Wideband digital ELINT / COMINT / SIGINT receiver for network based applications

Patria

Category: Digital Transmitters / Receivers | 10/04/2008 - 15:07:56

Only wideband receivers give real-time and precise situational awareness and electronic order of battle. By connecting wideband receivers into a sensor network location of adversary's radar and communication transmitters can be precisely obtained in real time. Patria has developed a reprogrammable wideband digital receiver to meet the requirements set by the most modern wideband LPI / LPD and time-sensitive threats. The receiver is software based in such a way that it can be easily reprogrammed for different networked applications.

Modern Waveforms and Dense Signal Environment

Traditional receivers are not enough Today, military and security operations are above all network centric operations. Real-time data and voice communications are transferred wirelessly between commanders, soldiers and higher echelon units. Radar sensors are used for battlefield (air, sea and ground) surveillance as they can provide very accurate targeting information and all-weather capability. Even insurgents have these kinds of capabilities by using civil infrastructure.

Radio frequency (RF) signals are increasingly used in modern battlefield so it is mandatory to secure own forces capabilities to use the spectrum. To gain information superiority and to dominate the electro-magnetic spectrum one must have efficient means to conduct electronic intelligence both in strategic and tactical level. In fact, tactical relevance of electronic intelligence has become more and more important over time in order to decrease sensor-to-shooter time cycle.

Today's threats are using very sophisticated wideband spread spectrum signals. Modern radars can change waveforms adaptively which makes interception and classification of radar signals very demanding. Communication systems are using LPI / LPD spread spectrum waveforms by default. With currently used receivers having instantaneous bandwidth of only few tens of megahertz, detection of modern radar signals can be even impossible. Additionally, huge number of radio transmitters and RF sensors have made signal environment very dense. High power signals efficiently masks LPI / LPD signals that may be of greatest interest.

Wideband digital receiver is the solution

Wideband software based digital intelligence receivers are needed in order to cope with modern radar and communication signals. Patria is very active in the field of electronic warfare and digital receivers. Related topics are investigated for several years resulting e.g. numerous thesis and conference papers presented in international radar conferences. As a result of research and development Patria has introduced a reprogrammable digital ELINT receiver that is the answer to today's demanding requirements.

It has a real-time capability to search, intercept, monitor and analyze the whole variety of the most modern signals. Signals can be searched and intercepted from the full radar band. Signals up to 500 MHz bandwidth can be monitored and analyzed in real-time. Signals can also be recorded for offline analysis.

Wideband real-time digital signal processing enables intercepting and analyzing LPI emitters such as fast frequency sweepers, frequency hoppers and spread spectrum transmitters. In order to improve sensitivity to LPI signals, band rejection filtering can be done already in the front end. It allows masking of interfering and non-important signals before digitisation thus making it possible to use maximum amount of dynamics for the interesting signals.

Patria's ELINT receiver's network-based user interface functions include intelligent signal search controlling with multiple spectrum displays, a real time spectrum display with sophisticated single signal detection capability, spectrum mask triggering, short time and long time waterfall displays, emitter discrimination, triggering oscilloscope displays, as well as signal de-modulation and measurement functions.

The digital receiver can be fully used and controlled over network. With networked receivers threats can be accurately positioned and their signals analysed in a timely manner. Signal analysis provided by digital receiver gives information about used radar mode and can help precise identification of even individual transmitters.

Digital Wideband Graph

Fig 1: Picture obtained with a digital wideband receiver. Three simultaneous radarsignals in adjacent channels (two pulse signals and one CW signal). Traditional wideband receiver would show only the strongest signal and sweeping receiver would show only one signal at the time.

The modular and scalable system consists of a receiver platform with advanced and real time signal processing capabilities. Any external antenna and wideband ELINT tuner can be utilized to provide the input signal for the IF sampling receiver. Thus, existing expensive RF front-ends can be utilized and a high-performance ELINT system built in a cost-effective way.

Digital ELINT Receiver

Fig 2. Patria's reprogrammable digital ELINT receiver is modular and scalable system that can be connected to any external antenna and existing wideband tuner.

Patria's digital receiver is designed for radar signal ELINT. However, its high performance signal processing functions are easily customizable and it can be easily used in COMINT applications by introducing e.g. de-modulation functions.

Introducing similar concepts to those of software defined radios and the ability to reprogram the receiver quickly have been key driving forces of the project. Effective way to reprogram the system is an essential feature in the race of countering new LPI/LPD methods introduced in tomorrow's radars and communications equipment.