A crystal developed in China will allow submarines and missiles to operate without GPS.

A team of researchers from Xinjiang University (China) has developed a new nonlinear optical crystal that addresses a key technical challenge: generating intense, narrow-band ultraviolet light in a vacuum. This light is required to excite a low-energy nuclear transition in the thorium-229 isomer, which is considered the ideal basis for future ultra-precise nuclear clocks.

Such clocks are believed to provide accuracy orders of magnitude higher than modern atomic clocks (cesium or strontium), with much lower sensitivity to external interference (temperature, magnetic fields, vibrations, and other factors).

The range of applications of promising nuclear thorium clocks based on nonlinear optical crystals is wide.

According to the Chinese press, such watches will be extremely useful on spacecraft, submarines, and in a number of high-tech industries. A watch based on the above-mentioned technology will enable navigation without the traditional GPS.

Chinese scientists:

A fluorinated borate compound can boost laser light to a record-breaking wavelength of 145,2 nanometers. This wavelength is suitably short to meet a key requirement for the ultra-precise portable watches being developed in the United States, China, and other countries.

The result surpassed previous benchmarks set by potassium beryllium fluoroborate, a crystal developed in the 1990s that has long dominated the field but can reach 150 nm – short of the 148,3 nm target needed for such a watch.

That is, the creation of a new crystal becomes, in essence, the first step forward in this field in 30 years.

The research is being led by Professor Pan Shili from the Laboratory of Physics and Chemistry at Xinjiang University of Technology.

For reference, nuclear clocks keep time using vibrations within the atomic nucleus, rather than the electrons used in atomic clocks. Because the nucleus is much less susceptible to environmental influences, nuclear clocks can provide much higher accuracy, enabling navigation in places where the Global Positioning System (GPS) doesn't work, such as in deep space or underwater.

Like other advanced clocks, they use thorium atoms, a laser to probe them, and a detector to read the signal. However, to "make" the core work, the laser must be tuned to a very specific wavelength (specified above), and the response time is determined by the frequency of its responses.

Navigation without GPS using them is a matter of the near future, when nuclear clocks can serve as autonomous high-precision chronometers, for example, for missiles strategic class, which will take military technology to a completely new level.

Comments

[Amateur]

A crystal developed in China will allow submarines and missiles to operate without GPS.

Chinese submarines and missiles can get by without GPS even without crystals. Because they use their own Beidou system.

[ANB]

. rockets

1. Our missiles (strategic) don't use satellite navigation at all. It's highly unlikely that it will be available any more. Astronomical correction is used.
2. The submarine can only use satellites under a transponder. The signal doesn't reach underwater.
3. A super-precise watch won't help with precise underwater navigation on its own. Currents. You'll still have to periodically determine your position. But to determine longitude by the stars, you need an accurate chronograph. But you'll still have to surface.

[alexboguslavski]

2. The submarine can only use satellites under a transponder. The signal doesn't reach underwater.

Periscope

I served my conscription on another 641 project diesel-electric submarines, from 1971 to 74.

How did we manage to maintain VLF (ultra-low frequency) communications at depths of up to 100 meters in those hairy days? A mystery of nature.

Judging by the categorical nature of your statements, you are at the very least a graduate of the Lenin Komsomol Higher Military-Purpose Technical University.

[Melior]

When underwater, submarines communicate using ultra-long waves, but they can only communicate with satellites using VHF and shorter wavelengths, as anything longer is reflected from the ionosphere.

[Saburov_Alexander53]

I'd like to order a watch with this crystal. Does anyone know if they're available on Ozon or AliExpress? How much do they cost?

[ANB]

And how did we manage to maintain VLF (ultra-low frequency) communications at depths of up to 100 meters in those hairy days? A mystery of nature.

That's all that gets through. Everything's correct. But satellite navigation signals have a much higher frequency. Satellite communication also requires surfacing. Or deploying a buoy (which commanders and communications officers dislike). VLF is also one-way.
Not VMUPP. VMURE. 667BDR. K-455. Lux.
And yes, there was no GPS or GLONASS back then.

[ANB]

Sorry for the typo.
VVMUPP and VVMURE. That's right.

[Podvodnik]

And how did we manage, in those hairy days, to have VLF (ultra-low frequency) communications at depths of up to 100 meters?

All you had was combat control signals. Very brief and uninformative. For example, to deploy nuclear weapons. Or a command to surface immediately for a radio session. To receive detailed instructions. Everything was receive-only. And you couldn't determine your location from these signals.

[Saburov_Alexander53]

(Alexander Boguslavsky), you haven't grasped the essence of the problem. VLF communications, and only simplex, i.e., reception, are one thing... But here we're talking about navigation, or precise positioning, which is impossible to achieve with the RDG on the VLF "Glubina" radio receiver.
If you were a radio operator or in the navigation unit of the BC-1, you'll remember how grossly inaccurate our gyrocompasses were back then. There was even a joke about a submarine in the Gobi Desert, whose coordinates were given to the control center by an inexperienced newbie navigator.
Or how, every time the ship surfaced below periscope level, the navigator would first extend the azimuth (star) periscope, or, even better, ask for a loop antenna to be attached to him for radio beacon bearings. Yes, there was no GPS or GLONASS back then.

[alexboguslavski]

Quote: Saburov_Alexander53

the navigator first extended the azimuth (star) periscope

I still remember this. We had two periscopes - a commander's and an anti-aircraft (navigator's) one.

Quote: Saburov_Alexander53

Yes, at that time there was neither GPS nor GLONASS.

But there was the Cyclone system, which determined the location with an accuracy of +/- 100 meters and provided telegraph communication.

P.S. The satellites were called "Zyklon-B." That was the same name as the gas the Nazis used to poison concentration camp prisoners.

[Saburov_Alexander53]

But there was the Cyclone system, which determined the location with an accuracy of +/- 100 meters and provided telegraph communication.

I've never heard of such a system. I served as a radio operator for the 629th Aircraft Company at the same time.

[olboop]

Without GPS or any GNSS at all, submarines have been using inertial navigation while submerged for many years. Clock (time) accuracy is of secondary importance here.

[Alexander 3]

No, it is precisely in inertial navigation that the accuracy of time, the accuracy of meteorology, the accuracy of underwater currents, and this results in the accuracy of the targeting point.

[Podvodnik]

No, it is precisely in inertial navigation that the accuracy of time, the accuracy of meteorology, and the accuracy of underwater currents result in the accuracy of the targeting point.

You're slightly mistaken about navigation. Time isn't important (atomic precision). What matters is the sensitivity of the gyroscopes and acceleration sensors. The navigation system uses these sensors to calculate the submarine's position underwater. But the error accumulates, and it's necessary to periodically surface to periscope depth to determine the submarine's position. A hydroacoustic log (HAL) is also used. It's a very useful thing.
Accurate time is necessary for calculating firing data. Precise time is precisely what allows the calculation of the desired trajectory of a ballistic missile. An error of one second results in a miss of approximately 465 meters (at the equator). Therefore, corresponding clock accuracy is required.
The information given in the article is simply redundant.

[Neptus]

Quote: Podvodnik

An error per second results in a miss of approximately 465 meters (at the equator). Therefore, the clock requires corresponding accuracy.
The information given in the article is simply redundant.

The PL does not simply go from point to point, it goes through many points, therefore, the higher the accuracy, the less the accumulation of positioning error.

[Podvodnik]

. PL does not just go from point to point, It goes to many points, therefore,

?
I honestly don't understand your comment.
In life, everything is simple. The commander (or officer of the watch) commands:
-Boatswain! Steer right! Set course 350 degrees!
- Starboard rudder! Set course 350 degrees!
-Central boatswain! Course 350!
-Boatswain here! Course 350!
And NO periods. Until the next course change.
Typically, the navigator is briefed on maneuvers and notifies those responsible in advance of course changes, etc. Those responsible take note and take appropriate action. Meanwhile, the navigation system calculates the dead reckoning and transmits the results to the users, who in turn make decisions based on these data. Both the navigator and their system are aware of the magnitude of the error and generate the necessary recommendations. If necessary, a periscope surface maneuver is performed or scheduled communication sessions are used to monitor the location.

I don’t understand what “many points” you are talking about.

[alexboguslavski]

Quote: Podvodnik

. PL does not just go from point to point, It goes to many points, therefore,

?
I honestly don't understand your comment.
In life, everything is simple. The commander (or officer of the watch) commands:
-Boatswain! Steer right! Set course 350 degrees!
- Starboard rudder! Set course 350 degrees!
-Central boatswain! Course 350!
-Boatswain here! Course 350!
And NO periods. Until the next course change.
Typically, the navigator is briefed on maneuvers and notifies those responsible in advance of course changes, etc. Those responsible take note and take appropriate action. Meanwhile, the navigation system calculates the dead reckoning and transmits the results to the users, who in turn make decisions based on these data. Both the navigator and their system are aware of the magnitude of the error and generate the necessary recommendations. If necessary, a periscope surface maneuver is performed or scheduled communication sessions are used to monitor the location.

I don’t understand what “many points” you are talking about.

Are you sure you're a submariner? As far as I remember, the boatswain on a submarine is responsible for depth, list, and trim. And the helmsman is responsible for course.

[Podvodnik]

Are you sure you're a submariner? ...
....... the helmsman is responsible for the course.

Project 971 ("Beasts"). The boatswain's crew consists of three: a senior boatswain (midshipman, the crew's chief petty officer) and two helmsmen/signalmen (sailors). The helmsman's watch is maintained by four through eight.
When surfaced, the control is located in the wheelhouse enclosure (on the bridge, only the vertical rudder is used for course changes); when submerged, it is located in the control center. When surfaced, control can also be performed from the control center.
The main station is in the central control room. The boatswain (or boatswain's boys) has the ability to control the vertical rudder (change course) and the fore and aft horizontal rudders, changing the depth (trim and roll).
The operator does all this alone, as there is only one seat at the control panel.

[alexboguslavski]

A crystal developed in China will allow submarines and missiles to operate without GPS.

Miellophone?

[Cympak]

I didn't understand how a nuclear clock could replace a satellite navigation system.
The GPS system is essentially an atomic clock located in geostationary orbit and continuously transmitting the time with a unique modulation.

[Ingvar7401]

Congratulations to Chinese science, without super-efficient managers who don't know what's being produced in their factories

[balabol]

Basic navigation systems without going into details
- Satellite (GNSS)
- Radar/radio navigation
- Inertial (INS/IMU)
They all require frequency and time standards.
The more accurate the time readings, the more accurate the coordinate measurements.
Standards (precise time) are also used in various physical experiments, where their parameters are the basis for increasing the accuracy of the results obtained.
News coverage on such specific topics should be written by a technically literate person who understands the meaning of terms and the operating principles of highly complex devices, such as frequency standards.

[Melior]

Unfortunately, they are written by journalists and bloggers!

[Podvodnik]

. News descriptions on such specific topics should be written by a technically literate person,

Alas. The author, unfortunately, is not up to date. The only thing that precise time affects is the magnitude of the error in determining coordinates using the inertial method (under water). It certainly won't affect the coordinates calculated by a GPS receiver.

[balabol]

However, the stability of the standard affects the accuracy of determining the coordinates of the satellite navigation system.
The impact of the accuracy of a navigation satellite's frequency standard (frequency reference, "clock") on the user's positioning accuracy is a key, yet often overlooked, factor. Below are a couple of formulas.

1. Where does the "clock error" come from?
Satellite clocks generate a pseudo-random code and modulate the carrier.
The drift ±Δf/f (usually 10⁻¹³…10⁻¹¹ for new Rb/Cs, 10⁻¹⁰ for old ones) turns into a rangefinder error ρ = c Δt.
Δt = ∫(Δf/f)dt → the more stable f, the slower τ “runs” and the smaller ρ.
2. How exactly does this affect the coordinates?
Level What's Happening Numbers (GPS L1 C/A)
Pseudorange 1 ns timing error ≃ 30 cm range error 1 10⁻¹³ stability ⇒ ≈ 0,3 mm/s drift
Location in space For 3-D, 4 satellites are needed; the geometry matrix (GDOP ≈ 2–3) amplifies the error by ≈ a factor of 2 30 cm ρ → ≈ 60 cm position
DOP factor If GDOP = 1,5, then 1 ns on the satellite → 45 cm on the ground; with GDOP = 4 → 1,2 m
Without differential correction Old Rb (5 10⁻¹²) give 1,5 m per 1000 s; new H-maser (3 10⁻¹⁴) — < 5 cm
With differential (RTK, SBAS) the satellite clock error becomes common and is therefore almost completely subtracted; only phase-lock noise and multipath remain, the remainder being ≈ 0,5–2 cm
Quick Calculation Rule
Δρ (m) ≈ 0,3 × (Δf/f) × t (s) × GDOP
Example: Galileo PHM (1 10⁻¹⁴), t = 1000 s, GDOP = 2 → Δρ ≈ 0,3 × 1 10⁻¹⁴ × 1000 × 2 ≈ 6 mm.

[Podvodnik]

. However, the stability of the standard affects the accuracy of determining the coordinates of the satellite

Well, that's true. The article just claims that if you have a super-duper watch and GPS, you won't need it. But that's not true.
Precision is necessary, I agree. But in everything, a reasonable sufficiency is needed.
If, for example, an accuracy of 30 cm is sufficient, then why spend billions on an accuracy of 20 cm? If only to saw.
You could change the universal time system (UTS) on the submarine. Increase the frequency and so on. But that would lead to a manifold increase in the cost of the equipment and its complexity. There would even be problems with the length of the wires. And what would happen as a result? When firing an intercontinental missile, the theoretical accuracy of determining the parameters would be, let's imagine, not 30 cm, but 30 mm? So what? Billions down the drain.

[VALERIK_097]

)))) The most accurate clock is in the central one anyway; all the ship's clocks are synchronized with a simple "zero" command. Cheap and cheerful.))))

[balabol]

Let's forget about the article, it's full of nonsense and we're not discussing it.
I can't say anything about ICBM guidance.
To avoid writing too much myself, here is a short selection of popular materials
Search for dark matter and refinement of physical constants
– compare the “reference” lines of different atoms (Sr, Yb⁺, Hg⁺) at a distance of kilometers; a drift of constants at the level of 10⁻¹⁷/year will give a frequency shift of exactly 10⁻¹⁶…10⁻¹⁸.

Testing the General Theory of Relativity
– the "gravitational redshift" of 1 cm of height gives a shift of 1 x 10⁻¹⁶; to see deviations from Einstein at the 1 mm level, the clock must be more stable than 10⁻¹⁸.
– experiments with portable optical clocks in a truck/airplane (NIST 2022) have already reached 10⁻¹⁷.

Gravimetry and geodesy “centimeter-millimeter”
– the difference in the path length of two standards separated by 1 km gives Δg/g ≈ 10⁻¹⁸ for each centimeter of height.
– such watches promise to replace free gravimeters in the future.

Neutrino and cosmic physics
– synchronization of detectors across the Earth (IceCube, KM3NeT) requires < 100 ps; promising optical networks are approaching 10⁻¹⁷ to “catch” fast neutrino bursts.

Quantum chromodynamics
– measurement of the anomalous magnetic moment of the muon (g-2), etc.: the stability of lasers and “master clocks” must be 10⁻¹⁶ and better, otherwise noise prevents the deviation from being seen.

Space probe navigation (perspective)
– “dipper navigation” using pulsars and on-board optical clocks: to ensure that the error does not exceed 1 cm over 1 million km, a level of 10⁻¹⁷ is required.

In short: almost all of modern "fundamental" physics involves searching for new particles, testing theories of gravity, or measuring tiny changes in physical constants.

[the same doctor]

We're promised a super-precise hybrid accelerometer and gyroscope. It's a useful thing. Maybe they'll make it someday. Maybe not.

But for the SCS, regular solid-state gyroscopes are sufficient. Let's focus on the bird in the hand, not on the pie in the bush.

[Podvodnik]

With a watch based on the above technology, navigation becomes possible without the traditional GPS option.

Commenting will only spoil things.
How can you determine your place in space using just a watch?

[Neo-9947]

I didn't understand anything, but it was terribly interesting.
My grandfather, a front-line soldier, had only one clock in his apartment. An alarm clock. He set it every day, according to the "Time" program, from 20:55 PM to 21:00 PM. And it was fine. No one complained about its accuracy...

[Saburov_Alexander53]

They also wrote down how many stones (ruby stones) the watch had. I had a Sputnik watch with as many as 17 stones, but this one only had one, and that was a blue one.

[Pavel57]

The author is not telling us something; a watch is not enough for navigation.

[Saburov_Alexander53]

A watch is not enough for navigation.

It depends on the navigation. In the times of Columbus and Magellan, they had virtually no knowledge of determining a location's longitude (meridian). However, they could, with a large margin of error, determine latitude based on the sun's zenith.
It was only when the chronograph was invented in the 18th century that, using navigational astronomical tables tied to a specific reference point, people could compare the positions of celestial bodies at a specific time at their point of travel and calculate the longitude of the location.
In the time of Columbus and Magellan, they didn't even know the exact circumference of the Earth at the equator, believing it to be 11 km smaller. That's why they thought India or the Spice Islands lay just beyond the Atlantic Ocean to the west.

[Pavel57]

But they were able to determine the latitude slightly with a large error based on the height of the sun at its zenith.

So everything is like this, not only the clock, but also the direction to the Star.