Very accurate. Guarnic zeros in with a precision between 5 and15 meters. The product is designed in a way that it does not publish any imprecise locations. If it is not possible to register the position with sufficient accuracy, a real time alert will be generated, indicating that the cellphone is not able to obtain an acceptable position, as opposed to sending a position that is not accurate. Thus, every position report includes for each point the accuracy in meters, making it clear what the margin of error is.