Germany, having been bloodied by the jamming chaff of the Red Army, stepped up its countermeasures in the field of electronic warfare. On the one hand, electronic technology experts were organized to study anti-jamming measures, including radar frequency conversion anti-active jamming technology and the use of Doppler effect to distinguish relatively fixed chaff strips from moving targets.

On the other hand, the Germans also tried to find a way from other fronts. The so-called other aspect is that long-range strategic bombing against the Red Army must be piloted or navigated. If you can take out the Red Army's pilot planes or interfere with the Red Army's navigational measures, will you be able to lure the Red Army's strategic bombers in the wrong direction?

In this regard, the Germans put considerable effort into it. At that time, the civilian and military airfields of the Red Army generally used the Lawrence radio navigation system and its modifications. Such a system consists of two identical directional antennas that emit a middle overlapping beam, one emitting a Morse "point" signal and the other beam emitting a Morse "scribble" signal.

When the aircraft flies in overlapping beams, it is possible to hear two signals at the same time, and since the two signals overlap, it sounds like one continuous signal. If the plane deviates, the pilot hears a "point" or a "scratch" signal. Based on this, the route can be corrected.

However, the problem with this system is that it can only determine the directionality but not the real-time position of the aircraft, and it still requires a good navigator to navigate. At the end of the thirties, the Red Army improved this system and developed a new navigation system. The beam generated by this system consists of several Lawrence beams. One of them is the main beam, also known as the approach guidance beam, which is directed directly at the target. Navigating aircraft formations.

The rest of the beams are auxiliary beams. Intersect with the main beam at predetermined intervals at certain locations. Because the driver can determine where he is based on the beam. This system is used in conjunction with a timer that controls the bomb to be dropped automatically at the intersection of the main beam and the last auxiliary beam (five kilometers from the target).

Immediately after the successful development of this system, the Red Army established system outlets in East Prussia and East Poland, and the maximum effective navigation distance of this system at that time was 270 kilometers, and the average bombing error was 30 meters.

Of course, with the fall of East Poland, the system could only be used in East Prussia. Moreover, with its effective combat distance, it can only meet the needs of bombing limited cities such as Berlin and Warsaw. Even so, the system was quite successful and caused Germany a lot of problems in 1942.

Hitler believed that in order to disarm the Red Army's bombing of Berlin, it was necessary to first paralyze the system. Soon Germany found out the frequency and mode of operation of the first generation of navigation systems of the Red Army through the interrogation of captured Red Army Air Force pilots and the analysis of the electronics on the downed bombers.

The first countermeasure given by German scientists was to disable the guidance system with noise interference, but in doing so, the Red Army would immediately perceive it, so this simple measure was abandoned. The Germans meditated. In addition to the development of a "fence" deception system, which was installed on the border of East Prussia. The transmitter and receiver are located at a distance of fifteen kilometers. After the receiver received the navigation signal of the Red Army, the transmitter immediately re-transmitted from the directional antenna with much stronger power, but the angle of its transmission was different from the signal of the Red Army's navigation system.

In this way, the bomber pilots of the Red Army heard the signal of deception from the Germans and thus piloted the plane off the correct course. At one time, the Red Army's strategic bombers were guided by the "fence" signal to uninhabited wilderness or wilderness, and they were disoriented for a long time, and sometimes even ran out of fuel and had to make a forced landing in Germany. During that time, a large part of the reason for the poor effect of the strategic bombing that Arksnes preferred was the navigation problem.

However, the Red Army soon became aware of the German "fence" deception system, so it immediately developed a second-generation navigation system, which the Germans called the "Archer", a new system with only two transmitters, one for the same intensity of "point" and "stroke" signals, and at the same time for only one main beam and one auxiliary beam.

The main and auxiliary beams intersect over the target, which is not only simple and easy to master, but also improves the accuracy of bombing and achieves good results. However, the confrontation was always there, and when Berlin and other large and medium-sized cities were once again bombed by the Red Army, the Germans began to think of ways again.

Soon they found the actual "Archer" system on the crashed bomber, and found out that its main operating frequency was 39 MHz, and then the Germans immediately developed the "Shield" system. The system transmits the "point" signal or "stroke" signal of the "Archer" system with a strong transmitting power, but the beam is slightly to the left or right, causing the Red Army bombers to unknowingly deviate. In addition, the German army's electronic reconnaissance system can also detect where the beams of the "Archer" system intersect, so that they know in advance the bombing targets of the Red Army, and naturally they can wait for the rabbit.

However, this method was not without problems, because when the Red Army developed the "Archer" system, it was thought that the system would likely expose the targets bombed by the Red Army. Therefore, when using this system to guide the bombing, multiple antennas were deliberately used to orient themselves at multiple targets, so that the Germans could not figure out what the Red Army was really attacking. In addition, with the change of the escort system, after the Red Army's fighter units were freed from the shackles of bombers, the Red Army would deliberately use directional antennas to create false air attack targets to lure the German fighters over, and then send a larger fighter force to annihilate them.

Of course, none of this will solve the problem at the root, as long as radio navigation is used, it will inevitably radiate signals, and it is only a matter of time before these signals are intercepted by the enemy. So the Red Army, while constantly improving the radio navigation system (more on that later), was also looking at other means of navigation.

The so-called other navigation methods are actually inertial navigation. Based on the principle of Newtonian mechanics, by measuring the acceleration of the carrier in the inertial reference frame, integrating it into the time, and then importing it into the navigation coordinate system, relatively accurate information such as velocity, yaw angle and position can be obtained.

In order to realize inertial navigation, the most important thing is the "inertial sensor", which is generally called the "inertial instrument". They autonomously and independently measure the motion of objects relative to space based on the principle of inertia. No external benchmarks or information are required. Such as radio waves, light, magnetic fields, etc.

Among them, the instrument that measures the angular motion of an object is called a "gyroscope". The instrument that measures the motion of an object in a line is called an accelerometer. Together, these two instruments can measure the motion of an object in six degrees of freedom.

In fact, these two instruments are not unfamiliar to everyone, gyroscopes are the most heard, and the famous V2 missiles in World War II used mechanical gyroscopes. The principle of the gyroscope is actually very simple, after the gyroscope is rotated, its axis will remain fixed in the same direction, which is actually a manifestation of inertia, also called the fixed axis of the gyro.

By placing the gyroscope in an airplane or ship, you can measure the declination angle of the fixed axis of these carriers relative to the direction of the gyroscope. In this way, the carrier can be controlled to correct the attitude or course.

It's just that this reason sounds simple, but it is quite difficult to implement. Because the axis fixation of the gyroscope is conditional, that is, it is not allowed to interfere with it with external forces. In other words, the gyroscope must not have any external disturbances after it is in operation. Once there is a disturbance, the axis of the gyroscope will be deflected, which is called "drift" in inertial technology. The angular velocity of the drift is proportional to the magnitude of the external interference.

So the gyroscope looks good, but in fact we all know that it is impossible not to disturb it completely, because the rotor of the gyroscope cannot be suspended in the air on its own, it must be supported by a frame. So it is impossible for any gyroscope rotor to be free of frictional moments. Therefore, reducing the frictional moment has become an obstacle to the manufacture of high-precision gyroscopes!

This roadblock can be said to have broken the brains of relevant experts, but. If there is a challenge, there will be motivation, and groups of outstanding experts have devoted themselves to tackling this difficult problem. 1908 year. The German scientist Dr. Anszütz designed a single-rotor pendulum gyrocompass for ships. In 1911, Dr. Sbury in the United States also made a single-rotor gyrocompass suspended with steel wire, which was completely different from Dr. Ansitz. This is actually the early mechanical gyroscope.

In World War II, in order to save its inevitable fate, Hitler developed a batch of doomsday weapons, such as the V2 missile, which uses a mechanical gyroscope supported by huge ball bearings to give the V2 the ability to attack targets hundreds of kilometers away, of course, the accuracy of the gyroscope is actually limited, resulting in the accuracy of the V2 is also quite ugly.

By 1949, Spurley had developed the MK-19 platform compass. It combines the functions of a compass and a horizon in one. The gyroscope and pendulum of the overall structure are separated, and the two are combined by electromagnetic control. It unveils the era when gyroscopes have entered electromagnetic control from mechanical control.

In the fifties, scientists discovered that the accuracy of mechanical gyroscopes supported by ball bearings was limited, so they developed a floating gyroscope. The so-called floating gyroscope is actually to replace the mechanical support structure of the gyroscope with liquid or gas for support. For example, liquid gyroscopes and air gyroscopes, whether liquid or gas, undoubtedly have a much smaller friction torque than ball bearings, and their natural accuracy is much higher.

After opening the idea, with the development of technology, electrostatic levitation gyroscopes and magnetic levitation gyroscopes have also appeared, and inertial devices have ushered in spring for a while.

For example, in May 1950, North American Airlines conducted flight tests of the XN-1, the world's first pure inertial navigation system. After appropriate improvements, the XN-1 was renamed the N-6 inertial navigation system and installed on the "Stingray" nuclear submarine for testing. Departing from Pearl Harbor, it took 21 days to cross the North Pole at a speed of 20 knots and sail 8,146 nautical miles to Port Porter, England. Upon arrival at its destination, the Stingray floated and was measured with a positioning error of only 20 nautical miles!

This feat shocked the world and made the liquid floating gyroscope instantly popular. However, the liquid floating gyroscope is not without disadvantages, its structure is quite complex, and the cost is not generally high. Except that the military can afford it, the civilian possibility is too low.

Therefore, in view of the shortcomings of the liquid floating gyroscope, a new round of research has begun. In 1965, Ferenti was the first company to develop a power-tuned gyroscope with flexible support. This kind of gyroscope has a simple structure and is easy to manufacture, relatively cheap to build, and has good accuracy. Its excellent price/performance ratio makes it widely used by people who do not need to work continuously for many months of adulthood.

Then there is the electrostatic gyroscope, which is a rotor gyroscope that rotates at high speed in a vacuum supported by static electricity. In fact, the relevant idea appeared in 1952, and it was gradually realized in the sixties. The accuracy of this gyroscope is quite awesome. Let's compare!

Early frame gyroscopes (mechanical gyroscopes) had an accuracy of about 1-10-1 degrees per hour. The dynamic gyroscope is about 5×10-2-5×10-3 degrees per hour. The float gyroscope is 10-3-10-4 degrees per hour, and the electrostatic gyroscope can be up to 10-6-10-7 degrees per hour. And in space, in weightlessness and vacuum, the accuracy of electrostatic gyroscopes will grow to an astonishing order of 10-9-10-11 degrees per hour. Therefore, high-precision electrostatic gyroscopes are widely used in satellites, intercontinental missiles and space vehicles.

There may be comrades who want to say, since the electrostatic gyroscope is so awesome, is it already the peak of technology? Not really, because the accuracy is really high, but the price is also rising. Moreover, it is quite difficult to manufacture, and ordinary countries simply cannot afford to play it. And for general navigation, it doesn't need to be as high a level of precision.

So smart human beings have not gone to the black on the road of gyrocopic bearing, the core of gyroscope is the bearing, and that bearing is also the difficulty of all problems, can you avoid it? In fact, it is possible, and then human beings invented the "gyroscope" without bearings and rotors, that is, without "gyroscopes". In fact, these instruments should be called "angular motion sensors" in the strict sense, but the "gyroscope" was too popular before, so everyone still calls it "gyroscope".

These new generation of "gyroscopes" fall into four categories: fluid gyroscopes, vibrating gyroscopes, optical gyroscopes, and particle gyroscopes. Among them, fluid gyroscopes are divided into thermal convection type and jet type according to their working mode; The vibrating gyroscope is divided into beam type, fork type, ring type and plate type according to the different vibration elements. Optical gyroscopes are divided into laser gyroscopes, fiber optic gyroscopes, and optoelectromechanical gyroscopes according to their different structures; The particle gyroscope is still in the stage of pretending to be tall (under development). According to the different particles in which they work, they are temporarily divided into atomic gyroscopes, ion gyroscopes and superconducting (electron) gyroscopes.

Let's briefly introduce the number of words of cheating (laughs, you can also use it to pretend to be forced). The principle of fluid gyroscope and vibrating gyroscope is based on the Coriolis effect. The Coriolis effect is a manifestation of the inertia of an object when it moves both wires and angles, and is a natural phenomenon that looks awesome and tall but is actually very simple.

It's like a person standing on a spinning roulette wheel, and if he doesn't move, he may only feel a centrifugal force that causes him to be thrown outward. If you follow this force and move outward, you will become unsteady and feel like you are going to fall backwards. This is because the radius of the outer edge of the roulette wheel is large, and its forward speed is fast, and the speed of the person is slow at the inner edge, and when he reaches the outer edge, he will feel that the speed of the roulette wheel under his feet has become faster, and the human body will tilt in the opposite direction due to inertia. And this force of inertia that leans backwards is called the Coriolis force.

The magnitude of the Coriolis force is proportional to the angular velocity of the turntable and the linear velocity of the human body moving radially along the turntable, while fluid gyroscopes and vibrating gyroscopes use the Coriolis effect to obtain the specific value of their rotational angular velocity by measuring the magnitude of the Coriolis force.

The working principle of optical gyroscopes and particle gyroscopes goes beyond classical Newtonian mechanics, and optical gyroscopes are based on the characteristic behavior of inertia, which is similar to the characteristic behavior of light, which is "the speed of motion remains constant". A beam of light is divided into two beams that rotate in opposite directions, and the axis of rotation is used as a sensitive axis to form a "gyroscope". When the gyroscope rotates at a certain angle around the sensitive axis, the distance between the two beams of light from the starting point to the meeting point becomes longer and shorter, so that the time of their arrival is also before and after. This time difference is proportional to the rotational speed of the top.

Therefore, the speed of the gyroscope can be known by measuring this time difference, but this time difference is not easy to measure, so people use the wave of light (thanks to Einstein) to transform the measurement of time difference into the phase difference of the equivalent light wave.

Particle gyroscopes work similarly to optical gyroscopes, which are also based on the theory of conservation of the velocity of particle beams, and at the same time, it also uses the quantum mechanical wave-particle duality (thanks again to Einstein) theory to examine the particle beam as a beam, and then uses the previous set of theories to measure its rotational angular velocity.

Of course, we don't need to know these tongue-twisting theories, we just need to know that developing new "spinning tops" based on these new theories can be made simpler and cheaper. For example, the laser gyroscope in the optical gyroscope does not have a high-speed rotation mechanism, which brings a series of advantages such as long life, high reliability and large anti-overload capacity. This is really good news for inertial navigation!

Of course, in the 1940s, these were still a little far away, with the technical basis and conditions of the Soviet Union at that time, whether it was liquid floatation, air floatation or electrostatic float gyroscope, it was impossible to do it, and even the early ball bearing mechanical gyroscope was stumbled.

Therefore, if the Soviet Union wants to open a breakthrough in inertial navigation, it really has to find another way. In order to avoid those mechanical components with high processing and technical requirements, it seems that the USSR could only find a way on optical gyroscopes. However, the core of the optical gyroscope is actually the laser, although Einstein has already proposed the concept of stimulated radiation, but how to achieve it has always been a problem, and the laser was only really realized in 1960. What a certain immortal is thinking about now is, should he pretend to be forced in the academic world? (To be continued.) )