Radar jamming protection--technical solutions.

Grzan, Marijan ; Covo, Petar ; Belak, Branko 等

Abstract: Radar protection from intentional jamming is a contradictory task that is difficult to solve in practice. Namely, if a radar is to carry out its task, it should emit an electromagnetic energy. Such an emission offers to enemy excellent conditions for the reception, analysis, selecting, as well as necessary time to take countermeasures. Consequently, radar electronic protection from jamming involves a group of well calculated measures and procedures that are to be carried out with consistency and on all the radar control levels in order to fully utilize the jammed radar.

Key words: selective jamming, radar jammer, jamming modes, radar protection

1. INTRODUCTION

Electronic protective measures should be carried out in all radar development and usage stages.

Stages through which the activities are carried out are included in:

* radar development stage: by selection of such a radar design concept that will, to the highest extent, disable the existing and known modes of jamming, and force the opponent to take its radar countermeasures with highly sophisticated units;

* radar usage stage: by applying such measures and procedures to leave the opponent only the remotest possibilities for its countermeasures;

* radar operator training course: by applying and performing the training that will train the operator to adopt the methods of interference identification and protective measures undertaking.

2. ELECTRONIC WARFARE STRUCTURE

Electronic combat includes a group of measures and procedures taken for electronic surveillance, electronic jamming and deception of enemy's systems and provision of electronic protection of own electronic systems, equipment and facilities. Electronic combat is planned, organized and carried out from land, sea, air and space. Electronic combat is divided into four main divisions:

* Electronic surveillance involves data gathering on electronic units and systems that radiate electromagnetic energy. Electronic surveillance is always a passive activity.

* Electronic countermeasures include procedures taken to deceive and impede-disable normal functioning of enemy's electronic devices and systems.

* Electronic protection includes organizational, operative, tactical and technical measures and procedures aimed at the protection of own electronic devices and systems.

* Electronic attacks are aimed at the destroying of enemy's devices and systems.

In addition to the above division, another electronic warfare division is in application in Europe. This division involves tactical and technical division against the Figure 1.

[FIGURE 1 OMITTED]

The division against the above structure is included in:

* SIGINT (Signal Intelligence), is intelligence-gathering by a signal interception and processing in the spectrum analyzer and allocation of the signal to the device type and equipment complement of platform.

* ESM (Electronic Support Measures), electronic support measures taken to detect, intercept, identify, locate, record and/or analyze sources of radiated electromagnetic energy for the purpose of an immediate threat recognition to own equipment.

* ECM (Electronics Counter-measures), is a set of electronic countermeasures taken to protect own systems from intentional interferences.

* ECCM (Electronics Counter-Countermeasures), is a part of electronic warfare that includes a variety of practices attempting to reduce or eliminate the effect of electronic countermeasures (ECM) on electronic sensors aboard vehicles, ships and aircrafts. ECCM is also known as electronic protective measures (EPM).

[FIGURE 2 OMITTED]

All the world armies that incorporate forces capable of making electronic warfare define the organizational structure against the Figure 2..

3. EFFECTS ACHIEVED BY RADAR COUNTERMEASURES

According to the effects achieved, intentional radar countermeasures can he divided as follows:

Countermeasures with masking effects--by an active or a passive mode certain parts of a radar display are covered so to cover--mask real targets.

Countermeasures with confusing effects--causing an effect on a radar display that is quite similar to the symptoms causing a device failure. The aim is to make an impression of device failure with the radar operator.

Countermeasures with imitating effects--generation of false reflexes close to real ones, with the same electrical characteristics to direct attention and measures towards false reflexes.

Change of target coordinates--generation of false reflexes with a successive change of coordinates towards the other side

Change of radar reflex surface of a target--by certain coatings or passive reflectors radar reflex surface of a target or environment can be increased or decreased.

4. RADAR POWER VS. JAMMER POWER

When transmitting radar power is concerned, then the following conclusions can be drawn. It is more favorable that this power is as great as possible in case of a jammer type responding to the radar-victim pulses. In case of high power radars (MW or KW), the levels of signals of main, side and back fans of the radiation diagram at satisfactory distance are high enough to overcome the threshold of detectability necessary to trigger the jammer transmitter.

In case of low power radars (the threshold of detectability is lower due to lower level of a reflected signal) signal level is not often enough high to induce the triggering of the jammer transmitter. According to Fig. 4.3 in the section dealing with the jamming analysis, there will be s situation when an object with the low power radar will observe the target with the jammer (on the radar display) before the detector system provides the signal level high enough to initiate the jamming cycle. At the end, we can conclude that the distance between the length of the crossing and BURN-TROUGH (distance at which the jammer efficiency ceases while the radar becomes effective) range is a variable that can often, in turn, adversely affect the target with a responder jammer.

[FIGURE 3 OMITTED]

5. RADAR JAMMING PROTECTION--TECHNICAL SOLUTIONS

Radar protection from jamming contains two main components:

Technical solutions linked to the very radar structure and built-in units for the protection from intentional and unintentional interferences when radar types, sorts and end-use areas are defined;

Operative solutions linked to tactical-operative measures taken during radar use and in the course of radar lifetime.

6. CONCLUSION

Awareness of the existence of an intentional interference in any form is of great importance, and should enable a radar operator to successfully handle the radar even under such circumstances. A part of awareness is in the fact that in the course of radar designing and usage we are to apply new technical and tactical solutions of electronic protection that will enable the collection of relevant and precise information from the radar. The measures to be taken have to be based on suitably dimensioned and designed radars, as well as on a well-trained and quality radar operator instructed to apply the best and timely measures. This will provide precise and valid data even in case of an intentional interference.

7. REFERENCES

Leroy B. Van Brunt (2001). Applied ECM ..., Library of Congress Catalog USA

Schslezinger R. (1999). Principles of Electronic Warfare ..., Peninsula Publishing USA

Grzan M. (1992). Selective radar jamming ..., Master's Thesis ETF Zagreb

Skolnik M. (2008) Radar Handbook, Third Edition

Barton D. (2004) Radar System Analysis And Modeling, Artech House Radar Library

Tab. 1. Electronic Protection Technical Solution

 The most dangerous types of
 interference

 destructive

 noise interference

Technical solutions to protect Cw Selective Bandwidth
protect radars from modulated
interference

 Frequency
Transmitter agility x x

 Visited
 diversification x x

 Change output x

 Pulse
 compression

 Short pulses

Antenna Conical scan

 Passive work

 Monoimpuls
 radar

 Phase antenna

 Suppress the
 lateral beams x x

Receiver/ Frequency
Processor selector x x

 Dicke-fix x x

 ARP x

 MTI

 TARP x x

 Maintaining a
 constant level x x

 Pulse-width
 discriminator x

 Strob distance

 Memory strobe
 distance

 Manual tracking

Others Passive
 monitoring x x x

 Multisenzors
 Systems x x

 Antiradar
 rockets x x x

 Transmitters
 baits x x

 Level of
 training x x x

 Radar's silence x x x

 The most dangerous types of
 interference

 radar deception

 noise interference

 With the
Technical solutions to Overwrite change of Imitacion
protect radars from amplitude
interference

 Frequency
Transmitter agility x x x

 Visited
 diversification x x

 Change output

 Pulse
 compression x

 Short pulses

Antenna Conical scan

 Passive work

 Monoimpuls
 radar

 Phase antenna

 Suppress the
 lateral beams x x

Receiver/ Frequency
Processor selector x

 Dicke-fix x

 ARP

 MTI

 TARP x

 Maintaining a
 constant level x

 Pulse-width
 discriminator x

 Strob distance

 Memory strobe
 distance

 Manual tracking

Others Passive
 monitoring x x

 Multisenzors
 Systems x x x

 Antiradar
 rockets x

 Transmitters
 baits

 Level of
 training x x x

 Radar's silence x x x

 The most dangerous types of
 interference

 radar deception

 noise interference

Technical solutions to Door Gate Direction
protect radars from distance speed
interference

 Frequency
Transmitter agility

 Visited
 diversification

 Change output

 Pulse
 compression

 Short pulses

Antenna Conical scan x

 Passive work x

 Monoimpuls
 radar x

 Phase antenna x

 Suppress the
 lateral beams

Receiver/ Frequency
Processor selector

 Dicke-fix

 ARP

 MTI x

 TARP

 Maintaining a
 constant level

 Pulse-width
 discriminator

 Strob distance x x

 Memory strobe
 distance x x

 Manual tracking x x x

Others Passive
 monitoring

 Multisenzors
 Systems x x x

 Antiradar
 rockets

 Transmitters
 baits

 Level of
 training x x x

 Radar's silence

 The most dangerous types
 of interference

 Anti
Technical solutions to Chaff radar
protect radars from missiles
interference

 Frequency
Transmitter agility x

 Visited
 diversification x

 Change output

 Pulse
 compression x

 Short pulses x

Antenna Conical scan

 Passive work

 Monoimpuls
 radar

 Phase antenna

 Suppress the
 lateral beams

Receiver/ Frequency
Processor selector

 Dicke-fix

 ARP x

 MTI x

 TARP x

 Maintaining a
 constant level

 Pulse-width
 discriminator

 Strob distance x

 Memory strobe
 distance x

 Manual tracking x

Others Passive
 monitoring

 Multisenzors
 Systems x

 Antiradar
 rockets

 Transmitters
 baits

 Level of
 training x x

 Radar's silence