Agilent Technologies recently introduced an integrated real-time radio frequency (RF) emitter geolocation technique using a network of RF Sensors. The Geolocation server software estimates position of a non-cooperative intermittent or short-duration RF signal using measurements from the sensor network and calculations with time-difference-of-arrival (TDOA) techniques.
"Traditional direction-finding systems are ideal for obtaining the line of bearing on higher power and narrowband signals. However, modern signals with complex modulations, wider bandwidths and short durations are driving a need for complementary geolocation techniques such as TDOA," said Tom Burrell, vice president and general manager of Agilent's Signal Networks Division. "Tightly synchronized receivers provide the foundation for transmitter geolocation techniques in commercial, radio regulatory, security and defense applications."
The geolocation system can be operated manually by the user or "tipped" automatically from a signal search/monitoring system. Then, three to five sensors at separate locations provide precisely time-stamped spectrum data to the server software. The software's visual displays show two-dimensional signal correlation and propagation characteristics in addition to the estimated position. Raster maps in most standard formats, e.g., jpg, gif, tiff and geotiff, can be imported and combined with the estimated position from the geolocation software.
The Agilent N6854A depends on low-cost receivers for accurate and timely geolocation of emitters. The small low-profile form factor receiver - about the size of a laptop PC - offers many discreet deployment and mounting options including pole-top or wall-mount. Co-locating the sensor with the antenna reduces antenna size and complexity plus helps to minimize signal loss due to coaxial cable attenuation. Announced on April 1, the N6841A RF Sensor monitors signals over a frequency range of 20 MHz to 6 GHz using a 14-bit ADC to accurately digitize signals with a 20 MHz information bandwidth. The network interface allows the sensors to be distributed within a building, throughout a city or across the world.