Chapter 1196 Chinese Aegis

Chapter 1196 Chinese Aegis

"maritime?"

Zhu Yongshun moved his head closer:

"To be deployed to an island?"

"That may require some special processing of some radar components..."

As he spoke, he thought about the various preparations needed to deploy high-precision electronic equipment in an island environment.

Ordinary land-based radars can be used directly at sea, but their performance and reliability will be greatly reduced.

In addition to the salt spray problem just mentioned, issues such as foundation stability, power supply capacity, and interference of water vapor on radar waves all need to be taken into consideration.

This is also why many equipment that appear to be the same on the surface also have a separate naval model.

However, before he could figure it out, he saw Li Jianqiang next to him shaking his head:

"I'm afraid... not on the island."

Zhu Yongshun blurted out without even thinking:

"If it's not on the island, could it be in ..."

He originally wanted to say, could it be on the water?

But he stopped talking halfway.

“Is it really on the sea?”

At this time, Li Jianqiang had already pulled out a map of the sea areas around Zhejiang Province from the computer next to him.

In fact, although there are many islands off the east coast of Zhejiang, there are only a few well-known ones where radars can be deployed and people can be stationed there for a long time.

Most of them can only be called "islands" from the perspective of maritime law, but in essence they are just reefs that are always exposed on the sea surface.

As for the location marked by Chang Haonan, it was surrounded by a vast ocean.

There is not even a reef...

"There really isn't any marked landmass."

Li Jianqiang shook his head:

"Moreover, not only is it not at that coordinate, but it is also not even within a radius of dozens or hundreds of kilometers..."

For a moment, the two men stared at the nautical chart on the computer screen in front of them, somewhat at a loss.

Although what Chang Haonan gave was just an example, they still need to make adjustments based on actual conditions.

But there is no land around, which means that the result after the adjustment will most likely still be on the water.

"It seems that the plan I just proposed is still difficult to implement..."

Zhu Yongshun couldn't help feeling a little discouraged.

However, Li Jianqiang's reaction was not so pessimistic:

"Actually... if you ask me, deploying radar at sea may not be impossible..."

"..."

There was silence for a few seconds.

Zhu Yongshun looked at the screen, then at the document on the table, and a solution suddenly popped up in his mind:

"You mean... let the AWACS go forward and act as the second transmitter to coordinate with the other shore-based radar positions?"

But after I finished speaking, I immediately felt that it was not appropriate:

"But the speed of the AWACS is too fast. If the mobile platform wants to synchronize with the fixed platform, it is technically difficult..."

"No no no..."

Before he could finish, Li Jianqiang quickly waved his hand:

"The technical problem is secondary. The key is that even if the current situation is unlikely to cause an accidental shooting, it is still a bit too reckless to send out early warning aircraft under the threat of stealth aircraft... Besides, the superiors plan to use the newly commissioned KJ-2000A as a backup measure, using L-band radar to prevent the opponent from really breaking through the air defense circle, leaving us no room for use." "So what I mean is that we can consider asking the comrades in the navy to contribute... Haven't the two Chinese Aegis built in Changxing basically completed the test and are scheduled to be officially commissioned before the end of July?"

This is completely explicit.

The ship-borne regional air defense system with the 346 radar as its core has an official name called "Star of the Sea", but because it is benchmarked against the US military's Aegis system, even within the military, some people prefer the nickname "Chinese Aegis".

Zhu Yongshun also understood Li Jianqiang's meaning instantly.

Destroyers are large enough and have their own air defense capabilities, so they face less threat than early warning aircraft.

Moreover, as a ship, it can also be deployed near a specific location for a relatively long time, just like ground radar, without having to seize the time window like early warning aircraft.

This is undoubtedly a huge benefit for the defender who needs to take advantage of his rest.

However, there are still some problems.

Zhu Yongshun suppressed his excitement and pointed out the difficulties ahead:

"Although the surface ship platform is relatively stable, it is not a completely fixed deployment mode. In addition, the 346 radar and the model we have on hand are inconsistent in many technical details. If we want to achieve transmission and reception coordination between the two, there is still a lot of work to be done next..."

Bistatic radars, especially those deployed on different platforms and using different types of hardware, first need to solve the synchronization problem between the transmitting and receiving ends in time, space and phase.

It is also one of the biggest obstacles to the large-scale application of this technology.

But Li Jianqiang was very optimistic at the moment:

"The 346 radar is a four-sided array that shares a backend control system. It has 360-degree omnidirectional detection and does not need to consider spatial synchronization issues from the beginning..."

He pulled over a piece of paper and drew a simple diagram on it:

"As for time synchronization... Between the ground and the water, it is definitely impossible to directly use cables to transmit the transmitter's RF code and frequency reference signal to the receiver. Fortunately, both radars can use linear frequency modulation to interrupt continuous wave signals, that is, the constant temperature crystal oscillator provides the transmitter and receiver with time, frequency and phase reference signals respectively."

"Thanks to our colleagues in the aerospace system, our Beidou system is equipped with its own onboard atomic clock. We can first use the timing module of the satellite positioning system to generate the world standard time and synchronized second pulses, thereby ensuring that each frame of the radar system's transmission signal and local oscillator signal are generated simultaneously and have the same timing."

"Then, use the phase-locked loop chip to tame the local constant temperature voltage-controlled crystal oscillator to achieve two clock sources with the same frequency and phase, which serve as the reference clock for the direct digital frequency synthesis module that generates the transmission signal and the local oscillator signal. In this way, the frame start pulse edge of each frame transmission and local oscillator signal after synchronization can be strictly aligned..."

"..."

Ten minutes later, with Zhu Yongshun looking a little surprised, the content on the paper had changed from the initial simple diagram to a complete technical schematic diagram:

"In short, although the accuracy of the first-generation atomic clocks in the Beidou system is not as good as that of GPS, when reflected in our radar system, the error between the transmitter and receiver will not be greater than the microsecond level. Moreover, this is just a temporary emergency after all, and there is no need to consider the problem of cumulative error. It is definitely sufficient for the needs of long-range alert missions."

Hearing this, Zhu Yongshun slapped his thigh fiercely:

"Then the principle of phase synchronization is almost the same as time synchronization. As long as the transmitter and receiver are provided with reference signals with coherent frequency and phase, the phase coherence of both sides can be guaranteed?"

"You're right."

Li Jianqiang closed the document in front of him and showed the other party the title written on the cover:

《Temporal and spatial synchronization and phase calibration technology of bistatic radar》

Then he continued:

“In addition, Academician Chang specifically reminded us that because the control voltage range of the voltage-controlled crystal oscillator is larger than the output voltage range of the CP terminal of the phase detector, an active loop filter circuit must be used to enlarge the voltage range of the CP terminal of the phase detector. He also provided an active filter model of the same-phase topology to eliminate ripple interference and stray components caused by the phase detection frequency.”

"The only drawback is that compared to the direct synchronization method, this scheme has poor frequency agility, especially since there are six receivers and transmitters in total this time. I'm afraid the frequency conversion information may even need to be preset in advance, and it has no resistance to continuous sampling and forwarding interference. What a pity..."

Although he said so, there was no trace of regret on Li Jianqiang's face.

As for Zhu Yongshun, he was already eager to try:

"This active filter circuit needs to be designed separately, but fortunately it can be connected to the existing radar receiver through a module, so it's not a major upgrade... Should we contact the Navy and the China Electronics Technology Group immediately to start targeted modifications to the equipment?"

Li Jianqiang almost subconsciously wanted to nod.

But I still managed to control it midway:

"That destroyer hasn't been officially delivered yet, so the ownership might be complicated... Besides, as an Air Force Equipment Research Institute, it's not convenient for us to directly contact other military branches."

After pondering for a few seconds, he made a slightly compromised decision:

"Well, you will be responsible for contacting the China Electronics Technology Group and ask them to cooperate with us in modifying the radar hardware... I will report to my superiors immediately and request the cooperation of the surface ship forces..."