> For the complete documentation index, see [llms.txt](https://px4.gitbook.io/px4-user-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://px4.gitbook.io/px4-user-guide/development/middleware/msg_docs/followtargetestimator.md).

# FollowTargetEstimator

[source file](https://github.com/PX4/PX4-Autopilot/blob/main/msg/FollowTargetEstimator.msg)

```c
uint64 timestamp                     # time since system start (microseconds)
uint64 last_filter_reset_timestamp   # time of last filter reset (microseconds)

bool valid              # True if estimator states are okay to be used
bool stale              # True if estimator stopped receiving follow_target messages for some time. The estimate can still be valid, though it might be inaccurate.

float64 lat_est         # Estimated target latitude
float64 lon_est         # Estimated target longitude
float32 alt_est         # Estimated target altitude

float32[3] pos_est      # Estimated target NED position (m)
float32[3] vel_est      # Estimated target NED velocity (m/s)
float32[3] acc_est      # Estimated target NED acceleration (m^2/s)

uint64 prediction_count
uint64 fusion_count

```


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