Translate the following sentences from English into Russian:

1) Crucially, the mismatches did not statistically correlate with either locational or orientational information.

2) They can also create an energy penalty through heat loss in cold weather.

3) In adverse weather conditions, ice and snow clearing equipment can be used to improve traction on the landing strip.

4) Since 1775, weapons have become more lethal, and with increased lethality has come an increase in both the number of casualties and the severity of wounds.

5) The range of conventional radar, the kind you see at airports with its rotating dish, is limited to direct line of sight.

6) Airborne and shipborne radar was significant in spotting surfaced submarines.

7) Another consideration, not mentioned by Mr. Forbes, may be added.

 

Match the phrases 1-5 with the same or similar meaning a-e

1. conspicuous	a) unfavourable
2. to mismatch	b) raised
3. adverse	c) blocking
4. elevated	d) obvious or clearly noticeable
5. obstruction	e) to differ from something

7. Work in groups. Brainstorm everyday applications which use radars. Choose one that interests you. Prepare a short presentation, showing how a radar works in application. Present your group ideas to the class.

8. Watch the video: How Does a Radar Work? Discuss in pairs the most specific features of radar and answer the questions.

1. How can a radar determine the distance to the target?
2. Give the example how the Doppler effect works with a radar.
3. Do you think it is easy to synchronize a radar`s transmitter and receiver?
4. What is “propagation loss”? How to fight it?
5. Why is the HF band so useful for a long-range radar?
6. What is the function of the automotive radar?

 

Write down a short description of how a radar works.

Look through the texts and decide if these statements are TRUE or FALSE.

1. Agile radars never change their frequency.

2. Modern PESA radars can hardly change their parameters during operation.

3. The RWRs radars can easily fight the AESA ones.

4. The possibility of detection will be small if you use pulse compression.

5. The use of minimal side and back lobes emission in a radar construction will be of no use at all.

6. Modern phased-array radars do no control their side lobes.

7. The reduction of the radar side and back lobes will give the radar some opportunities.

Agile radars

Agile radars like AESA (or PESA) can change their frequency with every pulse (except when using doppler filtering), and generally do so using a random sequence, integrating over time does not help pull the signal out of the background noise. Moreover, a radar may be designed to extend the duration of the pulse and lower its peak power. An AESA or modern PESA will often have the capability to alter these parameters during operation. This makes no difference to the total energy reflected by the target but makes the detection of the pulse by an RWR system less likely. Nor does the AESA have any sort of fixed pulse repetition frequency, which can also be varied and thus hide any periodic brightening across the entire spectrum. Older generation RWRs are essentially useless against AESA radars, which is why AESA's are also known as "low probability of intercept radars". Modern RWRs must be made highly sensitive (small angles and bandwidths for individual antennas, low transmission loss and noise) and add successive pulses through time-frequency processing to achieve useful detection rates.

Methods

Ways of reducing the profile of a radar include using wider bandwidth (wideband, Ultra-wideband), frequency hopping, using FMCW, and using only the minimum power required for the task. Using pulse compression also reduces the probability of detection, since the peak transmitted power is lower while the range and resolution is the same.

Constructing a radar so as to emit minimal side and back lobes may also reduce the probability of interception when it is not pointing at the radar warning receiver. However, when the radar is sweeping a large volume of space for targets, it is likely that the main lobe will repeatedly be pointing at the RWR. Modern phased-array radars not only control their side lobes, they also use very thin, fast-moving beams of energy in complicated search patterns. This technique may be enough to confuse the RWR so it does not recognize the radar as a threat, even if the signal itself is detected.

In addition to stealth considerations, reducing side and back lobes is desirable as it makes the radar more difficult to characterise. This can increase the difficulty in determining which type it is (concealing information about the carrying platform) and make it much harder to jam.

Systems that feature LPIR include modern active electronically scanned array (AESA) radars such as that on the F/A-18E/F Super Hornet and the passive electronically scanned array (PESA) on the S-300PMU-2 missile.

 

Word list

mismatches in speed - несоответствие в скоростях

directed energy weapon - оружие направленной энергии

energy penalty - увеличенный расход энергии

engagement range - дальность стрельбы

adverse weather conditions - неблагоприятные погодные условия

to reduce the lethality - снизить поражающее действие (убойную силу)

line of sight - зона прямой видимости

shipborne radar - корабельная радиолокационная станция

on elevated terrain - на возвышенной местности

conspicuous - [kənˈspɪkjʊəs] заметный, бросающийся в глаза, видный

another consideration - помимо этого, следует учитывать

obstruction zone - зона помех

cross - section reduction - снижение эффективной пощади отражения

bandwidth - ширина полосы пропускания, ширина спектра (сигнала)

agile radar [ˈædʒaɪl]- радар с быстрой настройкой частоты

AESA (active electronically scanned array) - антенна с активной фазированной решёткой

RWR (radar warning receiver) приемник радиолокационного облучения

side lobe - боковой лепесток направленности антенны

back lobe - задний лепесток диаграммы направленности антенны

UNIT 3