on a theme: "System of radio-location accompaniment of airplane on distance"
The radio-locations systems (RLS) of aviation complexes of distant radio-location discovery are intended for the distant discovery accompaniment of air aims both on small and on large heights. For the receipt in relation to the long-ranges of discovery of aims already more than century the air posts of supervision are used. In the first world war-time the air supervision was widely used not only from airplanes but also from balloons and fastened balloons on production of which in the world Great Britain took leading seat. In the second world war-time application of the radio-locations stations (RLS) for air defense combined with understanding those undeniable advantages which gives airplane RLS. However airplanes RLS the discoveries had the at that time very limited possibilities of supervision of aims, because the signals reflected from them were repressed by the preventing reflections from an earthly surface. Experimental work on creation of such RLS was begun in the USA in 1943 within the framework of project of Cadilac on basis RLS centimeter range with a transmitter. For the last 10 years works were constantly conducted on expansion of possibilities of airplanes RLS review of lower vision "downward"). As a result of fact the aviation complexes (AC)of distant radio-location discovery (DRLD) which about 250 are in exploitation, are created.
Presently opinion became firmly established in military powers, that application of AC DRLD for the aims of air DEFENCE and other can act important part vitally. Role and tasks of complexes of DRLD, in which RLS is just one (though and essential) of elements, determine and requirements to RLS. It is even visible from the name, that the main task of DRLD consists in the discovery of aims being outside the areas of discovery of ground RLS. There is the important task of these complexes also accompaniment of aims and aiming on them interceptors. AC DRLD can decide auxiliary tasks, for example implementation of radio engineering secret service, realization of retransmitting of signals of the systems radio contacts, discovery of ships, determination of direction on the sources of intentional hindrances with the purpose of finding of their location method by other systems of air DEFENCE or for the review of space on middle and large heights outside those regions which are out of area of action of ground RLS. In general introduction of auxiliary functions not must tell on possibilities and descriptions of aviation complex of DRLD at implementation to them basic task. The wholeness of supervision of aims necessary for the performance of basic objective can be no less distances of direct radio visibility on condition that a receiver possesses a sufficient sensitiveness. For the discovery of aims a method is presently widely used in lower.
- Distance of discovery of aims
- Frequency of radiation RLS
- Aerial
- Power of radiation
- Duration of impulse
- Frequency of reiteration of impulses and signal processing
The functional diagram of the system is shown on picture 1 The functional diagram of the system is shown on picture1 distance is Questioner influence of the system D1(t) to the purpose, continuously changing in time. This distance is measured with the help RLS. Information about distance from the output of receiver of impulsive RLS enters discrete moments of time with frequency, to equal frequency of parcels of the station. This information is contained in time of delay of the tc reflected signal from a purpose in relation to the impulse radiated by a transmitter. Indeed, distance D1 (t) to the purpose proportional to time of delay t3:
(where c is speed of distribution of hertz an waves). If distance to the purpose changes in time, for example, on a curve D1(t), on the output of receiver RLS reflected pulses string of Uden(t) appears. Moments 0, T, 2T,... corresponds to the moments of radiation of impulse by a transmitter. As is obvious from picture, a radio-locator carries out temporal impulsive modulation: by an entrance signal (by distance to the purpose) pulses string at times. Therefore RLS in this case can be represented by the transient impulsive member of the first family. The system of automatic accompaniment of purpose on distance by discrete values of distance reproduces the continuous function of change of distance to the purpose. This system is the impulsive watching system using management principle on declining. In the complement of the system enter: temporal, being an element comparisons, strengthener-transformer, executive device generator of supporting of distance. The system works as follows. During the short spans of time, when the revolved ray of aerial passes through direction on a purpose, there is the irradiation of purpose by the impulses of electromagnetic energy, which are reflected from a purpose, is accepted, is increased, will be transformed by the radio-location station and act on the entrance of the system of automatic accompaniment of purpose on distance. At every turn of aerial in the period of irradiation of purpose the short pack of impulses acts on the entrance of the system. Veritable distance to the purpose D1(t) proportionally to the temporal change (to the delay t3) of every acting impulse in relation to the moment of his parcel. From other side, distance to the purpose D2 (t) it is produced by the system. This distance is compared to questioner influence D1 (t) and declining turning out here D2(t) from D1(t) (error) it is used for the executive device with that this declining diminished. As information about distance D1(t) on the entrance of the system acts as pulses modulated at times string, and distance D2 (t), produced by the system, is a continuous size, for comfort of comparison D2 (t) with D1 (t) distance D2 (t) will be transformed also in a discrete size. For this purpose the generator of supporting, which carries out temporal modulation of pulses string by distance, is intended D2 (t). Delay in time t3 supporting of Ua, produced by a generator, in relation to the moments of radiation by the radio-location station, proportional to distance to the purpose D2 (t) in the discrete moments of time. Thus, the generator of supporting is an impulsive element. Distances D1(t) and D2(t) it is compared in the discrete moments of time in temporal by comparison of temporal positions of the impulses and supporting reflected from a purpose. Declining D(t) distances D2 (t) from distance D1 (t)
showing up in the difference of times of delay t' reflected impulse t3 and supporting t32,
will be transformed by temporal in tension of error. The last is used for the management by the executive device changing D2 (t) so that declining D2 (t) from D1 (t) diminishes. Simplified chart of temporal and exemplary forms of tensions, explaining principle of his work, represented on picture 2. Temporal integrates the impulse reflected from a purpose in times of left one D1 and then in times of right D2 supporting. On the output of tension is created in the moments of ending of the reflected impulse, value of which h proportionally differences of areas of ceiling of the reflected impulse by left and right. As this difference of areas at the small values of temporal change t' reflected impulse and supporting to the temporal change t', in accordance with foregoing expression the level of h output tension is proportional to the error of accompaniment of purpose on distance in the discrete moments of time:
At the rotation of engine the phase of tension changes on the output. Appearance of supporting corresponds to the zeroing phase of this tension. As a result of rotation of engine temporal position of supporting changes in the direction of removal of their disparity to temporal position of the reflected impulse. So there is automatic track for distances or discrete data conversion about distance in a continuous size. It is necessary to notice that tension of error on the entrance of strengthener-transformer in the examined chart acts as the «pack» of the peak-modulated stretched impulses through the intervals of time That, rotations of aerial equal to the period RLS. Duration of every pack of impulses of tension of error is very small as compared to the period of review. Therefore the packs of impulses can be examined as single impulses errors following through the intervals of time That. It allows to examine the system of automatic accompaniment as closed impulsive system with the period of reiteration That. The station of circular review can provide automatic accompaniment of many aims from discretely got data, but for accompaniment of each of aims the station must have a separate channel beginning from the output of receiving device. This channel includes the system of automatic accompaniment. The signals reflected only from one chosen purpose must act on the entrance of the separate system. For this purpose a channel is opened by the selectors impulses produced by the special generator, and the reflected impulses are skipped only from one accompanied purpose. The executive device, giving an output signal on the generator of selector’s impulses, provides the proper smooth moving of selector impulse in an interval between the irradiations, so that position of selector impulse to the moment of receipt of signal from the chosen purpose will coincide with position of the reflected signal from this purpose.