DE3605905A1 - METHOD AND DEVICE FOR AUTOMATICALLY TRACKING A SATELLITE WITH A RECEIVING ANTENNA - Google Patents

Description

D-8OOO MUNICH 86

11942 / Dr.v.B / An

DX Antenna Company, Limited

2-15, Hamazaki-dori, Hyogo-ku,

Kobe, Japan

Method and device for automatic tracking a satellite with a receiving antenna

The present invention relates to a method according to the preamble of claim 1. Also concerns the invention a device for performing a such procedure.

The invention is particularly suitable for tracking a communications satellite through a parabolic antenna, which is placed on a movable support, such as a ship, and ensures effective reception, by the elevation angle (elevation) and the side angle (Azimuth) of the antenna can be adjusted according to the movements of the wearer.

One for communication with a satellite serving parabolic antenna, which on a movable carrier, such as a ship or a floating platform, is usually installed with propulsion devices for adjusting the height angle (elevation) and the side angle (azimuth), also provided with a

Altitude and azimuth detector arrangement, an arrangement for Perception of the inclination of the wearer in the direction of elevation, an arrangement for detecting the level of the received signal and an arrangement for controlling the altitude and azimuth drives in accordance with a predetermined program as a function of the instantaneous values the altitude, the azimuth, the inclination and the reception level.

ι From DE-OS 35 18 587 are a method and a Device for tracking a communications satellite known with a parabolic antenna, in which the antenna is first caused to move the entire azimuth by a starting or starting point taken from a table or map Reference altitude angle to be scanned until the reception level exceeds a first reference value. Afterward the antenna is adjusted so that its axis describes a rectangular spiral on the sky, until the reception level reaches a second reference value which is greater than the first. This with a spiral scan working search program repeatedly when the reception level is due to movement of the carrier of the antenna has dropped below the second reference value.

The one carried out to correct the antenna setting Spiral scan is centered on the direction, with which had previously received the maximum signal level. The scanning is done so that on both sides of the original direction the same azimuth angle in each case is swept over, although the destination can only have migrated in one azimuth direction.

The present invention is based on this The prior art is based on the object of specifying a method and a device that have a faster Finding the optimal reception direction and a

• T-

Enabling an increase in the accuracy of the tracking.

The invention is based on the knowledge that the efficiency in the search for the new optimal Receive direction can be doubled if possible is to determine the sense or the azimuth direction in who emigrated to the destination.

The above object is achieved by the in claim 1 marked procedure solved.

An advantageous device for carrying out such a method and a further development thereof Equipment are the subject of claims 2 and 3.

A device according to a preferred embodiment of the invention for automatically tracking a communications satellite through a parabolic antenna a main primary radiator, which is at the focal point of the Parabolic antenna arranged and in its axial direction is aligned, a first antenna drive device to adjust the angle or azimuth of the antenna, a second antenna drive device for adjustment the elevation angle or the elevation of the antenna, a main level detector arrangement for detecting the level of the signal received by the main radiator and a first Antenna control device, which is dependent on the main signal Ipege I from the main level detector arrangement first and second antenna driving devices so adjusts that the reception level has a predetermined value exceeds. According to the invention, the device includes also a Hi Ifs primary radiator, which is equipped with a slight azimuthal deviation or offset is arranged with respect to the main radiator, also a Hi Ifspegeldektor for detecting the level of the through the

Hi LfsstrahLer received signal, a second Antenna control device operating on the main signal level and the auxiliary signal level L responds and controls the first antenna drive device so that the difference between the main and the hi LfssignaLpegeL assumes a predetermined sign, and a third antenna control device that operates on the difference between the main and the Hi LfssignaLpegeL and, if the main signal level below the specified value has sunk, the first antenna control device so controls that the main signal level again via the specified value increases.

In the following the invention will be explained in more detail with reference to the drawings, while others will be discussed Advantages and features of the invention come to the language. Show it:

Fig. 1 is a simplified block diagram of a

Device according to an embodiment of Invention;

Fig. 2 is a more detailed block diagram an embodiment of the invention;

3a and 3b are flow charts for explaining a Embodiment of the method according to Invention;

Fig. 4 is a graphical representation of the

Directional characteristics of the main and the Auxiliary spotlight to which in the explanation reference is made to the invention; and

Figures 5 and 6 are graphical representations of two Scanning tracks as they are when performing the

Method according to FIG. 3 can occur.

The device shown schematically in Fig. 1 contains a parabolic antenna 10, which is mechanically with a first and a second drive device 12 and 14 is coupled, which the antenna 10 about its side angle I or azimuth axis or its elevation angle or to adjust the elevation axis. The antenna 10 is with two antenna elements of the same type or Primary radiators 16 and 16 'provided, the structure by a suitable, not shown support structure on Antenna bodies are attached. The first radiator 16, which is to be referred to as the "main radiator" is in Focus or focal point of the parabolic antenna 10 is arranged and aligned in Axia I direction of the antenna, while the second radiator 16 ', which is called "Hi Lfs- or Secondary radiator "should be referred to near the Main radiator 16 and something in the azimuth direction this is arranged offset. The signals received by the radiators 16 and 16 'are transmitted through Frequency converter 18 or 18 'in a suitable manner in converted to the frequency and fed to a main or a secondary level detector 26 or 26 ". The Main level detector 26 responds to the level of the vom Main radiator received signal and delivers a corresponding, the value of the signal level indicating Signals to first, second and third control devices 20, 22 and 24, respectively. The auxiliary level detector 26 * speaks to the level of the auxiliary radiator received signal and delivers a corresponding signal indicating the Hi Ifs receive level to the second and the third control device 22 and 24. The first Control device 20, which is also used in the above-mentioned known device is present, responds to the instantaneous value of the HauptsignaIpegeIs and delivers Control signal to the first and the second

Drive device 12 or 14, which the antenna 10 so that the main signal level has a exceeds the specified value. According to the invention The second control device 22, which is additionally provided, responds to the instantaneous values of the main signal and the Hi Ifssigna lpege I s and supplies a second control signal to the first drive device 12, so that this the azimuth of the antenna 10 adjusted so that the difference between the main and the Hi I fssignaIpege I has a predetermined sign. the third control device, which is also additionally provided according to the present invention, speaks to the difference between the main and the Hi Ifssigna lpege I and delivers a third control signal to the first drive device 12, which when the Main signal level has dropped below the specified value is, the azimuth or azimuth of the antenna 10 adjusted so that the main signal again over the predetermined Level increases.

The control devices 20, 22 and 24 are shown in FIG. 1 as shown as separate units, but in practice they can be combined into one unit and, for example can be implemented by a microcomputer, as will be explained in connection with FIG.

Fig. 2 shows a parabolic antenna 10 for receiving a electrical vibration of a not shown Broadcasting satellite, which is arranged on a platform 32, which in turn is attached to a movable body (not shown), such as a ship in motion, is attached. The antenna can be driven by an elevation drive unit 36 about a horizontal axis rotated to adjust the elevation or elevation of the antenna; furthermore, the antenna can by a Azimuth or azimuth drive unit 38 by one

• ΛΑ-

vertical axis can be rotated to adjust the azimuth or azimuth of the antenna. The drive units 36 and 38 are each controlled by a height and a side control unit 40 and 42 with respect to the angle of rotation and the direction of rotation. The drive units 36 and can be electric motors that are controlled by switching devices such as the control units 40 and 42, but they can also be hydraulic drives that are controlled by a solenoid valve controller. Hit the elevation or side drive unit 36 or a height or a side angle sensor 44 and 46 are coupled to detect the size and meaning of an adjustment of the height angle or the side angle with respect to a reference direction of the antenna 10 and corresponding height and to generate side signals Vp. and V._, respectively. The sensors 44 and 46 can contain potentiometers, for example. An inclination sensor 48 is coupled to a second platform 34, which is driven by the lateral angle drive unit 38, which detects the amount and the direction of the inclination of the platform 34 in a vertical plane containing the axis of the parabolic antenna 10 and generates _{a corresponding inclination signal V INC.} The inclination sensor can contain orthogonal vials.

The antenna 10 is equipped with two primary radiators 16 and 16 ', a main radiator and an auxiliary radiator, which are arranged as it has been explained in connection with FIG Hearing radiation or horn antennas can exist. In which present embodiment, it is assumed that the Auxiliary radiator 16 'is arranged along the main radiator 16, if you look at the antenna from the front. The main radiator 16 is via a frequency converter 18 with a Haupt'Tuner 52 connected, while the auxiliary radiator 16 'via a

* / let '

Frequency converter 18 'coupled to an auxiliary tuner 52' is. The frequency converters 18 and 18 'set that from Broadcast satellites received microwell signals into a lower frequency signal. The main tuner 52 is set this lower frequency signal into a signal whose Frequency for a conventional television receiver 54 is suitable and also demodulates the input signal, wherein a main level signal M is generated, which is the received level of the main beam 18 received Signal. The auxiliary tuner 52 'demodulates the input signal from the converter 18' and delivers a Hi IfspegelsignaI S, which is the instantaneous reception level of the signal received by the auxiliary radiator 18 '.

The signals M, S, V _c , V _A7 and V _T .. _ are fed via an input regulator 56 to an analog-digital converter 58 for digitization, so that they are processed in a central processing unit (CPU) 60, such as a microcomputer can, as will be explained with reference to Fig. 3 ff. The CPU 60 supplies a set of command signals for controlling the elevation angle and the azimuth angle of the antenna to a driver unit 32 for amplification and leveling regulation. The output signal of the driver 32 is converted into two control signals K 'by a Ha Ib conductor relay 64. and K '. _7th

ti - AZ.

divided and these signals are converted by a rectifier 66 into direct current control signals K _C1 and K. ₇

CL H L

converted and a height or a side control unit 40 or 42 supplied. The CPU 60 is equipped with a digital switching device or keypad 6.8 for entering a desired elevation angle provided, as will be explained.

With reference to FIGS. 3a and 3b, a preferred embodiment of the invention is now

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Method for tracking a satellite will be explained. The first step in the process is to get the Parabolic antenna 10 to be directed at the satellite so that the maximum reception level results when the Platform 32 is stationary (or the ship is at rest).

In a method step 100, an initial value θ _{η of} the elevation angle θ is input into the CPU 60 through the digital switching device 68. This value 8 _Q represents the approximate height of the satellite at the geographic position of the ship and can be taken from commercially available tables or maps. Further, at step 100, X = 1 and N = 2X-1 are input to the CPU 60. X and N are variables with the unit degree. In a step 102, the CPU 60 and the subsequent control system are operated to set the antenna 10 to the angle of elevation θ. The antenna 10 is then rotated in a step 104 in a predetermined Nu II azimuth direction. In a step 106 the antenna is then successively rotated to the right in order to increase the azimuth or azimuth angle ψ and it is checked in a step 108 whether the signal level H exceeds a predetermined level value β or not. If the answer is negative, a step 110 then checks whether the azimuth or azimuth angle has reached ψ 360. If not, steps 106, 108 and 110 are repeated and, if the azimuth angle reaches 360 °, the height of the antenna is _{adjusted to B Q} +0.5 N in a step 112. In this case N = 1 since X = 1 and the new elevation angle is therefore θ = θη + 0.5. This means that the axis of the antenna 10 has described a track 0-1-2 on the celestial vault during steps 104 to 112, as shown in FIG.

In the next step 114 the antenna 10 is rotated successively in the opposite direction or to the left. During this azimuthal rotation, it is checked in step whether the signal level M exceeds the value 3 or not and in step 118 whether or not the azimuth angle has again reached its initial value of zero. If the Side angle reaches zero before the signal level M reaches the value β, the elevation angle θ becomes the Antenna 10 reduced by X in step 120, im In the present case by one degree of angle, and the value of X is then in a step 122 by one degree of angle increased and changed to two degrees. The trace of the axis of the antenna 10 on the celestial vault passes through during of steps 112 to 122 obviously the additional Distance from point 2 to point 4.

In a next step 124 it is checked whether X has reached the value five degrees or not. In the negative case, the method returns to step 106 and the antenna 10 changes the direction of the azimuthal rotation and corresponding further method steps are carried out until X reaches the value five degrees. When X has reached five degrees, the antenna has reached the end point 19 of the track shown in FIG. 5 and the method returns to the starting point _{to correct the initial altitude angle value S n.}

If the signal level H in step 108 or 116 is above the If the value ρ lies, the method goes into a correction mode according to the invention, which begins with a step 126. With this correction procedure, the Hi Ifssignalpegel S together with the main signal I H used. As FIG. 4 shows, the directional characteristics of the radiators 16 and 16 'are im essentially the same, they are only offset horizontally. The one mentioned above

predetermined signal level B has a value as it is for a Satisfactory reception of the broadcasts from the SateLLiten is required, and it lies somewhat below the intersection of the two curves S and M in FIG. 4. The difference M-S is therefore approximately NuLL or positive if the main signal level M is greater than the value 3 (Area A in Fig. 4). As can also be seen from FIG there are two prohibited areas E and D in which the main signal level M is less than 3. One looks 4 further shows that the difference M - S is negative in area E and positive in area D. If so the Main signal level M falls below the value β, the Direction of the antenna 10 from the SateLLiten to the left if M-S is negative and to the right if M-S is positive. This is exploited in the present method.

In step 126 it is checked whether or not M - S is positive or NuLL, i.e. whether the SateLLit is in the range C is or not. In the negative case means this is that the SateLLit is in area B or E (if it is certain that M is greater than 3, then it is in area B). In order to correct the azimuth or azimuth, the antenna is therefore adjusted in step 131 Turned to the left and it is checked whether M is greater thanLs 3 or not. This check is also made for confirmation if the answer in step 126 was "YES". If in step 128 it is confirmed that M is greater than 3, the antenna is in step 130 in the eye position stopped.

After stopping the antenna in step 130, repeat checked whether M - S is positive or not. In the negative case the antenna is rotated to the left in a step 136

as in step 131 and confirmation is obtained again in step 128 that M is greater than β. in the In the affirmative case, the instantaneous value a des Inclination signal V is stored in the CPU 60 and then steps 128, 130 and 132 are respectively performed Way executed. Through and during this repetition of steps 128 through 136, the antenna intercepts the satellite in the desired area C of FIG.

If the antenna fails to capture the satellite in area A of FIG. 4 because the ship is meanwhile has moved, the answer to step 128 becomes "NO" and the method goes to a step 138 in Fig. 3b above. In step 138 it is checked whether the difference M-S is positive. Is zero or negative. If it is positive, so this means that the satellite is in the area D, the antenna is therefore in a step 140 to the right is rotated and the method continues with a step 142. If the difference is negative, this means that the satellite is in area E and the antenna is therefore rotated to the left in step 144 and that Method continued with step 142. If the level difference is zero, the procedure starts immediately with the Continue with step 142. (If the directional characteristics are M and S, have the relation shown in FIG. 4 with respect to the reception level value β, the difference M-S never become zero if M is less than β. The possibility that M-S = O and at the same time M smaller than ß, however, can occur when the ship is at the border of the reception area or in the shade an island or the like and the received signal levels have dropped).

In step 142, the current value b of the inclination signal V _{INC is} stored in the CPU 60 and in

. η-

A step 146 then checks whether the difference a - b is positive, NuLL, or negative. This difference represents the deviation of the elevation angle of the antenna from the desired value in step 134 indicates a pitching and / or rolling movement of the ship. If the difference is positive, this means a lengthening of the angle of elevation L and the angle of elevation θ is therefore im Step 148 is enlarged and a step 150 is carried out next. If the difference is negative, means this is that the elevation angle is too large and the elevation angle is therefore decreased in step 152, thereafter Step 150 is successful. If the difference is equal to NuLL, So there is no discrepancy and the method goes directly to step 150. In step it is checked whether H is greater than ß or not. in the In the affirmative, this means that the SateLLLit is in the Area C of FIG. 4 is located and the method then returns to step 128 for the above To repeat procedural steps.

The above-mentioned program is most satisfactory for normal reception conditions in which the intersection of the two characteristic lines M and S lies above the predetermined value β of the reception level. In other words, when the main signal level M falls below the value β, the antenna can be rotated to the right as long as the difference MS is positive. If, however, the reception level has dropped abnormally for one of the reasons mentioned above and the mentioned intersection point comes to lie below the value β, conditions result as they are shown by the relatively higher value β ¹ in FIG. Under these circumstances, optimum reception cannot be restored by turning the antenna to the right.

when the satellite is in area F of Figure 4 even though H-S is positive. So if the answer is in the If step 150 is negative, the following special procedure is performed.

In a step 154 the value of X is reset to one degree and in a step 156 the antenna becomes rotated to the right to increase the side angle, In a next step 158 it is checked whether the main signal level H has reached the value 3 or not. In the affirmative case, the method returns to step 128 back and do the above procedural steps repeatedly to achieve the best possible reception maintain. In the negative case, on the other hand In a step 160 it is checked whether the magnification of the azimuth or side angle reaches the value five degrees has or not and in the negative case they will Repeat steps 156, 158 and 160 until five degrees are reached. When this value of five degrees is reached the elevation angle of the antenna is increased by 0.5 N degrees in a step 162, i.e., in this case by 0.5 °, since N = 2X-1 and X = 1. The antenna is then reversed or rotated to the left in a step 164 to reduce the azimuth and it is checked again in a step 166 whether the signal level H den Has reached value β or not. In the affirmative case, returns the method back to method step 128 and the mentioned procedural steps to maintain the conditions achieved are repeated. In the negative case it is checked in a step 168 whether the decrease in the azimuth or azimuth reaches the value five degrees i.e., whether or not the antenna has been rotated ten degrees to the left from step 164, and im Steps 164, 166 and 168 become negative cases repeatedly until that reaches azimuth or azimuth

is. If this side angle is reached, the elevation angle of the antenna is decreased by X degrees in a step 170, i.e. in this case by one degree. The value of X is then is increased by one degree in a step 172 and it is checked in a step 174 whether X has the value five degrees achieved or not. In the negative case it works The method returns to step 156 and steps 156 to 164 are repeated in a corresponding manner until X has reached five degrees. When X has reached five degrees, the antenna axis is obviously up the celestial vault described a trace as shown in Fig. is shown. From this figure it can be seen that the search over a range of azimuths of ten degrees around the Initial direction has been carried out, including the left side to avoid the above mentioned error.

If X has reached the value five degrees in step 174, this means that the SateLit has migrated too far to be able to correct the error, and the method therefore goes back to the starting point _{for a new setting of the elevation angle θ η.}

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Claims (3)

DR. DIETER V. BEZOLD DIPL. ING. PETER SCHÜTZ DIPL. ING. WOLFGANG HEUSLER V ZiOELASSENBElM PATENTANWÄLTE TELEFON .OO9.47O60O6 j EUROPEAN PATENT OFFICE MARIA-THERES1A-STRASsE22 TELEX S22 EUROPEAN PATENT ATTORNEYS POSTBOX 86 O3 60 TELEGRAM SOMBEZ EUROPEAN! PATENT ATTORNEYS P ΜΛΝΒΛΤΛ. ». EN BREVETS. "." UN. Ο'βΟΟΟ MUENCHEN β6 11942 / Dr.ν.B / An DX Antenna Company, Limited 2-15, Hamazaki-dori, Hyogo-ku, Kob.e, Japan Method and device for automatic tracking of a satellite with a receiving antenna Claims 1. Method of tracking a satellite through a parabolic antenna, with - a parabolic reflector, a main primary radiator that is in the focus of the Reflector is arranged, - a Hi Ifs primary radiator that is close to the main primary radiator is arranged so that it is somewhat in the azimuth direction with respect to the main primary beam is offset, - one coupled to the main primary radiator Main level detector and an auxiliary level detector coupled to the auxiliary primary radiator to detect the level of the emitted by the main radiator received signal or the level of the POSTOlRO MUNICH NO. 69148-800 - BANK ACCOUNT HYPOBANK MÜNCHEN (BLZ 7OO ₂ 00 401 KTO. 60 60 257 378 SWIIT HYPO DE Auxiliary emitter received signal, marked by the fact that - the azimuth and elevation angle (Elevation) of the antenna can be adjusted so that the main signal level has a predetermined value exceeded; - the side angle of the antenna is adjusted so that the difference between the main and the Hi LfssignalpegeI has a predetermined polarity and - if the main signal level is below the specified value decreases, the side angle of the antenna is adjusted according to the polarity of the signal level difference and this restores the specified signal level will. 2. Device * according to claim 1, characterized marked that the first, the second and the third control device in a single Microcomputers are included. 3. Device for tracking a satellite, in particular a communications satellite, through a parabolic antenna, with - a parabolic reflector, - a primary radiator arranged at the focal point of the reflector, - A first drive unit for rotating the antenna about a lateral angle or azimuth axis, - a second drive unit for rotating the antenna around a side angle or elevation axis, - a main maintenance detector that works with the Main primary radiator is coupled to the level (main level) of the received from the main radiator Signal to capture, and - A first control device on the Main signal level responds and causes the first and the second drive unit to so to the antenna turn that the Hauptsigna Ipege I a given Exceeds value, marked by - a Hi Ifs primary beam close to the Main primary star with a low azimuthal Offset is arranged opposite this, - one coupled to the Hi Ifs primary radiator Hi I fspege Idetector for detecting a level (Hi Ifspege Is) of the received from the auxiliary radiator Si gna les, - A second control device that responds to the difference of the main and the Hi I fssigna Ipege Is and the first drive unit causes the side or To adjust the azimuth angle of the antenna so that the Difference has a predetermined polarity, and - a third control device that acts on the difference between the main and the hi I fssignaLpege I responds and, if the main signa IpegeL among the predetermined value has fallen, the first drive unit causes the side or To adjust the azimuth angle of the antenna so that the HauptsignaLpegeI the specified value again exceeds.