Methods of detection of air, space or submarine targets by reflection of electromagnetic or acoustic waves

Claim 3

A method of detection according to claim 1, comprising dividing the scanned area of space into range sectors and setting the transmission duration of the signal at each elevation and azimuth position of the aerial beam in accordance with the range of the corresponding sector, said transmission duration being sufficiently higher in relation to the greater range as to obtain an adequate probability of detection.

Claim 4

A method of detection according to claim 2, comprising, during the identification scanning, scanning with signals whose transmission durations corresponding to the different range sectors are longer than those signals used during the search scanning.

Claim 5

A method of detection according to claim 1, comprising scanning each range sector several times by the aerial beam, the number of scans becoming higher as the range increases.

Claim 6

A method of detection according to claim 4, comprising repeatedly scanning each range sector a greater number of times during the identification scanning than during the search scanning.

Claim 7

A method according to claim 1, for the case of a monitoring radar intended for air traffic control around an airport, with a space limited to 120* in azimuth, 20 km in altitude and 250 km in range, comprising scanning said space by means of a beam having an aperture of 2* and which is shifted discontinuously by increments of 2* in both azimuth and elevation.

Claim 8

A method according to claim 1, wherein the range sectors of increasing values successively scanned by the aerial beam are divided into range zones of 20 to 72 km, 72 to 96 km, 96 to 114 km, 114 to 126 km, 126 to 144 km, 144 to 210 km and 210 to 250 km, comprising scanning during the search scan once in the first two zones with a pulse duration of 10 microseconds and twice in the succeeding zones with pulse durations of 10 microseconds in the third zone, 15 microseconds in the fourth zone and 30 microseconds in the last four zones, and scanning during the identification scan, which does not take place in the first zone, six times in the second zone with a pulse duration of 10 microseconds and fourteen times in the succeeding zone, the pulse durations being 10 microseconds for the third zone, 15 microseconds for the fourth zone and 30 microseconds for the last three zones.

Claim 9

Apparatus for detection of air, space or submarine targets by reflection of electromagnetic or acoustic waves, by means of successive ''''search'''' and ''''identification'''' scanning operations, comprising: an operation control device including a clock for producing pulses with durations corresponding to various range sectors and a memory in which are stored the parameters relating to the scanning of said various range sectors, said parameters including at least one of the pulse duration, number of scans and the reception threshold values, a transmitter for receiving from said operation control device a transmission signal having a duration depending on the range, two transmission-elevation-azimuth recorders and two reception-elevation-azimuth recorders assigned respectively to a search scanning operation and to an identification scanning operation, and for receiving aerial beam change of position signals from said operation control device, said reception recorders being controlled with a delay, with respect to the corresponding transmission recorders, equal to the time-length of the return trip of the signal, and a range control device, said operation control device sending, at the end of the sequence of operations relating to one sector, an advance signal to the range control device, said range control device including a recorder of the range sectors and which itself transmits to the operation control device, at each step forward, binary number values of the range sector to be scanned which determine the values of the operating parameters which the operation control device in turn distributes to other parts of the apparatus to which it is connected.

Claim 10

Apparatus for detection of air, space or submarine targets by reflection of electromagnetic or acoustic waves, by means of successive ''''search'''' and ''''identification'''' scanning operations, comprising: an operation control device including a clock for producing pulses with durations corresponding to various range sectors and a memory in which are stored the parameters relating to the scanning of said various range sectors, said parameters including at least one of the pulse duration, number of scans and the reception threshold values, a transmitter for receiving from said operation control device a transmission signal having a duration depending on the range, two transmission-elevation-azimuth recorders and two reception-elevation-azimuth recorders assigned respectively to a search scanning operation and to an identification scanning operation, and for receiving aerial beam change of position signals from said operation control device, said reception recorders being controlled with a delay, with respect to the corresponding transmission recorders, equal to the time-length of the return trip of the signal, and a range control device, said operation control device sending, at the end of the sequence of operations relating to one sector, an advance signal to the range control device, said range control device including a recorder of the range sectors and which itself transmits to the operation control device, at each step forward, binary number values of the range sector to be scanned which determine the values of the operating parameters which the operation control device in turn distributes to other parts of the apparatus to which it is connected.

Claim 11

Apparatus according to claim 8, comprising: a transmission aerial phase control device coupled to and controlled by said two transmission-elevation-azimuth recorders, a reception aerial phase control device coupled to and controlled by said two reception-elevation-azimuth recorders, said recorders controlling said phase control devices in accordance with the signals they receive from said operation control device, an echo receiver coupled to said operation control device, a signal counter coupled to the output of said echo receiver, the output of said counter being coupled to the transmission identification recorder and to the reception identification recorder for indicating the presence of an echo signal during the search scanning operation after counting the echos above a given detection threshold, and a data processing device receiving during the identification scanning operation the output signal from said counter, said data processing device being further permanently connected to an output of said range control device.