Radio spectrum monitoring - Interception, reception and detection

Communications have become essential, both in the civilian sphere (the political, economic and social functioning of our society, which is increasingly based on the transmission of information between individuals, economic players, managers and regulatory bodies), and in the military sphere (the conduct of forces and control of the theater of operations). Whether for :

• regulate spectrum use ;

• check that regulations are properly applied ;

• validate the correct operation of an installed network ;

• monitor a battlefield.

The essential prerequisite for the implementation of any radiomonitoring functionality is the interception of radio signals and their reception for immediate or delayed analysis, depending on the application and the complexity of the radio environment. To achieve this, the interceptors, receivers and detectors used in radiomonitoring are based on technical principles similar to those of radio communication systems. However, when they are designed for general use, frequency coverage and target signal ranges are greatly increased.

In the civilian sector, the signals to be processed by radiomonitoring do not generally have any particular stealth properties. Interception and reception therefore tend to focus on the quality of filtering of the carriers received, under conditions that are generally favorable to the production of precise technical measurements, to the detriment of scanning speed and rapidity (operations may be carried out in delayed time).

In the military field, warning and self-protection modes based on radiosurveillance of communications require fast scan modes and instantaneous broadband filters, to increase the probability of detection of versatile and stealthy signals (especially frequency hopping signals). Electromagnetic intelligence can use both fast scan acquisition modes to optimize the probability of interception, and slow scan acquisition modes with long recording times, to optimize the conditions for implementing downstream detection and analysis processing. In all military applications, the radioelectric complexity of theaters of operation (tacticality of carriers limiting the size and height of aircraft, the weight, volume and power consumption of receivers) and the difficulties of capturing signals (frequent distance from target transmitters, boiling, etc.) greatly increase performance requirements compared with the civilian context:

• improved reception sensitivity and selectivity ;

• higher instantaneous bandwidth ;

• parallelization...