The BlackHawk GPS tracker has three LED's on the front of the device. Below is an explanation of what each of these lights means.

The GPS light shows when the BlackHawk is attempting to acquire a location from the GPS satellites. It will blink rapidly while acquiring a location. Once a location is acquired the light will turn solid for approximately 5 seconds. The light sequence will repeat depending on the location interval set.
PowerThe power light will blink when the BlackHawk battery is low, when the battery is being charged, and during power on/off. While charging, when the power light turns solid the BlackHawk is fully charged.
CellularThe cellular light shows whether or not the BlackHawk has a cellular connection. When the green light is blinking approximately every 3 seconds the BlackHawk has a good connection on the cellular network. When the cellular light is blinking faster, about every second, the BlackHawk does not have a connection to the cellular network.