Summary: A drone by itself will not provide enough accuracy to measure the most critical measurements such as usage, forecasting, density, and shrink. Using more accurate positioning technologies allow us to make accurate silage inventory measurements.

Not Just Any Drone Will Provide Highly Accurate Silage Inventory Measurements.

It seems like just about everyone has a drone nowadays. And the images taken with that drone can create some pretty incredible things: aerial maps, 3D Models, and all kinds of measurements. But just because something can be measured, does that mean it’s an accurate measurement? If you’re only using a standalone drone by itself, then it’s probably not.

Typical professional or “pro-sumer” drones such a DJI Mavic Pro or Autel Evo II pro have built in GPS and IMU units that tag each photo with the drone’s position. The problem is that this GPS doesn’t have the accuracy required to get highly accurate positioning. This can result in those images being assigned an in-precise coordinate and altitude. 

Further, if the farm is flown again in the future, there can be a significant variation in the “global” position those photos are taken. The global position is the absolute position where something exists on earth. The variations of images collected from a standalone drone result in an inaccuracy that severely limits the insights we can gain from measuring silage inventories.

A standalone drone may still be better than using the old measuring wheel but you’ll never be able to have confidence in your measurement, or have accurate enough measurements for important metrics such as shrink, density, and forecasts. This is where accurate positioning technology comes into play such as Ground Control Points (GCPs) or Real Time Kinetic (RTK) technology.

The Importance of Using Ground Control Points (or RTK) for Accurate Silage Inventory Measurements

Using these technologies in coordination with the drone allow us to get incredibly accurate and consistent measurements of silage inventories. Because we can have confidence in our measurements, we can then track the most important metrics such as shrink, density, and forecasts.

What are ground control points? GCPs are singular points measured around a farm site using GNSS units. These GCPs are critical for accurate measurements because of the following reasons:

  1. They serve as a standard “control” for a scientific measurement. In any scientific measurement, it is important to establish a “control” to compare your measurements against. Without this control, it is hard to decipher what factors may have influenced your measurements. This is one of the key roles of ground control points. They have repeatable precision down to +/- 2 centimeters, so when we compare the position in our measurements to that of the GCP, we can understand if that measurement is within acceptable error parameters.
  1. They allow us to orient our images in the correct position. Without GCPs, we are dependent on the relatively inaccurate drone GPS to tell us where those images were taken. With Ground Control Points, we can align those images with the correct position based on the GCP that was established on site. When meshing these GCPs with the images, we then have an important spatial reference to correct for errors in the drone’s on-board GPS.
  1. They provide consistency. As with a ration, consistency is key for successful results. The same is true with inventory measurements. When measuring silage inventories, it’s not only important to have accurate imagery but also a consistent measurement area. With GCPs, we are able to establish an “absolute” position and thus, directly mesh each consecutive flight for a farm. This means that we can take the same measurement of a bunk, pile, or bag every time without errors in where that measurement is being created. This is absolutely critical for any metric that requires data from multiple points in time.