Force output sampling rate

[foo_fighter]

Hi Harry,

Is there a way to force the output log sampling rate? I'm using a QStarz 818Xt set to 5Hz(with DGPS on) and OBDLink LX(Reads 8Hz, 50-60 PID/s). When I look at the csv log, it's outputting at just over 4Hz. Time stamps are 0 0.2 0.6 0.8. It frequently skips one of the samples but not always so the sampling is not uniform. Is there a way to force output at a 10 Hz rate?(With interpolation if samples are missing). I'd like to get a higher a sampling rate for RPM/throttle, g forces(which is internally sampled at 30Hz?) even if GPS is only 5Hz. Phone is galaxy nexus(not sure if the cpu is a limiting factor)

Thanks.

[Harry]

OBD and acceleration are always collected at full update rate but finally interpolated to and stored at the GPS's rate. Although this creates some loss of data for your configuration (8 Hz are interpolated to 5 Hz), this should not create any "not uniform" development. No way to change this behavior currently. Please check your GPS compression setting, it should be "None".

- Harry

[foo_fighter]

Thanks for the clarification,

Here are the actual time stamps of the csv entries. Is there a reason why some entries are being skipped? In other words, there should be an entry every 0.2 seconds for a 5Hz sampling rate, but there are frequently entries 0.4 seconds apart, where there was probably perfectly valid data for OBD or Accel. There are enough missed entries that the average sampling rate of the output is 4.24Hz.

Why not up sample to the higher reading rate instead of downsample to the lower resolution?

I could try switching the 818XT to 10Hz to see if it makes a difference.

7479 4 29-May-14 18:45.0 1165.8
7480 4 29-May-14 18:45.4 1166.2
7481 4 29-May-14 18:45.6 1166.4
7482 4 29-May-14 18:45.8 1166.6
7483 4 29-May-14 18:46.0 1166.8
7484 4 29-May-14 18:46.4 1167.2
7485 4 29-May-14 18:46.6 1167.4
7486 4 29-May-14 18:46.8 1167.6
7487 4 29-May-14 18:47.0 1167.8
7488 4 29-May-14 18:47.2 1168
7489 4 29-May-14 18:47.4 1168.2
7490 4 29-May-14 18:47.6 1168.4
7491 4 29-May-14 18:47.8 1168.6
7492 4 29-May-14 18:48.0 1168.8
7493 4 29-May-14 18:48.4 1169.2
7494 4 29-May-14 18:48.6 1169.4
7495 4 29-May-14 18:48.8 1169.6
7496 4 29-May-14 18:49.0 1169.8
7497 4 29-May-14 18:49.2 1170
7498 4 29-May-14 18:49.4 1170.2
7499 4 29-May-14 18:49.8 1170.6
7500 4 29-May-14 18:50.0 1170.8
7501 4 29-May-14 18:50.4 1171.2
7502 4 29-May-14 18:50.6 1171.4
7503 4 29-May-14 18:50.8 1171.6
7504 4 29-May-14 18:51.0 1171.8

[Harry]

In case a certain time stamp is missing, it is either not delivered by the QStarz (e.g. due to BT bandwidth limitations, or problems with the overall system load), or it is compressed (removed) by LapTimer. For the later I suggested to check the compression setting in LapTimer.

- Harry