Communications: directive radio wave systems and devices (e.g. – Combined with diverse type radiant energy system – With television
Reexamination Certificate
1997-02-14
2001-10-09
Lobo, Ian J. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Combined with diverse type radiant energy system
With television
Reexamination Certificate
active
06300895
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of discreet radar detection as well as a system for the implementation of this method.
Multistatic radar systems have many advantages, notably as regards:
the discretion of the reception stations which are entirely passive and therefore practically invulnerable to electronic warfare means;
the possibility of detecting targets which, since they are seen at angles different from those that they present for standard monostatic radars, find it difficult to remain discreet;
the capacity to operate in an environment of clutter and the possibility of implementing waveforms with high repetition frequency.
However, these systems require the laying out of a network of stations. This makes them expensive.
2. Description of the Prior Art
It has therefore become necessary to use stations that are already set up and normally designed for another use but can easily be adapted to radar use. Thus, it has been proposed (H. D. Griffiths, N.R.W. Long, “Television based bistatic radar”, IEE Proceedings, Vol. 133, No. 7, December 1986), to use stations that broadcast analog television signals of the PAL, SECAM or NTSC type to detect airborne targets. This has proved to be difficult to implement. The authors of the above-mentioned article have then proposed the use of waveforms based on the standard pulsed transmissions of radars. However, this approach is limited by the operating constraints of television broadcasting transmitters, which are not compatible with pulsed signals such as those of standard radars.
SUMMARY OF THE INVENTION
An object of the present invention is a method and a system of discreet radar detection preferably using an existing network of transmission and reception stations that is dense enough to provide for sufficient radar coverage of the geographical zone monitored, given the transmission power in radar use that may be provided by the transmission stations, the modifications made to the existing network being as simple as possible in their implementation while at the same time enabling the setting up of a multistatic system with performance characteristic similar to those of standard multistatic systems. Should a network be created, it should be as inexpensive as possible while at the same time providing for efficient radar coverage of the zone to be monitored and a high degree of discretion. In the event of application to a monostatic radar, it should be capable of providing for radar detection as efficient as that of standard radar, with improved discretion.
The method according to the invention consists, at transmission, in producing an encoded waveform from a multicarrier signal repeated on at least N periods and, at reception, in carrying out a matched filtering operation on an integration time of N periods, N being preferably greater than ten, and being possibly equal to one for a monostatic radar. N determines the Doppler selectivity.
The radar detection system according to the invention comprises at least one transmitter and at least one receiver, the transmitter comprising a multicarrier encoded wave generator, the receiver comprising at least one distance gate processing stage, advantageously complemented by a Doppler gate processing stage.
REFERENCES:
patent: 4041489 (1977-08-01), Lewis
patent: 4450444 (1984-05-01), Wehner et al.
patent: 4622555 (1986-11-01), Doggett et al.
patent: 4851848 (1989-07-01), Wehner
patent: 4972194 (1990-11-01), Carrara et al.
patent: 5021782 (1991-06-01), Perron et al.
patent: 5113193 (1992-05-01), Powell et al.
patent: 5140621 (1992-08-01), Perron et al.
patent: 5202760 (1993-04-01), Tourtier et al.
patent: 5278915 (1994-01-01), Chupeau et al.
patent: 5291289 (1994-03-01), Hulyalkar et al.
patent: 5361072 (1994-11-01), Barrick et al.
patent: 5481270 (1996-01-01), Urkowitz et al.
Hershey et al, “An Adjunct Tracking System for Low Altitude Sector Aircraft”, IEEE Transactions on Broadcasting, vol. 40, No. 1, Mar. 1994.*
Patent Abstract of Japan, vol. 13, No. 57 (P-825) Feb. 9, 1989 & JP-A-63 247 682 (Tech. Res. & Dev. Inst. of Japan Def. Agency) Oct. 14, 1988.
I.E.E. Proceedings, vol. 133-F, No. 7, Dec. 1986, pp. 649-657, Griffiths et al. “Television-Based Bistatic Radar”.
Carrara Bruno
Pecot Michel
Tourtier Philippe
"Thomson-CSF"
Lobo Ian J.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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