To address this, it’s important to understand two concepts: Absolute Positioning and Relative Positioning:
- Absolute Positioning: This refers to the exact geographic coordinates (latitude, longitude, altitude) of a point on Earth’s surface.
- Relative Positioning: This focuses on the positions of points relative to each other rather than their exact geographic coordinates. It is important when the relative distances and angles between points are more critical than their absolute positions.
How accurate does your RTK base need to be?
If your project requires precise Absolute Positioning, it’s crucial to set up your RTK base with the highest possible accuracy, aiming for centimeter-level precision. Any inaccuracy in the base station’s position will directly transfer to the rover’s position.
On the other hand, if your project focuses more on Relative Positioning, then the exact precision of the base station isn’t as critical. This is because the errors in the base station’s position will affect all the rovers equally, which means their relative positions to each other will still be accurate. In situations like this, the coordinates don’t need to be extremely precise; an accuracy of up to 3 meters is acceptable.
What are the differences between the “Fixed Position” and “Survey-in” setup options for an RTK base, and when should each be used?
The “Fixed Position” method involves entering pre-determined, highly accurate coordinates into your RTK base. This option is ideal when you require absolute positioning precision, such as in detailed surveying or construction projects where exact location data is critical.
On the other hand, the “Survey-in” method utilizes the RTK base’s built-in GNSS receiver to calculate its position over a period ranging from a few minutes to an entire day. This duration reflects the achievable accuracy, which can vary from a few meters to centimeters. This is suitable for projects where ultimate precision absolute positioning is not essential, or when accurate RTK base coordinates are not initially available. It’s particularly useful in settings where relative positioning is more important than absolute positioning.