Determine GPS Delay

ArduCopter Copter 3.6
1

Hi all,

if we are using a GPS receiver we will have some delay until the position data arrives at the Pixhawk. This is compensated by GPS_DELAY_MS and EK2_GPS_DELAY. I was now wondering how to determine the delay of a GPS receiver and what exactly the difference between the two parameters is.
Anyone an idea/explanation?

Thanks,
Fabian

2

Per http://ardupilot.org/copter/docs/parameters.html?highlight=autotune#gps-delay-ms-gps-delay-in-milliseconds:
“Controls the amount of GPS measurement delay that the autopilot compensates for. Set to zero to use the default delay for the detected GPS type.”
So unless you experience issues, no need to change the default value (0), since it will automatically use the correct delay for your GPS.

EK2_GPS_DELAY isn’t in the docs anymore, so I guess it has been deprecated at some point.

Cheers

3

Thanks @Oli1 for your reply.
I’ve seen the description in the documentation and Mission Planner says “This is the number of msec that the GPS measurements lag behind the inertial measurements.” for EK2_GPS_DELAY. I think it is rather a new parameter than an old one. But I still have no idea what the difference is. Or maybe they both do the same?

1 Like
4

All sensors used in the EKF fusion experience this type of delay. Do you guys know how to find the delay for each sensor? For example, the airspeed uses 240ms, and the magnetometer uses 60ms. The height however, is able to receive an external parameter to this variable. How do we find this delay for the most varied sensors, any ideia?

thanks!