# Offsets, Rotations, and Reference Frames: SpatialExplorer Version 4-7

The SpatialExplorer layout has changed overtime and customers may note that their workflow in a previous version of SpatialExplorer no longer applies in the current version. The following is not an exhaustive list but explains the major changes associated with different versions of SE, particularly changes related to coordinate systems and acquisition workflows. For an exhaustive list of changes please review in SpatialExplorer the changelog (Help -> Changelog). 

### SpatialExplorer Version 4 and 5

* In rover profiles, translations and orientations from IMU to Sensor reference **Phoenix LiDAR Systems' vehicle frame** ( Z backwards, Y up, X right)**.**
* GNSS Antenna lever arms reference the IMU frame (dependent on IMU model).
* Project uses geocentric coordinates until point cloud is exported to LAS file.

### SpatialExplorer Version 6

* In rover profiles, translations and orientations from IMU to Sensor reference the **IMU frame** (dependent on IMU model).
* GNSS Antenna lever arms reference the IMU frame (dependent on IMU model).
* User must assign a project specific **processing datum.** Full coordinate reference system with projection, vertical CRS, and geoid model(s) defined during LAS export. 

### SpatialExplorer Version 7

* In rover profiles, translations and orientations from IMU to Sensor reference the **IMU frame** (dependent on IMU model).
* GNSS Antenna lever arms reference the IMU frame (dependent on IMU model).
* User must assign a project specific coordinate reference system with projection, vertical CRS, and geoid model(s).

**Legacy Documentation Links:**

Please use the legacy documentation for further details on these versions

* [SpatialExplorer Version 4](https://docs-6.phoenixlidar.com/spatialexplorer/introduction)
* [SpatialExplorer Version 5](https://docs-6.phoenixlidar.com/spatialexplorer/introduction)
* [SpatialExplorer Version 6](https://docs-6.phoenixlidar.com/)


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