Chapter 577 GPS Navigation Interference Test

When your boss asks you to go home for dinner, even if it is a question, it cannot really be treated as a question——

If you fail to answer, it will be difficult to maintain this working relationship in the future.

What's more, Chang Haonan subjectively really wanted to pay a visit.

Ding Gaoheng’s wife is one of the main persons in charge of my country’s underwater launch vehicles, that is, submarine-launched ballistic missiles.

An old man who is famous but very low-key.

Seeing Chang Haonan nodding almost without hesitation, Ding Gaoheng happily put on his hat and picked up his packed briefcase:

"Let's go, take my car and go together. After eating, let Xiao Zhu pick you up..."

…

At the same time, Jinling and Dajiaochang Airport.

Xu Yang jumped out of the passenger seat of a Jiefang truck, and together with several people in the car behind, carefully unloaded a cylindrical device placed in the cargo box onto the tarmac.

Compared with Beijing, which is still a bit chilly in the early morning or evening, the climate along the Yangtze River has clearly entered mid-spring.

However, for Xu Yang, a native of the capital, the climate here is not easy to adapt to.

She sniffed slightly, feeling a little uncomfortable from the sycamore catkins flying all over the sky just now.

But at this critical moment, she couldn't care less.

"Gong Guo, go to the back and unload the test trolley and push it over here, and then do a final check to make sure there is no fault!"

"For the others, one group will go to the test area to set up measurement and control points, the second group will go to the end of the runway to prepare to recover the test equipment, and the third group will debug the jammer..."

Amidst the noise, Xu Yang picked up a large speaker from the car and gave instructions to the crowd in an orderly manner.

About half a month ago, she was in the laboratory when she suddenly received a call directly from the director of the Commission of Science, Technology and Industry for National Defense.

The other party conveyed Chang Haonan's message, saying that the military GPS receiving module they had been waiting for had been obtained and was on its way to Jinling Electronics 14th Institute. He hoped that she could go there as soon as possible to wrap up the GPS jamming equipment project.

So, Xu Yang rushed from the capital to Jinling.

In fact, 14 had completed the main hardware part of the GPS jammer before. What Xu Yang needed to handle this time was mainly to write the software part according to the new algorithm and perform performance testing of the final product.

According to Chang Haonan and Xu Yang's expectations, the main function of this jamming device should be to deal with GPS-guided munitions, such as cruise missiles or satellite-guided bombs such as JDAM.

But the testing process certainly cannot be done this way.

On the captured unmanned submarine, there were only two sets of GPS receiving modules including backup. One of them has been installed in the jammer and is used to translate and distribute signals. The one that can be used to test the jamming effect is Only one remains.

Not to mention that China currently does not have ready-made satellite-guided weapons available. Even if it did, it would be impossible to drop this only remaining set of weapons from the sky.

Then it becomes a one-shot deal.

If the first test doesn't go well, you won't even have the chance to try it again.

What's more, Chang Haonan also wants to maximize the use of the remaining value after the test process is over, and then build a second jammer...

Therefore, the interfered object in the final test plan became a GPS-guided car that can perform simple turning operations and drive to the predetermined target.

However, this guidance is not automatic driving.

The action logic of the car is the same as that of a bomb. After discovering that the route has deviated, it will turn in the other direction until it coincides with the set route, without avoiding any obstacles in the middle.

Therefore, this test must be conducted in an extremely open area.

After choosing a lot, only the airport barely meets this condition.

So I made some contact with the Air Force and borrowed the Daqianchang Airport where the planes had returned in the evening as the venue.

"XCMG, we checked it and found no problems with the hardware and software."

Guo Lin pushed a metal car about half a person's height from a distance and said as he walked:

"But before formal testing, I think it's better to conduct a set of controlled experiments to see how it works without interference."

Xu Yang nodded decisively:

"Let's go."

Then, together with several fellow engineers, he pushed the car towards the set starting point for the test.

"XCMG, with this GPS jamming pod, I feel like Mr. Chang is very anxious?"

On the way, Guo Lin asked casually:

"In the past half month, he called me four times to check on my progress. Although he didn't say much each time, it shouldn't be so frequent."

"Four times?"

Xu Yang raised his eyebrows slightly:

"Why didn't I know this even once?"

Guo Lin wiped the sweat from his forehead:

"Uh... Mr. Chang is worried that you are under pressure, so he always tells me not to tell you until the project enters testing."

Hearing this answer, Xu Yang pouted slightly with a complicated mood.

In her scientific research career, this was the first time that someone else took special care of her progress.

Before, she had always slowed down to adapt to others.

"Fine……"

Xu Yang casually smoothed his hair that was messed up by the wind:

"However, he did inadvertently tell me before that he hopes this thing can be put into use before next spring. He also said that if used properly, it can have the effect of making a huge difference."

"Before next spring?"

Originally, Guo Lin just asked casually, but this sudden moment made him a little strange:

"Is there anything special about this time...or does Mr. Chang have any other plans?"

"I don't know about that..."

While talking, the car has been pushed to the starting point of the landing runway.

After a while, it will be "released" here to simulate the trajectory of a GPS-guided bomb on a flat surface.

"Path coordinate points 1-10 are set on the runway, 11-14 are set along the taxiway, and 16-20 enter the apron..."

After all, the maneuverability of a four-wheeled car is much better than a bomb that can only rely on its wings, so in order to better reflect the interference effect, the path setting is relatively complicated.

It is actually the process of an airplane landing on the runway and then taxiing back to the apron along the right taxiway.

"Okay, the setting is complete and ready to be released!"

Following Xu Yang's order, the tester turned on the battery power.

Immediately afterwards, this slightly crude car drove forward unsteadily.

Xu Yang and Guo Lin followed all the way behind, observing its trajectory.

Because the GPS accuracy in the 1990s was still relatively limited, if you look closely, it is actually a bit confusing.

However, in general, we are still moving along the preset route.

Ten minutes later, the two people and one car successfully arrived at the predetermined coordinate point, which was the location of the motorcade on the tarmac.

The deviation is about 2 meters, which is also in line with the accuracy standard of military precision capture codes.

Of course, in actual use, since the speed of the guided weapon is much faster than this car, the computing power of the chip on the weapon cannot keep up with that of a laptop, and the accuracy of satellite positioning for altitude is very poor, so the hit accuracy generally cannot reach this level.

For example, satellite-guided bombs generally have an accuracy of about 10-30 meters.

Of course, it is still far smaller than the killing range.

"Send the car back and prepare to start the interference test!"

…

On the tarmac, the experimental team operating the jammer had moved the equipment to a position near the runway and aimed the transmitting antenna on the side of the cylinder into mid-air.

Since the receiving antennas of many GPS-guided weapons have directional capabilities, interference signals sent directly from the ground are likely to be filtered out and require a round of refraction through the ionosphere to simulate satellite signals sent from space.

In order to achieve this requirement, the rated power of the entire jammer in working condition is very large, and the circuit design is also very clever.

It was still done by Chang Haonan himself.

"Let's set the interference method, use this runway as the axis, mirror all the GPS signals received within the range, and then re-send them..."

"Set an exemption threshold to prevent the false signals after processing from being too far apart and being discovered by the inertial navigation system..."

"..."

As Xu Yang spoke, he set the interference mode of the jammer on the computer.

Of course, after the device is officially finalized, there will be several preset interference algorithms to choose from.

After checking his settings one last time, Xu Yang stood up and took the walkie-talkie from Guo Lin.

"All attention, all attention, report on preparations!"

After a brief silence, a report came over the intercom that each group was ready.

"Group four, the test subjects can be released."

After Xu Yang finished speaking, he put down the walkie-talkie, picked up the telescope handed over by the person next to him, and looked at the far end of the runway.

The car drew a dragon while swaying forward.

It looks no different from last time.

"The measurement and control team, the data is all normal."

The first report came over the intercom.

Because the interference setting is symmetrical along the runway, there will be no difference in the initial straight line driving.

Soon, the car arrived at the entrance of the taxiway.

Based on the route setting, its front wheels veered slightly to the right.

Everyone's hearts instantly became tense.

But soon, the new navigation signal told it that this was the wrong direction.

As a result, the front wheel of the car turned around and turned to the "correct" left side.

That is, the exact opposite setting to the last route.

"Measurement and Control Group 2, the target route has deviated."

"Measurement and control group three, the target is traveling along the left taxiway..."

"Measurement and Control Group Four, the target enters the left apron area..."

"..."

In Xu Yang's telescope, he could also see that the car was firmly parked on the other side of the tarmac in an almost completely symmetrical position with them.

"Fuck, it's so amazing..."

Guo Lin, who was also holding a telescope, murmured to himself:

"Doesn't this mean that the satellite positioning system is... completely useless?"

"That's not the case."

Xu Yang put the telescope aside and went to the computer next to him to check the jammer's operation log:

"A set of these things can only work in a range of two to three kilometers in diameter. In order to ensure interference power, the size and weight are very large, making it basically impossible to achieve full coverage of the battlefield."

"Moreover, the opponent can also introduce more composite guidance on weapons and equipment or ammunition, especially terminal guidance mode, to deal with our interference."

"In short, there is absolutely no equipment that can solve all problems. You must not underestimate the enemy..."

Although he said this, Xu Yang still showed a bit of joy on his face.

Apparently the logs are running pretty well.

Then she changed the subject:

"However, it is enough for some targets or areas that need to be protected."