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Averaging base position in SINGLE

This guide explains how to use the Average SINGLE entry method in the Emlid Flow app to set up base position.

Overview​

When you don’t know your base’s position, you can average it in SINGLE using the Average SINGLE coordinates entry method in Emlid Flow. Averaging is done in standalone mode without using any corrections and the position of the base is determined with the accuracy of several meters. In this case, the rover measurements will be centimeter-precise only relative to the base but their actual (absolute) accuracy in the selected coordinate system will be at meter level.

tip

To learn more about the accuracy for RTK and PPK measurements, read our Simple Intro to Accuracy and Precision article.

Workflow​

Placing base in field​

To place your base station in the field, follow the recommendations below.

Clear sky view without any obstacles

Reach base needs to have a clear sky view 30 degrees above the horizon. There should be no obstacles that could block the view like buildings, trees, cars, humans, laptops, etc.

Take a look at 2 pictures below. The left picture demonstrates desirable conditions for Reach location. The right one is an example of poor surrounding conditions such as the reduced view of the sky, possible obstructions or vegetation nearby.

Figure 1. Examples of recommended and poor environments for Reach placement

Examples of recommended environments for Reach placement:

  • field
  • top of the hill
  • rooftop

Examples of poor environments for Reach placement:

  • indoors
  • urban area
  • forestry area

No electronics nearby

Electronic devices may produce RF noise that could affect the reception of the GNSS signal. Keep all electronics as far as possible from Reach.

Measuring antenna height offset​

When placing your Reach in the field, make sure your Reach device is placed precisely above the marked point on the tripod and leveled. When you are setting up base coordinates manually, you need to measure the antenna height offset. Follow the steps below:

  1. Measure the distance from the mark to the bottom of your Reach (h in Figure 1).

  2. Specify the measured distance in Emlid Flow. It will automatically calculate the antenna height.

    tip

    For Reach RS2/RS2+, the antenna height is the distance from the mark on the ground to the center point on the Reach’s bottom (h in Figure 1), antenna reference point (ARP), plus the height of the receiver to the antenna phase center (APC), antenna height offset. Emlid Flow automatically adds the antenna height offset, which is 134 mm.

    Figure 2. Antenna height

When you placed Reach over the mark and measured the antenna height, you are ready to set up the base position in the Emlid Flow app.

Setting up base’s coordinates in Emlid Flow​

Let’s see how to set up the base's position using the Average SINGLE coordinates entry method in the Emlid Flow app:

  1. Open Emlid Flow and connect to your Reach.

  1. Go to Base settings and tap Configure.

  2. Tap Coordinates entry method and choose Average SINGLE from the menu.

  3. Tap Antenna height to set the antenna height and save it.

  4. Set averaging time, tap Save.

Now, when your base coordinates are averaged, you can continue creating up a project on your rover.

tip

You can save these coordinates and use them later within the same project. Without knowing them, you won't be able to reproduce this project.

Further reading​