US2217404A

US2217404A - System and method for landing airplanes

Info

Publication number: US2217404A
Application number: US175430A
Authority: US
Inventors: Hahnemann Walter Max; Kramar Ernst
Original assignee: Standard Elektrik Lorenz AG
Current assignee: Alcatel Lucent Deutschland AG; C Lorenz AG
Priority date: 1933-05-10
Filing date: 1937-11-19
Publication date: 1940-10-08
Anticipated expiration: 1957-10-08
Also published as: FR768754A; GB433873A; US2215786A; US2226718A

Description

Ot. 8, 1940. w. M. HAHNEMANN Er AL 2,217,404

SYSTEM AND METHOD FOR LANDING'AIRPLANES Original Filed April 26, 1954 y 2'0 the courseso as to iiyY approximately parallel Figjl` diagrammatically"'illustrates Yin plan' a 45 sensitivity ,untilv landing in London, which will ever, as already explained in the foregoing, this 45 I' Patented Oct. 8,1940 51V" n Y* f` d UNITED "STATES N lP., snr ,o1-FICE Walter Max Hahnemann, Berlin-Marienfelde,

and Ernst` Kramar, Berlin-Tempelhof, Germany, assignors to C. Lorenz Aktiengesellschaft, Berlin-Tempelhof, Germany, acompany Original application April 26, 1934, Serial' No.. Y,

722,470. Divided and'this application November 19, 1937, Serial No. 175,439. In Germany May, 10, 1933 -3 claims. (01.250--115 The present invention vis a divisional from that to do on account of' the extraordinarilyy yhigh described in thecopendingU. S. Patent applisen sitivity'of modern receivers. cation Ser. No. 722,470, led on April 26, 1934, The" inventionrel-ates to a undamental'- i`m vfor System for landing airplanes, and relates to provement 'of the slip-way beacon method. f l'cf an, improvement upon such arrangements. cording `to the invention, the `beginning of the 5 It is well known .for the .purpose of 'facilitatlanding is indicated by-a radianthpattern which'` ing4 the landinggof airplanes to employ so-called also serves tor Ydefine an"equa l intensityA Zone,

slip-way beacons which radiate a torus-shaped while the indication ofthe field intensity'which bundle of ultrashort electromagnetic waves at exists at the momentof reception ofthe addia certain angle tol theground surface. The landtional 'signal indication 'is employedto :determine g.,

ing may be so eifected'that the airplane descends the'actual landing path. f

' on a curve of constant field intensity. However, 'The-invention will be more readily understood this method'involvesthe disadvantage that the from the following" description inconjunction curves of constant iield intensity are too steep with the'accompanyingdrawing, in "whi'ch: in major heights, While tooflat in minor heights AFig. ll'shovvs anelevation cfa landing ground immediately in fronti of the point. at which the Fig. 2' -diagramrnatically"illustrates a receiv` airplane touches ground within the airport. ingjarrangement according to the invention,

Consequently, anairplane flying in majorheights adaptedto beused'iri-an Aairp`leme`, whilel must at first descend rather steeply, while on FigfB schematically demonstrates an indicate reaching minor heights near the ground change ing device for use inlaniairplane, v

tothe ground surface. 'I lie pilot is notin a directional beacon'for use'withth'e glide path# position to continue the flight with idle motor, as a` marker 'beacon'.

vbut is, compelled to give full power justbefore Referring t`o Fig. l1, the referencenuinerals touching theground. The unduly high speedl in fl' to 5 designate different` ^curves ci equaleld the actuallandingmoment as a-result thereof intensity, either of a we llknovm obliquelyV upa5 is critical in many cases. In lorder to overcome wards directed bundle `of l rays, of two intermit` this disadvantage, propositionshave been made, tentlykeyed bundles of raysv for obtaining azone .Y according to lwhich vthe airplane should intersect of equal intensity, or o fa"toruseshapedradiationv different curvesgeachvofwhich having an equal diagram'. The invention is applicable to all field intensity, instead of descending on v one methods in connection withthe aforesaid types, "30

curve of constantiield intensity-V Forreliably while in case of need, Le., in casetwo Akeyed t realizing the above-saidmethod, it has hitherto bundlesare not used, the l, direction determinabeen .necessarytoA ensure that the transmitter tion must be '.eifected "by-additional means,` ra maintainsits power continuously constant, and pre'ferred'one 'of vwhich is'rnore'fully described that the receiver always has the same sensitivity. hereafter. The course line of the airplane is- 35 This requirement mayrelatively easy be fullled designated B in the drawing; on the transmitter side by` supervising not only The method' hitherto employed' is based on the transmitter, but alsothe transmitter field'. the fact that the airplane, which linv vthe 4first y On the receiving side, however, considerable dif-v instanc 'arrives horizontally on its guiding course 40 `iculty is experienced, as .the sensitivity of the line' B, remains on this tcourse in the bundle of 40 Y receiver must remainr the. same over a longer rays until it reaches'th'e eld intensity inwhich period of time. To. give van kexample in a Berlin it "must descend. As soon' as a'predeterminejd t to London flight, the, receiverwhich has to be deiiectionof the indicating device of the rei adjusted in vBerlin must maintain a constant ceiver is reached, the airplane descends. Howi,

take place several hours after.r It is, of cou-rse, requires va continuous `constancyvvith respectto possible to disconnect the receiver during the thesen'sitivity of the receiver: if' journey, but upon re-insertion before the actual Y According to thelinvention, the point at which landing in London it. must have the same sensithe landingshould be commenced Vis givenby ;v

tivity. In will easily'be seenthatthis isnot easy anfadditional` signal. indication y(i, which. is die' f rected perpendicularly, or obliquely upwards. This additional indication may either be given acoustically or by wireless. The airplane flies on horizontally until it reaches the point 1, at which it receives the indication 6. It then descends from point 'I so that the deflection of the indicating device remains the same as it was at the moment of the arrival of the signal indication 6. The curves 3, 4 and 5 are intersected at the points 8, 9 and I0 in order to obtain a particular landing path subsequent to the receipt of the indication. Thisis obtained for instance in such a manner that the sensitivity of the indicating device of the receiver is varied in dependence upon the time elapsed from the moment in which said indication was received,'or by shifting the scale of thein'dicating device. It is now immaterial whether the indicating instrument indicates two or six points on the scale, i. e., if the sensitivity ofthe receiver has been changed or not. It is by no means necessary that this change is linearly elected, on the contrary, it may be performed according to any` arbitrarily chosen rule. In other words, the landing curve may be optionally designed in response to the intersecting points 1 to l0', so as to be accommodated to the airport conditions and to the type of airplanes.

The Figs. 2 and 3 diagrammatically illustrate suitable equipments for realizing the above disclosed idea. These equipments are simple means adapted to be added to known devices. A shunt resistance or a series resistance may be connected to the indicating device, the magnitude of said resistance being varied in dependence upon time, e. g., by a watch or the like. Means are thereby provided which connect said resistance to the indicating device from the moment in which the signal indication was received.f Referring to Fig. 2, E designates the receiver mounted on the airplane, and J the indicating device which indicates the landing path and which is connected to the output side of the receiver E. A variable resistance P is shunted to the indicating device J, and the slidable contact S of said resistance is shifted dependent upon time in accordance with a certain rule from vthe moment in which the signal indication was received. It will also be possible to connect the resistance P in series with the indicating device J.

Furthermore, a particularly constructed indicating instrument as illustrated in Fig. 3 may be employed. The pointer Z is controlled by the output circuit of the receiver in the well known manner; However, contradictory to the known arrangements in which the scale is xed, the scale Sk is moved, e. g., upwardly, in dependence upon time by any well known means (not shown) from the moment in which the signal indication is received. Nevertheless, the pilot must navigate the airplane so, that the pointer Z continuously remains on the same point of the scale, on the zero line, for instance.

The additional signal indication may be given by means of devices which are in themselves well known, and arrangements for indicating the landing ground boundaries are readily adaptable for this purpose. In the simplest case a parabolic reflector may be employed which concentrates a beam of electromagnetic rays perpendicularly or 'obliquely upwards. In accordance with a novel feature of my invention I propose to employ'an arrangement which'produces a zone of equal intensity, particularly such anr arrangementl which operates by means of vertical polarization. Such an arrangement is described for example in U. S. Patent 2,028,510 issued to Ernst Kramar January 21, 1936, which shows a vertical dipole which continuously is fed by one transmitter, and two dipoles acting as reilectors. Fig. 4 shows such an arrangement together with a plan of the field pattern produced thereby. These reflector dipoles `are alternately manipulated according to one of the known methods, for example in the A-N-rhythm. Thus in the well known manner a zone of equal intensity is obtained, that is by the fact that the circular radiation diagram of the middle dipole continuously fed by the transmitter is alternately distorted so as to be displaced to one side and then to the other side in a pattern of oblate shape as more fully set forth in the above mentioned patent. If .an airplane overflies such an arrangement, the reception on this airplane decays because the transmitter is operating with vertical polarization. The moment of decay is extremely sharply dened so that it may be employed as the said additional indication and possibly for the automatic release of a suitable scale-moving or shunt-adjusting mechanism, which may be used in the arrangements of Figs. 2 or 3, in order to change the sensitivity of the indicating device in dependence upon time.

It is also possible to employ a plane of radiation instead of a bundle of rays, this plane being penetrated by the airplane. These arrangements are preferably such that two transmitters are installed at two diagonally opposite corners of the airport, each transmitter providing two sides of the airport with such planes of radiation. If `an acoustic indication is employed, then suitable directing means may be used for the sound transmitters or sound transmitting combinations.

What is claimed is:

1. The method of landing airplanes which comprises radiating a short wave field of electromagnetic energy at an angle to the ground, radiating two further vertically polarized elds upwardly and outwardly, said polarized fields having a zone of substantially zero intensity, employing the relative eld strengths of'said two fields lto determine the direction of night of the airplane, employing the zone of zero intensity formed by the vertical polarization of said further elds to determine a region of reference in space, obtaining an'indication of the intensity of said short wave field at a .point in said determined region in space, and thereafter employing said indication as a reference standard with which to compare the short wave eld intensities subsequently encountered in landing said airplane within said short wave eld.v

2. An airplane landing path system comprising means for radiating a short wave glide path eld having equal field strength surfaces obliquely inclined with respect to the ground to produce glide paths terminating at a particular landing point, means for radiating two distinguishable electromagnetic signals with substantially vertical polarization in upwardly and outwardly extending radiationpatterns which mutually intersect to define a zone of equal intensity to providek for lateral guidance of said airplane, said signals having aninherent zone of substantially zero intensity, said last mentioned means being arrangedso that the zone of equal intensity is in line with said landing point, and being spaced from said landing point a distance such that said zone` of zero intensity resulting from the substantially vertical polarization of said electromagnetic signals intersects one of said equal field strength surfaces of said short Wave field at a location suitabie'for commencing the descent of an airplane along said equal field strength surface.

' 3. A system as claimed in claim 2, wherein said means for radiating two distinguishable signals comprises a vertical` dipole, means for feeding Waves to said dipole, and a plurality of variably effective reflectors for variably distorting the patterns radiated by said dipole. WALTERMAX HAHNEMANN. ERNST KRAMAR.