DE2007049A1 - Bearing system - Google Patents

Description

"Peilsystem" The invention relates to a bearing system for bearing electromapetic High frequency oscillations in terms of azimuth and elevation.

A serious disadvantage of conventional shortwave DF systems is their failure in interference fields. Builds an interference field from azimuthal strongly diverging rays - this case is due to the steep rays incidence usually given for bearings in the close range (50 - 300 km) - so it is only rarely possible obtain a reliable short-term bearing.

The object on which the invention is based is to provide a direction finding system indicate that even under the aforementioned unfavorable conditions, the physical possible information delivers, i.e. every single incident Wave determined by field strength, azimuth and elevation. This task is performed according to the Invention achieved in that a network of automatic field strength sensors (field probes) regularly or statistically over a floor area with the extent A >> # (# - largest receiving wavelength) is designed and that of the field probes recorded high-frequency signals taking into account the respective position of the individual field probes are evaluated in a central computing device.

This becomes the complex field strength of the interference field on the ground scanned. With a finite number of probes, no locally continuous one is obtained Registration of the field strength, but this is also not necessary, because for the complete It is sufficient to record the information obtained in the field strength distribution in Samples can be taken at intervals of dz d <. Are the probes statistically about the Distributed over the floor area, the mean distances may be as large as desired. The uniqueness the bearing practically does not suffer if the total number of probes is sufficient high is Cca. 100).

From the local field strength distribution recorded in this way, the one that is being sought is obtained Information about the direction of incidence of the individual rays through two-dimensional Fourier transform calculated. In the special case of statistically distributed samples is an interpolation of the irregular before the actual Fourier transformation Measuring point grid (probe distribution) on an equidistant calculation grid is useful. It should be noted that the Zourier transformation is not the only possible way to calculate the incident rays.

Since the aperture of the field probe system and the measuring accuracy of the probes is finite, the incident rays can be calculated by evaluating the Field strength distribution cannot be reconstructed as sharply as desired. Rather, it results a result that resembles an antenna diagram, each with a sharp club per incident beam, the beam width # α is with the aperture A in the known way # α # # / A linked. Two discrete adjacent rays im Distance from ba can just be resolved separately. However, is the distance big against ta, so of course every single one can Beam essential can be localized more precisely than on t T by evaluating the center of the lobe.

The Fourier transformation between complex local field strength distribution (x, y) and complex beam distribution ("angular spectrum") F (#, #) is described by exp [-2 # j sin # (x cos # + y sin #)] dx dy, where @ / 2 - # means the elevation and # the azimuth.

is a bearing in a broader sense, because it also receives the elevation, from which one can conclude, for example, the distance of the transmitter can.

A practical embodiment of the field probe direction finding system according to The invention is described below.

The field probes are compact, miniaturized HF receivers for the 1.5 - 7.5 MHz range. They also contain a simple VHF telemetry transmitter and command receiver for connection to the mobile DF center (truck) in the middle of the probe field. The probes are in an area of expansion erected approx. 1 km or dropped from the air. The shortwave receiving oscillators all probes are phase-synchronized by the control center in order to measure the field strength phase to enable. The runtime of the command and the synchronizing signals to the probes and back are in the evaluation by the computer (Fourier integrator) in the Headquarters taken into account. For this purpose, a calibration bearing is required before the start of the bearing operation (Measuring) - for example with the help of an airplane - necessary, from which the computer does Reversal of the problem, the initially still unknown condense coordinates and the corresponding Run times determined from the bearing values known here.

The bearing evaluation takes place immediately after receipt of the probe data.

Assuming a sufficiently fast special computer is the computing time for a complete -Diagram on the order of @ sec. One way to do the Fourier transform for everyone -The simultaneous analog execution of points is provided by a proåection device using coherent light, which carries out the Fourier transformation as an optical process.

With the subsystem according to the invention, as a result of its through the large aperture large spatial resolution and sensitivity the ground wave too can also be taken if it is considerably weaker than the space cell.

Claims (5)

Claims Bearing system for bearing electromagnetic high-frequency oscillations with regard to azimuth and elevation, characterized in that a network of automatic Field strength sensors (field probes) regularly or statistically over a floor area is designed with the extension A Ä A (# = largest wavelength to be received) and that the high-frequency signals recorded by the field probes are taken into account the respective position of the individual field probes is evaluated in a central computing device will. 2. DF system according to claim 1, characterized in that with statistical Distribution of the probes over the ground the distance between neighboring probes greater than 7 may be. 3. DF system according to claim 1, characterized in that the field probes Receivers based on the superposition principle and that their superimposed oscillators can be remotely coordinated and phase-synchronized together from a central point. 4. Iveilsystem according to one or more of claims 1 and 3, characterized characterized in that the field probes contain command receivers and telemetry transmitters, with the help of which the field probes are matched and those recorded by the field probes Field strength signals are sent to the central computing device. 5. DF system according to claim 1, characterized in that the searched DF information from the local field strength distribution recorded by the field probes determined via a two-dimensional Fourier transformation in the automatic computer will.