This is a technical chart indicating the tracking status of the Timing Model for each device. In ToA systems it is essential to be able to determine the clock offset for each device in order to separate initial arbitrary clock offsets from the offset introduced by the propagation of the radio signal between transmitter and receiver.

In this chart the status of clock tracking is shown for each device on the selected list. When the device trace is at the top of the chart it indicates good tracking status; at the bottom of the chart indicates no tracking (and therefore positioning not possible). Rising lines indicates that timing is good and lock is being acquired; falling lines indicate that device measurements are faulty and lock is being lost.

The legend on the right shows the mapping between colours and devices. Each device on the list is assigned a different colour, but it is difficult to distinguish between more than about 20 colours. However, the devices are placed in micro-lanes (so they don't draw on top of one another) and these lanes correspond in order to the order in the legend, allowing large numbers of devices to be distinguished.

Lack of tracking lock usually indicates that adequate device measurements are not being received. This may be because the device is out of range, or it may be that radio interference is preventing proper operation. In rare cases it can indicate hardware failure of the device.