1. A method of estimating error in distance measurements, the method comprising: learning a function based on features representing aspects of a waveform transmitted between training wireless devices and a true distance between the training wireless devices; estimating error in a distance measurement by evaluating the function for a feature vector extracted from a waveform received at a first wireless device from a second wireless device to determine an estimate of distance estimation error or a distribution of distance estimation error of a distance estimate between the first and second wireless devices; and reporting the estimate of distance estimation error or the distribution of the distance estimation error to a module making use of the estimate of distance estimation error or the distribution of the distance estimation error.