Construction progress monitoring with drones: tracking and reporting

Progress monitoring answers one question every week or month: is the job where the programme says it should be, and if not, by how much? The answer is made of quantities, dates and a record of the site, and most of the argument on a construction project is about whose version of those is right. This guide is about producing a version that holds, using drone surveys for the part they are best at: measuring the whole site, the same way, every time.

What progress monitoring is made of

• Quantities. Cubic yards excavated, placed and compacted; tons of stone in the yard; area paved; the level a pad or a dam has reached. Quantities are what valuations and claims are paid on.
• The plan. The programme or schedule, and the planned quantities for each period. Progress is only meaningful against it.
• The record. What the site looked like on each date. Rarely needed, and invaluable the day a delay or a defect is disputed.
• The actions. What is behind, why, and who is fixing it by when.

The ways progress is tracked, and what each can measure

A drone flight is the one method that measures quantity across the whole site at a single moment, which is why it has become the backbone of progress reporting on earthworks, civil, mining and large building sites. It works best as the measured layer under the schedule and the site walk, not instead of them.

Monitoring progress with drone surveys

1. Fly on a fixed cycle, the same day of each week or month, with the same flight plan: height, overlap and roughly the same time of day. (Flight settings.)
2. Position every flight the same way: ground control left in place, or RTK or PPK with a few checkpoints. Two flights that disagree about where the ground is produce progress that never happened. (What each method gives you.)
3. Keep every flight on one timeline for the site, so this month's map sits beside last month's and the first.
4. Measure the change, not just the state: difference this flight against the last one for volume moved, and against the design for what is left to do. (Comparing two flights.)
5. Pin the walk's photos and issues to the map where they were taken, with a name and a date on each action.
6. Write the report from those, and keep it with the flights it was made from.

What a drone flight tells you that a walk cannot

• Earth moved this period, in cubic yards, cut and fill separately, over the whole site or inside the boundary of each work area.
• What is left to design, as cut and fill remaining against the engineer's surface. (How cut and fill is calculated.)
• Stock on hand, pile by pile, in tons. (Measuring stockpiles.)
• Levels reached: a pad at subgrade, a dam at its next lift, a cross-section along a haul road against last month's.
• Where things are: laydown areas, haul routes, the extent of each crew's work, drawn on a map that is true to scale.

The monthly progress report

A good progress report is short and built from things that can be checked. A structure that works for most civil and earthwork jobs:

Where progress numbers go wrong

• Two flights at different heights. Without the same control each time, a whole site can read as tens of thousands of cubic yards of cut that nobody dug. Check the offset on ground that did not change before reading any number.
• Comparing the wrong surfaces. A truck parked on a pad last month and gone this month reads as cut. Fly when the site is still, or compare the terrain models. (DSM, DTM and which to compare.)
• Survey noise counted as work. Two good flights disagree by a few centimetres everywhere; over a large site that is real-looking volume. A deadband of about the noise level keeps it out.
• Percent complete by opinion. A schedule updated by judgement drifts from what is in the ground. Measured quantities are the check on it.

How often to fly

Monthly suits most valuations and most clients. Weekly suits fast bulk earthworks, a programme in trouble, or a client who wants to watch. More often than weekly is rarely worth processing unless a specific operation, such as a large pour or a blast, needs a before and after. Whatever the cycle, keep it: a series of flights is worth far more than the same number of flights taken when someone remembered.

Doing it in Clarity

Clarity keeps every flight of a site on one timeline, plays them back as a film, swipes and differences any two dates, flags two flights that sit at different heights and lets you level them on unchanged ground, measures cut and fill against the design or the last flight with a deadband, and pins field quality observations to the map with a name, a due date and a review workflow. The measurements print as a report per flight, the observations export to Excel, and a share link lets the client open the site with no account. (Progress monitoring in Clarity.)