Products

The FM Tag is a system for providing an approximate trace of where an object has been by recording publicly available FM radio transmission signals and then using unique characteristics of the recordings to determine location. The system consists of a special low-power FM-receiver (the tag) designed for recording both digital and analog information from any standard FM radio broadcasting signal instead of the sound signals and a set of software correlation algorithms using a combination of publicly available and privately generated FM broadcast signal-characteristic databases to identify the probable location of a recording.

Background

Recent advances in RFID and GPS technologies have emerged in response to the need for improved security, item inventory and location tracking. While these technologies provide accurate location and item tracking information, they present many drawbacks both from a technical and privacy point of view. RFID tags, for example, require an elaborate system of expensive proprietary recording devices placed at strategic locations in order to identify when the tag has been in close proximity to the receiver. Although useful for actively tracking inventory items, the RFID system cannot scale easily. In addition, to get some range, the tag must b active.  GPS, which uses a set of publicly available Earth orbit satellites that transmit precise radio signals for determining location, speed and direction, is far more scaleable but is similarly limited by its requirement for a clear line of sight to the satellites, or reflection from nearby objects. In addition, GPS receivers have traditionally been costly to build and to power. Both technologies have raised concerns amongst governments and privacy advocates because of the high-resolution of the location information generated.

The Alternative

The FM-Tag system provides a highly available, low cost and low privacy-risk alternative using publicly available ubiquitous FM radio broadcasting signals. Due to the nature of FM radio signals, reception of the signal is possible in most urban locations and the development of the hardware circuit is relatively inexpensive and simple. By modifying the radio to only record very specific radio signal attributes at precise intervals, the receiver can be configured to be extremely low-powered. So low power, that it could be permanently place as a body implant for animal and human and powered by a thermocouple. A key aspect of the invention is that the correlation algorithm, which uses a combination of radio spectrum signatures (or fingerprints) and RDS (digital station information which is broadcast by many stations), can only provide location information to a resolution of 10 to 20 km. This avoids many privacy concerns while still providing important city-level location information for uses in both security and commercial market spaces. The location correlation algorithm is not a simple table lookup but is instead a predictive algorithm which relies on a combination of “last known reference points”, time, FM spectrum (radio stations both present and absent), RDS program identification information and pre-recorded RDS information as well as publicly available county-specific FM broadcasting databases to calculate the approximate location. The invention includes software that converts location points to standard latitude and longitude coordinates in formats compatible with standard mapping tools such as Google Earth and others so that the location history can be traced on a map for easy visualization.