a relative positioning system enabling a user to return to a starting position or some other point on the user &# 39 ; s path . the system may include an array of accelerometers . the output from the accelerometers may be integrated to quantify movement of the array . the various movements of the array may be reconstructed to determine a net two or three dimensional translation . the current location of the array may be compared to a reference point to derive at trajectory directing the user to the reference point , such as an originating point . the trajectory may be continuously or periodically updated . applications may include various displays presenting images , numbers , pointers , paths , vectors , or data by digital screens , watch faces , or other devices integrated with or remote from the processor calculating the vector back to the point of origin .