Comprehensive estimation of EMC between radioelectronic facilities placed at objects and in local groups

Comprehensive estimation of EMC between radioelectronic facilities is made in accordance with GOST В 25838-83 “Electromagnetic compatibility between REF. Methods of comprehensive estimation of EMC between radioelectronic facilities placed at objects and in local groups”.

Input data required for estimation are entered in REFs performance characteristics database in accordance with №1 Form of the State Commission for Radio Frequencies (SCRF);

Main window of the software system

There are three variants of estimation:

• within local group;
• between local groups;
• between local group and outer REFs.

Estimation variants and modes describing relative locations and mutual interference influence between REF are set up in calculation scenarios stored in the database.

Estimation results are displayed, documented and stored in the database.

Scenario window of the software system

REF group configuration, REF areas of responsibility and antennas radiation directions are displayed on the digital map of “Integration” GIS System. Terrain relief profile along radio lines is obtained from a digital map.

 
REF areas of responsibility displayed on the digital map

In the course of estimating EMC between REFs the following parameters are estimated, displayed and documented:

1. Radio interference attenuation factor in case of spurious emission.
2. Radio interference attenuation factor in case of natural and artificial obstacles presence on the radio propagation path.
3. Radio interference attenuation factor in case the radio propagation path is close to the ground surface.
4. Radio interference attenuation factor in case of energy atmosphere absorption.
5. Radio interference attenuation factor in case of time shifting.
6. Radio interference attenuation factor in case the receiver antenna main beam is not directed to transmitter.
7. Radio interference attenuation factor due to different polarization.
8. Radio interference attenuation factor for receiver antenna-feeder device.
9. Radio interference attenuation factor due to propagation loss for object or local group REFs.
10. Radio interference attenuation factor due to propagation loss alongside an object surface.
11. Radio interference attenuation factor in case of geographical gaps.
12. Radio interference attenuation factor in case the transmitter antenna main lobe is not directed to receiver.
13. Power flux density produced by an interfering transmitter at the interfered receiver antenna location.
14. Radio interference attenuation factor in case of frequency separation.
15. Spurious channels radio interference attenuation.
16. Radio interference power at a receiver input.

The calculations are made automatically for the following 4 possible combinations variants of antennas radiation pattern coupling of interference sources and receivers:

• M-M (main lobe of interference source antenna - main lobe of interference receiver antenna)
• M-S (main lobe of interference source antenna – side lobe of interference receiver antenna);
• S-M (side lobe of interference receiver antenna - main lobe of interference source antenna);
• S-S (side lobe of interference source antenna - side lobe of interference receiver antenna).

Results of calculations

Manual input of antenna radiation pattern spatial positions is also possible.

In the course of estimating EMC the possible channels of interference influence on receivers are identified (main and side channels, group interference, blocking and intermodulation effects).

In addition, the software system has the following functions:

• Full account of possible operating frequencies combinations for estimating EMC between a pair of REFs;
• Estimating frequency-distance separation norms;
• Estimating maximum possible levels of out-of-band and spurious emissions for various type transmitters in accordance with GOST В 24918-81;
• Estimating allowable level of radiation at working places in accordance with GOST 12.1.006-84;
• Estimating radio frequency spectrum occupancy at REF locations.

The described software complex operation has been tested on several local groups of REFs.

This software complex is using special Operating System for Army Mobile Systems that is certified for special information processing.

This software complex was developed in С++ KDevelop programming environment.

REF database is developed with the use of Linter ВС 6.0 DBMS.