GPS_update function

[Rouhi (Rouhollah)]

I have a question regarding the update_GPS function in sensor.cpp file under AntenaTracker package.

In the beginning of this function there is an if condition:
if (gps.last_message_time_ms() != last_gps_msg_ms &&
gps.status() >= AP_GPS::GPS_OK_FIX_3D)

I was wondering what is the condition that are being checked in this if statement?

I’m a bit new to the ArduPilot packages, my apology if the question is naive.

[iampete (Peter Hall)]

@Rouhi

(gps.last_message_time_ms() != last_gps_msg_ms

check to see if there is a new message that we have not already read

@Rouhi

gps.status() >= AP_GPS::GPS_OK_FIX_3D

checks that the gps fix is at least 3d

[Rouhi (Rouhollah)]

Thanks Peter for the prompt reply. What does the latter one mean? what is GPS fix? and what does it mean to be 3d for the gps status?