DE1279130B - Radio measuring device, especially portable patrol radar device - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN 4fl? 7iW PATENT OFFICE

EDITORIAL

Int. α .:

GOIs

German class: 21 a4-48 / 63

Number:
File number:
Registration date:
Display day:

P 12 79 130.9-35 (C 37810)

December 30, 1965

3rd October 1968

Radio measuring device, in particular portable patrol radar device

Applicant:

Compagnie Francaise Thomson Houston-Hotkiss Brandt, Paris

Representative:

Dipl.-Ing. Dipl. Oec. publ. D. Lewinsky, Patent attorney,

8000 Munich, Gotthardstr. 81

Named as inventor:

Louis Marie Fourdan, Viry-Chatillon; Georges Nard, Clamart;

Claude Skenderoff, Ruei-Malmaison (France)

Claimed priority:

France 8 January 1965 (1235)

The invention relates to a radio measuring device, in particular a portable patrol radar device, for electromagnetic Detection and location especially of relatively slow moving targets, where the is generated by an HF transmitter and pure undamped wave to be emitted by its directional antenna through a modulator with different, Modulation signals caused by the corresponding modulation signal generators, depending on the mode of operation, monitoring or distance measurement is phase-modulated and an arrangement for demodulation is provided, the one coming from one or the other modulation signal generator in addition to the echo signal Modulation signal is fed and to the low-frequency amplifier connected to information evaluation circuits are connected.

With such devices, a section of terrain
be monitored at a certain depth and
the distance and the speed cannot be 20
identified objects are detected. One such
Device also hits among the received signals
a selection insofar as there are only those echoes *

indicates that can be attributed to objects whose surfaces have a random or apparently random phase velocities lie in a selected area. 25 modulation is evaluated, although this has a correction Area can e.g. B. the speed of lation with sufficient sharpness, which is suitable, Fulfilling the telemetry function from a few kilometers to a few tens of kilometers is, however, for the per hour. Surveillance operation only poorly suited as they

A patrol radar represents an alert - not an automatic compensation for that caused by the Entschaftsradar, which, as a Doppler radar, has attenuation caused by many distances. For this possible object a slowly moving fixed reason is the sensitivity of the receiver should be able to put. In order to enable an accurate determination of the speed, it is necessary that the emitted electromagnetic
Vibrations are undamped. 35

Previously known radio measuring devices that use undamped vibrations and based on the Doppler effect based, suffer from numerous disadvantages, the most important of which is that they are a

high sensitivity to nearby echoes, making it easy to operate. It should also have that on the one hand be designed to be space-saving and interchangeable due to the strong damping of the distant echoes, as a result of their propagation, and contain other elements, causing it in its user side is very versatile due to the extremely short distance.

solvency are caused. These devices, when this task is the one proposed here

which a frequency or phase modulation before 45 radio measuring device of the type mentioned is taken, are also poorly solved that according to the invention when monitoring the for a telemetry operation, when they transmit a modulator and the demodularion arrangement of require high peak power and when receiving the one modulation signal generator a square wave have poor correlation function, which is supplied code, while its removal poor accuracy and the aforementioned poor measurement of the square code of the one modulation distance separating ability caused. signal generator and a pseudo-random binary code

Another type of standby radar, in which the other modulation signal generator

809 619/189

chosen to be extremely low in order to prevent it from being saturated so far by the strong, close echoes that the distant useful echoes are covered.

A standby radar according to the invention, on the other hand, should be a carry out safe monitoring as well as precise remote measurement and at the same time a high level of sensitivity and have a low energy requirement,

3 4

lator, which the signal to be sent out with the multi-preferably the immovable switching elements of the Application product of the two codes combined, and control and regulating organs arranged around the tripod frequency-wise in a frequency doubler, which supports the reflector of the antenna. That doubled Rectangular code and a device according to the invention via a multiplication has a high functional element the multiplication product of the rectangle 5 degrees, the z. B. when using a battery code and the delayed pseudo-random binary battery of 24VoIt and 10 ampere hours, codes of the demodulation arrangement are fed to the extraordinarily long operating time of about the one that, in a known way, after driving a hundred hours, correlation principle works. The subject matter of the invention is as follows

Such a radar device is ambiguous from the circuit shown in the drawing free and has a high distance measuring accuracy. It shows

ability and insensitivity to close, strong F i g. 1 the block diagram of a radio measuring device,

reflective objects and, compared to possible Figs. 2a to 2d, the pulse diagram of an apparent

Interfering signals. The emitted, undamped bar random codes, their autocorrelation radio oscillations are as indicated by the product 15 tion, a circuit for generating the apparently two-in-two Codes phase modulated. The first code is due codes and the control pulse train a symmetrical square code, the period of which is that of this circuit,

four times the transit time of a signal to and from a F i g. 3 a to 3 f the pulse diagram of a symmetrical

Object that is the same as Irish rectangle codes at the maximum monitored distance, which is around a time span d. The second code is a so-called so-called delayed, and which is obtained by superimposing this apparently random code with a very wide two codes at different delays d spectrum. It essentially serves to generate the resulting pulse sequences,

to determine the distance of an unknown object. F i g. 4 the HF head of FIG. 1, also as

A block diagram from another at a different distance, The signal reflected from the object is strongly influenced. 5 shows the block diagram of FIG. 1 in supplemented dampens. The representation used during monitoring and

The first code is mainly used to indicate the amplitude of Figs. 6.1 to 6.12 different possibly in

signals of the circuit that are reflected by the objects found to be assessed as a function of the distance to which the patrol radar according to the invention

Damping caused by the propagation, that of the, as stated, undamped vibrations fourth power of the distance is proportional to, to be phase modulated by two codes in order to compensate without affecting. overflow of the sensitivity of the receiver

The reduction in losses between the monitoring and telemetry operations to carry out Send and receive value, the coherent integra- can. The supervision of the relevant preparation, in which the phase of the signal remains unchanged, 35 is done by modulating the oscillation as well as the filtering of the Doppler frequencies, which correspond to a periodic rectangular code of low frequency, are possible due to the codes used, allow a so-called coarse code, whereby a Schalzum Send and receive a common processing arrangement is provided, which is the dependent antenna to use the sensitivity of the distance occurring attenuation compensate receiver maintain and unwanted echoes, 40 sated. The distance is measured by means of a either through floor noises or through the seemingly random codes, a so-called fine slow Movements of vegetation or by code that, by autocorrelation, distance Moving objects are caused whose speed - an unknown object with a high Gekeiten allows to measure over the speed to be monitored, ten lie to make them ineffective. 45 Fig. 1 shows the block diagram of an inventive

With a radar device according to the invention, patrol radars can be used. In this case, a high-frequency oscillation generated in a specific area, thus precisely the movements of unknown objects in a circuit 1, is determined, which is modulated according to a predetermined code. A transmitting and receiving antenna 10 speeds are measured at the distance of these objects and their speed is determined. It is connected by a corresponding processing of the reflected signals via which this oscillation can be emitted or which receives their reflections. In one of the monitoring processes using circuit 3, a coarse code generator 30 and one of the first code are carried out, fine code generator 31 and, if necessary, a control circuit 32 that can be operated manually from the display of the objects, with which is independent and only from the size and speed of which depends on the fine code delayed or switched off. can contain. The coarse code signals g (o) and

The second modulation code can be used to feed the undelayed fine code signals F (o), the remote measuring process being carried out, with a mixer 2, the output of which is connected to the circuit 1, with a high distance from the unknown object. Delayed fine code signals F (d!) As well as separating power, that is to say with high accuracy, cause the coarse code signals g (o) to continue to feed a mistake. Furthermore, there is an integration of the radiation from the shear 4, the output of which is placed on a demodulator shell by the main beam of the antenna 6. The energy reflected by the antenna 10 is possible, the echo signals will pass through a coherence demodulator contained in the circuit 1 compared to a substantial gain in useful echoes, that is to say enables de-interference signals. The switching modulator used, which does not require any change in the phase position of the signals during operation, is used for demodulator setting or regulation. They are preferably located in device 6 and to another gold-plated container. Next are presentation 7.

5 6

During the search for and detection of a corresponding and due to the spatial distance of the object, the switches 231 and 323 of the control-related target are delayed by the value d , connection 32 is open, whereby the fine code F (o) is performed . The distance is measured by no modulation, i.e. the autocorrelation of the fine code F by the antenna.
10 signals emitted only by the coarse code 5 The diagram in FIG. 2a shows an example of the g (o) being mudulated, and thus the output from the apparently random periodic binary code mixer 4 via a line 4 to 6 F (o). Such a code may contain only the coarse code g (o) as a sequence of the transmitted signal Im. pulses (+1, - 1) of width π and a period T,

The echoes received by the antenna 10, which contain N pulses, will be perceived. In the

the autocorrelation function reproduced when passing through the demodulator circuit 6 in FIG. 2b

and 7 by appropriate filtering in a predetermined manner if the mutually correct

Way processed, d. H. so-called amplitude-dependent signals have a very sharp maximum.

Subject to evaluations, this processing. If there is no match, then its value is

after the function almost zero. The maximum corresponds to this function

/ f> \ ^{15 In a} case in which the ^selection switch 322

sin l— \ selected delay d! equal to the delay d

of the emitted and received signal is a measure of the distance of the relevant

takes place at which R is the distance at which the object is represented.

Object is located that sends the echo, and R _ma ^ die so Fig. 2c represents an embodiment of the fine-removal of the more distant border of the over-code generator 31 of FIG. 1, which represents the apparently guarded area. Such is given by the random code. This generator consists of demodulator circuits 6 and 7 the power of a certain number of stages which form a blind received near-end echoes in a first approximation according to the resistance shift register. Each of the attenuated to the fourth power of the distance R , the register can assume one of two binary states, whereby the one caused by the transmission (+1 or -1), which, for example, is essentially compensated for the attenuation. Locked state or the saturation state of a tran-

According to one in the circuit 7 corresponds to the demodula- sistor. The duration τ during which a coherent status following the coherent code g (o) is retained is selected to be short and entIntegration, ie one in which the 30 also speaks of the distance measuring accuracy of the device. Phase of the signal remains unchanged, the De- At each output by a clock 312 modulator circuit 7 to a Niederfrequenzver- pulse, a stage / the generator transmits its stronger 8 a Doppler frequency signal, whose Fre- state on the subsequent stage i + 1 The sequence depends on the speed at which the first stage is moving is determined by the signal that an object 35 found in the monitored area is emitted by a mixer 311 which moves it. The Doppler product of the states output by the amplifier 8, for example the stages i and signal, is integrated in a circuit 9 and represented in / + 1, which are contained in the chain. Which made an indicator 91 visible. The integral number m of the stages of the generator is determined by the circuit 9 can also be replaced by a circuit 11, the number N of pulses which replace the period T of the fine, which contains a low-power 40 code. Fig. 2d shows the amplifier 111 from the clock generator 312 , which represents the amplified output pulse.

Signal to a loudspeaker 112 and / or The output 320 of the first stage gives the fine headphones 113 emits. In this case, code F (p) is ab. The outputs of the subsequent study integration through the ear of the person operating the device, which are guided to the selector switch 322 , give the person. 45 from the same code, but with a

The distance measurement by which an unknown multiple of the duration τ is delayed and with

tes object is to be determined locally, can be designated before F (d ') . For example, if the maximum

can be taken without monitoring the subject distance within the monitored area

interrupt the end of the area. By closing R _max 1000 m and the value τ is about 0.2 με, which

of switch 321 also gives mixer 2 the 50 of a transmission distance there and back from

apparently random fine code F (o) supplied. Since this corresponds to 30 m, the fine code generator 33 must

through the delayed taps emitted by the antenna 10 are included to an unknown

Vibrations through the code g (o) · F (p) modo object with an error accuracy of about + 15 m

to locate the product of the coarse code g (o) and des. The necessary delays

Fine codes F (o) represents. With the switch 321 , 55 will be given by the generator itself as soon as this

also the switch 323 is closed, whereby it contains the required number of stages, or

Mixer 4 a delayed fine code F {d ') placed through the stages with the addition of additional,

will. The value d 'of the delay is determined by delay lines, not shown, if

the position of a selector switch 322 is determined. That their number is less than thirty-three. Be it

The signal emitted by the mixer 4 thus contains the 60 indicating that the generator 31 of the

resulting code g (p) · F (d '), which by multi-Fig. 1, which contains only six stages, a fine code

plication of the femcode F (d ¹ ) with the coarse code F (o) of the period T with 206 μβ delivers, whereby this

g (p) is formed. The resulting code is about period

line 4 to 6 of the fine code demodulator switch 1023 = 31 · 33 = 2 ¹⁰ -1

tungö fed. The demodulator circuit 6 is 65

which contains changing pulses during the distance measurement via the cable.

device 1 to 6, the echoes, the code of which g (d) ■ F (d) with the aid of FIGS. 3a to 3f is the effect of the

radiated from the antenna 10 code g (o) ■ F (o) Grobkodes g (o), the Generator30 from FIG. 1

7 8

is given, explained in more detail. This generator fed. The circuit 1 contains a high frequency generator 121 which is modulated by reversing the phase of zero or quenzgenerator 121, which is preferably emitted by a generator contained in π the oscillations formed by the crystal-controlled oscillator transistorized in the HF head 1. In Fig. 3a and whose output to a frequency multiplier is a modulated wave, the period of which is placed 5 fans 122, which preferably consists of passive 2 T of the round trip time of a signal, discusses switching elements, such as varactors, that is reflected from an object would, des- stands. The distance output by the circuit 12, which contains the generator sen distance four times the amount of the maximum 121 and the multiplier 122, would correspond to the distance. If the maximum distance signal is an undamped oscillation with a low line of 1000 m, the period 2 T of the code is equal to io stung, which is 26.7 μβ in the frequency band around 10 GHz, for example. An object located at distance R reaches 10 milliwatts. This oscillation is caused by an echo that is delayed by the amount d. Passage through a ferrite insulator 13 on the Mo-Fig. Figure 3b illustrates an echo signal applied to the dulator 14 to which the code g (d) has the code g (d) via line 1-2. Provided the signal sent is routed to the output of mixer 2. The modulated g (p) · F (o) has been modulated, the echo signal 15 oscillation is transmitted via a ferrite circulator 15 to the code g (d) · F (d) . This code is output in the one movable reflective demodulator circuit 6 forming the antenna 10 using the port. The direction-dependent function of the train code g (o) or the code g (p) -F (df), which is transmitted via the ferrite insulator 13 and the ferrite circulator 15, is demodulated on the line 4 to 6. on the non-reciprocal effect of ferromagnetic

In Fig. 3 c is the resulting code g (o) · g (d) 20 materials at a very high frequency, reproduced, which results from the instantaneous, from- The modulator 14, which the phase modulated

radiated code g (o) and the delayed, received oscillation emits, preferably consists of a gene code g (d) results. The period of the resulting circulator 141 with three terminals and a diode of the code is with T ', thus half of the period 142. The diode of the code g (o) operating at a very high frequency is given and its pulse width d 25 142 is in some Distance from the circulator 141 in is the distance R of the found object a waveguide 143, which is one of the connections of the directly proportional. Circulator 141 forms, shunted.

3d, 3e and 3f illustrate cases, depending on whether, as a result of the modulation code, in which the distance R equal to a part or diode 142 is transparent or blocks, the phase is equal to half the maximum distance R _max or 30 to the Circulator 15 transmitted high frequency corresponds to this. oscillation π or zero. At the operating frequency

Since the demodulation during the distance measurement causes the modulator 14, which results in a loss of less than 1 db due to the demodulator circuit 6, gives the code with a time constant whose period is given by T , of a few nanoseconds, a decoupling of is it is used for demodulation in the demodulator switch- 35 a few tens of decibels.

tang 7 necessary a reference code of the period T, which in the monitored area by objects

z. B. a code with a compared to that of the gene-reflected oscillations are received by the antenna rator 30 doubled code to the 10 period. The received echoes will be available over and over. For this purpose, the reference code given by the generator 30 to the circulator 15 at the phase coherence mentioned is sent to a doubler 5, 40 demodulator 17, the output of which is controlled by the demodulator circuit 7 via a coupler. 16 a fraction of the non-modulated, undamped oscillation is supplied to the patrol radar according to the invention. The demodulator 17 thus has three reference codes, those from the mixer 2, generates a video signal corresponding to the code g (d) · F (d) output by the mixer 4 and from the doubler 5, its code based on the speed and with its HiMe simultaneously the over - 45 speed of the object, which causes a slow rotation of the guard of a certain area and through the phase of the reflected oscillation, up to autocorrelation the determination of the distance is 100% amplitude-modulated. This signal is made possible by an unknown object. The symmetrical square-wave code circuit 7 used as via the demodulator circuit 6 for the demodulator coarse code is transmitted, which at its output a g (o) is a periodic code, the period of which emits 2 T 50 Doppler frequency signal, four times the amount of the forward and return time Fig. 5 represents the interconnection corresponds to the front maximum distance to be monitored. The other hand, corresponds to the period T of the pseudo-coherence demodulator 17 emitted and via the bar random codes F (o) a multiple of the outgoing line 1-6 transmitted video frequency signal and the return time of the maximum distance. In this 55 of the demodulator circuit 6, which contains a period, are a very large number of extremely short, very broadband amplifiers 61, containing zen, changing pulses, which causes the signal with a sufficient level to a sharp autocorrelation function. To any demodulator 62 is delivered. The latter causes interference caused by the system to avoid, using the reference code g (o) · F (df), the period T is not a multiple of the period T. Way falls the frequency ^ of the code is transmitted, the demodulatbn after the fine

^ - T ' codeF (d). As shown in FIGS. 3c to 3f

g (d) · g (o) was not recorded with any higher order harmonics, the demodulator 62 delivers

tion (%) of the fine code F (o) . _β resulting signal whose code at the transfer

\ TI ^w 65 monitoring or distance measurement the penode T

As can be seen from FIG. 4, the two have. The Si output from the demodulator 62

the basic codes g (o) and F (o) via mixer 2. 1

a modulator contained in circuit 1 14 SM ^{mTd emem tuned to the} frequency ^ ₇ ,

9 10

narrowband selective amplifier 63 supplied. To do that. In this way remains at the exit

from the amplifier 63 acting as a filter output of the demodulation circuit 7 only the low

given via line 6-7 to the demodulator frequency Doppler signal, the size of which depends on the

schaltung7 transmitted signal is a sinusoidal oscillation in which the detected object is located,

whose A _m p _lta de to *, (.- <-) * .. · »^ ** S3SaScJaU7 bes« ,, "ie the and their phase see" ah

j / ", R \ .., the demodulation of the line 6-7 takes effect

^{0 Γ} I Rmaxl ' ίο transmitted vibration by the doubling

The waveforms of the signals thus formed are the 5 output codes. Since the phase of applied

shown in Figures 6.1 to 6.12. The in the th oscillation depending on the development

F i g. The signals shown in 3 d to 3 f, which changes at the distance, also provide the phase detector

When the demodulator 62 occurs, the demodulator circuit 7 acts as a signal whose

neglect of the amplitude caused by the Doppler effect for the second time depending on the

th modulation in Figs. 6.1, 6.4, 6.7 and 6.10 distance is assessed. The size of the resulting

6.2, 6.5, 6.8 and 6.11 illustrate. The proportional. This pretty much turns out to be an AbSignale with its corresponding phases at the weakening to the fourth power of the distance of the selective amplifier 63 are through the nungi? achieved. The Doppler filter 72 selects the at-Fig. 6.3, 6.6, 6.9 and 6.12. for example between 30 and 3000 Hz frequency

6.1 to 6.3 thus relate to those sequences. The cases below 30 Hz in which the object to be identified is subject to very slow movements corresponding to a sequence very much compared to the maximum distance R _max are suppressed. As a result, the distance R is also much smaller and the noise due to the delay d ' caused by ground echoes or movements of the selector switches 322 is attenuated. Furthermore, the delay d caused by the transmission are the frequencies above 300 Hz, which exactly coincide. In other words, greater speeds than those of the. inters the codes F (if) and F (d) are the same. The 30 eating objects, such as pedestrians or vehicles, FIG. 6.4 to 6.6 and 6.7 to 6.9 relate to those corresponding, also eliminated. By eliminating cases in which the distance R is equal to half of the high frequencies, the operation of the patrol radar from R _max or the maximum _{distance R max is} not due to the remnants of the lower self. Here, too, the two values d frequency components of the apparently random code and d ' are equal to one another. Figs. 6.10 to 6.12 are disturbed and the rectangular bait. The Doppler signal hit the case in which the object is in the is via the line 7-8 dem. Low frequency maximum distance i? _max is, but the more powerful 8 is fed. The latter amplifies the Doppler delay d ' differs from the delay d. 1 and 5 and signal leads it to the circuits 9 and 11 of the comparison of FIGS. 09/06 to 12/06 underlines the Fig. to. After the effectiveness of the 40-lengthening integration of the received signals, which is illustrated by FIG. 2b, the circuit 9 feeds the correlation function. In the case of the indicator 91 starting from the value d , which over the area of the detected decelerating deceleration d! is the amplitude of the object, e.g. B. vehicle, provides information. The Si circuit 9 output by the filtering amplifier 63 can also contain a needle frequency meter gnals substantially smaller than that which occurs, which indicates the speed at which the two delays are equal. 45 the object is moving.

The selector amplifier 63, which, as indicated, can also identify the object

also carries out an amplitude evaluation, is indicated acoustically. The circuit shows this

with an amplifier 111 of lower power on the line 6-7 to the demodulator switch 11, the

._.._... c · 1 λ τ? " ¹ U a volume control, headphones 113 and

tung7 a sinusoidal signal of frequency ^ ab, _5o ^ _LavLtsppchQT \ _t 2 contains the volume control

g p

_5o ^ _LavLtsppchQT \ _t 2 contains. The volume control

the modulated with the Doppler frequency and the development must be done early enough to free the harmonic fine code F (d) . To avoid the weakening of the distortion, which is disadvantageous for an exact identi-amplitude of this signal as a result of the evaluation and fication of the Doppler frequency. When its initial phase is dependent on the distance of the circuit 11 which takes place for a good interpretation of the object. The attenuation of the amplitude necessary for the recorded noise decreases sinusoidally from one to zero, and gration by the ear itself.

the chamfers ™, from i, NuU from, if ^

the distance R of the object changes from zero to the voltage of 24VoIt and about 10 ampere hours of maximum distance R _max . The output 60 has, whereby an operation of at least about signal also has a very sharp autocorrelation 60 hours is possible.

function, which means that if there is a slight change, the maximum rating of the device depends on the

tion of the value d ' compared to the value d a strong diameter of the antenna, ie the diameter change of the level occurs. of the reflector and its radome, which are not shown

The task of the demodulator circuit 7 consists of 65 sets which are associated with the container, in it, the incoming signal contains its code that of the controls of the patrol radar, Period 7 "and a second assessment. Another container holds the battery and the amplitude depending on the distance the power supply and control unit.

Using the patrol radar is extremely easy. The operator switches in the monitoring mode switches 321 and 323 from the generator of the fine code and directs the reflector the antenna, the opening angle of which is about 10 °, to the area to be monitored. Included With the same areas, near objects are no longer favored compared to distant objects. Is located If there is an object in the monitored area, this is indicated by an easily identifiable Doppler tone. To determine its removal, it is sufficient to close the switches 321 and 323, whereby the fine code is introduced in order to scan by the selector switch 322 all the distances contained in the sensitivity range. In one of these positions is the maximum acoustic or optical signal.

The examples given made it clear that the accuracy of the distance measurement ± 15 m. This accuracy can be increased by making the duration r of the elementary pulse smaller is chosen as 0.2 μβ. If the radiated beam of a few degrees is the accuracy of lateral distance to 500 m equal to the accuracy in the center of the beam.

The foregoing description shows that by means of a portable patrol radar according to the invention with a high sensitivity and a great accuracy the monitoring of a particular Area and identification of an unknown object can be achieved by using a radio signal lower power than a phase-modulated oscillation and emitted after receiving the reflection of which takes place demodulation and coherent integration. The emitted vibration is modulated on the one hand by a periodic coarse code, which is used for monitoring, whereby an automatic compensation of the different attenuation, that of the fourth power of the distance is proportional to the detected object is made. On the other hand, it is used to measure the distance an apparently random fine code superimposed on the coarse code, by means of which the distance of an object can be determined. The speed at which this object is moving is perceived with the ear or indicated by a needle device.

Claims (9)

Patent claims: 1. Radio measuring device, especially portable patrol radar device, for electromagnetic Detection and location especially of relatively slow moving targets the pure one generated by a high frequency transmitter and sent out by its directional antenna Undamped wave through a modulator with different, through the corresponding modulation signal generators induced modulation signals depending on the operating mode monitoring or distance measurement phase-modulated is and an arrangement for demodulation is provided, which in addition to the echo signal the modulation signal coming from one or the other modulation signal generator is supplied is and an.die low-frequency amplifier connected to information evaluation circuits are connected, characterized in that when monitoring the modulator (2) and the demodulation arrangement (6,7) from the one modulation signal generator (30) a square code is supplied, while the square code of a modulation signal generator (30) and a pseudo-random when measuring the distance Binary code of the other modulation signal generator (31) the modulator (2), which the signal to be transmitted combined with the multiplication product of the two codes, and the square code doubled in frequency in a frequency doubler (5) and via a multiplier (4) the multiplication product of the rectangular code and the delayed pseudorandom Binary codes are fed to the demodulation arrangement, which is known per se Way works on the autocorrelation principle. 2. Radio measuring device according to claim 1, characterized in that the modulator (14) is formed from a circulator (141) with three connections and from a high-frequency diode (142), two connections of the circulator (141) being connected in series in the transmission path and the third connection is connected to one end of a waveguide (143), the other end of which is connected to ground, and that the high-frequency diode (142), which is arranged in the waveguide (143) at a distance from its ends, with the product [g (o ) · F (o)] of the two undelayed codes is applied. 3. Radio measuring device according to claim 1, characterized in that for decoupling the transmitting and reception path, in a manner known per se, in the transmission path a ferrite high-frequency isolator (13) and a ferrite circulator (15) are switched on and that the high-frequency generator (12) a coupler (16) is connected, the output of which is connected to one between the antenna (10) and the demodulation arrangement (6, 7) provided coherence demodulator (17) for demodulation the received vibrations is used. 4. Radio measuring device according to claim 1, characterized in that the demodulation arrangement (6, 7) amplitude evaluation circuits (63, 71) through which the distance-dependent Damping of the vibrations received is compensated and the sensitivity to it Reduce echoes by going beyond the maximum distance for which the device is designed is caused moving objects located, and further contains a filter (72) which those echoes caused by objects whose velocities are not in that Suppress the area that is to be covered by the device. 5. Radio measuring device according to one of claims 1 to 4, characterized in that the first generator (30) has a symmetrical coarse code formed by square-wave pulses [g (p)] and the second generator (31) has an apparently random fine code [F (o)] emits whose product [g (o) ■ F (o)] phase-modulates the emitted vibrations, and that the first demodulation arrangement (6, 7) has a first demodulator (62) to which the output of the coherence demodulator (17) is placed and the with the product [g (ο) · F (d ')] of the coarse code and the delayed fine code is applied, and contains a second demodulator (71) to which the coarse code [g (o)] doubled in frequency is applied. 6. Radio measuring device according to claim 5, characterized in that the period (2 T) of the coarse code [g (o)] is equal to four times the transit time of the vibrations over the maximum distance. 7. Radio measuring device according to claim 5, referring back to claim 4, characterized in that in series with the second demodulator (71) the filter (72) is provided and that this one Doppler signal supplies, its size approximates depends on the fourth power of the distance, which compensates for the attenuation caused by the distance. 8. Radio measuring device according to claim 5, characterized in that the fine code generator (31) is designed as a slide register. 9. Radio measuring device according to one of claims 1 to 7, characterized in that the period of the fine code (F ) differs from a multiple of the period of the coarse code (g). Considered publications:
French Patent No. 1285956;
electronics, 36 (1963), 47 (November), pp. 34 to 37. For this purpose 2 sheets of drawings 809 619/189 9.68 © Bundesdruckerei Berlin