as necessary. Go back to the 100 foot station to recalibrate if needed.
  • 1% Slope = The laser elevation should be 0.5 Foot different from BASELINE (within 0.10 error)
  • 2% Slope = The laser elevation should be 1 Foot different from BASELINE (within 0.10 error)
  1. Put away the black GPS. We are finished with it.

CALIBRATE DOZER GPS

  1. SW Maps: Ensure green dot with RTK Fix in Dozer and on Yellow Tripod GPS. Wi-fi should be off.
  2. Set Dozer green dot 2 stations (or 100 feet) away from laser on blue center line
  3. Dozer blade should be on the ground and level
  4. Ensure all GPS and laser receivers on the Dozer are tightened
  5. Make sure the Laser Receiver is on
  6. Use YELLOW TRIPOD GPS to measure elevation of bottom of bulldozer blade in the center
  7. Dozer SW Maps: “Bluetooth GNSS” instrument height of 3.170 meters, and make sure to hit the small check mark and see the verification “Instrument height updated.”
  8. Adjust the instrument height to ensure the elevation matches the YELLOW TRIPOD GPS
  9. Margin of difference should be within 0.10

RAISING LASER TO DOZER RECEIVER

  1. Set the Dozer blade elevation to 0.167 feet (2 inches) above BENCHMARK (within 0.10 margin) elevation as indicated for the specific station on the blue line
  2. Adjust the height of the laser VERY CAREFULLY until the laser is aligned with the Dozer LASER RECEIVER
  3. The bulldozer operator should be communicating the directional arrows. If the UP ARROW is shown on the RECEIVER, that means that the laser needs to be LOWERED. If the DOWN ARROW is shown on the RECEIVER, that means the laser needs to be RAISED.
  • WARNING: Sometimes the arrows are wrong because of reflections and you need to verify with receiver
  1. Go past above the upper range of the Green box of RECEIVER, and then adjust down to the upper limit

VERIFY LASER AT STATION WITH DOZER

  1. Have Dozer drive to the next station 50 feet closer to the laser with the green dot on the blue, center line
  2. Verify the elevation is 0.167 feet (2 inches) above benchmark (within 0.10 margin). Err on the side of too high

GET PICTURE OF DOZER AUTOMATICS TO ENSURE SET CORRECTLY

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I have never seen any YouTube videos calibrating the laser height in relation to RTK fix, so I had to develop the procedures through trial and error.

We can complete this process in 45 minutes if everything runs smoothly. Usually takes about an hour because some kind of hiccup occurs which I have to improvise a solution outside the procedures.

I am very happy that I ended up taking on this project myself. Considering the complexity of the setup, I simply don’t know how standard road construction crews can get any sort of accuracy except by literally hiring licensed Surveyors to actually guarantee the placement of the laser.

I imagine hiring a surveyor to setup the laser every morning likely can get expensive.

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This is awesome, thank you for sharing!

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So one of the EXTREME time saving measures arises when we’re having to remove feets worth of soil. How do we know it’s feets?

Because in the morning, we just align one of the Rovers with the bottom of the Dozer Blade (which essentially acts as its own Rover with 3.07 meter height). It takes maybe 10 minutes. As long as the ellipsoidal heights match (close enough), the dozer is good to go.

We’re assuming it’s unlikely that both the dozer antenna and the Rover antenna altered in relative height exactly.

No need to setup lasers or even send another surveyor out with the operator since we’re so many feet away. Then periodically through the day, we can “recalibrate.”

We have the ScreenStream.io and have him lower his blade to the ground, and we know the exact height. (this is assuming the antenna didn’t move feet in the middle of the day which is always a possibility). We can now let the operator know they are now only X feet away from their target height.

Generally, when operating with a 2 foot margin, you’ll notice if the antenna moved vertically 2 feet. Likely, it would’ve fallen off the actual dozer mast.

When we get within 1 feet of the target height, we will setup the laser.

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Almost a month and a half later and we’re still trucking along.

We’ve found that the CR700 paired is the most cost effective solution for laser receivers, but you MUST have a tech on hand to troubleshoot all the problems that arise. The Johnson laser receivers are OK, if we can get the remote device working. Everything is cabled.

Milwaukee dual slope lasers have been problem headaches. Thank God for Home Depot’s generous return policies. We just return them. I’m not sure if all dual-slope lasers are headaches.

Everything is strung together with any component breaking at any moment.

Speaking of which, the SparFun RTK Expresses have been having issues pop up including Bluetooth connectivity issues, charging components, etc.

The disaster is the shortage of SparkFun RTK Expresses. We can’t get replacements fast enough, and you can’t be stopping a multi million dollar project because the RMA item you sent in does not have a replacement available to send out.

I would like to push this product into my region, but if I can’t be 100% sure I’ll have replacement units, this simply will not work.

The antennas have been rock solid. I just think the vibrations in the Dozer and heavy equipment is perhaps a little too much for the RTK Express units. And then also on the survey sticks.

Despite the headaches, it’s still cheaper than the $100k and hiring professional surveyors.

If you look at my previous posts, I’ve ran into random little hiccups, but luckily, I have a VERY small crew, so any technical delays that we have to figure out, don’t cause me a lot of money. Also, I’m my own client, so I don’t get angry at myself, especially considering the $400/hour surveyors I’m saving on!

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Late October, Google Satellite view updated, and I can see my KML lines on Google Earth matching perfectly with some of the roads and pads we’ve lined up with the Sparfun RTK products & Reference Station.

I can’t tell you how satisfying it is to see how well the satellite view matches with the KML lines. These are the same KML files that get uploaded to SW Maps, and from SW Maps with the rovers & RTK Express.

Everything has been coming together despite the various challenges.

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I would also be remiss to not include the numerous times that the surveying capabilities outside of the dozer have been extremely beneficial.

Manhole placement, irrigation pipe, conduit for electrical lines. Elevation matters.

Normally, this is a $1600/half-day minimum sort of job.

Also, checking a monument every morning is important as the Reference Station may end up getting reset on accident and I haven’t figure out how to save the settings. Without the offsets, we’re about 6" off both horizontally and elevation wise.

Even without the bulldozer component, the Sparkfun surveying equipment already made back its cost.

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To explain just how far behind the construction industry is and generally tech retarded, watch how cutting edge the laser is in video.

Meanwhile, one can get even more precision using Sparkfun RTK.

This is a potential business opportunity if you can get the construction guys to stop throwing their iphones in fits of rage.

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