DE2318856A1 - TARGET OBJECT EVALUATOR FOR MARINE OVERWATER RADAR SYSTEM - Google Patents

Description

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M Δ Λ c υ ο η 22, ßtofnedorfstr. 10 2318856

April 13, 1973

IQTRON CORPORATION, Bedford (Mass.) V. St. A.

Target evaluator for marine surface radar system

The invention relates to a marine surface radar system, in particular a navigation and collision protection device for use on moving vehicles, in particular a pulse device such as a radar device for use on surface craft like ships, more precisely a target evaluator. The invention is a further development of the subject matter of DT-OS 2 06i 129 (attorney's file: 021-16.4O5P).

The requirements for an automatic radar evaluation and vision system on board ships has not yet been implemented

021-2 ^ 3.646-Hd-r (7)

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satisfactory, particularly because of the problems posed by reflection, signals from extensive land masses or massifs, and sometimes waves; these signals are often stronger than those of desired small target objects, in particular other ships '', as well as navigation aids, so that they obscure their signals. For example, because of the continuous movement of the ship, the many target objects created by the land masses cannot simply be eliminated by the marking technique used in fixed radar systems because the large amount of information due to the existence of such land masses is impractical for signal processing by an electronic computer is considered, as it is used in certain stationary systems for air traffic monitoring (cf. e.g. Proceedings of the Eighth Symposion at the A.GoA.RD Avionics Panel, London, 21-25 September 1964, pages 525 - 556, Chapter 28, Digitalization of Radar Signals and their Evaluation by a Computer for Automatic Tracking of Targets and Chapter 29, Evaluation of Track-while-Scan Computer Logics; see also US Pat. No. 3,235,867) For this reason, until now, marine radar has been limited to relatively simple systems, the visual display of which is known to be difficult to interpret, especially in large workload when there is a risk of collision.

All of these difficulties naturally increase with the size of the ship, since the larger ships have Maneuver times are much longer and the distance within which other ships pose a risk of collision.

3098437Q937

It is therefore the object of the invention to have a navigation and collision protection radar device or the like on board of ships that overcomes the above difficulties, especially a relatively simple one Automatic radar evaluation device on a moving ship as an aid to the detection of ship objects for collision protection, the target object evaluation being significant is improved.

According to the invention, a target object evaluator for marine surface radar systems has the digitized target object range impulses output, a target leading edge signaling device which generates a target leading edge signal pulse for successive Azimuths, and further a target trailing edge signaling means which a target trailing edge signal pulse for successive azimuths, the initial is separated in distance from the target leading edge signal, wherein the distance-wise coincidence of a leading edge signal pulse and a trailing edge signal pulse is a target envelope end detection signal triggers.

The invention also deals with the problems caused by the existence of target objects such as vast land masses by moving between such Targets and smaller targets such as ships and navigation aids. More precisely, this is achieved by a discriminator, the preferably to a maximum number of consecutive responses azimuthal target leading edge signal pulses, the maximum number with successively increasing distances decreases to distinguish between landmass targets that are larger than one in azimuthal direction

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predetermined actual length, which is a maximum Represents ship length, and target objects below the predetermined actual length in azimuthal direction, which represent possible ship targets, so that a discriminated target object output signal is generated in the case of target objects, which are less than the predetermined length which represent the possible ship targets. These target output signals, whose number is much smaller than the total number of echo sequences received represent small ones Represent target objects that can pose a risk of collision; these signals can be converted into a suitable Electronic computers are fed to calculate the speed and course of the target objects, and preferably into a suitable viewing device in order to display them as well. Preferably the discriminator also generates a Land mass output signal emitted at target objects that are greater than the predetermined length to represent a larger part of the leading edge in the azimuth of Landmassenzielob objects and display in contrast.

The invention also deals with land mass recording, by processing the received signals so that target object echo pulses from areas which is farther from the ship than the leading edge of a land mass, but closer than the more distant edge of the land mass are removed, while target echo pulses are retained for tracking and display purposes, the from areas beyond the more distant edge of the land mass, around the edge of a land mass target to be able to display with minimal distance, while the more distant parts are eliminated to the detection of viewing wanted objects near it.

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The invention is explained in more detail with reference to the drawing » It show: ι

Fig. 1 is the simplified block diagram of a complete automatic radar system;

2 shows a plan view of various possible target objects and a land mass;

3 shows the display corresponding to FIG. 2 on the radar screen;

Fig. H is a more detailed block diagram of the plant;

5 is a schematic view of a target object envelope;

6 shows a list of the logical method steps which are carried out by the target object evaluator according to the invention;

7 to 11 are circuit diagrams of parts of the target object evaluator according to the invention;

12 shows the circuit diagram of an interface or interface part of the complete system;

13 to 15 program flow diagrams of programs that are generated by the computer when processing the Target and land mass output signals processed for the screen image; and

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16 shows the circuit diagram of parts of the display device.

Because of the exact structure of the various assemblies described below, reference is made to the drawing self-referenced where the individual components as logical or logic elements (e.g. AND and OR elements), amplifiers, registers, etc. with common (US-American) Symbols are shown. ■ ·>

Fig. 1 schematically shows a marine surface pilot according to the invention in the form of an automatic radar system consisting of a radar transmitter and receiver 110, a target object evaluator 112, which will be described in more detail, a digital computer 1ik which is a well known general purpose computer with an arithmetic unit, a master or control unit and a memory, and a cathode ray tube viewing device 11 6, which is also well known per se and does not need to be explained in more detail.

Fig. 2 shows schematically a land mass and three target objects of the same size, which are in different Distances from the radar transmitter.

According to the invention, the antenna of the radar transmitter 110 rotates continuously and transmits pulses in the process at regular intervals. After each impulse there is a Obtained sequence of echo signals, the delay time of each echo signal being a function of the distance of the Is the place of reflection. Each echo train is received from a different azimuthal direction because the antenna is located turns. The transmitted pulse and the received echoes

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are digitized or converted to be either "1" or "0" and then by the target evaluator or processor 112 processes to digital data to gain that the distance of the target object, its Extent or breadth and a discretionary decision represent whether the target object is a land mass or a ship. This information is stored in the digital computer 114 fed in, which the data accordingly stored programs and possibly ■ 'the Information for a visual display to the display device 116 gives away.

For purposes of illustration only, it is assumed here, as shown in FIG. 5, that one radar pulse occurs every 5 during the antenna rotation is transmitted. Therefore, the radar-monitored area is divided into azimuth sectors of 5 each thought. The echoes from each pulse are reflected from targets at different distances, the Distances are subdivided into successive target object or range rings by the processing according to the invention will. The spatial unit from which a single echo pulse is reflected is called the target object field here; In this way, a sequence of target object fields in the distance direction forms an azimuthal sector, and a sequence of target object fields in the azimuthal direction a distance ring. A range of 13 distance rings and containing 18 azimuth sectors is shown in FIG pictured. When a target object is present, a generally contiguous group of target object fields, which generally extend in both the range and azimuth directions, as the target object envelope as defined 120 in FIG.

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It can be seen from Fig. 5 that after each Transmit pulse up to azimuth sector no »5 no echo pulses be received. After the sixth pulse, an echo pulse 122 is received from the 12th range ring; after this seventh pulse .an echo pulse 124 from the same range ring; after the eighth pulse, an echo pulse 126 from the ninth Range ring and an echo pulse 128 from the 12th range ring with two empty fields in between, etc.

Fig. 5 shows a digitized representation of a typical target envelope 120 passed through by the target received digitally converted echo impulses is formed »There is no such echo envelope Course that exactly matches the shape of the target object itself matches, but can instead have an irregular shape with incisions on its outer edge, even have holes where no echo pulses are received will. It is highly desirable to display the target object in a simple form on the display device, in a single form indicating distance and azimuth, "these values being derived from information as in 5 shown in FIG. It is also desirable because echo pulses at every azimuth increment or step are received to determine whether the echo pulses are not a target object (i.e. noise or Clutter), a previously identified target new target object or a land mass, and determine whether the echo pulses passing through empty fields in the * distance or separated in azimuth, as are to be interpreted as coming from a single target object or from several target objects. All of these objects are achieved by the invention solved. .

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overview

One. Overview of the invention is given with reference to FIG. 6, after which the detection of a New target object is assumed if echo pulses from three adjacent target object fields in a single range ring such as the echo pulses 122, 124 and 128 received from the target object fields, those by azimuth sectors 6, 7 and 8 in the twelfth range ring in Fig. 5 are formed. If this condition is met (step Ί), parts of the evaluator generate 112 a "start" or "S" pulse called a leading edge signal, which is recorded at the distance of the three neighboring ones Echoes and in azimuth of the third consecutive Echoes. If there is no echo from the nearest range ring at the same Azimuth is received, a trailing edge signal called the "tail" or "E" pulse is generated and in the first empty distance field recorded (Scjiritt 3)

If more echoes from consecutive azimuth sectors are received, the S and E pulses are passed on through devices to be described or propagated. The propagation of the S-pulse along of the leading edge of a target object envelope leads to a scan of the leading edge of the target object (step 4). In the 18th azimuth sector according to the example of FIG. 5, the S and E pulses are determined by the target object evaluator recorded by means of a circuit to be described as both located in the distance ring 10, and this Coincidence state is taken as a sign that the end of the target object envelope has been reached (steps 6 and 7).

309843/09 3-7

In addition, when the S-pulse propagates to scan the leading edge of the target object, a count is made in the evaluator 112 which indicates the angular extent of the target object (step 5). This count is compared with a predetermined number which is slightly larger than the angular extent of the largest known ship, e.g. 600 m (2000 feet) ¹ , viewed at that distance, and the result of this comparison is used to distinguish between possible ship targets (ships or navigation buoys for example) and land masses (steps 8 and 9).

The information obtained in this way is then fed into the digital computer 114 to be processed in a manner to be described in more detail (steps 11, 12 and 13).

FIG. H is a more precise block diagram of the assemblies from FIG. 1, preferably with a ship's gyrocompass 152 and a speed log 15 **, which deliver input signals to the evaluator 112.

The target object evaluator 112 according to the invention consists spatially of a group of eight circuit boards, called "front ends", one of which is the interface or interface board 156 and is specially designed for the type of radar used, while the remaining seven circuit boards have a standard unit . Specifically, these circuit boards are a clock board 158, three shift register boards 160, a start / end board 162, an extent count board A6h, and a data format and buffer board 166.

3 0 9 8 A 37 0 9 3.7

Interface plate

In Fig. 7, the interface plate 156 is shown, which is connected to the conventional radar video output to his display device, as well as the conventional radar trigger pulses and converts the returned echo pulses into digital form in order to use them in the target object evaluator to process according to the invention.

A trigger to digital converter 130 sets a trigger input signal at 214 into a pulse 215 of about 1.5 / µs duration, delayed by a time that is equal to the Properties of the particular radar used depends. This delay is required to get the trigger signals to synchronize with the incoming echoes.

The video to digitizer 132 includes two resettable ones Integrators 134 and 136, a difference comparator 138, an output data lock 140, a threshold circuit 142, and a differential error corrector 144. Two differential analog video lines 146 and 148 are the Input lines to digitizer 132. If none Echoes are reflected from a target, the outputs on 146 and 148 are the same. However, if a Echo is reflected, the output signals are different, so that the integrators focus on something different Charge level; this condition is detected by the difference comparator 138. If the difference is above of the threshold value, an output signal is provided to the output lock 14O. After the data is in the lock has been loaded, the integrators are reset by a clock pulse, and a new cycle

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begins. Each cycle lasts 0.5 / us. Quantized video pulses (Echoes) occur at exit 149.

A sector control block 131 ~ is a lock that controls the Can control detection of target objects behind land masses. This lock is controlled by computer 114.

Clock

The clock plate 158 has seven sections. A 8 MHz precision oscillator 168 provides a stable time reference for all "front end" functions. His exit 169 is the input of a real-time clock generator 170, which reduces the 8 MHz signal by a factor of 27 456 or 109 824, a 291.37 Hz or 72.84 Hz signal 1? 2 or

174 to generate. The signals 172 and 174 are used as a time reference in the computer 114. A power supply 176 gains a + 14.00V output signal at 178 from one +19 V input voltage at I80 from a power supply I505 output signal 178 is used by the shift registers. A clock control 182 receives a "stop" signal 184 from the data buffer disk 166 and ensures that all clocks in the same phase are stopped at the exact end of a distance block. The clock control -rung 182 also ensures that all clocks are synchronized with the 8 MHz clock.

A front end timer 186 provides clock signals to the other front end plates at outputs I88, 190, 192, 194, 196, 1987 200, 202, 204 and 209. These signals are used to ensure that the data is continuous

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are processed with the same frequency and thus maintain their order. Outputs 2O6 and 208 of the clock 186 also serve as an input for a clock control block 210, which sets the voltage to the correct level changes to drive the shift registers. A shift register 412 that is 405 bits is not functionally one Part of the clock generation, but only arranged on the clock generator plate 158 for reasons of expediency.

In addition, each register plate 160 has four other 405 bit shift registers 212. These are all mutual interchangeable.

Front and rear edge signal facility

The digitized radar echoes from the i4 ° output Interface plates 156 become start / end plates 162 transferred where decisions are made, the beginning and determine the end of an object, and the leading and trailing edges of the target are then scanned. An echo sequence is read in via an input swahlb lock 218, from which it is entered through a video 1 register 220 and then after the next radar trigger pulse through a video 2 register 224 and after the third radar trigger pulse passes through a video 3 register 230 after which it is lost. Three parallel echo sequences from three neighboring azimuth sectors therefore revolve continuously and are scanned by a new object readout block 232. If the condition for the presence of a target object (three azimuthally adjacent pulses for a only distance) is met, a new property

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solve-SignaX is generated, which is part of the S-bit control block 246 causes an S-bit to be generated at this distance. This S-bit is then at this distance forwarded if further echo sequences are received in the case of positive reflections in this area; it can move be "forward in terms of distance up to two steps all at once or backwards any number of steps to bring it the distance appropriate to the corresponds to the closest contiguous leading edge of the target object. If in a particular azimuth sector two S-bits forwarded and continuous between the corre- sponding. corresponding distances have been discovered, the S-bit in the greater distance is destroyed to only correspond to the S-bit forward to the leading edge.

Depending on the generation of an S-bit, an E-bit is generated by an E-bit control block 266. That Ε bit is behind in the distance of the target object field generated at this azimuth last detected echo pulse and can be propagated if further echo sequences be received. It can be moved forward or backward in distance to the rear edge of the target object to feel. .

If there is no positive echo back from a radar pulse in the distance of a detected target object, the S-Bit is still forwarded at this distance, under control by a major bang-sticking Block 268. A Ε bit is placed in the next range ring forwarded. If after a second radar pulse no Echo comes back from this distance, the block 268 scans the target object end control block 270, which a target object

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jektendesignal emits at 271, after which data in the computer 114 can be read out for the display device.

More specifically, the radar transmitter · 110 sends a time trigger pulse, the k as an input signal at 21 to trigger digital converter 130 on the interface plate 156 passes, where he called, is converted into a digital timing pulse "MB" (215) "the" main bang ". Each major bang is the beginning of a two-part cycle that lasts at least 412 / us. The first part of this cycle is the read-in operation, which lasts 206 / us, the second part is the read-out operation, which normally lasts 206 / us, but is sometimes longer if, for example, some data have to be saved for transmission to the computer and therefore data processing is temporarily delayed.

After a special radar impulse sent, e.g. the pulse A, during the read-in operation of cycle A, For example, the digitally converted echo train A is fed to input select block 218 at 216 and then to the 8-bit video 1 register 220 at one of the inputs 222. The echo sequence A is transferred from register 220 to a 405-bit shift register read in on one of the register plates ΐβθ. While During the readout operation, this sequence A is read back via an input 226 into the video 1 register 220 and a 405-bit shift register.

After the next radar pulse (pulse B) in read-in mode each echo sequence A is read out of the 405-bit shift register, input into the input reader 2i8 at 226, through the 8-bit video 2 register 224 and read back into a 405-bit shift register. Simultaneously

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becomes a new echo sequence B of the pulse. B entered at 216 and becomes, via video 1 register 220, a 405 bit shift register read in. The two echo sequences A and B are kept parallel in distance when they circulate »During the readout operation of cycle E, sequence A runs via video 2 register 224 to a 405-bit shift register.

During the third cycle G ₉ that follows radar pulse C, a new echo train C is entered at 216 and passes through video 1 register 220, while train B passes through video 2 register 224 and train A at 228 is fed into selector 218 and then read through 2-bit video 3 register 230, after which it is lost. The sequences A, B and 'C are kept parallel throughout in terms of distance.

During the read-in operation of cycle C, the first bits of registers 220, 224 and 230 (which contain the digitally converted echo signals, either "0" or "1", from adjacent azimuth sectors in a single Removal) 'continuously by the new object readout block 232 scanned. When three adjacent pulses are detected, a signal asserts on line 234 if not at 235 by the propagation of a previously generated S-bit at this distance is prevented from targeting the target pulse lock 236. The lock 236 is activated by a clock pulse reset at 238.

The output 240 of the target pulse inhibitor 236 is generated a new object pulse at 242 directed to the extent count plate 164 gets where the target extent

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is set to "T ^1" and the bit ("X") for extended target object is set to "0" in register 243. The output signal 240 of the target object pulse lock 236 also passes through line 244 to S-bit control block 246 and on line 24i to S-bit control block 247 "the signal on line 248 is an output on lines 250 and 252 to data buffer disk 166 and extent count disk 1-64 and enables shift register 254 to be preset.

When an echo travels back a distance where a target has already been detected during previous cycles and has not ended, an S bit goes into the start / end plate at 249 in parallel with the video signal coming out this distance from a shift register and disables the new object trigger block on line 235 · Hence Although three neighboring echoes at that distance have been received, they will be part of an existing one Detected target object. The S bit then plants through the remainder of the S control blocks 246 and 247 where the S-bit moves backwards or forwards in terms of distance is moved.

When it is determined by S-bit control that the two S-bits have continuous positive echoes from all distances in between, there will be another S-bit destroyed at 264, and a "compare" signal occurs on Exit at 252 for expansion countinga-Platt on. The result of this will be given later.

The S bit is provided to a shift register and extent count plate 164 at 325.

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During the readout operation, an S-bit is fed into an E-bit control block 266 at 288. This S-bit is ORed with the output signal 240 of the new object lock 236, in order to set a target object flip-flop 273, its output signal locks the retrigger block at 235 as previously described. The current echo train is fed at 270 to a gate 269 in the E-bit controller; the grid 269 is opened by a flip-flop 272 which is set and reset by signals from the target end controller 270. When the first hole in the echo train is detected, gate 269 allows a register 277 to be preset. Mode signal inputs at 278 and 279 determine the shift of the Ε bit; During the read-in operation, the EB ± t cannot be shifted in terms of distance over a hole in the echo sequence; during the read operation, it can be shifted "Besides, E-bit control block the Videofölge and the S bits are checked to determine whether the Ε · * bit should be postponed distance moderately to scan around the back edge of the target. The Ε bit is the output from control block 266 at 282 for a shift register. The Ε bit is the input from the shift register to the target end control block 270 at 275 (ED).

As an example, the generation and propagation of S and Ε-bits and its displacements in the distance under control of the blocks 146, 266 and 1 ^ 7 k, reference is again made to FIG. "In this figure, uncoated S-bits indicate the situation after the the read-in part of the cycle, while canceled S-bits show the position after reading out if the position has changed. Originally in the twelve

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The S-bit generated in the eighth azimuth sector on the th range ring is "forwarded to the ninth sector if an echo travels back the same distance. The Ε bit is forwarded similarly in the" 13 "range ring. At the tenth azimuth sector the S bit is forwarded (Si); however, since positive echoes also come back from the eleventh and tenth range rings, the S blocks 246 and 244 move S1 forward two steps during the read-in operation and two more steps during the read-out operation (S1 ·) to the eighth range ring. At the same time, a new S- Bit (S2) is generated on the ninth range ring after three consecutive bits have been detected at the same range. This S2 is ^{passed step by step to the seventh range ring (S2 1} ), which is actually the leading edge of the target object, as shown in FIG. 4 can be seen.

At the eleventh azimuth sector, the trailing S bit (S1 ') destroyed and a "comparison" signal generated. As a result, the expansion count in the expansion counting plate becomes 164 stopped according to the twelfth distance ring, but recorded at the seventh range ring, which corresponds to the leading edge of the target.

The S and E bits are through the 13 x azimuth sector forwarded. In the 14th sector, a Ε bit is placed in the eighth distance ring during the read-in operation, however destroyed during the readout operation. The Ε bit on the trailing edge of the target becomes the twelfth range ring forward step by step. The S and E bits sample the edges of the target object during the extent count continues until the 17th Azi-

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mutsector, at which point in time no echo in the target object distance runs back. In this case, as has already been explained, the main bang adhesive block 268, that the S and Ε bits propagate despite the lack of radar echoes. In the 18th sector, the S-bit is brought back one field to the 10th range ring, and its coincidence with the Ε bit together with the two consecutive absence of echo signals causes the target end signal is delivered at 271.

Target object extent count

The expansion counting plate 164 has the main function of continuing the counting depending on an S-bit to thereby add a running total count Reach, which indicates the azimuthal extent of the target object. Also, a "compare" decision is made (between two target counts) if two S bits occur in an echo train.

This disk has four parallel storage levels 3O6, 307, 308, 309, a stage control block 310, an output buffer 312, a count control block 315 and a Compare control block 316.

An S-bit from output 299 of the start / end plate is injected at 300 along with clock signals at 302. The extent count data for the removal of the S bits are specified at 304 from a shift register 212. The data loaded at 304 becomes concurrent input to the data buffer disk 166 via outputs 3185 the data is then available for output from the

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Data buffer disk l66 in digital computer 114. The extended target bit X is loaded at port 320. A new object pulse 242 from start / end plate 162 triggers the expansion count with "1". and clears all other count bits; it also clears the X bit for extended target. The X-Bit can be put through an input at 343 from data buffer disk 166. A clock pulse at 322 from the continuously operated clock automatically loads data from stage 1 (306) Level 2 (307). However, loading from level 2 to the next level does not take place automatically; when a Target object mark is set according to the target object data in stages 3 and 4, and is detected by level control block 310, no level 2 data becomes loaded. The target object character occurs in the target object character shift register block 342.

Counting continues to stage 4 (309) only if an S bit is set (entered in count control block 314 at 324, eventually from 325 on start / end plate 162) when the processor is in readout mode (entered at 326 in control block 314 from operation control block 346 on data buffer disk 166) and when a clock pulse 328 is input. The extent count data is then output to a slider at 330 at the same time the S bit exits start / end disk 162 at 325 .

The "Compare" operation is triggered by a Compare signal at 255 from the start / end disk, the is released when an S-bit is destroyed. The data in FIG. 3 is compared with the data in stage 4.

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If one of the displayed target objects is expanded (X bit set), the data from this Level saved and the others given. Venn at all no target object or both target objects are extended, the data representing the extent count will be saved. ,

Data buffer and discriminator "

The data buffer plate 166 has eight functional sections of a range synchronizer 344, one Clock and operation control 346, a removal lock 347, a count lock 348, an extent formatter 350, a computer interrupt controller 352, a Extended object decider 354 and an extended object data inhibitor 356

Range synchronizer 344 receives a clock pulse at 362; Counters 363, 364 and 365 count 0.5 yus-lrapulse up to 412 (206 / us or half period). The data path through the "front end" is 412 bits long and the synchronizer 344 provides a count equal to the number of range fields from which echoes are processed. The 4th pulse sets the lock 366. The output signal 367 of the lock 366 is at the same time the input signal for the clock and operating control 346, whose output signals 368 change the state of all 412 pulses in order to determine the redemption or readout operation. The output signals 368 are input to the start / end plate at input select block 218, to count control block 314 at 326 on description count board 164, and

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3318856

at 278 and 279 in the E-bit control block 266 on the Start / end plate 162.

The clock and operation control 346 also outputs a "stop" pulse at 184 at the end of a readout operation and, if necessary, by a "computer busy" signal 372 from the computer interrupt controller 352, it holds Stop pulse on the front end clock. The clock are restarted by a main bang at 370.

The expansion count data is entered in the formatter 350 at ports 318 from the extent count board 164. Venn a circulating S bit back into the start / end plate at 249 from a shift register is passed, a signal at 299 is applied to the extent count plate 264 delivered »A signal (" charging distance ") is then passed to the extent count at 36O Plate and entered into removal lock 347 · The "loading removal" signal causes loading the extent count lock 348 from the inputs 318. At the same time, it causes the range count to be loaded into range lock 347 from the range synchronizer 3 ^^ · The distance count is given at 347 to a "conglomerate" plate (Con plate), the Stores data for the computer. The extended object bit (Xu) (if already set) is taken from the extension count disk 164 loaded at 319 and at 376 to the Conglomerate plate issued.

The extended object decider 354 discriminates between land mass targets and smaller targets.

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It provides a set of locks 378 which are set sequentially at counts (indicated in the drawing) 8, 16, 32, 80, 128 and 256 , uin to act as a switch, which determines which bits of the extent count data are entered into the extent count lock 3 ^ 8. For more distant targets, the most significant bits are hardly needed, while for closer targets the least significant bits are irrelevant eight bits entered at 3 ¹ §, but only six bits loaded into the expansion counting lock 3 ^ 8 and given at 382 to the conglomerate disk and thus to the digital computer 114.

An S-bit (from the start / end plate 162), a read-in mode signal (from the operating status 3 ^ 6) and a Signal representing a distance greater than eight distance fields (from locks 378) are all required before a target object can be viewed as a possible land mass in block 35 ** ·; these signals are entered at 384. Extent count data from the lock 3 ^ 8 are together with distance data at 386 is entered into a logic tree, the function of which is essentially is to compare the expansion count with a test number that has a predetermined actual length im Represents azimuth. If the extent count exceeds this test number, the target is considered a land mass, and the output 341 is in the extent count plate where they entered the extended object lock puts.

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However, the number of tests depends on the distance. In In this context, reference is made to Fig. 2: If the next target object Λ00 is at a distance R1, while the most distant target object 402 is at a greater distance R2, and if both Targets have absolutely the same area, then the extent count for the closer target is greater than for the more distant. The extent count is therefore essentially an angle and not a linear measurement. Therefore In order to determine whether a particular target is a land mass, its extent count must be compared with a number that is inversely proportional to the distance.

The Extended Object Inhibitor 356 normally prevents that the computer interrupt controller 352 (at 357) outputs data for target objects behind a land mass. However, this function can be excepted if desired Force are set by suitable input signals, and including a "Sector-N" signal (390) from the sector controller 131 on the interface disk 156. The Capture target objects behind you as land mass identified target may be desirable in some circumstances; z. For example, if a bridge is identified as a land mass, it would normally not be targets be detected behind it.

The computer interrupt controller 352 sends in Signal to the digital computer 114 instructing it to Redeem data from the front end in three cases: when a target object ends, when an extended object decision is made * or if an extensive target object

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■ ²⁶ "2318858

project result in an expansion count divisible by 16 Has. The end of target signal from start / end plate 162 is input to block 352 at 271; four bits the extent count and the XD bit are entered at 391. The "ISR" signal asserted at 392 determines the loading of the data from the data buffer disk in the conglomerate plate 373

Connection to the digital computer

The con (conglomerate) plate 373 is used for connection (interface function) to the computer. 114 and receives data from the "front end" for transmission to the computer. The target extent is loaded at 382 (6 bits); the distance at 37 ** (9 bits) and the extended object code at 395 ° This data is output to the computer 114 at 396 in response to a signal from the computer on line 398. The "INT" signal hOO is the computer interrupt signal. The ¹¹ INH "signal from the conglomerate disk at 39 ^ prevents further loading of data from the" front end "while the computer is busy. This signal is deleted by a computer signal on line 39 &.

Digital computer and display device

Data indicating the extent of the target object, the distance and representing the expanded object code are input to the computer 114 from the conglomerate plate 373. Everyone Suitable computers can be used to process the data obtained by the target object evaluator 112.

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In the embodiment shown and described is the Calculator a general purpose calculator from the Lockheed Electronics Company (see their publication "MAC Computer Reference Manual ", TM 13010009800, issued November 1970, 5th edition),

This computer has a memory 4θ8 ₅ a core memory 4i0 and a central unit h \ 2 .. The ROM 4o8 has a number of programs, each with a different priority level, which are all under the control of a program interrupt controller 4I4. The programs are executed as needed in response to interrupt signals (such as from the interrupt controller 352 on the data buffer disk 166). The program interrupt controller 414 automatically switches the programs in response to these interrupts. A program with a lower priority is interrupted for the execution of a program with a higher priority} If this has been completed, the program with a lower priority is resumed at the point of interruption.

13 through 16 are program flow charts for four Programs of different priority are shown, which together the target object data from the target object evaluator 112 to the display device 116 transferred. (Other saved programs that not directly related to this transmission are not discussed). The highest priority, namely 9, has the program to get target data from the target evaluator read in (Fig. 13) · This program is started by an interrupt signal ^ 00 (INT) from interrupt block 352 on the data buffer disk 166. If the sub-

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break signal is received, the program does so Reading into the memory 4iO of the distance, target object extension and extended object code data of terminals 396 on conglomerate plate 373 and the azimuth data from radar transmitter 110. The data is temporarily in a "circle file" is stored in memory and the file location is incremented for the next target object.

A program for target acquisition and tracking (Fig. 14) has priority k. Execution of this program causes the range, azimuth, and target extent data to be read from the circle file into which they were input from the conglomerate disk 373. Selected target objects are point objects stored in the land display file in memory ^ -10 after being corrected to place the sector origin in the middle of the extent count, compared with data in the trace file in memory Λ10 to try to find data for the same target object from previous radar scans to find. If a match is found, the speed is calculated and stored (based on location) in the tracking file. If a match is not found in the trace file, the potential file is checked; if a match is found, the range and azimuth are updated and if the target has been in the potential file for 56 seconds it is transferred to the track file. If no match is found in the potential file, the new target object is entered there. The computer waits for the "wait for interruption" step when all target objects have been read from the circle file.

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The data is transferred from the trace file to the view file by a program with priority 0 (lowest Priority).

Referring to Fig. 15, the program for reading out the data has from the view and trace files in computer memory 410, priority 6 and automatically becomes 60 times / s executed. The data is first read from the land view data, which contains the position of target objects, identified by the target evaluator 112 as being expanded and this data is then read out into the display device 117 (without speed data).

When the entire land file has been read out, the tracking file is read out, including velocities and vector length. Alone
the data contained in the entire visual file are depending
1 / 6O s displayed. The computer readout speed is designed so that the entire file can be read out in less than 1/6 s. The computer then exits priority 6 to process programs that have lower priorities (if they require processing at all) until a clock pulse indicates that 1/6 of a second has elapsed. The file is then displayed again.

The display device 117 (display hardware) (FIG. 6) has
Storage registers 4i6, 4i8, 420 and 422 into which the X,
Y position, X or Y speed can be read in by the computer 114. The digital data from each storage register is fed to a digital-to-analog converter 425. The X-position and X-speed together determine the input signal for the X-axis deflection coil,

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while the Y-axis deflection coil receives a signal similarly, which is determined by the Y position and the Y speed. -

Summary

According to FIGS. 2 and 3, ships 402 and kok and a buoy kO6 reflect radar pulses from a radar transmitter as well as the land mass 407. The ship kO5 _t behind the land mass can also reflect pulses, but these are normally not displayed; In special circumstances, ship 405 may also be displayed if desired by entering a command into the control panel. With each radar scan, ships kok and 402, buoy ko6, and land mass 407 reflect echoes to radar transmitter 110; these echoes are converted digitally and scanned for a target object jektvorhanden state. For each target object, an S and a Ε bit are generated and propagated or forwarded to scan the leading and trailing edges of each target object until the S and E bits coincide after two missing echoes, around the end the envelope. An extent or width count of the target object is stored. At the end of ship objects 402 and kok and buoy 4 Oo, the detail count is less than a predetermined actual length that is slightly larger than the largest known ship at the distance of the target object; each such target is therefore counted as a point, but not as a land mass. The Zielobjektausdehnungs- -entfernungsdaten and are then in the Punktöbjekt view file in the computer 11. k

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Claims (1)

Claims (1. Target object evaluator for a marine surface radar system, the digitized target range impulses for a number of distances, g e identifies by a target object leading edge signaling device (1Ö2) which a target leading edge signal pulse for each successive one Gives azimuths,. . a Zielob j ekthinterrand signal means (1 62), which emits a target-trailing edge signal pulse at each successive azimuths ■ is distance excessively separated from the leading edge of pulse signal initially, wherein said distance even coincidence of a leading edge signal pulse and a trailing edge signal pulse triggers a Zielobjekthüllkurvenende detection signal. 2 * target object evaluator according to claim 1, -characterized by a discriminator (35 * 0> which is responsive to a maximum number of the target leading edge signal pulses, which decreases with continuously increasing distance in order to differentiate between land mass target objects on the one hand, which is greater than a predetermined actual length im Azimuth, which represents a maximum ship length; and, on the other hand, possible ship target objects that are shorter than the predetermined length to be a. discriminated Target output signal for possible ship target objects to create. Jc. 30984370937 7318856 3 target object evaluator according to claim 2, characterized in that that the discriminator (35 * 0 is a land mass exit signal generates a larger part of the target objects that are larger than the predetermined length Display leading edge in azimuth of landmass targets. 4. target object evaluator according to claim 1 or 2, characterized by a distance increment device for changing the distance position of such an edge signal as a function of the distance position of the digitized target object range impulses. 5. target object evaluator according to claim 4, wherein the target object distance pulses are digitized so that they have one of two values, which means that g e ken η draws, that the target leading edge signaling means (162) the first value of the digital target range pulses appeals to; that the target rear edge signal means (162) pulse responsive to the second value of the digital Zielobjektentfernungsim- _/, wherein the target object trailing edge signal pulse occurs for the same azimuth, in that azimuth propagation means (2h6 _r 2 ^ 7, 266) are provided for propagating the edge signals along successive azimuth intervals to define the target envelope; 309843/0937 " ^3k ' 7318856 that the distance increment device defines the target object envelope distance, that a target end detection device (270) is provided which is responsive to a predetermined number of target range pulses with the second ¥ ert in successive azimuth intervals and in the Target envelope distance as well as the coincidence in the distance of a leading edge signal pulse and a trailing edge signal pulse to the target end detection signal to generate, and whereby the discriminator is based on the propagation of such a Leading edge signal pulse along the maximum Number of azimuth intervals responds. 6. Target object evaluator for a marine surface radar system, the digitized target object range signal pulses for a number of distances indicated by ' a discriminator that responds to the signal pulses for filtering out at least a major portion of land mass targets that are larger than a predetermined one Length in azimuth, but output signals accordingly Outputs target objects that are smaller than the predetermined length to represent possible ship targets. 7 target object evaluator according to claim 6, characterized in that that the discriminator is based on a maximum number of successive azimuthal target object pulses 309843/0937 7318856 that responds for successively increasing distances decreases to weed out land mass targets above a predetermined actual length in azimuth, the represents a maximum ship length. 8. Target object evaluator for a marine surface radar system, the digitized target range impulses for a number of distances indicated by a discriminator, which responds to the signal impulses for differentiation between target objects larger and smaller than a predetermined length in azimuth, namely discriminated output signals delivers in selective dependence on Target objects smaller than the predetermined length that the represent possible ship targets, and Target objects greater than the predetermined length representing at least a portion of land mass target objects. 9. Target object evaluator according to claim 8, characterized in that that the discriminator gives an output signal that a larger part of the leading edge in azimuth of land mass targets. 10. target object evaluator according to claim 9 »characterized in that that the discriminator is based on a maximum number of consecutive azimuthal target object pulses responds, which decreases for successively increasing distances, the predetermined length in azimuth being a maximum Represents the length of the ship. 309843/0937 11. Marine surface radar for elimination at least a larger portion of azimuth-extended target objects while maintaining smaller target objects, marked by a counter (i64) for counting a sequence of generally sequential target pulses in azimuth at a specific range, a target impulse discriminator (166, 35 * 0 based on a number of the pulses below a predetermined maximum responds to display such a smaller target object, and a computer (114) which, in response to the target pulse discriminator, generates a target computation signal ^{indicating the speed and course of a 1} "such smaller target. 12. Radar system according to claim 11, characterized by a viewing device (116) for displaying the smaller target objects and their speed and course. 13 · Radar installation according to claim 12, characterized in that the target is object impulse discriminator (16'6, 35 * 0 also responds to a number of these pulses in excess of the predetermined maximum, by part of a such extended target object (407) for a Contrast indicator to be displayed by the display device (116). 14. Radar system according to claim 11, characterized 30 9843/093 7 indicates that the target impulse discriminator (i66, 354) is responsive to any number of specific distances up to a maximum number of pulses, the maximum Number decreases for successively increasing distances in order to display such a smaller target object, that is below a predetermined actual length in azimuth at that particular distance. 15 · Marine surface radar system with a target evaluator according to claim 5 »characterized by a computer (114) which, depending on the end-of-target detection signals, the target envelope distance and the discriminated target output signal velocity and heading of such a possible ship target (402, 4o4, 4o6) and a display device (116) for displaying the possible ship target objects with the calculated values of speed and course. 16. Radar system according to claim 15 »characterized in that that the calculated "values of speed and course are displayed as a vector (402, 4o4, 4O6), which is based on the visual representation of the ship's target objects (Figures 2, 3). 17 · Radar system according to claim 15 »characterized in that that the discriminator also generates a discriminated land mass output signal for land mass targets 3098A3 / 0S37 1319856 shows that the computer also responds to the discriminated land mass output signal, and that the display device _{displays the land mass target objects (407 f} 408) in contrast (Fig. 2, 3). 309843/0937 JJ Blank page