Patent GB-1313402-A (GB)
Title: System for avoiding the collision of a moving body with other object
IPC: G01S13/937
Filed: 1970-04-29
Abstract: 1313402 Radar TOKYO KEIKI SEIZOSHO CO Ltd 29 April 1970 [29 April 1969 (2)] 20611/70 Heading H4D A system for avoiding the collision of a moving body with other objects comprises means for storing information about the body and information obtained by radar observation about the other objects, means for displaying a first image picture indicative of present information, means for displaying a second image picture corresponding to one or more data of past information by reading out from the storing means, and means for superposing the two image pictures. The system further comprises means for replacing that part of said data of past information corresponding to the moving body with new data based on estimated information to form a trial image picture on said second displaying means. In this way, should a possibility of collision arise, a number of simulating operations may be performed, using information already stored, so that the safest course and/or speed to be adopted may be decided in advance. As described with reference to a ship's installation, a terminal 21, Fig. 3, is supplied with signals # 0 , V 0 , representing, respectively the ship's bow bearing and speed, and with signals D 0 , S 0 , T 0 , representing respectively the video output of the ship's radar, synchronizing signals, and trigger signals. The terminal 21 is coupled to a video tape recorder (VTR) 24 having three read-out terminals 23 1 , 23 2 , 23 3 , which are respectively delayed from present time by 2, 4, 6 minutes, and to a first display tube 22. The signal # 0 , which is only required when true bearing indication is used, is supplied to the tube 22 through a switch 29 0 . The readout D, S, T signals from the terminals 23 1 , 23 2 , 23 3  are coupled to respective display tubes 25 1 , 25 2 , 25 3 . The displays of the four tubes are superposed by means of three semi-transparent mirrors 26 1 , 26 2 , 26 3  which are disposed at 45 degrees in line with the tube 22 and reflect respectively from the tubes 25 1 , 25 2 , 25 3 . Signals relating to the ship's bow bearings # 1 , # 2 , # 3  at - 2 min., - 4 min., - 6 min. from present time may also be supplied to the tubes 25 1 , 25 2 , 25 3  through switches 29 1 , 29 2 , 29 3 , which are interlocked with the switch 29 0 , when true bearing indication is used. The signal representative of V 1  (ship's speed at - 2 min.) consists of an amplitude modulated 400 Hz carrierwhich is applied across a chain of resistors in a multiplier 271. The signal representative of # 1  (ship's bow bearing at - 2 min.) is in the form of a pulse modulated wave having a positive or negative polarity in order that there may be detected one pulse each time the bow bearing is deflected, e.g. by 0À1 degrees, thereby distinguishing displacement to the right from that to the left. This signal after amplification and rectification is applied to a pulse motor, which is mechanically coupled to the rotor of a resolver 28 1 . The whole of the V 1  signal (or a proportion thereof, if representation at a smaller interval than 2 mins. is required) is selected by switching means (Fig. 4, not shown), is amplified, and is applied to the stator of the resolver 28 1 . The sine and co-sine outputs of the resolver 281 are connected to first input terminals of respective summing circuits whose outputs, after amplification and rectification, are coupled through switches 32 1  to the deflection means 33 1  of the display tube 25 1 . When the switches 32 1  are closed, and the only inputs to the said summing circuits arise from the resolver 281, the display tube 251 shows the actual situation at the first time interval before the present. However, for simulation purposes, trial signals # P1 , V P1  may be applied to a resolver 31 1 , with a multiplier 30 1 , providing outputs applicable through switches 34 1  to second input terminals of the aforesaid summing circuits. As regards the display tube 25 2 , a resolver 28 2 , with a multiplier 27 2 , receives signals # 2 , V 2  relating to the ships bearing and speed at - 4 min., and provides outputs which are summed with those from the resolver 28 1  before application to first input terminals of summing circuits similar to those associated with the display tube 251. Similarly, a resolver 31 2 , with a multiplier 30 2  receives simulation signals # P2 , V P2  and provides outputs which are summed with those from the resolver 31 1  before application through switches 34 2  to second input terminals of said summing circuits. A similar arrangement applies in respect of the display tube 25 3 , signals from the resolvers 28 2 , 31 3  being combined with signals from resolvers 28 3 , 31 3  which are respectively fed with (# 3 , V 3 ) and (# P3 , V P3 ) signals. The displays upon the various tubes may be individually adjusted as regards contrast, brightness and focus, and a suitable circuit is described (Fig. 6, not shown). In a second embodiment, instead of having a display tube for each image, as in the first embodiment, a multigun tube with a deflection system for each tube is used (Fig. 7, not shown). In a third embodiment, the means for storing information is a photographic film for recording pictures photographed by a camera from a radar image indicating tube. The film travels between feed and take-up reels and a plurality of projectors spaced therealong superpose timedisplaced images upon a common screen (Fig. 8, not shown). A fourth embodiment is similar to the third embodiment, but utilizes electrographic, instead of photographic, film and apparatus (Fig. 9, not shown). In a fifth embodiment a scan converter tube, which combines a write-in radar information indicating tube and a read-out tube with TV type scan, generates video signals which are recorded on tape. The tape is drawn through a plurality of spaced apart reproducers which operate respective TV receivers, whose images are projected upon a common screen (Fig. 10, not shown).