# To initialize on a known point

Initialization on a known point is available for all Trimble GNSS receivers, with the following exceptions:

- If the receiver has an IMU, the IMU must be disabled. To initialize on a known point, the receiver must be in GNSS‑only mode. To switch to GNSS‑only mode, tap the receiver icon in the status bar to view the GNSS functions screen and then tap IMU tilt compensation to toggle on/toggle off GNSS‑only mode.

- Initialization on a known point is not available when using the Trimble DA2 receiver.

1. Position the rover antenna over the known point.

   In an RTK survey, the known point must be a previously measured point in the current job.

   In a postprocessed survey you can initialize on:

   - a point measured previously in the current job
   - a point that you will provide coordinates for later (before the data is postprocessed)
2. Tap and select Measure and then select RTK initialization or PPK initialization.
3. In the Method field, select Known Point.
4. In the Point name field, select the known point from the list of points in the job.
5. Enter values in the Antenna height field, and make sure that the setting in the Measured to field is correct.
6. When the antenna is centered and vertical over the point, tap Start.

   The controller starts to record data, and the static icon appears in the status bar. Keep the antenna vertical and stationary while data is recorded.

   If you are using a GNSS receiver with a built-in tilt sensor, tap eBubble (or press Ctrl + L) to display the eBubble. When the bubble is green, tap Start to ensure that the point is measured within the predefined tilt tolerance. The tolerance is that specified for a topo point.

   A message confirms when the receiver is initialized, together with the deltas from the current position to the known point.

7. Tap Accept.

   If the initialization fails, the results are displayed. Tap Retry to retry the initialization.