Network and method for wireless data communication network using flying relays

0001The invention relates to a wireless data communication network according to the preamble of claim <b>1</b> and a method for operating the data communication network according to the preamble of claim <b>9</b>,

0002In wireless data communication networks, the data to be transmitted are known to be without the interposition of a line medium, such as a electrical conductor or a glass fiber transmitted. The data to be transferred here transmitted by means of suitably modulated electromagnetic or optical waves.

0003Data transmission method using high-frequency electromagnetic waves are widely known and are currently used in particular in the telecommunications sector. For example, let phone calls from a landline or mobile network Radio frequency microwave links extraterrestrisch over short to medium Stretching forward. Moreover, this data transfer method is for about 20 years very successfully used information via satellite over long distances to be transmitted. The satellite transmission is currently in particular for transmitting radio and broadcasting frequencies but also for intercontinental telephone connections used.

0004Wireless Optical data transmission methods work with data modulated laser pulses. Compared to high-frequency radio links prove to the optical Space connections for data transmission for many reasons to be very beneficial. Thus, an optical laser beam can, thanks to its extremely short wavelength very easily with a relatively small transmission optics and thus having a very small solid angle radiate. This good focusing of the laser beam may be obtained at optical Data transmission, unlike the aforementioned radio transmission of very small Senders and receive antennas are used. These minimalized optical antennas can be wide with a minimum transmission power greater data rates transmitted than in, for example, in data transmission by radio would the same transmission power possible. Finally, optical data transmission method advantageously virtually no background noise on.

0005The good focusing or Bündelbarkeit the optical transmission beam requires however a highly accurate determination of the direction of the transmission beam in the transmitting station and accurate tracking and alignment of the optical receiving system at the receiver station. In addition, results in particular in the free-space optical data communication the problem that at least one of these stations free in space is movably disposed, which is a Provision of the optical laser beam to the optical receiver system makes necessary. A method and an arrangement for uninterruptible Operation of optical data links between satellites, in which for data transmission between the respective satellite is a laser beam for use is in the<i><b>EP 0876013 A1</b></i> described.

0006In addition to high data transfer rate, the lowest possible energy consumption are of transmitting / receiving stations and a noise-free data transmission possible particularly in the military aerospace engineering even more requirements placed on generic data communication networks: <sl><li>Especially for military reconnaissance and communication of information in crisis or War zones have a data communications networks used there ensure utmost privacy and noise immunity of data transmission. While there is in such a crisis or war zones usually an existing communications network, but is this for reasons of lack of or missing Privacy are not in use. So far, therefore, as was obvious Solution uses a satellite-based data communication network, in which the to transmitting data from a ground-based or flugzeuggestützen transmitting station via Satellites are transmitted to the receiver station. The data transmission is here via radio signals. It has been found, however, that this data transmission method Neither system is totally secure line and also interfered undesirably by third parties can be or interrupted.</li></sl>

0007A crucial factor is the fact that a tap-proof communication network possible be set up very quickly and with relatively simple means can. This communication network should almost independent of the existing its infrastructure operable. Moreover, for example, a change able to make it necessary that the structure of the data communication network changes must be what a certain flexibility of the network topology used makes desirable.

0008Such a data communications network that fulfills all the requirements referred to, could not yet be implemented satisfactorily.

0009Assuming the object is placed on the present invention, a universal applicable, largely tap-proof and interference-free data communication network provide, which also suitable for transmitting data with high information density is. Further, a method of operating said data communication network is provided will.

0010The arrangement related object is through a data communication network with the features of patent claim <b>1</b> dissolved.

0011Accordingly, a wireless data communication network is provided with at least two portable flying objects in a common, restricted Area in the atmosphere or in erdatmosphärnaher distance to the surface are, at least one optical transceiver station in every flying object, respectively interruption over first wireless data connections that at least partially are formed as laser-optical data connections that are coupled to one another, with at least one stationary ground or near-ground -Station, each having at least a transceiver station via second wireless data connections can be coupled.

0012The procedural problem is solved by a method for operating the data communication network with the features of patent claim <b>9</b> dissolved.

0013Accordingly, a method for operating a data communication network is provided, the following steps comprising:<sl><li>(A) between at least two respectively arranged in flying objects transceiver stations via the first data connections, data transfer, wherein for the Data transfer sections a laser optical signal is used at least.</li><li>(B) at least one intermediate transceiver stations and a ground or near-ground Station takes place via the second data connection, a wireless data transfer, wherein receiving a data signal from the respective transceiver station and / or is sent to the corresponding transceiver station.</li></sl>

0014The dependent claims are directed to preferred embodiments and further developments of the invention addressed.

0015The present invention describes an optical data communications network based on stationary ground or near-ground stations and stationary free flying objects based together are connected via wireless data connections and thus over wide Areas form freely configurable communication network. This data communication network meets the aforementioned, to a data communication, especially in Crisis or war zones stated requirements and allow an electrically non-reactive Linking the input and output signals of the data communications network.

0016The proposed concept is based essentially on an uninterruptible optical laser communication between various flying objects, the cloud cover over the operate. This laser-optical data links offer an excellent service Privacy and can also advantageously build very quickly or change. This data communications network to satellite-based competition in Communications networks is, can be in contrast with relatively simple install and cost-effective means. For the construction of such a data communication network in addition to the already existing floor or ground-based stations only at least two flying objects required. Since the individual flying objects, each represent the network nodes of the data communications network, within broad limits independently of each other can operate, a maximum autonomy of the network nodes be guaranteed. In particular, this may be the data communications network be quickly reconfigured and adapted to change. By Use of additional flying objects also can be a redundancy and thus a generate greater flexibility in the topology of the data communication network.

0017Further details and advantages of the invention will in the following two embodiments explained. The invention is here below with reference to the figures in the specified Exemplary embodiments explained in more detail. It shows:<dl tsize="7"><dt><b>Fig. 1</b></dt><dd>a first embodiment of a data communications network according to the invention;</dd><dt><b>FIG. 2</b></dt><dd>A second embodiment of a data communications network according to the invention,</dd><dt><b>Fig. 3</b></dt><dd>a diagram of the maximum range distances depending the cloud base and the altitude of the aircraft indicates.</dd></dl>

0018In all figures of the drawing, identical or functionally identical elements with same Reference numerals.

0019<b>figure 1</b> shows a first embodiment of the invention, from aircraft established data communication network. In<b>figure 1</b> are with <b>11</b>. <b>12</b> two at high altitude flying aircraft shown. In both planes<b>11</b>. <b>12</b> is in each case an optical transceiver station <b>21</b>. <b>22</b> built-in. The transceiver stations<b>21</b>. <b>22</b> are via an optical Data Connection <b>31</b> directly coupled to each other. Further, a is at the surface<b>51</b> arranged base station <b>61</b> provided that in the present embodiment with an airplane <b>21</b> an additional data connection <b>71</b> connected is.

0020Essential to this coupling of transceiver stations <b>21</b>. <b>22</b> is an uninterruptible optical data link <b>31</b>, For this reason, in the present example, the two aircraft <b>11</b>. <b>12</b> and connecting these data link <b>31</b> above the Cloud border <b>41</b> arranged. The altitude of the aircraft was<b>d3</b>, The distances the aircraft with one another <b>d1</b> and the cloud height with <b>d2</b> indicated.

0021The transceiver stations <b>21</b>. <b>22</b> can for bidirectional or unidirectional data transfer, that means for transmitting and / or receiving modulated optical data be designed, wherein the data to be transmitted in the form of a broad-band laser beam be modulated. The optical transmitting unit for transmitting a designed transceiver station <b>21</b>. <b>22</b> comprises means for optical transmission of the data, a laser unit and an optical output amplifier. An optical receiving unit for a Receive designed Transceiver Station <b>21</b>. <b>22</b> typically includes a receiver amplifier and means for optical data transfer. Further, the transceiver stations have<b>21</b>. <b>22</b> Means for stabilizing position and means for tracking the optical Beam on. This can be ensured that in case of minor vibrations or relative movements of the transceiver stations <b>21</b>. <b>22</b> played an uninterruptible Data Connection <b>31</b> will ensure. The optical transmitting and receiving devices a transceiver station <b>21</b>. <b>22</b> are free advantageously in space pivotally mounted so that it also with floating other transceiver stations<b>21</b>. <b>22</b> Uninterrupted data connections <b>31</b> can build.

0022The construction and operation of such transceiver stations is in the <i><b>EP 0847150 A1</b></i> and in the <i><b>EP 0863627 A1</b></i> accurately described. The contents of these patent applications is hereby incorporated in full in the subject of the present patent application ( "Incorporated by reference").

0023The operation of the data communication network is from <b>figure 1</b> short described.

0024The first plane <b>11</b> stays in the example shown on a Part <b>52</b> of the Surface, while the second plane <b>12</b> over one of the Part<b>52</b> distant range staying. The Part<b>52</b> an example his crisis or war area over which the first plane <b>11</b> for the purpose of air reconnaissance flies. The data obtained from these aerial reconnaissance will have broadband, data modulated laser beam <b>31</b> from the first transceiver station <b>21</b> to second transceiver station <b>22</b> the second plane <b>12</b> Posted. This broadband Laser can be advantageously data rates far above 100Mbit / sec transfer. The data modulated laser beams have a minimum Scattering angle, thus preventing unwanted radiation. This type the data transmission can be ensured that at least on the partial section<b>52</b> a tap-proof and interference-free data transmission takes place.

0025From the second plane <b>12</b> can the demodulated data on the additional data connection<b>71</b> the ground or near-ground station <b>61</b> be sent. The data transmission on the further data connection <b>71</b> can be effected via radio signals, since the Ground station in the case shown far outside of the subsection <b>52</b> is and Here thus a reduced requirement for the interference or eavesdropping of Data transfer results. However, it would here also an optical data transmission between airplane <b>11</b> and the ground or near-ground station <b>61</b> conceivable.

0026<b>figure 2</b> shows a second embodiment of a data communications network according to the invention. There are here three aircraft <b>11</b>. <b>12</b>. <b>13</b> provided, the transceiver stations (in <b>figure 3</b> not shown) respectively through data links <b>31</b>. <b>32</b> together are connected. In addition, two ground stations (or close to the ground stations)<b>61</b>.<b>62</b> shown, each with one of the planes <b>11</b>. <b>12</b> over more data connections<b>71</b>. <b>72</b> are connected. In the example shown according to<b>figure 2</b> can be a characterized create a closed network with data communication, in which a completely bug-proof and noise-free data communication between two ground stations <b>61</b>. <b>62</b> about very long distances is possible.

0027The <b>figures 1</b> and <b>2</b> indicate that any data communication networks according to the invention can be generated by any number of aircraft <b>11</b>.<b>12</b>. <b>13</b> and ground stations <b>61</b>. <b>62</b> coupled via suitable laser-optical data links will.

0028As mentioned above, an interruption-free optical data connection <b>31</b>. <b>32</b> essential for the operation of the data communication network. A long stretches uninterrupted optical link not necessarily can be typically, however, above the cloud <b>41</b> to ensure. For this reason, the Data Connections <b>31</b>. <b>32</b> interconnected planes <b>11</b>. <b>12</b>. <b>13</b> at least fly so high that the corresponding data connection <b>31</b>. <b>32</b> between them reliably above the cloud level <b>41</b> are arranged (<b>d4</b> > <b>d2</b>).

0029figure <b>3</b> shows a diagram showing the maximum range distances (<b>d1</b>) in between two planes as a function of altitude (<b>d3</b>) And the cloud base (<b>d2</b>) Indicates. It shows that, with an assumed Cloud limit of 12 km and an altitude 16 km to a maximum length of the route between the aircraft of about 500 km results, while at an altitude of 30 km, the free path length almost doubled.

0030In the <b>figures 1</b> and <b>2</b> were for realizing the data communication network according to the invention such aircraft <b>11</b>. <b>12</b>. <b>13</b> used for the flight at high altitude are designed. Such usually jet-powered high-altitude aircraft have a mostly excess of the maximum limit of clouds lying on service ceiling. In each Case but should have at least the aircraft an altitude of more than 12,000 m. Instead of using aircraft, it would also be possible to use tethered flights. With captive balloons to very high altitudes can reach into the stratosphere. This can of course also as a so-called unmanned drones be formed, as frequently for educational purposes in crisis areas used will.

<b>LIST OF REFERENCE NUMBERS</b>

0031<dl tsize="11" compact="compact"><dt><b>11</b>. <b>12</b>. <b>13</b></dt><dd>Aircraft, flying object</dd><dt><b>21</b>. <b>22</b></dt><dd>transceiver station</dd><dt><b>31</b>. <b>32</b></dt><dd>(Optical) data connection</dd><dt><b>41</b></dt><dd>Cloud border</dd><dt><b>51</b></dt><dd>earth's surface</dd><dt><b>52</b></dt><dd>Part of the earth's surface</dd><dt><b>61</b>. <b>62</b></dt><dd>base station</dd><dt><b>71</b>. <b>72</b></dt><dd>more data connection</dd></dl>