Get current speed and heading by GPS

[laiketa6]

Hello @riebl,

I've seen that in the function CamApplication::on_timer(Clock::time_point) inside cam_application.cpp, when the cam message is generated, the values of speed and heading are set to 0:

To get the current speed and heading correctly I've tried to set these variables in this way:

auto position = positioning_.position_fix();

bvc.heading.headingValue = position.course.value();
bvc.heading.headingConfidence = HeadingConfidence_equalOrWithinOneDegree;

bvc.speed.speedValue = position.speed.value();
bvc.speed.speedConfidence = SpeedConfidence_equalOrWithinOneCentimeterPerSec;

But in the generated cam, the heading and the speed are still 0.

Could you explain me how to get the current speed and heading correctly?

Thank you.

[riebl]

Have you built socktap with GPS support, i.e. is the CMake option SOCKTAP_WITH_GPSD set to ON? Otherwise, the static position provider is used, which is simply a fixed position without any speed or heading.

[laiketa6]

Hi @riebl ,

Yes, the flag SOCKTAP_WITH_GPSD is set to ON and I have te position (Latitude and longitude) correctly and is not the static one, but the heading and speed are 0.

[riebl]

Can you verify (e.g. by setting a breakpoint in your debugger) that the speed and course attributes are set to non-zero values at all, when the lines 124 and 125 are hit in gps_position_provider.cpp? Does the gps_data.fix structure contain non-zero speed and track values?

[laiketa6]

Hello @riebl,

Now I have the device fixed (with no movement). Setting a breakpoint in line 131 in gps_position_provider.cpp I have the following values:

• For the fetched_position_fix structure:

So, it seems apparently OK.

• For gps_data.fix structure:

It seems OK too.

But then, inside cam_application.cpp, although I have the correct position (image below), I have a zero in course (Teorically it is 198) and a zero in speed (In this case the speed is 0, but trying this with the device in movement still in zero) (Second image below).

[riebl]

I have trouble reproducing your issue. My position object at cam_application.cpp:80 shows a non-zero course.