Expert Insight: The AP20-Equipped Surveyor

The recently released Leica AP20 AutoPole, the world’s first tilt-compensated TPS pole, has already proven its merit in the surveying industry and garnered accolades, including the 2022 Wichmann Innovations Award. It’s no surprise: field research and customer testimonials have confirmed significant productivity gains with the AP20 across the survey workflow.

The combination of measuring with a tilted pole and automated pole height readings and target identification enables the surveyor to approach many former challenges with ease, all while retaining confidence in measurement quality. But what does this look like in practice, and what are the actual time savings and productivity gains?

In this expert insight, Leica Geosystems’ Product Engineer Rafael Eder provides answers to these key questions based on his thesis research and gives a glimpse into the new and transformed daily workflow of the AP20-equipped surveyor.

1. The AP20 has been described as revolutionising the measurement process in the field. Can you describe how the AP20 changes the surveyor’s workflow across an average workday?

The AP20 is truly revolutionary. In terms of innovations to the automated total station workflow, it is comparable to the introduction of the one-person-measurement mode, as it is such a big change for the surveyor in the field.

To describe the AP20’s impact, let’s walk through a scenario featuring the common tasks of a surveyor who works for a small to medium sized company, combined across a typical workday.

Morning: Excavation stakeout and plot survey

Our surveyor’s day begins with driving to and working on an early-stage construction site, staking out points for excavation and the location of a crane. Equipped with the AP20, the surveyor can hold the pole at any angle to quickly reach and mark points. This saves a significant amount of time compared to previous workflows where the pole needed to be carefully levelled to true verticality for each point to stake – an iterative and cumbersome process. Paired with Leica Captivate field software running on a Leica CS20 field controller our surveyor is guided by 3D views in navigation mode and a variety of other shortcuts for efficient use of the AP20’s features.

Next is a plot survey to provide stakeholders with heights, positions, and details of buildings and objects. The plot, covered in tall vegetation, requires multiple height changes to obtain visibility to the Leica TS16 total station. However, with the AP20’s PoleHeight feature which automatically reads the actual height from the pole and registers it in Leica Captivate, our surveyor doesn’t need to manually enter anything. This also makes height entries error-proof, removing time-intensive corrections later in the office.

Here the AP20 continues to display its strengths, enabling the surveyor to measure more points with fewer total station setups. While surveying a small building on the site, the AP20 allows measurements of all four corners with one total station setup where two setups were necessary before. Points that were hidden from line of sight because the prism pole needed to remain level become visible and measurable with the tilted AP20.

Former workaround solutions like corner tip prisms, measuring offsets, and more are no longer necessary, removing the need to carry around and set up extra equipment. With fewer time-consuming setups across the site, the surveyor is finished faster and off to the next task.

Afternoon: Construction site survey and plot boundary stakeout

After lunch, our surveyor drives to another construction site. Here, setup is easy because control networks are already established, and fixed prisms are mounted on the walls. However, it’s a large and busy site with other surveyors working at the same time. Without the AP20, the total station could initially lock onto the wrong target as it searched for the correct prism.

However, the AP20’s TargetID functionality eliminates this problem and the lost time that accompanies it. The total station automatically locks onto the correct prism and work proceeds as though the surveyor were the only one measuring on site.

The next stop is a coffee break followed by a visit to the last site of the day - a plot where an area division takes place. The existing boundary points need to be verified and potentially restored before new borders can be staked.

The AP20 helps our surveyor quickly measure the existing visible points for location confirmation, and easily reach the new boundary points that must be staked from scratch, even when difficult to access or partially obstructed. Once again, the AP20 saves our surveyor a noticeable amount of time.

Changing combinations of a surveyor’s daily work means productivity increases will be variable. However, one thing is clear – the surveyor speeds measurements across tasks, applications, and sites and significantly reduces errors with the AP20.

2. Where can surveyors expect to find the most time savings, and how much will productivity improve?

The AP20 connects into the already digital and automated parts of the total station measurement workflow, so that the highest productivity gains will be on survey tasks where the user interacts with Leica Captivate field software and Leica instruments to find, stake, or measure points.

My thesis research analysed a typical surveyor’s workday with the same tasks described above, including related work, like performing a GNSS measurement with a smart antenna to establish controls or spraying points, drive times, and breaks. Looking purely at the median time needed to stakeout a series of sprayed points, productivity increased by 50%, requiring only 14 seconds per point with the AP20 compared to 28 seconds without.

While total time savings are dependent on the required manual tasks that follow, such as placing a new metal mark in the ground or spraying points for layout, the AP20 saves time overall with each point measured.

For example, the total time to complete common survey tasks without the AP20, including site familiarisation, setup, and locating existing points, required 6 hours and 49 minutes. This dropped to 4 hours and 42 minutes when using the AP20, a 31% reduction in survey task time. Factoring in breaks, driving time, and GNSS measurements, time saved across the day still averaged a significant 25%. In practical terms, this amounted to approximately two hours saved every day.

3. Do the benefits of using the AP20 extend beyond more productive time in the field? How can surveyors benefit in terms of post-processing and quality assurance?

Tilt Compensation and PoleHeight both have a large impact on quality assurance, reducing the need for post-processing work or remeasuring.

For example, opportunities for mistakes increase with each height adjustment that needs to be manually recorded in the field software. This in turn can result in extra post-processing work to correct height errors or return trips to the site to remeasure. However, automatically recorded height changes with the AP20 provide accurate and traceable measurement data, the benefits of which extend through deliverable creation.

Continuing the theme of quality assurance, errors related to the prism pole’s true verticality were difficult to determine and time-intensive to minimise before the AP20. Influences from a non-calibrated bubble, for instance, could produce incorrect measurements that remained undetected.

Additionally, in cases where an operator accidentally tilts the pole while measuring, no record of the error would even exist. Since the bubble is no longer needed with the AP20 and the quality of the tilt is indicated and stored with the measurement results, errors are minimised and quality is clearly traceable.

Ready for more details on the technological innovations enabling the AP20’s productivity enhancing capabilities? Download and read the Leica AP20 AutoPole White Paper.

Contact us to learn more about how the Leica AP20 AutoPole can optimise your automated surveying workflow.