IMU, GPS, RTK?

nes9966

Hello.  I have purchased the MID40.  I inderstand this unit does not have a built-in IMU, so IMU information must be provided?
With the driver instructions there is GPS connection details.  
Here is my question - IMU, GPS and the new RTK are different techs and provide different information and levels of accuracy.
Which is actually needed?  Which would be best?

Livox Support

GPS and IMU have their own strengths. GPS is a component with relatively accurate measurement, but the update frequency is low, about 10Hz, and it is updated ten times per second. The IMU happens to have a high frequency, but the IMU has errors, and this error will accumulate over time, so we can only use the IMU in a very short time interval. This is how GPS and IMU complement each other. The GPS update is slow, so in a very short period of time, the vehicles we rely on the IMU have data; and the IMU has time accumulation errors, so we can rely on the GPS readings to give the IMU errors to " pull" back. Compared with GPS signals, RTK positioning results become more accurate.