Hybrid+ Surveying Case Study: Bringing Geodetic Coordinates Inside for Rodded Boretrak® Testing

By Bruce Carlson • October 15th, 2018
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Available new in SurvCE and SurvPC 6.0 is powerful Hybrid+ Surveying, which is a mixed use of GNSS and robotic total station measurements. One of the many attractive features of Hybrid+ Surveying is GNSS Resection by Total Station. In July 2018, we used this feature to bring true geodetic coordinates, with true north azimuth, into our Carlson Building to test the Carlson Boretrak.

We set the instrument up inside our building at a position where we could see through the open front door to the street and through one of the offices with an open window to the park outside, as shown below:

The instrument stayed in the same position throughout the entire exercise, but the Carlson BRx6+ GNSS was mounted on top of the prism pole. Then in Hybrid+ Resection, with a single measurement, both the GNSS position (at the unknown point) AND the robotic total station laser reading were taken to each of the two points. It is important to note that these points had no known coordinates. They were just random positions that we could see. The BRx6+ provided the GNSS position, and the total station measurements provided the resection from these positions to the instrument. This brought true projection coordinates (in this case KY NAD 83 North Zone) into the interior of the office. Closure is provided, and on our first try, we recorded a closure of over 1: 1,000,000! Beginner’s luck or the power of Hybrid+?

Here is a view of SurvCE in the field during the Hybrid+ Resection process. This references the measurement taken through the office window to the park. With the tilt option activated, the goal is to get the blue circle inside the black circle for confirmation of vertical positioning.

Shown below are 2 views of the interior setup within the Carlson Corporate Office. George Washington, as a surveyor, looks over our work. The open window to the park is shown in the lower right.

The Hybrid+ Resection is very fast. Just select the command, take the first measurement, move to the next point and take the second measurement. You now have true projection coordinates at the total station, with due north correctly defined for all interior measurements.

The true north direction was important for the measurement of the dip angle and azimuth of all points along the blue PVC pipe shown above. This pipe simulates the bending of a drill hole at a mine site. By precisely measuring the deviations of the PVC pipe going downhole, we can then confirm the accuracy of our Rodded Boretrak device, shown being deployed below.

Shown at left is Boretrak Mobile running on an Android data collector. Boretrak Mobile is our first full Android product (with more to follow). Boretrak Mobile connects to the head of the Rodded Boretrak by Bluetooth, and shows the downhole azimuth and varying dip angles by segment. These can then be compared to the data measured precisely by total station. The orientation reference for the Rodded Boretrak is the surface-measured azimuth of the rod assembly shown in the upper left. The data match was impressive. For example, the deviation from vertical at the base of the PVC pipe/drill hole was accurate to 1 centimeter or 0.02 feet!

The Rodded Boretrak is one of many products now manufactured by Carlson Software. The Rodded Boretrak is assembled both in our York, U.K., office as well as in our Maysville, Kentucky, corporate headquarters. These products add to our ever-expanding portfolio of hardware serving the surveying, construction, and mining industries.

As President of Carlson Software, I am excited to say this fulfills a dream of mine. Carlson Software is more than software: We make things. We are in manufacturing. If we can imagine it, we will make it, and through software, we will make it work really well!

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