An attempt is made by a portable device to wirelessly detect an object. While detected, respective sweeps are executed. At a sweep, each channel in a plurality of wireless channels, sequentially pulsed during the sweep by the object, are recorded using a receiver of the device, thereby obtaining a plurality of signal measurements for the sweep. Each measurement corresponds to a channel. The measurements are filtered against measurements for corresponding channels obtained from prior sweeps, thereby obtaining filtered signal measurements for the sweep. Signal measurements that satisfy an outlier criterion are eliminated from the sweep. A measure of central tendency of the remaining filtered signal measurements is converted to a distance between the object and the device for the respective sweep using a path loss function. This is repeated for each sweep thereby determining a plurality of distances. The sweeps are aborted when the device fails to detect the object.