Critical Wireless Communications and
Weather Information Systems



Direction Finding Systems

WD-3300 Direction Finding System

direction finding system: flexible, transportable, and deployable.The WD-3300 system satisfies the need for a flexible, transportable, affordable and easily deployable direction finding system. It is a ruggedized transportable DF system comprised of fully integrated receivers, battery, charging unit and control circuitry in a compact sturdy carrying case, ready for quick and easy deployment anywhere, with or without external power sources with a high contrast display and standard laptop computer facilities which can be also used simultaneously for other applications. The unit contains one or more WiNRADiO card receivers which are available up to a very wide frequency range of 20 MHz to 1.8 GHz (receiver range can be extended to 3.5 GHz with option).

For maximum operator convenience, the bearings are indicated in numerical format, both as instantaneous and averaged values.

The circular azimuth display, with a freely adjustable North reference, has an additional “polar mode”. This allows the user to assess the signal strength relative to the trace length. An adjustable trace decay time can assist with recognizing random reflections. The direction finding software performs statistical calculations and presents the results in several ways, making it possible to determine the signal direction even under the most difficult conditions.

The waterfall and histogram graphics give an instant overview of the signal bearing distribution over time, assisting in validating the quality of the signal azimuth indicators.

WD-6300 HF Direction Finding System

This is a system designed especially to provide accurate direction finding (DF) for HF signals. It has a frequency range of 500KHz to 40 MHz. It employs a sophisticated phase-coherent multi-channel interferometer-based method, combined with statistical signal processing, to deliver a cost-effective yet robust and accurate HF DF solution for government, military, and law enforcement applications that need to geo-locate HF emitters.

The system is small, lightweight and ruggedized, suited for deployment in stationary and portable situations. Each WD-6300 system comprises of three main parts: antenna array, three phase-coherent receiver channels, and associated processing computer.

The WD-6300 is a true none commutated system, ensuring excellent performance against short duration signals. The sensing antennas utilized are specially adapted AX-81SM active monopoles. The antenna array size can simply be varied according to the desired frequency range of the system, whereby the antennas are positioned in a “L”-shape configuration, which each leg being typically 5 meters in length for optimum coverage from 3 MHz to 30 MHz, and typically 10 meters for best coverage between 1 MHz to 15 MHz.

In addition to accurate azimuth measurements, the WD- 6300 system is also capable of measuring the elevation of an incoming signal. Providing the height of the reflecting ionospheric layer is known, it allows for an estimation of the target’s location, without having to revert to a traditional multi-sensor approach for the necessary triangulation.

The entire antenna array can be assembled by two people in less than 30 minutes, while the receivers and the processing computer system can be operated either stationary or mounted inside a suitable vehicle.

WD-9300 Hyperbolic Geolocation System

Most Direction Finding Systems rely on the so called “Wattson-Watt” technique or interferometry to determine the azimuth to the target emitter. These techniques are vulnerable to signal reflection off nearby obstacles or other environmental conditions. The state-of-the-art WiNRADiO TDOA V/UHF position fixing system overcomes these limitations by utilizing a highly sophisticated “Hyperbolic Position Finding” method, also known as “Time Difference Of Arrival” (TDOA) system, where the signal propagation delay time is analyzed as it is being received from spatially separated receiver positions, and computed against their exact location in combination with a high-precision time reference. This technique is very robust against environmental radio frequency reflection conditions, while at the same time enabling highly accurate and stable azimuth readings for pulsed signals, as well as phase and frequency modulated signals.

the heart of the TDOA PF system is the main processing station. It comprises a powerful industrial computer system with high-speed networking capabilities. The processor analyzes incoming data from at least two receiver stations, which are deployed at suitably placed positions.

Using more than three receiver systems is highly recommended, best is four or more radio receiver stations, as it will remove any ambiguity of the signal direction, increase the robustness against environmental reflection conditions, and increases the accuracy of azimuth readouts even further.

3656 Centerview Dr. Unit # 1
Chantilly, VA 20151, USA

Phone: (703) 263-9305
Fax: (703) 263-9308