Direct Position Determination: A Single-Step Emitter Localization Approach

Direct position determination (DPD) is a promising approach that yields superior results in difficult conditions such as low signal-to-noise ratio (SNR), model errors, and NLOS. It requires good synchronization between base stations, both in frequency and time, which can be easily achieved by exploiting the global positioning system (GPS). It also requires the transfer of raw data between stations and therefore larger communication bandwidth. Apart from DPD, emitter localization attracts significant interest in the signal processing, radar, sonar, bioengineering, seismology, and astronomy literature. Emitter location techniques are currently used for many purposes, such as emergency cellular phone location, radio spectrum monitoring, medical imaging, law enforcement (and law breaking), fraud detection, and homeland security. The localization process is based on the exchange of signals between the emitter and a number of reference stations. There are mainly two types of positioning situations: self-positioning, where emitter position is determined based on the transmitted signals from the stations, and remote positioning, where the system determines emitter position.