公开(公告)号：JPH11118919A

公开(公告)日：1999-04-30

申请号：JP29487397

申请日：1997-10-13

Applicant: NEC CORP

Inventor： YAMASHITA JUNJI

IPC: G01S7/285 ,  G01S7/36 ,  G01S13/44

Abstract: PROBLEM TO BE SOLVED: To accurately measure an elevation angle of a target without affected by a reflection wave due to multipass. SOLUTION: When measuring angle of a target of low elevation angle subjected to multipass, two aerial wire patterns in axial symmetry about a beam center of an aerial wire 1 are formed for obtaining an elevation angle of the target. A mean value of the obtained elevation angle of the target and that of multipass reflection wave is calculated, and the beam center of the aerial wire is directed in the elevation angle direction of the obtained mean value for stably measuring target's elevation angle.

公开(公告)号：JPH0634745A

公开(公告)日：1994-02-10

申请号：JP18775192

申请日：1992-07-15

Applicant: NEC CORP

Inventor： YAMASHITA JUNJI

IPC: G01S7/02 ,  G01S13/74

Abstract: PURPOSE:To increase the separating and discriminating capacity in the azimuth on an approacing aircraft without enlarging the antenna aperture diameter of secondary surveillance radar equipment. CONSTITUTION:In a P1/P3 pulse generator 2, which generates interrogative signals, i.e., P1, P3 pulses, which are sent from a secondary surveillance radar device on the ground to a transponder on a plane, an angle signal data theta1, which is supplied from an angle signal generator 1, is sent to an electronic scanning antenna 3, being made correspond to the P1 pulse. Meanwhile, P3 pulse is sent to the electronic scanning antenna 3, being made correspond to the angle signal data theta2. In the electronic scanning antenna 3, a p1-pulse-based, P1 sending pattern in the direction of theta1 and a P3-pulse-based, P3 sending pattern in the direction of theta2 are sent in such a manner that the part of the patterns are spatially overlapped with each other, so that reception of P1, P3 pulses, which is necessary to send an answer signal, becomes possible. Thus, it becomes possible to send an effectively sharp interrogative signal. In this case, theta1 and theta2 are set in such a manner that both form a spatially overlapping range.

公开(公告)号：JPH06347546A

公开(公告)日：1994-12-22

申请号：JP16390593

申请日：1993-06-08

Applicant: NEC CORP

Inventor： YAMASHITA JUNJI

IPC: G01S13/95

Abstract: PURPOSE:To provide a radar device for weather conditions which can extract the altitude distribution of weather conditions information by utilizing radar used for aircraft control. CONSTITUTION:An exclusive station having an antenna 3 with fan beam characteristics having a wide beam width in elevation angle is installed at a position away from a radar device for aircraft control and receives reflection waves from a weather clutter 7. The time change of the level of a signal received in this layout corresponds to the change in altitude of weather clutter intensity. The position in the air of the target weather clutter 7 is calculated from beam directions theta1 and theta2 of two antennas 1 and 3 and the lapse of time t until signal reception and then it is allowed to correspond to the signal reception level, thus obtaining the altitude distribution of weather conditions information.

公开(公告)号：JPH03239980A

公开(公告)日：1991-10-25

申请号：JP3889790

申请日：1990-02-19

Applicant: NEC CORP

Inventor： YAMASHITA JUNJI

IPC: G01S7/02 ,  G01S7/36 ,  G01S13/76

Abstract: PURPOSE:To suppress the forgery by comparing whether receiving signal levels of a question antenna and a forgery suppressing antenna are high or low, and inhibiting the passing of a question antenna receiving signal, in the case the receiving signal level of the forgery suppressing antenna is higher. CONSTITUTION:A question antenna pattern is formed by a fact that a radio wave excited by a question antenna feeding device 4 is reradiated by a reflecting plate 3. Signals received by this question antenna, a side lobe antenna 1 and a forgery suppressing antenna 2 are amplified and detected by receivers 5 - 7, respectively, and a large/small relation is decided by level comparators 8, 9. In such a state, in the case a side lobe suppressing antenna receiving signal level or a forgery suppressing antenna receiving signal is higher than a question antenna receiving signal level, outputs of the comparators 8, 9 become a logical value '1'. Subsequently, the outputs of the comparators 8, 9 are added by an OR gate 10, and when the outputs of the comparators 8, 9 are '1', an output of the gate 10 becomes '1', an inhibiting gate 11 is controlled, and an output of a question antenna receiving signal is inhibited. Accordingly, forgery can be suppressed.

公开(公告)号：JPS6353479A

公开(公告)日：1988-03-07

申请号：JP19838586

申请日：1986-08-25

Applicant: NEC CORP

Inventor： HORIGUCHI KOICHI ,  YAMASHITA JUNJI ,  HASEGAWA MASANOBU ,  HASHIMOTO MOTOHIRO

IPC: G01S7/14

Abstract: PURPOSE:To perform a highly accurate monitoring by displaying a magnified expected arbitrary bearing range and displaying reduced the other bearing range. CONSTITUTION:An arbitrary display magnification ratio K(>1) and a bearing angle range theta1-theta2 desired to be magnified are inputted to a computer 7 is advance. Based on inputs thus inputted, a calculator 71 calculates a reduction ratio (k) outside the range. A calculator 72 calculates display angles corresponding to angles in a real space in accordance with (k), K and the bearing angle range theta1-theta2 to feed the display angles to a RAM 8. An operation process is executed off line. The contact of a changeover device 9 is connected to the side of a counter 1 by a calculation termination signal, a counter output is fed to the RAM 8 and the output of the RAM 8 is fed to a ROM 2 to produce sweep saw-tooth-like waves 5a and 6a. This structure enables the inside of the magnified specific range to be monitored and controlled with a high accuracy and no target outside the range is missed.

公开(公告)号：JPH04161881A

公开(公告)日：1992-06-05

申请号：JP28971490

申请日：1990-10-25

Applicant: NEC CORP

Inventor： YAMASHITA JUNJI

IPC: G01S13/78

Abstract: PURPOSE:To improve a degree of renewal of SSR data by sending a plurality of question modes by the aid of time division so as not to overlap responses from a plurality of airplanes in next questions after the positions of the flying airplanes are detected. CONSTITUTION:After the recovery time of transponders mounted in airplanes is delayed with the use of delay circuits 6, mode 2 question signals are composed with mode C question signals with the use of a composer 7. A switch 5 changes over the output of a mode A question signal generator 1 and the question signal of the output of the composer 5 on the basis of a control signal from a switch controller 4. In the first sweep the question of the mode A alone is performed in the same way as the conventional and a response signal is received after Ta late alone from the question signal to detect concord. In second sweep, it is continuously transmitted at intervals of the question signal Td of the mode C and the mode 2. And the information of the mode C and the mode 2 can be simultaneously obtained by judging these signals the response from the same airplane.

公开(公告)号：JPH02198381A

公开(公告)日：1990-08-06

申请号：JP1902589

申请日：1989-01-26

Applicant: NEC CORP

Inventor： YAMASHITA JUNJI

IPC: G01S13/76 ,  G01S13/78

Abstract: PURPOSE:To remove garble by controlling the transmitting timing of a question signal sent to a transponder mounted in an air plane entering an air port from a plurality of secondary monitoring radar stations thereby to form the selected question area. CONSTITUTION:At a first step, question signals 201 and 301 are sent out through a question signal antenna respectively by secondary monitoring radars SSR2 and SSR3. Moreover, a transponder suppressing signal 401 is transmitted by an SSR4 while the transmitting timing is controlled by a transmission timing controlling circuit. In this state, an entering air plane 4 is enclosed by a suppressing area 15 and the area except the area 15 is a responding area 16. In the next place, a transponder mounted in the entering air plane within the area 15 is released from the inoperative condition, thereby resuming the operation. The SSRs 2 and 3 send transponder suppressing signals 202 and 302, and the SSR1 generates a question signal 101 prior to the transmitting timing of the signals 202 and 302. A responding area 19 is spatially overlapped with a transponder operating area 20, thus forming a selected question area 21 designated by double frames.

公开(公告)号：JPH02173587A

公开(公告)日：1990-07-05

申请号：JP32991888

申请日：1988-12-27

Applicant: NEC CORP

Inventor： YAMASHITA JUNJI

IPC: G01S13/76

Abstract: PURPOSE:To obtain the equipment which can suppress the generation of a false image even against an aircraft positioned in a long distance by switching a question signal consisting of two pulses and a transponder suppressing signal for suppressing the receiving sensitivity, based on a transmission switching control signal. CONSTITUTION:A question signal generator 12 generates a question signal consisting of two pulses. A transponder suppressing signal generator 13 generates a transponder suppressing signal for bringing the receiving sensitivity of the transponder to suppression control. A transmitter 10 inputs the question signal and the transponder suppressing signal, switches the question signal and the transponder suppressing signal, based on a transmission switching control signal, generates a transmitting signal and outputs it to an electronic scanning antenna 9. In this state, when a main beam of the antenna 9 emits a transmitting signal of a first pulse question signal toward the azimuth direction of a current reflecting object which becomes a factor for generating a false image, a controller 15 executes a beam scanning control so as to turn the main beam in the azimuth direction of an aircraft for receiving a reflected wave reflected by a radio wave reflecting object, and also, executes a transmission switching control so as to emit a transmitting signal of the transponder suppressing signal.

公开(公告)号：JPS6319578A

公开(公告)日：1988-01-27

申请号：JP16331986

申请日：1986-07-11

Applicant: NEC CORP

Inventor： HASHIMOTO MUKOU ,  HORIGUCHI KOICHI ,  YAMASHITA JUNJI ,  HASEGAWA MASANOBU

IPC: G01S7/22

Abstract: PURPOSE:To attain highly accurate supervisory and to attain also sure supervisory for a far distance object by simultaneously displaying plural videos with different range scales. CONSTITUTION:A SIN/COS generator 11 generates signals corresponding to the deflecting signal components of the X and Y directions of a CRT and shifting respective phases by 90 deg. each other as a SIN wave and a COS wave. The generator 11 generates the SIN and COS data relating to respective angles of a directional angle signal 6 based on a prescribed bearing resolution by using a real north signal 7 obtained from a radar device body as a time reference and supplies SIN and COS wave components 11a, 11b respectively to sweep generators 12, 13. A range switch 19 determines a prescribed expansion range in a prescribed bearing range based on a signal outputted from a bearing/range selector 10. The selector 10 is specified at its sweeping range in a prescribed bearing position and its range based on the signals 6, 7 and a bearing/range setting signal 5 and switches full range sweep and range expansion sweep by controlling the switch 19. Thereby, only a necessary bearing range can be expanded to attain highly accurate supervisory and a far distance object also can be surely supervised.

公开(公告)号：JPS62169071A

公开(公告)日：1987-07-25

申请号：JP1143586

申请日：1986-01-22

Applicant: NEC CORP

Inventor： YAMASHITA JUNJI

IPC: G01S7/02 ,  G01S7/36 ,  G01S13/528

Abstract: PURPOSE:To remove the generation of a bearing jitter by synchronizing the rotation of an antenna and the timing of transmitted pulse generation with each other. CONSTITUTION:A frequency divider 1 divides the frequency of the azimuth change pulses ACP from an antenna driving apparatus based on a reference pulse ARP indicative of a specific bearing (for example, the north) to make sector signals for every constant bearing angle range. A leading edge/trailing edge detecting circuit 2 detects the edges of the sector signals and outputs them via an OR gate 6 as the part of transmitting triggers. A data selector 3 selects a pulse repeating period T1 at an odd number'th sector and a period T2 at in on an even number'th sector. A counter 4 set every transmission trigger counts range clocks and a coincidence circuit 5 produces an output every time when the value of counted range clocks coincides with the period selected by the selector 3. The last-said output is outputted via the OR gate 6 as transmission triggers. Then, since pulses T1 or T2 with a determined period are generated in the sectors in synchronism with the bearing of an antenna, no bearing jitter is generated.