Communications: directive radio wave systems and devices (e.g. – Determining velocity – Combined with determining distance and direction
Reexamination Certificate
2000-09-28
2003-09-09
Sotomayor, John B. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Determining velocity
Combined with determining distance and direction
C342S108000, C342S115000, C342S156000, C342S157000, C342S158000
Reexamination Certificate
active
06618002
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to HF radar.
It particularly relates to RF radar installations consisting of arrays of receive/transmit modules and to modules for use in such installations.
As depicted in
FIG. 1
, whereas microwave radar is generally limited to line-of-sight surveillance. HF radar allows “over-the-horizon” surveillance to be made.
It is the practice in HF radar to provide different antennas for transmission and reception.
FIGS. 2 and 3
depict an example of a prior art HF radar consisting of a transmitting antenna
20
, receiving, antenna
30
, RX/OPS cabin
32
, TX/OPS cabin
22
and generator
34
.
In order to provide the necessary directivity and radiation efficiency, the prior art HF radar utilises a transmitter antenna consisting of a conventional phased array. To obtain a satisfactory efficiency, the prior art has utilised relatively tall antennas so that the radiating elements are as high as possible. This has required the use of substantial bracing and/or substantial concrete foundations for each antenna element. To avoid excessive leakage of transmitted signal into the front end of the receiver, a discrete receiver antenna
30
is provided some distance from the transmit antenna array. The individual antenna elements of each array have also had to be disposed in accurate spatial relationship with each other. While this prior art arrangement has been found to be satisfactory in terms of its effectiveness as a radar, it does require the availability of a level site of substantial area and linear extent and the accurate spacing of the individual elements of the transmit antenna in particular. While such an arrangement may well be satisfactory for a permanent installation, it is not easily implementable as a mobile or temporary transportable installation which can be set up quickly on an unprepared site, or on poor, relatively weak, ground such as marshland or beaches. The present invention seeks to provide an arrangement in which the disadvantages of the prior art are at least ameliorated.
SUMMARY OF THE INVENTION
A first aspect of the invention provides a transmit/receive assembly for a HI radar apparatus, the transmit/receive assembly comprising a power transmitter for generating radio frequency signals, a receiver for receiving radio frequency signals and a duplexer arranged to couple the output of the power transmitter and the input of the radio receiver to a common port connection to a transmit/receive antenna.
A second aspect of the invention provides a transmit/receive antenna assembly comprising a transmit/receive assembly in accordance with the first aspect of the invention and an antenna.
A third aspect of the invention provides a HF radar comprising such transmit/receive assemblies or transmit/receive antenna assemblies.
REFERENCES:
patent: 3603992 (1971-09-01), Goggins, Jr. et al.
patent: 3836973 (1974-09-01), Shnitkin et al.
patent: 3898657 (1975-08-01), Jensen
patent: 4823136 (1989-04-01), Nathanson et al.
patent: 5160932 (1992-11-01), Bull
patent: 5257030 (1993-10-01), Aoki et al.
patent: 5952955 (1999-09-01), Kennedy et al.
patent: 0 172 094 (1986-02-01), None
patent: 2 302 990 (1997-02-01), None
“Experimental trials on non-Gaussian environmental noise mitigation for surface-wave over-the-horizon radar by adaptive antenna array processing”, Abramovich, Y.I, et al;Higher-Order Statistics, 1999. Procs. of the IEEE Sig. Proc'g Workshop on , p 340-344.*
“Reduction of interference by high power HF radar transmitters”, Topliss, R.J.; Maclean, A.B.; Wade, S.H.; Wright, P.D.; Parry J.L.; HF Radio Systems and Techniques, Seventh International Conference on (Conf. Publ.No. 441), Jul. 7-10, '97 p: 251-255.*
“Using sources of opportunity to compensate for receiver mismatch in HF arrays”, Fabrizio, G.A.; Gray, D.A.; Turley, M.D., Aerospace and Electronic Systems, IEEE Transactions on , vol.: 37 Issue: 1,Jan. 2001, p.(s): 310-316.*
“Parametric localisation of space-time distributed sources”, Fabrizio, G.A.; Gran, D.A.; Turley, M.D. Acoustics, Speech, and Signal Processing, 2000. ICASSP '00. Proceedings. 2000 IEEE International Conference on , vol.: 5 , 2000, p.(s) 3097 3100.*
“Adaptive cancellation of nonstationary interference in HF antenna arrays”, Fabrizio, G.A.; Abramovich, Y.I.; Anderson, S.J.; Gray, D.A.; Turley, M.D., Radar, Sonar and Navigation, IEE Proceedings—, vol.: 145 Issue: 1 Feb. 1998, p.(s): 19-24.*
“A new multibeam receiving equipment for the Valensole skywave HF radar: description and applications”, Six, M.; Parent, J.; Bourdillon, A.; Delloue, J.,Geoscience and Kemote Sensing, IEEE Transactions on, vol.: 34 Issue: 3, May 1996, p.(s): 708-719.*
Kingsley, S., and S. Quegan,Understanding radar systems, McGraw-Hill, 1992, See Fig. 1.1 on p. 3 and accompanyign description.
http://www.britannica.com, “Component parts of a radar system” and associated Fig. 3. See arrangement of transmitter/receiver and duplexer system.
http://www.gsoft.com.au/ionospheric.htm, “HF/VHF Ionospheric Radar Systems”, see description and block diagram of “standard radar system”. Note that such radar systems have been used for several years.
Alenia Marconi Systems Limited
Kirschstein et al.
Sotomayor John B.
LandOfFree
HF radar does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with HF radar, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and HF radar will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3025534