A Wireless Local-Area Network (WLAN) access point includes a WLAN transmitter, a WLAN receiver, and a processor. The WLAN transmitter is configured to transmit WLAN packets via one or more transmit antennas, and to send a timing-synchronization signal over an internal interface. The WLAN receiver is configured to receive, via one or more receive antennas, echo packets including reflections from an object of a selected subset of the WLAN packets transmitted by the WLAN transmitter, to receive the timing-synchronization signal from the WLAN transmitter over the internal interface, and to time-synchronize the echo packets and the corresponding WLAN packets using the timing-synchronization signal. The processor is configured to estimate one or more parameters of the object based on the time-synchronized echo packets and WLAN packets, and to output the estimated parameters to a user.