# Time Convention



As found here: [https://github.com/OSOceanAcoustics/echopype/issues/656](https://github.com/OSOceanAcoustics/echopype/issues/656)

### Time coordinates in `Platform` group

* `time1`: will be used for data variables related to GPS lat/lon
  * this will be the same for all sensors
* `time2`: will be used for data related to platform motion and positions, such as pitch/roll/vertical\_offset
  * `EK60`: source `ping_time` (not yet implemented)
  * `EK80`: source `mru_time` (already implemented)
  * `AZFP`: source `ping_time` (added in [Rearrange AZFP attributes/variables and remove a variable according to #642 #669](https://github.com/OSOceanAcoustics/echopype/pull/669): `tilt_x/y` -- these may eventually be removed)
* `time3`: will be used for anything from environment type of datagrams, such as water\_depth
  * `EK60`: ping\_time (not yet implemented)
  * `EK80`: environment\_time (already implemented)
  * `AZFP`: X (not yet implemented)

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