Hello,
Thank you for reaching out. Indeed, a vehicle must be able to accelerate by 7km/h + in one second in order for autocalibration process to succeed.
In your case, if it is not possible to accelerate fast enough, FM trackers have to be mounted appropriately. The idea is to match the Axes of the vehicle (which can be seen in image (1)) , with the axes of the FM trackers (images 2,3)) With autocalibration disabled, device will assume its' axes are perfectly aligned with the vehicles' axes.
1. Vehicle axes
2. FMC1XX orientation (applies to Your FMC130).
3.
FMC640 Orientation
Make sure that the tracker is secured properly and does not move/change orientation.
Best regards, Martynas