DE1616243A1 - Synchronized radio messaging method and system - Google Patents

Description

f; ' —Ψ

5424

Control Data Corporation, Minneapolis, Minnesota, TJ ₀ SA

Synchronized radio messaging method and system

The invention relates to a method and a system for the synchronization of several radio stations and in particular to a radio communication system through which several Stations can determine information about their mutual distance, their mutual azimuth and their altitude, to thereby to air traffic control, to avoid collusion. and contribute to the control of air traffic.

Synchronized reference signals are used in the system, in all stations by an optional comparison between the stations are generated and according to the invention only by advancing or advancing the phase of Reference signal generators are synchronized.

I. Introduction .

A system has already been proposed in which several stations work together to control air traffic, avoid collisions and for air traffic control. In this system, a main station transmits synchronization signals to several fixed ground stations. The ground stations whose distance from the main station is known and for which the delay times between the transmission and reception of the synchronization signals are therefore also known

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are known, use these synchronization signals for synchronization with the main station. In this way a network or a group of synchronized ground stations is created.

Each ground station of such systems transmits with a predetermined pulse frequency on different carrier frequencies Reference pulses off. These reference pulses can can be received by multiple mobile stations such as aircraft. The moving stations send out interrogation pulses to which the ground stations respond Reply impulses. Sufficiently different carrier frequencies are used so that one unambiguous Query and answer a special ground station is possible.

As each mobile station is its distance from a ground radio station can determine and therefore knows the running time of the reference pulses, it is possible to use the interrogation pulses synchronize moving stations with the reference pulses. Since every mobile station is synchronized with one or the other ground station and all ground stations are synchronized with each other, all moving stations are also in synchronization. Each moving station can therefore determine the distance to each other mobile station or to any other ground station by taking the arrival time of pulses observed from these stations. By the fact that the transmission time of various impulses of the moving Stations limited to predetermined transmission times, it is possible to get additional information about the moving Station, for example about its height. It is also possible to take measurements on various types of received

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Impulses aurE & g ^ iiJitegfiP- 'The proposed systems serve therefore for navigation, to avoid collisions and to control air traffic.

However, the system described has some disadvantages, although you can use it to perform all the punctures you want can. So several ground stations are necessary to each other need to be synchronized, for which you need a help synchronization system needs. Due to the fact that the different ground stations are on different frequencies work, one also needs a wide high frequency band in the already overcrowded frequency spectrum »Furthermore, the mobile stations with transmitters and receivers be equipped that are both frequency-stable and adjustable over a wide frequency range «, Da die-Receiver of the mobile stations must have such a bandwidth that the stations query pulses with all If possible frequencies can be received from a wide frequency band, the range of the system is limited as a result of these broadband receivers.

In an already proposed system for navigation and air traffic control, some of the disadvantages mentioned are already present eliminated and operational benefits achieved. at This system does not need a main station, and there is no intermediate ground stations, all of which have to be synchronized with one another by an auxiliary system. Instead, each station synchronizes itself with every other station, regardless of whether the station in question is fixed or movable. It is also used to send and uses the same frequency to receive both mobile and fixed stations. The sender and the The recipient of each station is therefore no longer so expensive

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This is associated with better receiver sensitivity and the transmitters can work with less power.

In this proposed system, each of two leads synchronizing stations half of the pulse generator setting required for synchronization.

The subject of the invention now achieves compared to the proposed Systems in terms of simplicity, reliability and speed of synchronization considerable progress in that the correction between two synchronizing or comparing Stations is carried out by the station whose reference signal generator is lagging «A synchronization is thus brought about by only advancing or advancing.

An exemplary embodiment of the invention should be based on Figures are described

Fig. 1 is a timing diagram of various transmissions or transmission pulses from fixed ground radio stations and mobile ones Stations.

Figure 2 is a timing diagram of transmitted and received pulses two stations in a synchronized state.

Figure 3 is a timing diagram of transmitted and received pulses two stations in the unsynchronized state.

Fig. 4 is a block diagram of a circuit for phase correction an oscillator to synchronism.

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Pig. Figure 5 is an illustration of the number of inter-station comparisons required for synchronization.

Figure 6A is a diagram with three hypothetical or fictional stations,

Mg. 6B is a timing diagram showing the use of start pulses (B) shows the rough synchronization between the three stations. '

Pig. 7 is a block diagram of a transmitting and receiving device for the system described.

Pig. 8 is a timing diagram illustrating certain principles of operation of the invention.

Pig. 9 is a simplified block diagram of the system according to the invention.

Pig. 10 is a detailed block diagram of typical assemblies used in the system of the present invention will.

Pig. 11A, 11B and 110 are block diagrams of parts of the system according to the invention.

Pig. 12A is a block diagram of the Hö'hene cimltwerk.

Pig. 12B is "a timing chart for illustrating the operation dee height derailleur.

Pig. 13A and 13B bind chronological representations of a synchro nization correction with the help of a pulse counting method.

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Pig. 14 is a block diagram of a device in a station for performing synchronization by means of pulse count"

Pig. 15A and 15C are block diagrams of various types of up and down counters.

Pig. 15B represents a binary counting method

Pig. Fig. 16 is a block diagram of a circuit showing the Generation of information pulses when not synchronized Station prevented.

Pig. 17 is a block diagram of a circuit for selecting the transmission times for the pulses B _Q , A _Q and Gq.

Pig. 18 is a block diagram of a circuit for selecting the _{transmission times for the I Q} pulses.

Pig. 19 is a block diagram of a circuit for performing coarse synchronization of the start pulses.

Pig. 20 is a frequency control circuit of the master clock oscillator by Pig «, '14«

Pig. 21 is a block diagram of a circuit for selecting the _{transmission times for the pulses A Qe}

Pig. 22 and 23 are block diagrams of a pulse encoder and decoder

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161 & 243

TI.Syst ero signal transmissions

To explain the mode of operation of the system according to the invention, the following abbreviations are used for the various transmission pulses chosen:

E = response pulses

I = query pulse -

B = start impulses

G = interrogation pulses from a ground station A interrogation pulses from an aircraft

0 = index to identify a transmission signal of your own Station.

In the description, the expression "ground station" is used throughout used for a station that is stationary relative to moving stations * The ground station can, for example, be a fixed land radio station or a relatively stationary one Be a radio beacon on the water. The term "moving station" is used for stations that are relatively move to the ground stations and / or to each other. this For example, aircraft, helicopters, or other types of stations that are in the air on the Land or move on water. As a result, it should be noted that other stations are also covered by the term "Land" or "movable" as defined above.

To explain the mode of operation of the system, reference is made to FIG. 1 Referring to which some of the signals are shown which are sent during each operating interval that was assumed to be one second for explanation.

For illustration purposes, the 1-second interval ± § t is divided into 548 transmission positions or times, which occur after each

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Occur 1/548 of a second. At time t = O, i.e. at the time of transmission No. 1, the transmission interval begins with a start pulse B, which is sent by every station in operation. -The times or positions No. 2 to No ₀ 200 are transmission positions for data, with the even-numbered position numbers, No * 2, No. 4 No. 200 ,. assigned to the particular ground stations for transmitting ground station information pulses G, while the odd-numbered ones

Item numbers starting with No, 3, No. 5 to

No. 199 associated with the moving stations. By doing The application example of the system described for explanation are the odd-numbered positions for the transmission of Air station information pulses A corresponding to the altitude layer, in which the respective air stations are located, provided.

For example, the ground station X is position No. 2 for the transmission of an information pulse G, the ground station Y position No. 4 for the transmission of an 'information pulse G o ".." and the ground station ZZ the position No. 200 assigned to the transmission of an information pulse G «, since a certain ground station is only in the one you are in A ground station can send an information pulse in relation to the transmission time assigned to the start pulse B their transmission time can be identified. Be on it pointed out that the same transmission positions can also be used for two different ground stations, provided that that the two ground stations are far enough apart so that a mobile station that operates in the area of one ground station that cannot receive the transmission pulses from the other ground station.

In the illustrative embodiment of the

1 O δ 8 U / O A 3 6

Invention are the odd positions No. 3 ... · No ₀ 199, which are used to send aircraft interrogation pulses, assigned to several elevation layers that follow one another at intervals of 10Om. Thus, those aircraft that fly at an altitude of 0 to 100 in send interrogation pulses A at the time no. 3, those plug toys that fly at altitudes of 100 to 200 m, impulse A at time no. 5 etc. It should be said that several aircraft flying in one and the same altitude range send their respective altitude information pulses only at the appropriate point in time. The height of the height areas can be determined according to the requirements of the overall system, including the plug heights of the various plug tools. It must be said that the individual height areas do not have to have the same height throughout. For example, the height of the individual height areas can increase with increasing height, if one wants to take into account the fact that the accuracy of the plug-in altimeter decreases with increasing height. Because in this case the upper height areas would have a greater height than the lower height areas. For example, the lower areas would be 100 m high and the upper areas 300 to 500 m high.

The transmission positions No. 201 to No. 548 by Pig. I are used by both ground stations and mobile stations to transmit interrogation pulses I for the purpose of synchronizing and maintaining the synchronism of all stations with one another * The synchronization is therefore necessary so that the various stations can send the information at the appropriate times and identify all times in order to receive information from the other stations «According to the invention, no station, be it fixed or movable, sends information pulses α or A at times no. 2 to No · 200, before ate is not synchronized. Whether there is synchronism is autoeatlsoh

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from each station by generating Hull or minimum error signals determined in the station fault determination circuits, and how the synchronism is achieved will be described later «,

If the individual stations are synchronized with each other, you can determine the distance and height of the other stations determine within their transmission and reception area. In the synchronized state, for example, every movable one knows Station the transmission time of the information pulse G a special ground station, and the measurement of the time between the transmission time and the reception of the information pulse G gives the distance or the distance between the mobile stations and the ground station. A ground station can distance and altitude of an aircraft by measuring the time between an odd point in time and the receipt of information impulse it A detect the aircraft. In the same way, any aircraft can measure the distance and altitude of any other Detect aircraft «,

Although the system is described on the basis of 548 sending positions of which 199 are used as information pulses and 348 for Synchronization purposes can also be used, others Numbers of sending times «, either higher or lower be used. If you want, you can also change the ratio the information and synchronization time β design differently «The choice of suitable conditions depends on several factors, including the station density (number of stations per area), the desired one Operating distance between stations, the performance of the Systems etc.

The following is a summary overview of the

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given different transmission pulses of the system. At the start of each transmission interval, each station transmits, whether fixed or movable, a start pulse B at! time No> 1; the information pulses G and A are received from the ground stations, respectively and the moving stations in each of them assigned even-numbered and odd-numbered times No »2 to No · 200 sent; the interrogation pulses 1 are both from the fixed as well as from the movable stations for synchronization purposes in times no. 201 to No. 548 sent.

During the time provided for synchronization (times No. 201 to No. 548), each station sends, under certain conditions, a response pulse R (not shown in FIG. 1) in addition to the above-mentioned pulses. The response pulse is sent by a station in the time interval between the transmission time at which the station sends its own interrogation pulseE and the next transmission time. _{A station only sends a response pulse t} after receiving the first interrogation pulse from another station, which is then used by the other station for synchronization

Thus each station sends during the for synchronization provided time their own impulses I and receives impulses Ϊ from other stations. Every station also sends E-impulses in response to certain received I-pulses and receives R-pulses from other stations as a response sent to the first-mentioned I-impulses of the own station · As described below, * is used each station its own interrogation pulses Γ and those of other stations as a response to their own interrogation pulses I. received response pulses R for synchronization *

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III. Synchronization of two stations

To explain how several stations in a network area (doh. all those fixed or movable stations that work together to synchronize each other) will be on Pig. 2 referred to. In. d eser Figure is the timing of the transmission pulses of two synchronized Stations of a network area shown. The term "synchronized" should be understood as follows: Provided that from each station at the moment a pulse is sent when an oscillator in the station controlling the pulse generating device has a has a certain phase angle, e.g. at the time of a positive zero crossing of a sinusoidal oscillation, there are 2 stations or their respective oscillators are considered to be synchronized if those of each station are in a particular Time sent pulses in the middle between the two stations can be observed simultaneously. This requirement applies to the synchronization of two moving stations, one fixed and one moving station, or two fixed ones Stations. It should be said again that the stations only perform synchronization during times no. 200 to No. 548 perform. However, once a station synchronizes is, this state is during the other times No «1 to 199 by various circuits in the station maintain.

To view the stations during broadcast times No. 200 to No. 548, each station sends two ways of pulses, namely interrogation pulses I and response pulses R. Each station sends interrogation pulses I in several Times according to No. 200 and response pulses R as a response on receipt of the first interrogation pulse I from another

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(second) station they own after sending out the first I-pulse receives. The first I-pulses that would be received would then come from the closest station of those stations in a network area that happen to be in the same area Send time.

Tried to get into the synchronized state each station the time of sending its own interrogation pulse I to synchronize with the interrogation pulse of another station. Each station first determines its distance from the other station. Each station measures the running time between transmission of the own interrogation pulse and reception the response pulse sent by the second station on the basis of this interrogation pulse. As the round trip time between the transmission of the interrogation pulse by a station and receiving the from the other station in response to this query pulse transmitted response pulse multiplied with the propagation speed of the signal equal to that double the distance between the two stations can be determined by dividing this result by two.

By measuring the distance between two stations, each station can also determine the actual transmission time of the interrogation pulse I received from the other station. This is achieved by determining the time of receipt of the interrogation pulse of the other station in relation to the time of transmission of the interrogation pulse of the own station and the receipt of the response pulse from the other station. If the own interrogation pulse of a station was not sent synchronously with the interrogation pulse of the other station, the main oscillator of the station is corrected>. so that the Syaterairapulse transmission time of the following transmissions is corrected ₀ It should be noted that normally both stations are synchronized

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must seek to achieve so that both corrections at the same time carry out.

Pig. 2 shows the synchronized state of two stations X and Y. The pulses sent by stations X and Y are shown on time axes a and b, while pulses received by stations X and Y are shown on time axes c and d, respectively. At time t = t _Q , both stations X and Y send interrogation pulses Iy and Iy in the synchronized state (time axes a and b). This transmission would be at any of the times No, 201 to ϊίο. 548 take place. The pulses Iy and Iy are received by the respective: Stations X and Y at the time t = t .. »The time between the transmission of Iy (or Iy) and the reception of Iy (or Iy) is called Tjjjrjj and can be in the form a voltage Ejjjrji can be measured.

In response to the receipt of the interrogation pulses at time t = t ₁ , station X sends response pulses Ry and station Y sends response pulses Ry (time axes a and b). The response pulses Ry and Ry are received by the respective stations X and Y at time t «to (time axis c and d). The time between sending Ι _χ (or Iy) and receiving Ry (or Ry) is called Igpy and can be measured in the form of a voltage E _R py or as the number of pulses from a clock generator counted during this time.

For explanation, line e shows that the station X ten time units (Tj _N rji) and / or intervals between the times t «ι« and ΐ »t .., ie between the transmission of the interrogation pulse Ι _χ and the reception of the Abfregsiapulses Iy from station Y is measuring. The X station measures 20 units of time (T _R py) or the intervals between the application of the

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16162A3

own query pulse Ι _χ and the receipt of the response pulse Ey. Since the interrogation pulses ϊ _χ and Iy are initially synchronized, the station Ϊ also measures the same number of units of time or intervals (10 and '2O) between the transmission of its own interrogation pulse Iy and the reception -cLes interrogation pulse Ι _χ and between the transmission of the query pulse it Iy and the receipt of the response pulse E ^. In the synchronized state, ^T RPY or ~~ RPY behaves like 2:!. 'This time and / or distance

INT ^E INT,. ~ '

measurements can be made analog by storing one proportional to the time Voltage with the help of a capacitor or digitally by counting the pulses of a high-frequency clock generator take place. Both methods are known per se.

It should be noted that, in the case of synchronized stations, the distance from station X to station Y in station X is determined by measuring the transit time between the transmission of the pulse Iy and the reception of the pulse By. Station Y determines the distance to station X by measuring the transit time between sending I _Y and receiving EL »Der

also λ -

The distance between two stations is equal to half the measured time multiplied by the speed of propagation _o , The distance between two stations is also equal to the time from the transmission of the pulse Ι _χ (or Iy) to the reception of the pulse Iy (or X ^) multiplied by the speed of propagation . .

As can also be seen, when the interrogation pulses Ι _χ and I ^ are initially synchronized, each station receives the interrogation pulse sent by the other station in the middle of the time between the transmission of its own interrogation pulse and the reception of the Änt sent by the other station -

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word pulse. This follows from the fact that the running time between the transmission of an interrogation pulse by a Station and the reception of the "interrogation pulse sent at the same time by the other station is equal to the distance between the two Stations divided by the speed of propagation 'is. The duration of the pulses between the sending of a Interrogation pulse by a station and the receipt of a Response impulse, which when receiving this interrogation impulse from the other station is sent is the same as the double The distance (the outward and backward path) between the two stations is divided by the speed of propagation.

Finally, it should be mentioned that there is a small mistake in the measurement results when the two stations move relative to each other. This error is proportional to the distance and the relative speed of the stations. With a typical distance of 300 km between stations and one Relative speed of about 1000 km per hour

_q this error only on the order of 10 seconds, which is negligible compared to the overall accuracy of the system is.

If the interrogation pulses of the two stations do not start from the beginning are synchronized with, a station sets after measuring the time from the transmission of its interrogation pulse to Receipt of the interrogation and response pulses from the other station realizes that their own interrogation pulse in relation to that of the other Station is too late (or too early). The other station notes that your interrogation pulse with respect to that of the first station came too early (or too late). Behave accordingly the time or voltage measurement results are not displayed in any station ΐ ^ ργ or Ε ^ -ργ from the measurement of the larger inter-

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valls from the transmission of an I-pulse to the receipt of an R-pulse. to the time or voltage measurement results "from the measurement of the smaller interval from the transmission of an I pulse to the reception of another pulse such as 2: 1o ·

The unsynchronized state between two stations is in Pig. 3 shown. Here the station Y sends its interrogation pulse Iy at time t = t ₀ + ΔΛ * This point in time is delayed by Δ ± t compared to the point in time t = t _{Q of} the transmission of the interrogation pulse Ι _χ . You can see (time axis c) that station X receives the pulse Iy at a point in time that is a little later in relation to the middle point between the transmission point in time of the own interrogation pulse Ι _χ and the reception point in time of the response pulse Ry, which was sent by station Y as a response to the interrogation pulse I _v . It can also be seen (Zeitaehse d) that the station receives the interrogation pulse Ι _χ before the middle point in time between the sending time of its own interrogation pulse Iy and the receiving time of the response pulse R _x , which is received from station X as a response to the interrogation pulse Iy was sent. The size of the deviation of the ratio of the two times measured by the stations X and Y from the ratio 2: 1 in the synchronized state is proportional to the synchronization error. This is quantitative in Pig. 3 , from which it can be seen that station X has 13 units from time t * t _Q to reception of the pulse Iy at time t = * t .. + At and 20 units from time t "t _Q ^Μ " to reception of the response pulse Ry at time t * t £ . The station Y measures 7 units from the transmission "time t = t" + Δι dee pulse Iy to the reception time t "t. Of the pulse Ι _χ and 20 units from the time t * t _Q + At to the reception of the response pulse it R _x at the point in time t »tg '+ At

1 0 9 8 H / 0 43 6

or voltage ratios of 20:13 and 20: 7 for the stations X and Y, from which it can be seen that the stations are not synchronized are. If the error was reversed when sending, i.e. that station X sent later than station Y, then the measured values and ratios would also be reversed. In both cases, the result is the opposite of the measurement the deviation from the synchronization ratio 2s1 resulting from the Synchronization related.

The operation of the system is based on the fact that at each station the time between the transmission of its own interrogation pulse I and the reception of the response pulse H generated by another station when the pulse I is received is independent of the synchronization and only, as in conventional punk beacon systems, of the distance between the two stations depends. The measurement of the distance is based on a time measurement. On the other hand, the time at which the interrogation pulse sent by the other station is received depends on the synchronization and the distance between the two stations. If the time of receipt of the interrogation pulse of the other station is before or after the middle time between the time of sending an interrogation pulse and the time of receiving a response pulse sent by the other station in response to this interrogation pulse, the result is that the two stations are not synchronized . The value of the error, whether greater or less than half the time interval, is used to correct the oscillators of both stations so that the stations are brought into the synchronized state.

The temporal synchronization error can occur in several ways be measured. For example, capacitors and

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uchaltglieder are used, with the own query impulse the station charges two capacitors to the voltage predetermined by a voltage source by actuating an electronic switch which is connected between each capacitor and the voltage source. The charging process of one capacitor is when receiving

the interrogation pulse sent by the other station ended, by this impulse to measure the time Üj ^ and to Generation of the voltage E-j- ™ the switch to disconnect the Switching initiated by the voltage source. The charging process the other capacitor is affected by the interrogation pulse the response pulse received from its own station Measurement of Τ-οργ and generation of Ερργ finished. The different Pulses are decoded by a pulse decoder and suitable circuits in the station receiver fed. Also the capacitor that has the time Tgpy between Measures query and response pulses, loads on half Value of the one who measures the time Tjjym between the transmitted and received interrogation pulses »Im synchronized The state of both stations is therefore the tensions and E-pjjm are the same on the two capacitors

If the stations are not synchronized, then a Error voltage generated that is used to phase control an interrogation pulse oscillator is used in one or both stations. However, others can also measure the time known timing circuits can be used. A circuit digital type would be a circuit in which two counters for Counting the pulses of a clock oscillator from the interrogation pulse your own station can be started »The counting process of the one The counter is determined by the one arriving from the other station Interrogation pulse ended while the other was counting is terminated by the response pulse arriving as a response to the interrogation pulse from its own station. The difference in two counting results is used to generate a control voltage which in turn is the phase of the interrogation pulse oscillator

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controls. If you want, you can also design the second meter so that it counts every other pulse of the clock, so that the counts of both counters are subtracted directly and used for generation the fault voltage can be used.

Figure 4 shows an analog circuit of a station for generating the error voltage which is used to synchronize the interrogation pulses of the station with those of the other station or stations operating in the area. The Sqhaltung contains an interrogation oscillator 11 which controls an interrogation pulse generator 10. The pulse generator 10 supplies interrogation pulses to an interrogation pulse switching element and a transmitter (not shown in this figure) and to two timing circuits 13 and 15. The circuits 13 and 15 measure the times Tjjjm and Τ ^ ργ and generate the respective voltages Ej ^ and Ε ^ ρ _Τ . The interrogation pulse of the generator 10 triggers the timing cycle of the circuits 13 and 15. As I said, these circuits can be capacitors that charge to a certain voltage. In the case of voltage 13, the charging process is terminated by another interrogation pulse, which is received by the station receiver, decoded from other received pulses and fed to the measuring circuit 13. The voltage Ep ™ generated by the measuring circuit 13 is a measure of the time between the time at which the station's own interrogation pulse was sent and the time when the other station received the interrogation pulse. The measuring process of the circuit 15 is terminated by the response pulse arriving from the other station and the voltage E "py" is generated. As already mentioned, the circuit 15 preferably loads to half the value of the circuit 13 to _s so that when the two stations are synchronized, the voltage Ej, ™ equal to the voltage Ε ,, ργ is. The synchronization error voltage is generated by a subtraction circuit 19 in which E * «« is subtracted from Ε «ργ. When the "two stations are synchronized, the output of circuit 19 is Hull and thus no error voltage is generated. However, if the two stations are not synchronized, an operating voltage is generated. J

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The magnitude and polarity of the error voltage depend on the size by which the query pulses of the two stations were too early or too late in relation to one another. The error voltage is fed via a low-pass filter 2 to a motor 3 which controls a phase shifter 14, which is connected between the interrogation pulse generator 10 and the interrogation oscillator 11. Depending on the magnitude of the error voltage generated by a circuit 19, the motor 3 moves the phase shifter 14 in such a direction that the signals from the oscillator 11 are corrected and are advanced in their phase by the correct direction in order to synchronize the interrogation pulses of the generator 10 with the pulses of the other station. The synchronization is preferably achieved by advancing the sensor of the trailing station or of the other Station, a correction in the reverse direction is not carried out.

With such a constant correction carried out at a station, instead of half a correction - _f: the synchronization is achieved more quickly and furthermore the so-called "red-green logic ¹¹ in a known system is avoided. Large corrections are preferably repeated before they are carried out Confirmed to Correct Noise or Faulty Clock Oscillator Errors 25U * For this reason, large corrections must be displayed twice and of the same amount before being made. For this purpose, known digital storage and comparison devices can be used for timing. '\

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IV. Synchronization of more than two stations

In the previous section, the synchronization of two stations described. In this section it should be shown that the synchronization of more than two Stations belonging to the station network or station group to be synchronized can be reached, although multiple stations make synchronization difficult. The difficulties that arise are intended for the lall of three stations X, Y and Z to be synchronized are explained, which are not initially synchronized. In any who Each station sends no. 200 subsequent transmission time X, Y and Z an interrogation pulse. These interrogation pulses are initially not synchronized. In addition, each station sends a response pulse in response to receiving each query ^ · impulse. Therefore each station receives two interrogation pulses, which are sent by the other two stations, and four reply pulses, namely two reply pulses each from every other station as a response suf the "two interrogation pulses, which each of these other stations receives. Two of these four response pulses received by each station are the answer to the one sent by the station itself Query pulse *

With the synchronization carried out only by advancing or advancing, no difficulties would arise if station X with station Ϋ, a station Y mil? the station Z and the station Z synohr & nieiert with the station X. It can be shown that in such a case the _; Synchroni sat i ^ nsfehler verainffejrl is AUOH _r how big y always the correction will be. All stations try to synchronize themselves with the station whose clock oscillator is most rapid. I.

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To adjust how several unsynchronized stations are spichronized in a convergent way, the following qualitative explanation is given. It is assumed that there are 200 stations in the Yerbund area. Each station contains an oscillator to control the interrogation pulse generation. Let the output signal of each oscillator differ in phase by the same amount "with respect to that oscillator" whose phase is closest, so that the phase angles of all oscillators are evenly distributed. This results in a synchronization interval of 360 ° for 200 unsynchronized stations _t in which the oscillators are not synchronized, a phase difference of 1.8 ° between the phase angles of successive oscillatorsIf iä & n represents the output signal of each oscillator as a time vector or * pointer, then there are 200 pointers, whose sightings are each dead 1 _s 8 ° differ from each other «If all pointers point to the same sighting, then all oscillators are synMirö & iistert»

If one, any two pointers from the rovh & iiäen & n selects 200 pointers and "the ■ naolioilesadaa feitfcors advances j Phase" until it covers.-Die, with & r phase of / leading pointer * then the staüd two pointers or "stations synchronized" Such a phase correction of the oscillator of each station can be achieved with the help of the switching of I ¹ Ig ₀ 4 * The motor is driven in such a way that it changes the phase of each oscillator via the phase shifter simply by shifting the phase j so that the lagging oscillator moves with the end of the gate Oscillator ■■ synchronizes _a iferöen, dana-swei · other arbitrary pointers hersu $ ge.sue! X & - ₇ which neither € © a first nor the second pointer of the first pair of pointer holdii ^ ■ then these two can come together. ' Pointer also through -fox ^ üulmn of the lagging pointer

_e .WeBa © s sieit, with the second pair of hands.

_24-

is again about the first pair of pointers, then none will be found Correction takes place because the two pointers are already synchronized. However, it becomes a pointer of an already synchronized Pair of pointers used for a further comparison, then the synchronous state of the pair from which the one pointer was searched is canceled.

By continued random selection of pairs of hands and by moving the cursor with the lagging phase the uniform angular distribution of the pointers changes with 1.8 ° between the pointers in a non-uniform distribution, in which the angular areas with higher angles are more densely populated with pointers. As a result of the larger Number of pointers in the angular ranges with larger. Angles More and more pointers are quickly moved from the angular regions of lower angles to those pit higher angles. When more and more pointers advanced into the preferred angular range will take the. Probability that two pointers from the preferred angle range will be used for comparison instead can be used from the unpreferred area. That means that, despite the statistical comparison process, there is a finite number of comparisons, so that all Stations can be synchronized with each other, even if initially no station is synchronized with another was.

The convergence or synchronization of all stations The time required depends on the once a given tolerance or a given error! Number of stations to be synchronized in a network area, on the other hand on the number of required Comparisons and finally on the speed with which the comparisons "can be carried out * The last

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-25- ■ - ■ - ■ ■ ·

named factor changes with the maximum expansion of the system. D _a s means that the time between the individual transmission synchronization times also increases with increasing expansion of the system or the irerbund area in which stations are to be synchronized with one another. This also reduces the number of intervals provided for synchronization purposes per second. Even if several times are reserved for data transfers, fewer are left for synchronization purposes, so that the time required to achieve convergence increases. -

With the help of Fig. 5, a typical example is used to explain how much time is required for synchronization (convergence): is. In Fig. 5, the synchronization times are plotted for a system in which 350 of a total of 550 intervals per Second are available for synchronization purposes. The oscillators of all stations oscillate deäialb during the synchronization time with a frequency of 550 Hz »i.e. a period of 1818.1 microsecondji or approximately 1800 microseconds. If the oscillators save for one Oscillating errors of no more than 0.01 ° phase-synchronously, i.e. that the pointers all but a part of 56000 Divide converge, is the maximum equivalent timing errors between the oscillators 1800/56000 or 0.05 microseconds. This means a maximum error when measuring a distance of only about - 15 m as a result an incomplete convergence * This error is; insignificant at the current high airspeed »

In Pig. 5 shows the number of comparisons that are necessary to produce n stations with a probability of 0.99 to synchronize, being utterly brazen state

109814/0438

Asynchrony is assumed. It should be noted that this is the most unfavorable state, since it is assumed that all stations are initially not synchronized. Normally in the worst case only those situations arise in which the network area contains only a few non-synchronized stations or in which there are only a few non-synchronized stations add some unsynchronized stations to many "already synchronized" stations in the area. The prerequisite for deriving the functions plotted in Fig. 5 is a convergence with a probability of 0.99 starting from a state of uniform distribution of the phases of the oscillators of the various stations. As can be seen, this is necessary for complete synchronization Time relatively short. With 100 stations around 800 comparisons are necessary to achieve perfect synchronization with a probability of 0.99. Under the conditions mentioned with 350 synchronization intervals per second, synchronization takes around 3 seconds.

As already said, the worst initial conditions have been assumed for the diagram of Figure 5, namely that all stations were originally not synchronized. In the normal case, however, the conditions are such that in the entire network area only a few unsynchronized stations that are synchronized in a few seconds, or there is a network area with several synchronized s Stations to which a few did not synchronize Stations to be added. In the first case, the few stations in the area could possibly be without a special one Procedures are synchronized. Instead of these few; unsynchronized stations belonging to the larger group synchronized stations are added, see below, a. or more of the last-mentioned stations from the Synchronis-? If you have to move, in the latter case a search and take-away.

109814/0431

■ ■■ -.-. - ν- 1816243

procedures are applied. If the majority of the comparisons made in a station in the network area for synchronization purposes show that an oscillator phase correction is required, which indicates that the station is not synchronized from the start, the station applies the full correction (ie the search method). However, if the majority of the synchronization comparisons result in little or no phase correction, which would mean that the station is synchronized, only a fraction of the correction (the entrainment method) is applied. Thus, the phase of the oscillator of a station already synchronized with several other stations only shifts Tim a very small amount in the direction of the phase of a newly added, unsynchronized station, since the majority of the phase comparisons in the synchronized station show that there is no oscillation phase correction is required. On the other hand, gives every comparison that performs the nichtsvnchronisierte new station, a large! Error so that sine erheKLiclie phase correction is required "That's why this station applies the full Phasenko33Ektur in the search process, ils ife ^ si oscillator with oscillators of other stations ia © löiefefsicft BU

The synchronization of all stations ^ in a predetermined i ^ ebiet can werdem achieved faster by a coarse Synöhronisationsverf _f is applied Ahren re ation wherein j ny in the area adventitious St the ^ nktinftszeitpunkt the received start pulses "beobaohtet and sxeii initially with these Pulses synchronized before they are finally synchronized with the query pulses »This procedure is described below».: -; - ^v "-.-.-" .- "■" ■

¥ ie already stated above Isimm- the "& m SynehroniBation

^BAD OBiG

two stations required. Time through a rough Synchronization can be reduced. - In the case of coarse synchronization 'there is a temporary setting in the synchronization interval the time at which the interrogation pulses of a station are sent, taking into account the times when the start pulses are received other stations. The coarse synchronization method prevents also the transmission of interrogation pulses by a * station, before the synchronization with the rest of the stations in the area is carried out *

When a new, unsynchronized station that is in a Area of synchronized stations wants to change the start pulses sent by the other stations in the area B observed, she will notice a few start impulses of greater amplitude from stations in the immediate vicinity, those an increasing number of start pulses with a smaller amplitude from more distant stations follows * This follows from the fact that that the number of stations for a given traffic density with the square of the distance from a station increases. if the new, unsynchronized station the distance to the closest synchronized station in the area knew, she could the Seale time of her interrogation impulse like this set it to be in sync with the area as soon as it was sent. This is easy to achieve, though the distance between the synchronized and non-synchronized station is known, since the non-synchronized station is derived from it can determine when the synchronized station sent. Therefore, the new station can be synchronized as soon as it does first time sends. Such a device can be used when, for example, an unsynchronized aircraft wants to leave an airport whose airport station has the Stations of the network area is synchronized, and if the new station the distance from your current position, e.g.

at the end of a rollbann »to the airport station. Dip lets

BADORIQiHM. ί

109814/0436

can be easily realized by making roller track markings, Auxiliary radio signals, etc. "provide" for the! Case that the distance two stations "is known, the rough synchronization procedure is • not mandatory.

Coarse synchronization is used when the. new Station does not know its distance from the nearest synchronized station in the area. In which large / en synchronization method shifts the new non-synchronized Station the phase of your oscillator so that your query pulses synchronized with the first start pulse B (Time # 1) synchronized them from the closest synchronized station in the area. It should be said again that every interrogation pulse in Zettpunkt must be sent, which are some time after the transmission of the start pulse (i.e. from the time Mr. 201 an), but with a fixed temporal relationship to the Start impulse as determined by the main oscillator of the station. So the new station sends its own Interrogation pulse before any other interrogation pulse. receives because the first start impulse is that of the next synchronized station located and the interrogation pulse that nearest station will be received by the new station before the interrogation pulse of any received by another synchronized station. With this method, the maximum time error that a new stetion can take is .when entering the area regarding the "have synchronization." can, like the transmission gazei "^ of an impulse from the am next synchronized station to the new one Station.

To explain the advantage of the gross synqhronisaijion let assumed that the interval between the permitted synchronization transmission times (Points in time Sr. 201 etc. ») 1800 microseconds

109814 / 0-436

1676243

and another station 50 km (180 microseconds Transfer time-) is removed · In this 3? All would be the possible Initial synchronization error between the "two stations, if the new station were allowed to transmit at any point in time, plus or minus 900 microseconds. By using "coarse" synchronization it is possible to eliminate the initial synchronization error in the Reduce airtime between the two stations. In the example shown, this Pettier is approximately 180 microseconds. This becomes clear when one assumes that, when the station starts its oscillator with the time it receives a start pulse from the one in close proximity Station synchronized, the oscillator of the new station is no longer out of synchronicity, than it is determined by the transmission time of the start pulse B from the other station. Therefore needs just a phase correction to compensate for this initial one Transmission time to be made in order to achieve a coarse synchronization. Is the rough synchronization once reached, the new station "carries out" the real one Synchronization in the manner described above. The fact that a rough synchronization is carried out first allows the absolute synchronization of the new station with the area faster, so that the ready synchronized stations in the area cannot be pulled apart by far Oscillators, if any, are brought out of sync. This also follows from the above description of Synchronization. '

To explain the coarse synchronization process, Referring to Figure 6A, there are three stations X, Y:

and Z shown, which differ in some ent £ $ 3? biaig from each other t

109814/0430

but not in a straight line. These

stations may not initially be synchronized. The letter indices of the pulses in FIG. 6B relate to the transmitting station and the numerical indices to the interval in which the event takes place. In FIG. 6B it is assumed that station X is the first to send a start pulse B _{v Λ} (time axis a) during the first 1-second operating interval, and that stations Y and Z are to be roughly synchronized with X. The start pulse By * is received by station Y during the first 1-second interval {time axis b) at a point in time that corresponds to the distance between stations X and Y. The station Y shifts the phase of its oscillator so that this aainen start pulse B ^. ₂ sends when it receives the second S-cart pulse Β _χ _ ₂ from station X (time axes b and "c) during the next 1-second interval. Station Ϋ wet its start pulse By__ ₂ one second after receiving pulse B _x - send enξ, in order with the arrival of the second start impulse Bj_2 of station X mx fcoinzidiereii, since station Y does not receive the first start impulse B ^ * of station X at the same time, the phase of its "oscillator ire & ea and. can send its own start impulse _o Di © Stetioa 2 receives the start impulse B ₇ . from the station X, - b © irö2 -;? may ömpfangen .. ssle feu ..Impuls By _-2 from the station Y * Therefore AEIE station sends a start pulse% _-2 Bg v hile, d the second interval in Brnpfangsseitpunkt ^? s Impulses Bv- ^ ₂ #.! EatsaekLich the station % receives the start impulse from the Statics X always in the interval that follows the first one, unless Q.mm _s the S tat ion Y lies on the connecting line between the stations. X and 2 * You can see that all stations are now except for öeU-iaa ± ffialeÜeiiler. _s which are conditioned by the transfer ae.lib or running between the stations X and Z, are roughly, syüelaonisiert * Is it necessary to know _? that the stations J waä% a closer - in synohroUism. sitia as the StstöJieii. t -imä K ■ or "-3

YI. Synchronization of two pairs of stations in a network area with several stations

In section Y it was assumed that the synchronization was only possible during a certain synchronization interval if three stations were transmitting. It is possible, Build systems in which each station randomly receives I pulses during a fraction of the synchronization interval sends. This would result in several intervals in which only two stations send I-pulses, so that one successful phase correction can be carried out. However, as will be described below, this is not necessary since the synchronization takes place during an interval can be reached when three or more stations are transmitting.

If only an "advance of the trailing pointer is made, all stations can converge with the most leading station clock oscillator. This affects the fact that only phase corrections are made in the forward direction.

In this synchronization method with advancing phase correction, the synchronization with the first received interrogation pulse and the first received response pulse carried out, assuming that the first response pulse received is not from the same station needs to be that sent out the first received interrogation pulse. Since phase corrections are only carried out in the leading direction, a mismatch occurs the response with the query pulses none Overcorrection. The right one to match the query pulse

1098U / OA36

Response pulse can only be followed by the first, the query pulse received response pulse or a later pulse. • In the last! Case, a mismatch occurs. The response time is too early and E-npy (see Mg. 4); too small. The error signal sent to the phase shifter is therefore also too small and a correction occurs. This synchronization attempt does not lead to synchronization, but is at least as harmless as no attempt to synchronize at all as a result of an uncertainty as to whether an interrogation pulse belongs to a response pulse.

If the transmission of the interrogation pulses to a special Station with a relatively fixed frequency is optional, then you can mathematically show that the number of successful comparisons that require synchronization a station will result in about $ 62. That means that a station corrects its synchronization time in $ 62 of the total time at which it sends out interrogation pulses. It is also possible to increase the random or arbitrary pulse frequency as the traffic density decreases. In order to you can optimize the efficiency of the system.

VII. Selection of the number of permissible transmission intervals

As described with reference to Figure 1 and in Section II, are specific transmission time in each 1-second period of the Data transfer reserved during other times (and the one following this until the next time Interval) excluding the synchronization or the Maintaining the synchronism of the stations with each other

109814/0436

are reserved. It should be noted that it is desirable to have as many points in time for the transmission of information pulses available as possible, since the amount of data that can be transferred per unit of time increases with the number of to Available transmission times increased. On the other hand, it is also desirable to keep the number of times available for synchronization purposes as large as possible as this minimizes the time required to synchronize the stations with one another. It should however, it should be mentioned that the reduction in the number of points in time, i.e. the lengthening of the time intervals between the transmission times, contributes to reducing the average distance between the stations that synchronize with each other, because with a certain number of stations that transmit with a certain frequency, several in some certain Time will be sent.

In any case, by increasing the number of times for data transmissions or for synchronization purposes, the upper limit of the number of permissible transmission times of a station is determined by the possibility of an error when receiving any pulse, namely whether this pulse was sent in the current transmission time interval or in the previous interval became. In general, the reception of pseudo pulses, ie pulses from a previous interval, can be prevented by providing a sufficient time interval between the permissible transmission times so that the reception of these pseudo pulses by the attenuation occurring on the transmission path of these pulses and / or by interruption the straight transmission path through the earth's surface is prevented. In most cases , the interruption of the straight transmission path due to the curvature of the earth is more reliable. The criterion for the interruption of the straight-line transmission path as a result of the ^? Earth's curvature is explained below »'

109814/0438

A pulse sent by a station will be sent by a other station at a distance r after, t seconds received:

ß is the speed of propagation of the signal (300,000 km / sea), The distance of an aircraft from ^; Horizon, which flies at a height h above the surface of the earth, is:

(2) r. = 2 (2. -A-) ¹ /. 1.6 km ';

ⁿ o, 3 m "-" ■■■ ".-.- ■

Therefore the maximum distance between two planes is · that fly at a height of h meters and which are straight can still see above the horizon:.

(3> 2 r _h = 2 (2 » ^Ά ) / _v 1.6 km;

ο, 3 m

If the direct distance r between two stations is greater than 2r, is, -will be the pulse sent by one aircraft from the other aircraft as a result of the interruption the earth's surface received a strong dampening. Although that after signal received from the interruption by the earth's surface as a result of refraction, scattering and reflection; of the signal is not lull above the horizon, the amplitude will be. so much attenuated that it is through a suitable threshold value circuit can be easily suppressed *

If you see the curvature of the earth (the radio horizon) to Undersection of the transmission pulses of two neighboring, network areas to scoop, can possibly get "by inappropriate

LÄD ORDINAL ■ '

- ■ 1098U / 0A36

• 1618243-

> WaJiI the transmission time instant repetition frequency in the synchronization a mix-up or confusion between already synchronized stations result. This confusion can arise among the various interrogation and response pulses sent during two successive synchronization intervals by two or more stations that use these pulses to maintain the synchronous state. In order to avoid confusion during these intervals, an interrogation pulse sent at a permissible point in time or a response pulse sent in response to a received synchronized interrogation pulse must not be received by any station at a point in time that follows the next permitted transmission point in time. The query or response pulse sent in a certain synchronization interval should not be received by another station in the next synchronization interval. Since the response pulses are sent later than the question pulses in each interval, the response pulses can easily be eliminated as a source of confusion by preventing the transmission of the response pulses from a station after a time which is greater than the maximum distance P-. . up to which the synchronization with other stations should take place.

In order to explain this quantitatively, it is assumed that the maximum height of the stations (e.g. aircraft) using the system is 12,000 m. From the above equation (5) results in the maximum viewing distance 2r. between two stations of 900 km and a transmission resp. Running time of 2r ^ _ ^ milliseconds. If the system is like that

BATHROOM QM (NAL 109814/0436

should be interpreted that the stations never interact with others Synchronize stations that are more than 160 km away *, the transmitter of each station can be controlled in such a way that it starts running after 0.577 milliseconds, calculated from the time of transmission of its own Query pulse, no longer sends a response pulse. The time of 0.577 milliseconds is the time it takes for a response or Interrogation pulse required to cover 160 km. Will the Transmission of the response impulses after 0.577 milliseconds interrupted, then a station cannot respond to interrogation pulses from another station that is more than 160 km away. It follows that when the synchronization transmission timings

- seconds are away (3 + 0.577 = 3.577 milliseconds in the example above), an answer from a first station to a received interrogation pulse, which was sent by a ,, other Station sent at a given time, the reply pulse sent not from the other in line of sight of the first Station located station can be received during the interval following the next point in time. The reason for this is that any response pulse of the first station before

max seconds (0.577 milliseconds) are sent r -. · '. .

^c 2r / - *

must, while the line-of-sight time of h seconds ^ milli-. "

Seconds) ensures that the pulse * is from one in sight the station located at the first station is received at the same interval. For me one that is flying beyond the horizon ! In the aircraft, the response pulse is interrupted or attenuated by the surface of the earth. Although as an example a maximum Altitude of 12000 m has been selected, it is pointed out that that this also applies generally to aircraft that are in larger Flying highs. For example, if the maximum flight altitude h = 15000 m, then the viewing distance increases, and the The time between the transmission times must be increased proportionally to Th to avoid confusion (see equations (2) and (3) y | kj> ^ i £ 'Correspondingly, the time between the

109814/0436

-38- 16162 A3

Transmission times are reduced when the maximum flight altitude is decreased.

It should be noted that "at a distance of 3.577 milliseconds between the individual transmission times' a permissible transmission frequency of only 280 Hz for data transmissions and synchronization purposes. This corresponds to about half of the total number of points in time at the description of FIG. 1, with only about 80 points in time remaining for the synchronization. The number of times can, however, be as follows in the description of FIG. 1 Way to be doubled. The interrogation and response pulses of the preferred embodiment of the invention are real Pairs of pulses which, as in a well-known TACAKT system, can be used to distinguish between noise and interference pulses. By systematically assigning different distances between the pairs of impulses there can be many impulses in different Points in time are differentiated. For example, every pair of pulses with even times (Br. 200, 202, etc.) are assigned, a certain interval can be assigned, while the pulse pairs of the odd-numbered points in time (No. 201, 203 etc.) a different distance is assigned. Then the pseudo impulse or the pair of pseudo impulses is that in a straight line or odd transmission interval of a certain station appears, but was sent in the immediately preceding interval, incorrectly coded and can therefore be disregarded be left. If, for example, station A tries to synchronize at an even point in time and polling and / or receives response pulses in the preceding were sent at an odd number of times, these will be the have wrong pulse spacing code so that they are from station A

1098U / 0436

can be excreted * The two time points earlier in 'a number of degrees strength at the time the transmitted pulses would be, however, sent by a station, which is so far away that the amplitude of these pulses ist§ at the receiving station too small to become noeh _x detected. The number of points in time can therefore be doubled with the aid of the erosion process, to a total of 560 points in time, in order to remain with the above example. ;

The above statements with regard to the pseudo query and response pulses also apply when a non-synchronized station is present in the Q-area. Plug-in tools ₉ that are within sight (above the horizon) of one another, the aircraft status is already synchronized before it moves away from the. Floor lift-off can correspond to the above statements. Signals from the non-synchronized station, if it is at low altitude or on the ground .., are not received by a station that is more than 480 km away (if these stations do not fly higher than 12000 m) . The distance of 480 km corresponds to a synchronization error of the oscillator of the unsynchronized station of approximately 180 °. This means that this non-synchronized station would have to send its interrogation pulse by half the distance between three transmission times so that its interrogation pulse arrives after the next time, which begins at another station 480 km away. As "" ■ said before, "errors of this magnitude are avoided by a coarse synchronization that precedes the transmission of any pulse from a non-synchronized station« .- ■ ■ ■ ■, ■ -. _: , -.... ...

109814/0436

This consideration of some criteria that must be observed to determine the transmission frequency "in order to avoid confusion between the query and intwertimpulses, a further possible risk of confusion should be considered. This risk of confusion arises when information signals - from synchronized ground stations and from" mobile stations (Aircraft) are sent. As explained with reference to FIG. 1 and also shown in FIG. 8, the information signal transmission times change between ground stations (even times) and aircraft (odd times). In order for the system to work accurately, each ground or flight station should have any or every received pulse in relation to its origin in space (from an aircraft or a ground station) and in relation to its temporal origin. Origin (the time or the interval at which it was sent). The first point to be examined would be the likelihood of confusion that could arise in flight stations between information pulses sent by a ground station and information pulses received from an aircraft that was transmitting at the previous point in time. This is explained with reference to FIG. 8 "In FIG. 8, time no. 5 represents a transmission time of an aircraft flying at a certain altitude ", while time Mr. 4 represents the transmission time of the information from a ground station B. the time ITr 4folgenden time can receive information pulses. that He sent · 3 from another synchronized aircraft at the time, received from the first aircraft pulses can cause confusion. is the possibility of confusion wiedemn from on high © the flight station, Time between the airtime pudcten and the distance between the stations is determined.

109814/0436

TJm "to stay with the example in which the first. Flight / bation, in which a mix-up can occur, in one Flies altitude of 12000 m, this station is 450 km from the Horizon away. For the purpose of explanation it is also assumed that the transmission times are now with a frequency of 400 Hz occur * This means that the time t. between these. Points in time is 2.27 milliseconds and a Signal covers a distance d of 680 km during this time.

Weii / -Sren
So that a from a / airplane at the time of Mr. 3 transmitted information pulse the aircraft viewed after the point in time Er. 4 and causes confusion, the distance between the two stations must be at least equal to the distance covered by a pulse in the time between two transmission pulses. In this example this is 680 km. Therefore, one more: Station that can cause confusion must be at least d - ■ r. km (or 680 - 450 = 230 km in this example) beyond the radio horizon of the first station. So that the transmission between two aircraft is not disturbed by the horizon, the other interfering aircraft must fly at least 3000 m high in this example. Thus, there is no interference or mix-up in the first station in all those information transmission times and those following intervals that are assigned to possible disruptive aircraft flying at altitudes below 3000 m, since the information pulses of the possible

"-ι- '. ■ ■. - ■ jamming stations interrupted by the surface of the earth.

If the possible Stor aircraft flies at a higher altitude than is necessary for the linear visibility expansion, and cause confusion, there is a possibility that interference will occur in the first station, and in the interval that follows that of the information transfer assigned to aircraft flying at an altitude of 6750 ra.

109814/0436

In general, no interference "or" confusion of the information pulses of two aircraft can occur if the sum of the distances of the "two stations" to the radio horizon is less than the distance that a pulse can cover in the time between two transmission times. The reason for this is to be seen in the fact that an information pulse is received in the correct interval if the distance between the stations is smaller than the distance that the pulse can cover between two transmission times. If this condition is not met, which will only be a small fraction of all of the 3? All, namely if "both stations fly at relatively high altitudes and have a large, straight-line visual propagation distance, pulse coding is sufficient to capture the information pulses sent by airplanes from different pulse codes are assigned to the odd and even transmission times of the aircraft and ground stations. This coding can relate to the pulse intervals as explained above "b the received information pulses come from a station that sends at an odd or even point in time. If the code ä & m corresponds to the instantaneous transmission time, then the pulse is accepted. If the pulse is coded according to the previous point in time j it is suppressed. According to the concept used here, the expected number of possible interfering information pulses in a station is kept so low that the probability that "knows; Aircraft pulse pairs randomly the ground station pulse spacing; have is extremely low. ,. i

1098U / 0A36

* ■. -43-

Another possibility for eliminating the few plug-in information impulses from previous intervals, which can interfere and cause a mix-up with the received ground information impulses, is Met et the relative intensity difference of the impulses received from an aircraft, which results from the distances between the stations » Assuming that the first aircraft under consideration and the potential interfering aircraft are both in the worst! from the interfering aircraft in the previous interval Tlnd in the interval under consideration received information pulse from the first aircraft at the location of the first aircraft · is minimal. This ratio can be calculated as follows. Let the distance of the receiving first aircraft from the ground station be r and the distance "which a signal has traveled in the side between two transmission times, let d" be taken. then for the Abstatt? Sending times, for example 2.27 milliseconds, the Batfäijnung must reach the interfering aircraft (d \ r) or (68 (Hr) km b © trageii _s so that the interference information pulse of the interfering aircraft sent during the previous interval arrives at the same time as the information pulse from the ground station. The top-position ratio of the two signals is ■ "■■." - '

C —Ξ— Γ or (Γ
d + r 680 ^ r

This ratio increases with increasing ^: .r. However, if both airplanes fly at a height of 12Ö0Ö m ^ the maximum distance between the two aircraft (due to the horizon) is 900 kins, so that you can see from the difference% ^ d the maximum r _s d * h #

109814/0431

In this example, r results in 220 km. The smallest "ratio of the signal amplitudes is therefore ^r max,

which in this example results in (220/900) or approximately - 12 db. Is the distance of the plane from the ground station less than 80 km, the * balance difference is - 20 db, "while beyond r___ (220 km), calculated from the ground station almost at all: there are no interference signals. With the appropriate setting the amplification of the receiver of a flight station, namely so, that signals with a smaller amplitude than corresponds to the smallest signal ratio (-12db) are not amplified v / ground, all signals that are sent from distances greater than d = 680 km can be based on their amplitude distinguished and eliminated. With the above description, of course, the same output power of both the iTugzeug and also accepted the ground stations. In addition, the ground stations should preferably transmit with greater power, about the greatest possible ratio of Hutz to interference signals available even at extreme distances for emergency purposes * because this makes it easier for interfering signals to be separated from useful signals can be distinguished and eliminated or suppressed. The adjustment of the gain of the receiver can also be done automatically with the help of a suitable automatic gain control or by hand so that only signals above a certain amplitude are amplified. This is at Common to radio receivers *

The next step is to examine whether there is interference or mix-ups in an airplane between information impulses of another aircraft that was at that point in time

109814/04 38

and information pulses from a ground station may occur that were sent in the previous time ". Since in the example described, the removal of the Aircraft is 450 km "from the horizon, if it is 12,000 m high, flies and the time between two transmission times corresponds to 680 km, such interference cannot occur, there is a potentially disruptive ground station beyond the Horizon lies. Therefore, interference in itself is not so problematic as long as the time t ^ between the transmissions it is chosen accordingly.

Also the interference of the signals from two ground stations in the one ground station is not problematic in itself, since the signals of the ground stations are generally not received from each other because the stations are out of order Visibility, i.e. * are below the horizon in relation to each other. So there is no confusion, - because t. is not exceeded.

Briefly summarizing this section, it can be said that the various criteria for selecting the transmission frequency have been discussed in order to minimize the possibility of impulses being mixed up, both earth station and Hag station impulses, due to the reception of a plurality of impulses. In general, the interruption of the signals by the earth's surface is used to minimize confusion . A system has been described on the basis of a gouge in which pulse coding is used for the even and odd times, as is the case in a preferred embodiment , and it has been shown that for

109814/04 3 6

Flight stations that fly at a maximum altitude of 12,000 m, to avoid collisions "up to a distance of km, a group of optimal frequencies for synchronization and information impulses, namely 560 Hz" or 440 Hz resulted- If the system works with 440 Hz and 200 points in time are assigned to information pulses, then these pulses are sent in a time of ηττπ sec, while for the Synchronisetia

remain in which 305 points in time with a frequency of 550 Hz occur. In Section II 350 points in time per second were discussed for synchronization purposes, but the loss of these few points in time hardly affects the synchronization capabilities of the stations.

In practice, the number of transmission times per unit of time, taking into account the various ones discussed above Criteria selected and can be greater or less than 440 Hz. Finally, a compromise is sought, the one measured air traffic control, avoidance of collisions and the measurement of distance and sighting and in which see the risk of confusion of Transmit pulses according to the maximum speed and altitude at which the aircraft can fly using this system use reduced to a minimum. As was also mentioned with regard to the query and response pulses, it brings itself the entry of a non-synchronized station into the network area and the transmission of information pulses by this unsynchronized station poses a problem. Mix-up in the ground or flight stations with "Bar" it follows that the system according to the invention with any any number of times per tent unit or with different frequencies for the information impulses and the Synohronisationsimpulse can be operated. Although for information and synehronia & ionszwecfeö different frequencies can be chosen, preferably only one

109814/0436

ICreoLuenz uses ** to oil clock settings in everyone Simplify station. Therefore the "in the description the frequency of 548 Hz specified by iBjgur 1 can be used, although then as a result of the shortening of t- die -rue see- ■■ ' likelihood of confusion slightly increased. This minor However, a shortening of the time can generally be accepted.

VIII. Annex

FIG. 9 shows a block diagram of the components which are used according to the invention in a * station * Each stationary or mobile station which is to operate according to the above system contains such a circuit similar oscillators of other stations is synchronized and kept synchronized with the aid of synchronizing circuits 152. As with the description of Pig. 4 said i use 'the synchronizing circuits for synchronization the interrogation pulses sent by the station and the interrogation and response pulses received from other stations. These latter pulses are received by an antenna 146. and fed to a receiver 148 via a transmit / receive switch 144, where they are first decoded by Bekoaierern 150 and then fed to the synchronization circuits 132. The decoders 150 also sort out the pulses for the purposes of navigation and avoidance. Collisions, to be used for distance measurement, etc. The synchronized oscillator 130 controls the system clock circuit 134, which sets the operating intervals or time intervals between the transmission times to the selected frequency according to the number of transmission times in a 1-second perlode or another predetermined period.

IMS 14/0436

. The time pulses generated by the clock circuit 134 are fed to several switching elements 136, the still others Data in the form of data pulses corresponding to the station height obtained from an interrogation pulse from another station. at simultaneous occurrence of a timing pulse from circuit 134 and a data pulse becomes the corresponding Pulse generator of the generators 140 triggered, which then the Signal for the interrogation pulse I of the station, for 'the height information pulse_ A and the response pulse R delivers. The index "o" should indicate your own station that is being described. The start pulse B is also generated at the beginning of each 1-second interval. The outputs: impulses the generators 136 ″ are first a radio transmitter 142 and then fed to the antenna 146 via the transmit / receive switch 144. As will be described below, the switching elements 136, which control the emission of the I pulses, are switched through statistically in order to ensure that the / attempts at synchronization, as described above, take place statistically.

Figure 10 is a detailed block diagram of the building blocks used in each mobile and stationary station will. The formwork in Part I framed by dashed lines are the standard transmitter-receiver circuits; part II contains the synchronization and clock circuitsi the circuits of part III relate to generation the impulses for the switching elements in connection with the transmission the data and synchronization information; and the one in Part I? The circuits shown are the decoding postures for separation the data and the pulses received from other stations for synchronization purposes. The identification of the various The symbols used correspond to pulses and circuits the symbols previously chosen in Section II. The index "o"

1098U / 0436

refer again to the "own" aircraft in which the individual blocks are arranged.

• ■ - ■

First of all, be. the receiver part of Part I "is considered. From The pulses sent by other stations are received via an antenna 26 and via a transmit / receive switch 24 a receiver 28 is supplied. Db output pulses from the receiver 28 are, for example, as in the well-known TACAIT system decoded, and the received pulses R and I at the output of the Decoders 96 and 98 become the synchronization error control circuit 42 supplied. Furthermore is at the exit of the recipient 28 a signal level beater 29 is arranged in front of the decoders, to discard the small amplitude impulses from stations beyond the horizon that can cause confusion and suppress. This has already been explained in Section VII. . .-

The clock and synchronization circuits arranged in circuit part II contain a conventional voltage-controlled oscillator 40, preferably a quartz-stabilized oscillator, its output frequency or phase is controlled by the output voltage of the synchronization error control circuit 42 will. Suitable voltage-controlled oscillators are known per se and therefore do not need to be described in more detail here to become. Synchronization error control circuit 42 receives the pulses I and R from the decoders and their own interrogation pulses 1 of the station supplied by the generator 84 will. The time relationship between these three pulses is shown in measured in the manner described with reference to FIG. The circuit 42 generates an output voltage that controls the oscillator 40 controls so that it works with the oscillators of the other Stations in the area is synonymous. Since all oscillators 40 are designed to be very stable from the start, the for

BADORIEiNAL

Synchronization of any oscillator required correction value relatively small. - ■ "".

The output of the oscillator 40 is connected to the input of a Frequency divider 44 connected, which the! Frequency of the oscillator output signal on one of the number of permissible transmission times corresponding frequency reduced. For example, if you use ' 548 time per second, then the oscillator delivers a multiple of this frequency, a frequency that is close to is in the HF range, so that smaller, more easily stabilized components can be used. This will be higher frequency then scaled down by the frequency divider 44 to the desired value. Such divider circuits are known per se.

The output signal of the frequency divider 44 is fed to a timing pulse generator 46 which has a number of Pulses per second which is equal to the frequency of the output signal of the divider 44 is. These impulses correspond the transmission times. The transmission time pulse generator can for example be a known asymmetrical monostable Be a multivibrator, which is based on the output signal of the Frequency divider 44, for example, at the zero crossing of the output signal is triggered. These transmission time pulses preferably have a "relatively short pulse width, around the Precisely define or localize the occurrence of each transmission time. . ,. ...

The pulses of the generator 46 are counted in a counter 50 which is previously set so that it only counts up to a number, ie equal to the number of transmission times in the selected time segment. Like "said in the description of Figure 1, this number 548 can be. However,

109814/0436

T616243

the number of possible transmission times depends on the ₉ different operating criteria discussed above «When the counter has counted the set number after a certain time, it is automatically reset to zero ο The time required for counting then corresponds to a larger period. For example, one second within which the desired number of transmission times set on the counter lies. Corresponding counters that count up to a set number and then automatically reset themselves to zero are known per se from digital computing technology and therefore do not need to be described in more detail.

If the large synchronization is used, e.g. * with When a station enters a network area, "the counter 50 reset from the start impulses B of other stations »This Pulses pass through the B-pulse decoder 90 and the synchronization switch; 52 on the counter. When closed. Switch, the pulses B are also fed to the oscillator. this to synchronize with the B-pulses. This will make the oscillator roughly synchronized with the other gfb ations, unä with a time error equal to the transmission time between the two stations is. As I said, this is a faster one Way to synchronize a station with a network area. The switch 52 is then opened again after a short time, so that the final fine synchronization with the help of the Synchronization error control circuit 42 can be done.

As long as the station is roughly synchronized, are also the following times of the larger Pei-iode with the received E-pulses synchronized as the oscillator 40 with these received pulses is in phase. Therefore everyone has the following

1098U / 0436

.Sending time and each pulse sent in the larger Period has the same phase error in relation to the corresponding transmission time of the station that received the pulse B sent. The first part of the second period becomes the end and used to receive information and the second part for synchronization purposes. .

Every time the counter 50 is reset, be it automatically "when the set number is reached or" when a B-pulse is received, it triggers the B -pulse generator 80 so that it emits a D -pulse, which starts the larger " . marks period of the pulse B from the generator 80 is supplied to a modulator 21 supplied, w: it is modulated onto a carrier signal, the modulated carrier signal is applied via a transmitter 22 and the T / R switch 24 to intenne 26 ₀ the transmitted pulse B may from another. The B pulse generator 80, and all other pulse generators in the system, are circuits that generate coded pulses to distinguish them from each other. The pulse spacing is preferably used for coding, although also other types of encoding based on pulse height, frequency or phase can be used.

The pulse B generated by generator 80 is also a Function pulse generator 70 supplied. The function pulse generator 70 generates a puncture signal that is sent to an altitude switch 72 »an interrogation switch 74 and a response switch 76 is fed. The signal from the function pulse generator 70 keeps the level switch 72 from the transmission times No., 1 to Ho. 200 open so that the plug-in height information can be sent, and keeps the query and response

1098U / 0436 badoriÄaL

• J ₁

Switching elements 74 and 76 closed during this time. During the transmission times Eo .201 "to Fo. 54Ö. The second signal from the generator 70 opens the switching elements 74 and 76 and closes the switching element 72. The function pulse generator 70 is, for example, a conventional bistable multivibrator which, when the trigger pulse B _{0 is received} at its output emits a positive pulse, which lasts from time No. 1 to Ho. 200. This positive pulse is fed to and opens the level switch 72. The negative pulse that appears at the other output of the multivibrator is the hold members 74 and 76 to keep these switching elements closed. When the positive pulse from the generator ends, the multivibrator tilts to the other side, so that switching element 72 is closed and switching elements 74 and 76 are opened.

The level switching element 72 is also controlled in such a way that it is only opened in an odd or even transmission time can be, depending on whether. it is a movable or is a ground station. This can be achieved, for example, by adding another to the function generator 70 odd / even-I'unktio.nsgenerator is connected downstream with the altitude switching element is connected, so that the altitude switching element is only opened during the odd or even transmission times. This odd / even puncture generator will triggered by the beginning of the pulse from generator 70 and delivers switching pulses, the duration of which equals the time between two transmission times, the switching pulses being the even Transmission times for a ground station and the odd transmission times blank for a moving station. The altitude switch 72 is then designed or biased so that the ! • Function impulses and the odd / even switching impulse at the same time must occur in order to open the switching element 72,

1098H / 0436

In a preferred embodiment of the invention, the odd / even transmission function is realized in that the Altimeter is caused to generate an output signal only at an odd point in time. In a ground station the ground station information generator G only triggered at the specified even transmission times o- This is described below.

A random pulse generator 60 is also included in Part III. The random pulse generator is triggered randomly or statistically, for example by a noise source, so that it emits as many pulses per second as the noise signals from the noise source exceed a certain threshold value. The threshold value can be fixed, as a result of which the frequency of the pulses I remains relatively constant. However, the threshold value is preferred. variable so that the impulse frequency increases as the number of stations in the area decreases. This can be achieved by counting the number of pulses B received in a period of one second and by generating a threshold voltage (A, G, C) in generator 60 which is proportional to the number of received pulses B. As the number of received pulses B decreases, the threshold voltage also decreases, which results in an increase in the I pulse frequency. Each pulse of the generator 60 does not prepare a random switching element 64 (for opening) for quite as long as it corresponds to the time between two transmission time pulses. This means that the next transmission time pulse from the generator 46 passes through the switching element 64 after the random pulse has been generated. The random holding element 64 is, for example, from a monostable multivibrator which emits a switching pulse of the desired length when it is triggered by the pulse from the generator 60

1098U / CU36

is formed, and a UED element * The output of the monostable multivibrator is connected to one input of the TIHD element (not shown) and the output of the Senäezeitpunktsimuulsgenerators 46 to the other input of the UITB-Q element. If the switching pulse and a Send © timing pulse occur at the same time at the inputs of the IHTD-G element 64, the Send point pulse passes through the UED element to the input of an interrogation pulse switching element 74 which is also an AND element * If the switching element 74 receives a function pulse with the corresponding polarity at its other input during the times Ho ₀ 200 to No.548, the transmission time pulse from the switching element 64 passes through the switching element 74 to the I pulse generator 84. The pulse generator 84 generates its own interrogation pulse I of the station, due to the transmission time point ■■ :. pulse. As already said before, the pulse may consist of I _Q zv / ei pulses exist, the distance is encoded, to allow decoding in another station. this corresponds to the known TAGAN system _s and the circuits for generating these pulse pairs are also known per se.

One of the entrances to the Altitude holding element 72, which is an AND element with at least three Inputs is that. Transmission time pulses from the generator 46 are supplied. The other two inputs each receive the puncture signal of the generator 70 u * id a pulse "h" at a point in time which corresponds to the altitude range in which the moving station is located. The switching element 72 is used for switching through of a transmit timing pulse through the: simultaneous occurrence of the! function impulse (during the times Uo. 1 to Mo. 200), of the pulse h and the timing pulses. The pulse passing through the switching element 72 triggers the A pulse generator, so that it generates a pulse A at the time of transmission, which corresponds to the height range of the moving station.

- * 109814/043 6

"■ .-- ■ -56-

A circuit for generating the pulses h is shown in Figure 11A. The altitude of the aircraft is measured with the aid of a conventional barometric altimeter 160, which adjusts the tap 161 of a potentiometer 162 via a mechanical connection 165. The voltage tapped at the tap 161, the size of which is a puncture of the altitude of the aircraft, is used by one The input of a switching element 165 is supplied, the other input variable of which is the pulse B generated by the generator 80. When the pulse B is present at the stepping element 165, which is the case at the beginning of every larger 1-second period, the voltage at the tap 161 of the control electrode is fed to a pulse delay circuit, for example a Phantastron 167. D'as Phantastron generates one output pulse h in a time which depends on the magnitude of the current supplied to the control electrode of the input voltage. the potentiometer is calibrated to generate a voltage which makes the Phantastron its output pulse leave just before the odd-numbered time that corresponds to the Höhenberolch in which the aircraft is flying, The duration of the impulse h is shorter than the time between two transmission times.

The output pulse h of the Phantastron 167 is fed to an input of the altitude switching element 72, which also receives the function pulses from the generator 70 and the time pulses from the generator 46. If all three pulses occur simultaneously, the pulse h, the function and the point in time pulses, the point in time pulse passes through the switching element 72 to the A pulse generator 82 which generates the height information pulse A. The pulse A is coded as desired and is sensed via the modulator 21, the transmitter 22 and the antenna 26. In this way the momentum becomes A
sent at the appropriate time.

In this way the momentum A becomes that of the altitude cbr station

BATH ORIGINAL

1 0 9 8 U / (K 3 6

. -57-

It should be noted that other information apart from the altitude information through the emission of the impulse A can be sent at the assigned times. For example, the true magnetic or relative The station's course will be sent in each information broadcast course angle can be assigned at the time. If someone "moving station 100 information transmission times Are available, each point in time corresponds to 3.6 ° from a total of 360 °. When course information is sent ^ will be the altimeter T60 to generate the switching pulse h replaces a compass or similar course measuring device.

It should be pointed out that other suitable circuits can also be used instead of the phantastron for generating the switching pulses h at the appropriate point in time for switching through the point in time pulses which represent the altitude of the aircraft. For example, as shown in Fig. 11B, an output shaft of the altimeter 160 is ei. Analog-digital converter 170 connected, which digitally reproduces the angular position of the shaft. The AD converter generates a binary number which corresponds to that even-numbered point in time before the odd-numbered point in time at which a pulse A _{Q is to be} sent which corresponds to the altitude range of the aircraft. The output number of the converter is compared in a binary comparator 172 with the output number of the time pulse counter 50. Whenever the two even-numbered counts are equal, the comparator 172 generates an output signal which is fed to an h-pulse generator 174, which can be, for example, a multivibrator. After a slight delay, which ensures that the even-numbered point in time pulse is not switched through, the generator 174 generates the switching pulse h, which is fed to the honey switch element 72 in order to keep the next odd-numbered point in time pulse through at the correct, uneven point in time at the specific height of the aircraft is assigned. In this way the pulse h is always generated so that the correct one

bad om _mal 109814/04 30

odd-numbered time pulse is switched through to the generator 82 in order to generate _{the pulse A Q.}

Should the "described system be used in a ground station
then the altitude switch 72 and the A ₀ pulse generator 82 are not used, and a ground information switch 120 and a pulse generator 122 are used to generate the pulses G _Q at the even times assigned to the airport station. These components are shown as blocks 120 and 122. It should be noted that it
These are optional components that can be used in addition to or instead of the components 72 and 82. In this case, no altimeter 160 and the other circuits need to be used to generate the equivalent switching pulse h at the point in time corresponding to the altitude of the aircraft. Instead, as shown in FIG. 110, the odd-numbered instant pulse at the output of counter 50, which-just before that of the
Ground station associated even-numbered instant pulse is switched through by a comparator 182, which is set to the same even instant number. The time pulse switched through by the comparator is slightly delayed,
to trigger the generation of a switching pulse g by a generator 84, which can be a conventional multivibrator. The switching pulse g is fed to the ground information switching element 120. This switching pulse g has the appropriate duration to switch through the next even point in time pulse of the generator 46, and the even-numbered point in time pulse causes the GQ pulse generator to emit the pulse Gq.
As already said, the pulse G _Q can be coded as usual
be.

The same Phantaetron circuit as that shown in FIG. 11A can be used to generate the hold pulse g by providing a control input with a variable voltage

109814/0436

who is assigned to the Phantastron in the one of the ground station even time triggers. The preselected timing control input of the comparator 182 is adjustable so that the same (Jerät can be used in various ground stations, to which different even-numbered transmission times are assigned are. "" -. "-

The response pulses Rq are generated by a generator 86, which is controlled by the switching element 76. The response signaling element 76 receives the function pulse from the generator 70, so that it only occurs during the times ITo. 200 to Uo ..; 548 is opened. The interrogation pulses received from an I-pulse decoder 98 are also fed to the control element 76, and it is these! to reduce 9 © received interrogation pulses, as explained in section VII, the AntwortsahaItglxed 76 is prepared so that it can open only when the station has an interrogation pulse I ₀ is sent. the first interrogation pulse from the decoder 98 then passes through the response Switching element 76 and triggers the response pulse generator 86, so that it generates a pulse Eq for transmission /. The pulse Eq is fed back to switching element 76 in order to close it until it is again at the next transmission, a pulse I _Q Dias is achieved, for example, with the help of a bistable multivibrator 87 (flip-flopj, which generates the response pulse. The IQ generator 84 is connected to the set input de s multivibrators and the E _o -G -enerator 86 ah connected to the extinguishing input, the output of the multivibrator connected to the response switching element 76. An I ₀ pulse "sets" the multivibrator and prepares the response circuit so that the next I pulse is switched to the pulse generator 86 when the function pulse is applied. The pulse E ₀ resets the multivibrator so that the switching element 76 is closed until the last Iq pulse is generated.

10981 A / 043

BAD ÖRJSIFSFÄL

16162A3

It can be seen from this that the respective synchronization and information pulses are sent at the correct time by the station. The pulses A _Q , B _Q and I "are controlled directly by the time pulse generator 46 so that they are synchronized for generation at a" certain time, while the pulse R _Q when the first I pulse is received after an I ₀ - pulse is produced. further, the information pulse A is in the generated corresponding time _0, the height of the plug-finished product, while the pulse G _Q in which the base station assigned time is generated. It is further darauf.hingewiesen that although the I ₀ pulses synchronized are, they are also sent at random times because of the random pulse generator 60 and the switching element 64. The mean transmission frequency of the Iq pulses can be changed by changing the number of pulses from the generator 60. This is done, for example, by changing the The statistical noise source is reached by the generator 60. The trigger threshold can also be determined by the mean number of answers received rtimpulse can be changed automatically, whereby the system automatically adjusts itself to the optimal I ^ transmission frequency.

Part IV of the diagram contains the various decoding and information circuits, some of which have already been described. The output of the receiver 28 is fed to each of the B, A, R, I and G pulse decoders 90, 94, 96, 98 and 99 via the level adjuster 2Q. However, separate level or threshold value settings can also be connected upstream of each individual decoder, so that the impulses below a certain amplitude are suppressed. As described above, this helps to avoid mixing up different stations. As I said, each decoder sorts the received pulses mch the applied Kodierun ^ Bverfohrtui, .- depending on whether the received pulses abstände-, 'de oquenz- au ρ he hn ώ onmoduliert, π ^"int - BAD.

1098 U / (H 3 6

- ■ 61 -,: ■■

As mentioned before, all stations can use the same "Send frequency. This simplifies the amplifier 28 and the Transmitter 22 in each station considerably. The first received Pulse B decoded by decoder 90 is made used to reset the counter 50 and to synchronize the oscillator 40 when coarse synchronization is applied will .. The rough synchronization is only available during a ■ applied a relatively short time after the station has re-entered the area, so that the switch 52 after opened for a short period of time and the station is allowed to deal with the received interrogation pulses accurately to synchronize. A monostable multivibrator (not shown) preferably blocks the output pulses of the B-pulse decoder 90, approximately for a larger period after the first pulse B was received. Instead of this or an amplitude discriminator can also be provided at the output of the B-Impilsdekodierers 90 to only the during a larger period received pulse with the largest amplitude. This impulse will normally sent by the nearest station. None of these circuits are shown for the sake of clarity the drawing would affect.

The output signals of the R and I pulse decoders 96 and 98 are fed to the input of the synchronization error control circuit 42 which generates the error voltage for controlling the oscillator 40. This is described with reference to FIG. The I-pulses from the decoder 98 are also fed to the response circuit 76 in order to trigger _{the pulse-R Q at the appropriate time.} This feature has also already been described.

109814/0436

The outputs of the A and G pulse decoders 91 and each of the A-pulses from the aircraft and the G-pulses decode from ground stations, are used to measure the respective Distance of the station to the other plug equipment and / or the ground stations. Tray, the decoding are received A-pulses fed to an altitude-range switching element 102, while the decoded G-pulses are sent to a ground station distance switch 1.08 can be supplied. In general, a station only deals with other aircraft that are in the same Fly altitude range, or with a specific ground station to which you determine the distance and / or direction want. The altitude and ground station selection circuits are used for this purpose 104 and 106. These circuits control the range finder gates 102 and 108 to measure the distance only to measure to the desired stations.

A circuit that measures the distance to certain aircraft as well as to certain ground stations is shown in Fig. 12A, while Fig. 12B shows the different output voltage curves of this circuit shows. A BQ pulse B from generator 80 (line a of Figure 12B) switches the output voltage of a treble or Aircraft position transducer 190 via a switching element 192 on a Phantastron 194. The transmitter 190 can Altimeter and potentiometer arrangement shown in Fig. 11A where the circuit is used to measure the distance of another aircraft flying at the same altitude. If the circuit is used to measure the distance to a ground station, then the transmitter is 190 a device that generates a voltage equal to that of the concerned The even-numbered transmission time assigned to the ground station triggers an impulse from the Phanta * rons. This Device can also be a potentiometer.

109014/043 *

The Phantastron 194 generates a half pulse. (Line c), the duration of which is less than the time between two transmission times and which is fed to one input of a switching element 196. The time ( ^u end time) of the generation of the phantatron pulse is determined by the voltage supplied by the transducer 190, so that the correct transmission time pulse of the generator 46 (line b) is switched through via the switching element 196 (line d) Transmit time pulse switched through via switching element 196 is fed to one input of a bistable multivibrator or other suitable time (distance) measuring device in order to initiate the start of the distance measuring cycle. The A- or G-pulse received by the Seifdezeitpurikt-pulse triggered by the distance measurement is fed to the other input of the multivibrator to determine the end of the distance measurement cycle (line e). The output signal of the multivibrator is a pulse with a pulse width or duration that corresponds to the distance between the own station and the stations whose A or G pulses were received (line f) .This is because the A or G pulse from the Station was sent at the same point in time in which the transmission time pulse (line d) was switched through to circuit 102 or 108, since the stations are all synchronized. Thus, the width of the output pulse: Ises (line f) corresponds to the distance between two stations the distance switching elements are used to control any suitable analog or digital distance display device 199, for example an analog or digital device driven by a voltage esser, in which meters, kilometers, etc. are calibrated.

10 9 81Λ / 0436

-.64-

In many cases, an aircraft wants the presence -and determine the distance of another aircraft in a different altitude range into which the first aircraft is ascending or wants to descend. Information of this kind is extremely desirable in order to avoid collisions between aircraft, which change their height. To make this possible, the transmitter is 190 of Fig. 12A made adjustable, e.g., by the height selector position 104 to generate a tension that the Phantastron triggers so-that another level switching element results, which is similar to the h-switching element and h -contact element is called. The one controlled by the selector switch 104 Transmitter 190 is set so that the h -scIe element corresponds to the changed altitude range into which the aircraft wants to ascend or descend. Therefore, the vnn the other Aircraft at the correct transmission time in relation to the changed altitude range and according to the time of the Triggering of the h switch pulse on the distance measuring switch 102 so that the distances of these aircraft can be determined. Then can determine whether it is safe in the h oil area to transfer.

The h _c hold signal is also fed to the altitude switch 72 of FIG. 10 to allow the aircraft wishing to change altitude to notify other aircraft of the change. When the h switching signal is fed to the switching element 72, the station sends an information pulse at the transmission time which is assigned to the altitude range h to which the aircraft wants to change. In a preferred embodiment of the invention, the aircraft stations are provided with circuits with which both the h and the h switching signals can be generated in each period. Therefore, each aircraft can measure and transmit the desired information both in its own altitude range and in that altitude range to which it wants to change.

1 0981 A / 0436

Depending on your requirements, the setting element on the transducer 190 be mechanically coupled to the altimeter and adjusted so that that a voltage is generated which triggers a switching signal, that triggers a transmission time pulse that corresponds to a transmission time which is in front of or behind the actual flight altitude. Therefore the h -chaltglgnal becomes as a function of the changing Generated aircraft altitude to indicate to other aircraft whether own aircraft is ascending or descending. flow £ and also to the distance to these other aircraft at a higher level or lower altitude range. It is important to pointed out that while your own aircraft was in a different altitude range changed over to the generation of the normal h-switching ■ impulse changes automatically. This is how other stations notice in the new altitude range of your own aircraft, and ^ in addition Your own aircraft can thereby determine the distance to these aircraft measure up. - ·. ;

Similarly, the circuit of Figure 12A can be used to measure the distance to any other station transmitting at a set time. Now the selection circuit would be 106 set so that they have the Phantastrons triggers at the output 194 a pulse g, the durcj a transmission time pulse would turn that those Bodenstationizugeordnet lot _t whose distance will measure the own station. The distance is measured in the manner described above , except that the pulse Gr sent by the selected station and decoded by the decoder 99 in the own station is now used to terminate the switch-on period of the multivibrator 198. The distance is indicated by the display device 199 »

IX, detailed maintenance instructions

For a further description of the possibly indungggemeii circuits in a station, the Hguyen 13 to 2f $; Beaug taken. The in the lig. 14-23, positions shown in FIG. 14 can be used in place of the construction parts of Figure '10, and these additional positions are specifically counted with regard to a syrichronization method in which the impulses of a toohfreauent factor are counted

109814/0438 '"'

A. Synchronization BC Keeping

As already mentioned, the present system is based on the exact synchronization of transmission timing pulses in all stations in operation. Basically, there are two different requirements for the synchronization circuits in each station. First, the timing of the own interrogation pulses Iq, which coincide with the transmission time pulses of the own station, must be controlled so that an interrogation pulse I received from another station appears midway between the own interrogation pulse and the received response pulse R. A complete correction must be carried out with a pulse group Iq, I and R. Secondly, it was shown above that the interrogation pulse sent by another station and the response pulse must have been sent by one and the same station if only a single interrogation pulse sent by another station appears between its own interrogation pulse and the first received response pulse fc. However, if more than one interrogation pulse sent by another station occurs in this interval or in this period, then the correction made can only reduce the existing synchronization error,.

You synchronization of the transmission timing pulse old help an Iropule count is on hand the Pig. 13A, 13B and H described «fig. 13A sends the pail that the "own" query eirapul β the "other" interrogation pulse, i.e. the interrogation pulse the other station leads, inter alia, a time Δ. This means, that the transmission time pulses of the own station precede those of the other station and that nothing unteroaetn is to ait its own transmission timing to bring the impulses of the other station in Synohronieus.

109814/0436

- 67- ■ '. .

On the time axis 1 shown in FIG. 13A there is a separate one Interrogation pulse time which is at any position behind the position with the number 201 falls, also a received interrogation pulse from another station and a received response pulse shown »which was sent out by the other station as a response to its own interrogation pulse * its own When it occurs, the interrogation pulse coincides with the transmission time pulses of your own station, which occur with the assumed frequency of 548 Hz and which transmit the * Time impulses of other stations can lead or lag behind. As can be seen in Figure 13A, the generation of the own interrogation pulse of the generation of the other interrogation pulses at a time ^. in advance. This is shown in Fig. 13A the time interval ^ shown. The time interval begins an.der place in the middle between the generation of the own interrogation pulse and the receipt of the corresponding reply pulse (where the other interrogation pulse would be received if the two stations were synchronized) and ends at the point at which the other interrogation pulse is actually received.

A synchronization counter 200 (Fig. 14) is used for measurement of the digit error A is used · The measurement is carried out in the on the time axis 2 shown in Fig. 13A. By doing Moment in which a separate interrogation pulse occurs, the is sent at one of the transmission times, those of a master oscillator or clock 210 supplied ! Clock pulse e, for example in the order of 4 * 48 MHz, added in counter 200 »those from counter 200 counted number increases until a query pulse of the received by another station. From that moment on the clock pulses are subtracted from the value counted up to then "until the response pulse is received *

10981 A / 0436

As seen in Fig. 13A, at the time the response pulse is is received, a non-zero value is stored in the counter 200. This means that the stations are not synchronized with each other. In this case, the one displayed in the counter 200 shows Value indicates that the generation of the generation's own interrogation pulses the other query pulses leads by the time Δ. Thereafter the invention only made a correction in the feed direction synchronization errors will only appear in the corrected trailing station. The timing of the position counter 220 of its own station is therefore leading in this Errors as shown in Fig. 13A not corrected. Nevertheless when the response pulse has been received, the frequency of the pulses supplied to the counter 200 is doubled by the stored meter reading already after a time ZV to zero bring.

If leading errors occur repeatedly, this can mean that the main oscillator 210 of the own station is too high Frequency has. In this case one can use the measured time Δ, during which is used to bring the stored count to zero, to decrease the frequency of the main oscillator 210.

The position impulses or transmission time impulses are marked with a Frequency of 548 Hz / trliugt that the output pulses of the oscillator 210 are counted electronically in a transmission time counter 220 will. The counter 220 generates 548 transmission time pulses per second, 'TTm to generate each transmission time pulse is a larger one Number of pulses of the oscillator 210, e.g. 1635 pulses, required. The counter 220 counts this set number, e.g. 1635, and generates an output pulse. This is done in the synchronized State of the station 548 times per second. After generation the counter sets itself automatically for the 548 transmission time pulses to start over, provided it is not reset earlier by another signal. Counting circuits of this Kind are known.

In FIG. 13B, there is a delay in its own transmission time pulses compared to the transmission time pulses one

1098 U / 0436

other station at a time * An error time interval Δ. is generated and the frequency of the payer 220 pulses supplied during this interval are doubled. As a result, the next timing pulse supplied by the counter 220 is advanced and with it the next interrogation pulse, and indeed for a time

With the start of the generation of the interrogation pulse (time axis 1) of the own station, the clock pulses of the main oscillator 210 are added in the synchronization counter 200 with the normal frequency until the other interrogation pulse is received. From this point on, the clock pulses are subtracted from the value stored in counter 200 at the normal frequency until the response pulse is received. Since the other interrogation pulse is received a time Δ earlier than it would be received if the two stations were synchronized with one another, the value stored in the counter when the response pulse is received is proportional to -2Δ *. This is explained below. When the other interrogation pulse is received, the count value in the synchronization counter 200 is proportional to T-ZV (time axis 1). When the response pulse is received, a value corresponding to T + ^ is subtracted from this count. When the response pulse is received, the total value in the synchronization counter 200 is proportional to -2Z ^ · - This means that the transmission time pulses of the own station lag behind the transmission time pulses of the other station by 'a time' Δ *. This indicates that the transmission time pulse counter 220 of the own station must be advanced by a time ^^ in order to achieve synchronization.

In order to generate the error time interval * &, the 200 stored meter reading clock pulses with the two

times the normal frequency supplied until the stored value is brought to zero. From the moment the response pulse is received a time interval Δ is required for this. During this interval the pulses are sent to the transmission time counter 220 with the twice the normal frequency, so that the generation of the next transmission time pulse and all subsequent transmission time pulses happens earlier by a time Δ, as shown on the time axis 4 of FIG. 13B. Both the counting direction the clock pulses (i.e. whether subtraction or addition) during the correction as well as the type of clock signal correction of the transmission time counter are determined by whether a zero crossing of the total number of the synchronization counter 200 (Time axis 2) takes place before the response pulse arrives or not. No zero crossing means a lead of the phase error (Fig. 13A), during a zero crossing Trailing the phase error (Fig. 13B) means. A more detailed one Description of the devices required for synchronization follows later. ■

B. Block diagram of the synchronization circuits

A block diagram of the circuits used to carry out the Synchronization according to the counting method is shown in FIG. Both the synchronization counter 200 and the Timing pulse counters 220 are from the same signal of the main fect oscillator 21Ö controlled. The output signal of the oscillator 210 has twice the frequency of the clock pulse frequency. o The oscillator 210 supplies the clock pulses for the synchronization counter 200 and the transmission time counter 220. Both counters are constructed in a conventional manner, e.g. as ring counters with several bistable multivibrators (Flip flops). The counter 200 can contain, for example, 13 bistable multivibrators, while the counter 220 comprises 15 bistable ones Can be built up. The counter 200 can also

BADORl ©! NÄl. · 109814/0436

subtract on command (count down). The sending time counter 220 generates 548 output pulses per second or any other desired number of transmit timing pulses.

A switching element 211 is connected to the output of the oscillator 210 connected, and a further switching element 212 to the first Switching element 211 connected downstream. Both switching elements are • normally open so that the pulses from clock oscillator 210 are continuously fed to counter 220 after they through a "frequency divider 215 to half the normal Counting frequency were divided * The down counting of the counter takes place in such a way that-at the output ues counter about 548 pulses appear per second «, these are the transmission time pulses required by the system.

The time synchronization of the transmission time pulses is by appropriate control of the switching element 211 and a switching element 213 reached, which is normally closed is. The switching element 213 receives clock pulses with double Frequency directly from oscillator 210. A healing error is corrected in that the switching element 211 is closed and the switching element 213, which is normally closed, is opened, so that the transmission time counter 220 the clock pulses are fed at twice the frequency. Lead error are not corrected,

In a similar manner, switching elements 201 and 202 control the clock pulses at the input of the synchronization counter 200 »The output signal of the switching element 201 is with the help of a frequency divider 203 divided into half, while the Switching element 202, the clock pulses with twice the frequency from oscillator 210. During the response pulse previous counting process of the counter 200 is the switching

10 98 147OA36

link 201 open. The switching process of the switching element 201 is controlled by a switching pulse generator 205. Of the The generator is switched to the "on" state by its "own" interrogation pulse (on) and triggered by the received response pulse in the "off" state (closed). During the "on" time of the generator 205 ,. from »" own "query to impulse to when the response pulse arrives, the synchronization counter 200 Taktiropulse supplied. The "own" interrogation pulse is also .a command circuit 207 for the commands "Add" or "subtract" fed to the reversible synchronization counter 200 to issue the command, the clock pulses to add or subtract. The "other" interrogation pulse received is fed to the command circuit 207 in order to switch the synchronization error from addition to subtraction as shown in line 2 of Figs. 13A and 13B. .

When the response pulse is received, it closes the switching pulse generator 205 and triggers a second switching pulse generator 208 so that it opens the switching element 202. As a result, the clock signals of double frequency can reach the synchronization counter 200 from the oscillator 200. At the end of the correction period, the switching pulse generator 208 is triggered by the trailing edge of the correction pulse and the switching element 202 is closed. The duration of the correction period is determined by the leading and trailing edges of the output pulse of a correction pulse generator. The correction period is initiated by the incoming response pulse and terminated by a pulse from a circuit 206 which responds to the number zero of the synchronization counter. The circuit 206 contains an AND element made up of diodes with several inputs in order to determine the states of a corresponding number of bi-stable flip-flops in the synchronization counter 200.

BAD 0FH6INAL 1098U / CU36

Keys. In the example described, the AND element contains 13 diodes, since the counter 200 consists of 13 flip-flops is constructed. If all bistable multivibrators assume the state assigned to the binary number zero, which means that the count is zero, the AND gate 206 is a Pulse from which turns off the generator 209. When the count of the counter 200 reaches zero before the arrival of the response pulse, which in the event of a delay error of the Is the case, the output signal of the zero sampling circuit 206 has no influence on the state of the generator 209, so the the correction pulse is generated because it is already in the "Off" state. The reset input (for switching off) of the generator 209 generating the correct pulse is with connected to AND gate 206 and the set input (for switching on) receives the response pulse.

The correct pulse from generator 209 will be several different Circuits distributed that are actuated during the correction cycle to synchronize the transmission timing pulses Need to become. These circuits contain the following:

(1) AND gate 223 - Before the correct pulse of the generator 209 is fed to this AND element, it is inverted or negated by an inverter or NICHI element (not shown). The other input signal of the AND gate 223 is the zero signal of the sampling circuit 206. The switching element 223 has an output signal if a zero crossing occurs before the Response pulse arrives.

(2) Zero-crossing flip-flop 225 - This bistable multivibrator is "set" by the output signal of the AND gate 223 and "reset" by the trailing edge of the correction pulse. So there remains for the time being

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of the correction period and indicates by tilting it back that the count of the counter 200 has passed through Hull goes. This therefore indicates whether the time errors are leading or lagging. - -

(3) AND gate 227 - The input signal to this AND circuit are the correction pulse of the generator 209 and the output signal of the zero-crossing flip-flop 225. Both input pulses must be present at the same time, so that the AND gate 227 is only then emits an output pulse when a correction for a DelayBoperation of the system should take place.

As with the description of how the Said clock gates, the gate 211 is always closed during the correction cycle when lagging to close prevent the normal frequency clock pulses the counter keep counting. In order to achieve this mode of operation, the pulse from the AND element 227 is fed to the switching element 211, see above that the switching element 211 is only open when no time correction is carried out.

(4) Shift Pulse Generator 208 - This generator controls that Switching element 202 which, when open, supplies the synchronization counter 200 with clock pulses at twice the frequency. The trailing edge of the correction pulse closes the switching element 202 by switching the circuit 208 to the off state retriggered.

Another circuit is indirect from the correction pulse actuated. This is the AND gate 230. It should be remembered that that the counting direction of the synchronization counter 200 during the correction cycle of the type of synchronization to be corrected, whether leading or lagging depends.

109814/0 ^ 36

-: 75 - ■ <, .- ■■■■ "". ■ -

During the correction pulse shown in Fig. 13A, at counting backwards during a leading error counted up in Mg. T3B in the event of a lagging error must become. If there is no zero crossing in the counter 200 » then there is a leading error. As shown in FIG is, the received "other" interrogation pulse changes the add command of circuit 207 into a subtract command, possibly for both types of errors. The AND gate 230 emits a pulse which coincides with the response pulse ^ when a Zero crossing has occurred (trailing error). In in this case, the subtract command must be switched to an add command when the response pulse arrives, and this is achieved by the output pulse of the switching element 230 of the addition trigger terminal of the command circuit is fed.

Other circuits shown in Fig. 14 which have an edge function the synchronization function include the following:

(.1) Switching element-. 212 - This switching element is used for rough synchronization. When the coarse synchronization circuits (described below) indicate that the transmit timing counter 220 should begin counting, the trigger voltage applied to the switching element / 212 goes to zero, so that the switching element 212 is opened. The trigger or start voltage also serves to clear the transmission time counter 220 so that it starts counting at zero, or at another set number, if desired. If the coarse synchronization is not used, the switching element 212 remains open .. .'- '■. ..'__

(2) delay delay generator 252 - The »is a mono-stable pulse generator that is generated by its" own "interrogation pulse

109 8T U / 0 43 6

is triggered and shortly before the next "own" Ab-. question pulse time falls back to its normal state. The generated erase pulse is transmitted to the circuits 200, 205, 208, 209 and. 225 to ensure that, -what whatever happened before, the flip-flops of the various parts of the synchronizer are reset or deleted before the next synchronization attempt is made.

Before proceeding with this description, let us consider the operations with both leading and lagging synchroniza- flaws examined:

Leading error (Pig. 13A)

When the station receives its "own" interrogation pulse, the switching element 201 opened via the stop pulse generator 205, and the Synchronization counter 200 starts taking single frequency clock pulses to be added up by the divider 203 counting. When a "different" interrogation pulse arrives, it becomes the command circuit 207 to change the addition instruction to a subtraction instruction. In the case of a leading error, the result is no zero crossing (no number zero) before the response pulse arrives. Thus, the zero sampling circuit 206 is speaking not on. When the response pulse is received and the switching pulse generator 205 is supplied, the generator closes the switching element 201. The response pulse switches the switching pulse generator 208 to open the switching element 202 and thereby the clock pulses with a higher frequency (double Frequency) to the synchronization counter 200, which still counts down (subtracts) «The correction is terminated when the circuit 206 determines that the counter reading of the synchronization counter is zero. There-

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the correction pulse supplied by the generator 209 becomes terminated or blocked. The leading edge of the correction impulse switches off the switching pulse generator 208 and closes gate 202 to prevent the sync counter 200 continues to count until the next "own" interrogation pulse opens the switching element 201. A time correction is not carried out in this case.

Trailing Error (Fig. 13B)

In the event of a leading error, the mode of operation is the Switching up to the zero crossing of the counter reading of the synchronization counter is identical to that in the case of a leading error. The one at the moment of this zero crossing The zero pulse supplied by the circuit 206 is transmitted via the AND gate 223 is turned on and sets the zero-crossing flip-flop 225. The one from flip-flop 225 in the set state Output voltage is fed to AND gates 227 and 230. When the response pulse arrives, it happens Switching element 230 and switches the command circuit 207 from subtraction to addition, the response pulse also triggers via the generator 209, the correction pulse, which by the AND gate 227 passes to the switching gate 213 to open and the switching element 211 to close. This allows the clock pulses doubled in frequency reach the third time counter 220 and carry out the time correction. As in the case of a leading error, the counter reading is also Zero of the double frequency driven counter 200 from the zero continuous circuit 206 during the correction decoded or sampled to that of the correction pulse generator 209 to interrupt the correction pulse supplied and thereby to close the latch member 213. Daduroh will be the The supply of the two-frequency pulse to the counter 220 is interrupted opened again. .

C. Binary addition and subtraction in the synchronization counter 200 ^

As already mentioned above, the synchronization takes place by addition and subtraction in the synchronization counter 200. The counter can be used for binary counting if it is constructed from bistable multivibrators which are connected as shown, for example, in the block diagram of FIG. 15A is shown for several stages of such a counter. Differentiating circuits 252 are connected between the flip-flops 250 of the counter, which the. Differentiate the output voltage of the flip-flops, so that when a flip-flop is flipped, a thread pulse results, the polarity of which depends on the direction of the change in state of the flip-flop. As a result, a frequency reduction of 2: 1 is achieved if the pulses of one polarity are suppressed by an OR gate 254 that can be selected to be + or -, and the subsequent flipflqp 250-1 with each trigger pulse of the other polarity that is allowed through, changes its state »The * choice of addition or subtraction is made by choosing the polarity of the trigger pulses that are transmitted between the flip-flops, which is done by the addition / subtraction control 207, which prepare the OR gate 25 so that this is positive or lets through negative impulses.

15B shows some voltage curves of a three-stage up / down counter, which thus counts to 2. The upper group are impulses that change state when the previous impulses go positive. In the middle group of impulses the states of the impulses change when the preceding impulses go negative and one sees that the middle group represents the negation or inversion of the upper group. So if a number from the middle

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Group to the corresponding number from the group above is added, the "binary sum is always 111. That's why the number represented by the middle group, in the diagram, increasing steadily from left to right, must be the decrease steadily in the same direction as the number shown in the upper group. In other words: in the upper group the pulses are subtracted, whereas they are in the middle Group can be added. As an example, in the First group 5 pulses added and 4 pulses subtracted, starting from 000 ....

The run time of the flip-flop chain of the counter of FIG. 15A is approximately equal to the sum of the rise times of the flip-flops up to the last changing digit. This term can can be reduced to almost a rise time when adding or subtracting the circuit shown in Fig. 15C is used for counting up and down. In In this counter, the trigger pulses are not relayed by the flip-flops, but by switching elements 260-1, 260-2, 260-3β · ο for positive trigger pulses and via switching elements 262-1, 262-2 and 262-3 ... for negative trigger pulses. The rise time or switching speed of these switching elements can be kept very short. The trigger pulses are made by differentiating the single-frequency clock pulses The command circuit 207 controls the supply of the_ trigger pulses to the corresponding switching elements, depending on whether they should be added or subtracted. The switching elements 260-1, 260-2 and 260-3 are opened when the output signal of the respectively connected flip-flops 264-0, 264-1 and 264-2 is a binary "1", i.e. when the Flip-flop is "set", while the switching elements 262-1, 262-2 and 262-3 "are opened when the respectively connected Flip-flop is reset. The counting speed

1098U / Q436

ness of the circuit of Fig. 15C is only limited by the rise time of a single flip-flop ", since the flip-flops implemented, ie _o to be tipped almost triggered simultaneously. Me counter chain may arbitrarily by ■ expanding many counter stages or supplemented.

The operation of the counter of Fig. 15C is exemplified simple binary number example once for an addition and then described for a subtraction. In the addition example, an arbitrarily chosen binary number becomes a "1" is added and, in the subtraction example, a "1" is subtracted from another arbitrarily chosen binary number:

Addition subtraction

100111 101100

+1 - 1

101000 '. 101011

You can see that if a "1" is added, starting from the right, the first four flip-flops must be flipped. In the subtraction example, on the other hand, the first three flip-flops must be flipped; various numerical examples were chosen to better demonstrate the formation of the yield. In FIG. 150, the trigger pulses which command whether ad-di.ert or subtract is to be carried out run through the switching elements 260 and 262 until they hit the last flip-flop stage, which must be toggled opposite state flip-flop located includes the subsequent switching element and thereby prevents the trigger pulse continues. By tilting this flip-flop · the switching element, which was closed until then, is opened; however, the flip-flop process is delayed until the trigger pulse disappears. For very fast trigger pulses, the rise time of the flip-flop is for this purpose

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sufficient «The" circuits described from the relative A few levels existing counters are lined up in order to the necessary for the counter 200 levels received. _> ■

Th Select the transmission times for pulses B, A and G

As explained with reference to FIG. 10, each station sends a start pulse B _Q and an altitude information pulse A 'or a ground information _{pulse G Q} , depending on whether it is an aircraft or an unclean ground station Station know whether the interval following a transmission time pulse is used for aircraft or ground station information purposes. In this system, the clock sequence is repeated approximately once every second and begins with a start pulse Bq, which is followed alternately by altitude information and ground station intervals; the beginning of each interval (each period) is determined by a transmission time pulse. This is in Pig. 1 shown. From about the middle of the T-second period, the time Hr _β 201, the alternating sequence ceases and the remaining time is used for synchronization purposes.

17 shows the block diagram of a circuit which derives _{the pulses B Q} , A ₀ and / or G _Q from the transmission time pulses supplied by the counter 220 during the first half of the sequence. In FIG. 17, the sequence is generated by a continued scaling down of the output pulses of the transmission time counter circuit 220. A frequency reduction of 548 is effected by a counter or divider 279 which has corresponding flip-flop reduction stages. The divider 279 generates the startinipulee B with "a frequency which is equal to t / 548 of the input frequency, or 1 pulse per second ·

1098 U / 0436

The start pulse is triggered when the counter 279 reaches a count of 548. The count is scanned by an AND element 284 which is connected to the flip-flops in the counter. As long as the counter reading is 548, the AND element has a "one" as its output signal. For any other number, the output signal is "zero". The one signal of the AND element is somewhat delayed in an RC delay network 386 and fed to a further switching element 287, the input signal of which is the transmission time sequence from counter 220. The delay element 286 keeps the switching element 287 open during the transition of the frequency divider input signal from 548 to 1, so that the next time pulse, which corresponds to the start pulse B, is switched through via the switching element 287 with only a slight delay. This switched through pulse corresponds to the start pulse B _Q and is also used to generate it.

The aircraft transmit timing pulses A and the ground station transmit timing pulses G are generated in a similar way. They alternate in time, so that two switching elements 288 and 289 can be opened and closed alternately. After a frequency reduction of the pulsating with 548 Hz Send timing pulses in divider 279 by a factor of 2 will be the Square wave at the output of the counter is delayed in a delay circuit 290 and fed to the switching element 288. The other switching element 289 is from that in an inverter 291 (NIGHT-GIied) inverted (negated) square voltage curve the same delayed rectangle voltage controlled. the Transmission time output pulses of the switching elements 288 and 289 then oscillate in antiphase, the output signal of the Switching element 288 the aircraft information input pulse A and the output signal of the other signal element 289 the ground control information impulse train G represents.

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-83 -. ■ - ■. ■■■. : / ■ '... . .

The determination of the specific aircraft or ground station _{pulse for the transmission of an A Q} or Gq pulse for identification of the station is achieved by determining the flip-flop states in the frequency divider at the moment the pulse appears. This is described in more detail below.

A switching pulse generator is also attached to the frequency divider 279 292 for information synchronization. This circuit also decodes the count of counter 279, and if it is below 201 is where it is indicated that the station information pulses (B, A, G) sends and should receive, delivers the Switching an information switching pulse of one polarity. If the count is greater than 201, the circuit switches around and generates a synchronizing stop pulse to the Sending and receiving of I and R impulses suBUTkassen »

- ■■■ · - "j

Eo generation of "own" query pulses ■ =

The "own" interrogation pulses are supplied by the circuit shown in FIG. This circuit corresponds to the random ehaltgenerat or 60 and the random switching element 64 of the Fig. 10. The transmission timing pulses of the counter 220 are from the synchronization hold voltage of circuit 287 the switching member 300 is switched through. This will make the "own" query pulses during the information half of the Cycle sequence interrupted. The transmission time pulses at the output of the switching element 300 are also linked in a switching element 304 with a voltage curve, the pulse spacing of which statistically fluctuates and its pulse length is fixed at one smaller value than the time between two transmission instant impulses en is set. The random stop pulse is from

10S8U / Q436

a noise generator 305, the output pulses of which, which exceed a certain threshold value, trigger a monostable blocking oscillator 307. If the switching pulse is pending at switching element 304, there is certainly only a single transmission time pulse during the switching pulse and is switched through (unless it is blocked by the switching element 300 mentioned above) the mean value of the frequency, the switching pulses from the switching element can be adjusted by setting the trigger threshold of oscillator 307 to be changed and is, for example, to 10 to 20 Hz ^- adjusted. This is carried out with the aid of a counter 308 which counts the B pulses received and those decrypted in the decoder 486. The decoder 486 is described below. The counter 308 is _{reset by the B 0} pulse generator 287 every second. The output signal of the counter 308 is converted in a digital / analog converter 309 into an output voltage proportional to the counter reading. Converters of this type are known per se. This analog voltage is stored for the duration of the 1 second period in a threshold value circuit 310, which varies the level at which the pulses from the noise generator 305 are switched through to the blocking oscillator 307. With the appropriate number of B pulses received, the threshold voltage also falls, which also results in an increase in the frequency with which the blocking oscillator 307 is triggered, and with which the number of Iq pulses is also increased.

F. Start pulse B (B) synchronization

When using coarse synchronization, your own start pulse B ₀ must be synchronized with the first received start pulse from another station before the transmitter of your own station is activated. Therefore the first received start impulse must always trigger a correction if it arrives before

1 0 9 8 U / 0 4 3 6 ^ßAD

the "own""startpulse" is triggered. Figure 19 is a "block diagram of a" preferred start pulse synchronization "circuit. On the left in the picture, the received and decoded start pulses from other stations are fed to the information synchronization clock voltage from the circuit 292 of FIG 320 are switched through. These are the start impulses that are received before the generation of its own start impulse Bq. When a start pulse is switched through by the signal element 320, it triggers a flip-flop 322 and thereby opens an AND element 324 for any pulse that appears at its other input. The information synchronization clock voltage is differentiated by a circuit 321 in order to derive needle pulses of corresponding polarity from the leading and trailing edges. The differentiated form of the information synchronization clock counter voltage is fed to the other input of the AND element 324, a positive pulse indicating the beginning and a negative pulse indicating the end of the synchronization period. When the next positive, differentiated pulse appears at the input of the AND element 324 (at the beginning of the next synchronization period, one second later), it is switched through by the switching element 324 and triggers a second flip-flop 326. The output signal of the flip-flop 326 closes the switching element 212 (Fig. 14) and resets the counter 220. The transmission time counter can thus be synchronized.

Since the flip-flop 326 is triggered at the beginning of the synchronization period after the period in which the first start pulse is decoded, the first start pulse in the second period is durably switched by the AND gate 320 and the AND gate 328, which is activated when dee Flip-flop 326 is opened

1098U / 043S

This start pulse triggers the flip-flops 322 and 326 back into the normal state. As a result, the switching element 212 is again opened and the counting process started again in the transmission time counter 220. The desired coarse synchronization is carried out, since the transmission time point counting process is started in the counter when the first start pulse in the second Synchronization period is received. The circuit for coarse synchronization shown in Fig. 19 is switched off, as soon as the coarse synchronization is finished.

If you do not want to try to synchronize roughly with a single start impulse, but with a group of impulses, then the flip-flop 322 can be replaced with a conventional staircase generator. If the number you want of start pulses has been received, the output voltage would be of the staircase generator exceed a critical voltage and open the AND gate 324 Mode of operation of the circuit the same as described above « Such a circuit might be required if stray or Interference pulses occur during control start pulse decoding.

G. Main oscillator (210) frequency control

It is possible to control the frequency of the master clock oscillator 210 so that constant corrections in one direction can be minimized. This reduces the possibility that synchronization will not persist due to drift of the main oscillator. A circuit by which this can be achieved is shown in FIG. Here the correction pulse from generator 209 of FIG. 14 is used to control the oscillator frequency. In the case of the method, the correction pulse of the generator 209 (FIG. 14) switches those of the

1088U / 0438

- 87 - ■■ ·., ■ '"■.

Zero crossing flip-flop 225 emitted zero crossing voltage via a switching element 340. The polarity of the zero crossing voltage is determined by the direction of the correction, either leading or lagging, since the zero crossing flip-flop is either set or cleared correction cycle corresponds. Once the corrections .the phase shift in one direction for a long time, like the corrections of the phase shift in the other direction, then the average value of the DC component in the output of Schaltgliedes- 340 approaches zero _# If, however, a kind of phase lead or lag correction predominates, then the same current component will not be zero, but its polarity depends on the type of phase shift.

In Fig. 20, the DC voltage component is used to control an electromechanical servo system to correct the oscillator frequency. When the switching element 340 is opened, a capacitor 342 is charged from the switched-on voltage via a resistor 344. This partially charges the capacitor 342. Closing the switching element 340 interrupts the charging process, so that the capacitor begins to discharge - "The discharge takes place much more slowly, since the resistor 344 is not grounded during the closed period and a second resistor 346, which is connected to the capacitor- is much larger than resistor 344. The error DC voltage of the capacitor is with the help of a chopper 348, z, B _o with 400 Hz, chopped, then amplified in an amplifier 350 and finally fed to a servomotor 352 driven. The gear ratio of the gear is chosen so that it

takes a relatively long time, about 30 to 60 seconds in the system described as an example to "run through" the entire potentiometer range. The voltage tapped at the potentiometer becomes a voltage-dependent capacitor (not shown) of the clock oscillator 210 in order to regulate the frequency of the oscillator in a limited range. This type of voltage dependent frequency control is known per se.

If there is no control deviation (error residual voltage), the motor is not driven, so there is no frequency correction is carried out. If a control deviation occurs, the motor 352 adjusts the tap of the potentiometer 354 so, that the control deviation by feeding back the correction voltage is reduced via resistor 346 to capacitor 342. Since the correction pulses have a frequency of approximately 2 Hz have, the time constant of capacitor 342 and resistor 346 must be large enough to allow a certain smoothing, for example 2 or 3 seconds. However, this time constant must not be so large that the control loop this becomes unstable when the control loop is controlled by the clock oscillator is closed. Also the integration of the frequency correction voltage on the right to the actual one Phase errors on the left must be taken into account when considering the stability of the control loop. the The manipulated variable of the motor / amplifier combination is fed back, to prevent a double in the control loop Integration results. The DC gain of the servo amplifier is so high that the system deviation is also in the If the stops or the connections of the potentiometer remain small »All these methods are known per se. Due to the low sensitivity (gain) of the clock oscillator the simple integration and the

109814/0438

■ - 89 - ■; ■■; ■ ".

ration time of the RC element in general not to the To let the control loop become unstable.

A truth analysis for the observation of pre- errors of alignment or alignment in a real system shows that with an even distribution of leading and lagging errors almost twice as many apparent ones Leading errors such as apparent lag errors occur. (This is one pole of the non-corresponding query and response signals). With only in a hurrying direction Synchronization correction made can therefore be made improve the frequency correction by making the correction in increasing oscillator frequency makes twice as large as in decreasing oscillator frequency

However, the frequency of the master clock oscillator 210 can also can be controlled in other ways, for example by means of thermostats, temperature measuring circuits and other similar means methods known per se. These procedures can be used alone or in conjunction with that described in Pig. 20 is applied will"

I. Generation of the plug-in information pulse (A)

After the synchronization has been carried out, the information pulses are sent according to the altitude range in which the station is located. In Pig. 21, the plug height information is introduced via a three-phase synchronization 370-1 and 370-2 running at two speeds from an altimeter 271, for example from a Kollsmantype Ur. 1686-05 * The Synchro 370-2 rotates faster to transfer smaller units of the height measurement value ZVL . The height information of the two synchros eraeh @ int is amplified again as an analog sleiehspanramg on © inem potentiometer 374> that of an amplifier

^: 1098-14 / 043: 8

Servomotor 375 is driven via a gear transmission 376. The largest angular rotation takes place via the servomotor 375 > by the signal of the fast synchro 370-2, which is fed via a relay 377 and a drive amplifier 378. Then, when a fast cycle is inserted when the error output of the slow synchro 370-1 is certain exceeds the critical threshold value, a relay driver stage 379 is actuated to change the state of the relay « las relay 377 picks up and connects the slow one Synchro 370-1 with the servo 375 to set the synchro error to ifull bring to. If so, control is passed back to the fast synchro 370-2 by the relay falls off.

The time at which the aircraft _{information pulse (A Q} ) is sent relative to the start pulses Bq is programmed according to the user's own plug height. As already mentioned, the synchronized transmission timing pulses are generated with a frequency of 548 Hz. Any aircraft information pulses that are sent must coincide in time with these _{transmission time pulses, more precisely, only one information pulse A Q is} lowered in the time segment between two start pulses Bq and this pulse Aq is generated by selecting one of the odd-numbered transmission time pulses that occur in the time segment between the transmission times Hr, 3 to no. Occur (see Pig * 1) _{O at the} top left in Pig »21 the transmission time selector divider 279 (Fig. 17) is shown. The output signals of, for example, 7 flip-flops of the middle divider are fed to a precision voltage divider summing device 380. The attenuation or division factor of the attenuator or voltage divider 380 takes up with each frequency divider stage of the central frequency divider 281 from left to right, ie from the high-frequency outputs in the direction

BATH ORIGINAL 109814/0436

1016243

the low-frequency ones do away with a factor of 2. The muted. Output signals are added directly, so that a staircase voltage results as the sum signal, which with the start pulse at Bull begins.

The analog high voltage from the potentiometer 374 is fed to an input of a precision comparator 383 via a low-pass filter 381. The other input to the comparator is the staircase voltage from the attenuator 380. If the two input voltages are equal, the comparator 383 generates a pulse which is fed to a switching pulse generator 385 to trigger the switching pulse generator 385 either "on" or "off"_f; } e according to the magnitude and polarity of an altitude anticipation voltage.

When the plane ascends or descends, it is desirable Information impulses in the altitude areas approached next to the current height range of your own plug-in. That is why there is a proportional control provided at the number of height ranges in which Aq pulses sent by the rate of change of the Aircraft height depends. The speed of change in altitude becomes by differentiating the analog high voltage at the output of the filter 381 obtained in a differentiating element 387. There the speed voltage at the output of the differentiator 387 is usually very small, it is used in a conventional chopper stabilized feedback amplifier 389 amplified, demodulated in circuit 391, and then the analog high voltage in the summing circuit 393 added. The total voltage at the output of the summing circuit 393 is fed to another precision voltage comparator 395, either before or after the output pulse of the other comparator an Iffi> u> Ls. gives away. The duration of the output pulse

1-0981-4 / 0438

of the second comparator 395 depends on the rate of change in the aircraft altitude and on whether the aircraft is climbing or descending. The latter determines whether the altitude change rate voltage is added to or subtracted from the analog voltage. The first pulse from one of the two comparators 383 or 395 triggers the switching pulse generator 385 into the "on" state (by emitting a stop pulse), while the second pulse from the other comparator resets the generator. The interval determined by this switching pulse is the altitude-coded transmission time for the aircraft information pulses e _o

The information pulses are transmitted in the following way. The information synchronization Sehaltimpuls from Counter 292 (FIG. 17), inverted by an inverter 396, and the odd transmission time interrupt pulse from switching element 289 (Fig. 17) are fed to the inputs of an AND gate. The AND element 397 only gives when the transmission times are odd emits a pulse during the information period. The output pulses of the AND gate are a pulse generator 399 to shape the pulses if necessary, and the shaped pulses are fed to a second AND gate 401. The AND gate 401 also receives the level switching pulse from the generator 385 and the transmission timing pulses from counter 220 (FIG. 14). The AND gate 401 therefore only switches during of the height switching pulse and in an odd-numbered transmission time a transmission timing pulse through. These send time pulses control the Aq information pulses that are sent should be.

The reset voltages from a suitable source (not shown) are fed to the comparators 383 and 395 in order to manually set the level switching pulse to one or more set the desired height ranges. The rucksack pan

1098U / 0A36

. . ■ '- 95 -' - ■: ■: '.. ■■ Λ ■' ■ '■'"'". voltages control the timing of each comparator's pulse generation.

It is not advisable to send the aircraft information pulses A ₀ * 'until your own station is fully synchronized with the other stations in the system. Referring to Pig. 21, the transmission of the pulses A _{0 can be} prevented by interrupting the input signal of the pulse generator 399 so that it never reaches the AND gate 4-01. An AQ information pulse breaker circuit is in Pig. Shown * The S ehalt voltage from AND gate 597 is fed to an AND gate 410. If there is no signal at the other input of the AND element 410, the switching voltage cannot pass through the AND element 410. As you can see, this state can occur when the start reset voltage from flip-flop 326 (Pig. 19) or the voltage from a monostable multivibrator "412" is applied to the input of a NOR element 413. The NOR element is an OR element with a downstream inverter (NICHI element). Therefore it does not provide an output signal if one or more input signals are present. The start reset voltage is present at an input of the NOR element 413 when the coarse synchronization takes place 'Information pulses are not sent during this time, the start reset _{voltage blocks the AND gate 410.' The transmission of an A 0} pulse is preferably also prevented if the Pein synchronization corrections to be carried out by the station are too great Wrong information is sent Here the received response pulse is delayed and to trigger a signal trap generator 416 via a delay circuit 417 is used. The delay time is equal to the maximum synchronization error * which can be tolerated, _s and di & sa time is set, ¥ ®on the correction pulse from generator 209 (Pig. 14), which is sent by the response

i -

109814/0436

- 94 -. "■ '■■

pulse is triggered, is still pending, when the switching pulse arrives from generator 416, a switching element 418 is opened and the monostable multivibrator 412 is triggered in such a way that it opens the AND element 410 and prevents _{the generation of the information pulse A Q *}

It should be noted that the AND gate 410 of FIG can be switched either before or after the AND gate 401 of FIG. 21 or to any other suitable place, to prevent the generation and / or transmission of the AQ pulses.

It should also be pointed out that if the own station is a ground station, the height coding arrangement of FIG is not required. Instead, the switching pulse is specified by the generator 385 so that it is at a predetermined time triggers the transmission time pulse in an even number assigned to the ground information time of the station Time to hold out. Here would be the odd-odd switching pulse to AND gate 397 from odd switch generator 288 of FIG. If you want, you can do that too Use the same breaker circuit as shown in Fig. 16 to prevent the Gq pulse from being emitted, if the own station is not synchronized.

I. Irapula encoding and decoding . -

To identify the various types of impulses that appear in are transmitted to the system, pulse coding is preferably used applied. With each individual start (B), query (I), answer (R) and information impulse (A or G) a pulse pacor is sent, the transmission delay sswischen the impulses of each pair are determined by the impulses is. Ms' block diagram a® »Iapule coder one

I -

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individual station is shown in Fig. 23. For each type of pulse pulse pairs are supplied by two blocking oscillators, by separating one of the oscillator from the delayed pulse of the Trigger pulse of the first oscillator is triggered. Among other things each blocking oscillator has a relatively long recovery or release time, does not become the same blocking oscillator used for both pulses.

As shown in Pig. The transmission time pulses can be sharply shaped before they are fed to the various oscillators. Both blocking oscillators generate individual pulses of a predetermined duration. The delay element 451 determines the coding delay in the case of a B-pulse, so that the oscillators 450 and 452 generate two pulses with a certain delay interval. The two pulses are passed through to the modulator of the transmitter via an OR <gate 455. In a similar way, the send time pulse assigned to _{the I 0 send time triggers the Pig circuit.} 18 directly the oscillator 452 and via a delay element 456 the oscillator 450. The delay time of the delay element 456 is different from that of the delay element 451 in order to implement the coding of the pulse I. The pulse pair I ₀ is switched through also by the OR gate 455 to the modulator of the transmitter _T

To generate the coded pulse pairs for the pulses R _Q and Aq (or G ₀ ), two further blocking oscillators 460 and 462, which are again set differently, are used. These blocking oscillators are each preceded by a R ₀ delay element 464 and an A ₀ delay element 466, each of which has one

1098U / CH36

■ Realized a certain time delay for the pulse pairs. The trigger signal for the pulse pair of the own response pulse Rq is the interrogation pulse j arriving from another station, which is fed via an AND element 468 * A switching pulse from a monostable switching pulse generator 470 opens the AND element 468 when the own interrogation pulse Iq appears, and switches the interrogation pulse from another station through when it arrives. This limits the transmission of the response pulses R ~ to periods triggered by its own interrogation pulses. The trigger pulse for the pulse pair (A ₀ or Gq) is that of the Pig circuit. 21 switched information transmission timing pulse.

The pulse coding takes place at the output of the station receiver with the aid of the circuit of FIG. 23. The video signal a threshold detector 480 is fed from the receiver, which changes its state when the video voltage exceeds a critical amount «Below a certain threshold value Lying received impulses are blocked in order to avoid the possibility How to reduce confusion or confusion explained above. The received signal is sent from the threshold value detector to two delay chains 482 and 484, where the delay chain 484 is tapped at points which correspond to the delay of the pulse pairs B, I and R. Three AND gates 486, 488 and 490 become the plague position a coincidence between pulses of the two delay chains is used. As for the AND gates, so is the difference in time delay between the two Input pulses equal to the time delay between the to decoding pulse pair. The first and last impulses then coincide, so that only a single impulse am The output of each AND element appears. Two delay chains instead of one are used to reduce the decoding delay time regardless of the type of pulse that is decoded,

1098 U / CU 3 6

to keep constant »The Jt ₀ and / or GQ pulses can be decoded similarly.

J. Receiver - Sender "'

In the system according to the invention, only a single transmission channel is used used. This simplifies both the Both the sender and the receiver considerably. As a receiver-transmitter a known design is used. The block image is shown in FIG. Pig's coded pulses. 22nd are delayed via a delay element 502 with a small delay a modulator 500 is supplied. The coded pulses are modulated onto a carrier wave generated by a carrier wave oscillator 5Q4- and the composite wave is broadcast via an antenna 506.

The send and receive units 506 and 508 are preferred attached to different places on the aircraft, e.g. at the top and bottom of the fuselage. This makes them up to isolated from each other to some extent. Fm; however the first mixer 510 in the superheterodyne receiver protect ^ a varactors holder 509 is connected between the receiving antenna 508 and the first mixer 510, to a additional attenuation during the duration of the transmitted pulse to introduce. This switch is triggered by a pulse from a switching pulse generator 520, which in turn is generated by the Pulses of the pulse encoder is triggered. The from the delay element 502 introduced a slight delay in the modulator input circuit that the switch 509 before the Switching on the transmitter switches off.

Tray of the first mixer stage "-510 are the received signals in a received broadband intermediate frequency amplifier 512 amplified, demodulated in a demodulator 514 and converted into

100814/04

a video amplifier 516. The reinforcement of the Intermediate frequency amplifier 512 is controlled by an ζextvariable Gain signal generator 518 varied over time, namely from 0, during the occurrence of the transmission pulse to Maxinnim in the reception time of the impulses from maximally distant Stations, 30 that the received pulses on the demodulator all have approximately the same amplitude. An automatic shrinkage compensation regulation 522 (AVG) 522 is also provided, to compensate for medium or slow changes in gain.

X summary

With the help of the system according to the invention, the oscillators (Clock) of several fixed as well as movable Stations that are not initially synchronized with each other are synchronized. This "takes place without a main synchronization device, E.g. an atomic clock with which all stations have to synchronize. Instead, the various stations in an area synchronize each other until a perfect synchronicity is established. The synchronization method according to the invention, namely a correction only in a leading direction the clocks are synchronized very quickly. The means to do this are simple. The problem of matching interrogation and response pulses is practical avoided. As soon as perfect synchronization is achieved, each station can determine the distance to the other stations measure with high accuracy. It should also be noted that the system can also work without a fixed station.

The system according to the invention also allows all stations, whether fixed or mobile, to transmit on one and the same frequency or to receive. This has the consequence that the

109814/0436

Radio transmissions available, frequency spectrum is effectively used, the device-technical execution simplified will get a maximum it-receiver sensitivity results and a minimum transmission power is required.

1098U / PA36

Claims (10)

! Patent claims 1. Method of synchronizing the generation of first Signals in all stations of a group of transceiver stations, in which during a time period the temporal The difference between the generation of the first signals of a pair of stations in the station group is measured, characterized by the fact that the Time of generation for the first signals from the station with the lagging signals due to the measured Generation time difference approximately to the generation time of the first signals from the station is brought forward with the leading first signals, and that this synchronization is repeated with further pairs of stations in the station group. 2. The method according to claim 1, characterized in that g e k e nn ζ e i c h η e t that the station pairs are selected optionally will. 3. System for carrying out the method according to the preceding claims, in which in each station to be synchronized a generating device for the first signals and a Measuring device for measuring the time difference between the generation of the first signals of each station is included, characterized in that a Setup based on the measured time difference The time of the first signals in the station advanced with the lagging signals by approximately the measured time difference. 1098 14/0436 1816243 4 ". System according to claim 3» because d u r c h characterized that the generation time of the first Signals in the station with the lagging signals like this is brought forward that they with the generation time of the, first Signals from the other station with the leading signals coincides. 5. System according to one or both of claims 3 and 4, '. d a d u r eh marked that each Station sends out its own first signals and the first signals from the other station "receives, and that the Stations the time difference between the generation of their first signals due to the sending and receiving of the first signals. . 6. System according to claim 5, d a d u r eh g e k e η η draws that in each station a transmitter sends a second signal in response to a received first signal and a receiving device the receives second signals sent by the other station » that each station taking into account the time difference of the first signal sent by it, furthermore that of the other station in response to the sent-first Signal received second signal and the received first signal -of the other station measures. 10 9814/0436 Jim 7. System according to claim 6, characterized in that the station with the trailing Signals the transmission time of their next first signal brought forward in such a way that the next received first signal from the other station occurs at a time that is approximately lies in the middle between the next transmitted first signal of this station and the received second signal, that the other station sends in response to this first signal. ■ 8. System according to one or more of claims 3 to 7, characterized in that a Means in each station generates periodic position or transmission time signals, and that the first signals in a predetermined time relationship to the transmission time signals stand. 9. System according to claim 8, characterized in that the first signal with a transmission time signal coincides. 10. System according to one or both of claims 8 and 9, characterized in that the first signals of a station can be generated randomly. 11. System according to one or more of the tests 3 to 10, characterized in that the Generation time of the first signals in a station is only changed if a first signal is received after the transmission of a first signal. 10 9814/0 43 6