Communications: directive radio wave systems and devices (e.g. – Testing or calibrating of radar system – By monitoring
Reexamination Certificate
2002-12-18
2004-03-23
Sotomayor, John B. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Testing or calibrating of radar system
By monitoring
C342S169000
Reexamination Certificate
active
06710737
ABSTRACT:
BACKGROUND OF THE INVENTION
FIG. 1
shows a scheme for testing a radar. In this scheme, a radar target simulator system
10
is located a distance r from a radar under test (RUT)
12
, and is used to generate an apparent target
14
that is located a greater distance R from radar
12
. The characteristics of the simulated target, such as delay and radar cross section (RCS), are established by the simulator so that the performance and functionality of the RUT can be verified. Radar target simulators can be designed for a specific radar to be tested or can be designed for use with the testing of many different types of radars. Examples of the latter of these can be found in U.S. Pat. No. 5,223,840 and in the article titled
Universal Radar Moving Target Transponder
, presented at the IEEE 1996 National Radar Conference, Ann Arbor, Mich., May 13-16, 1996. Both of these publications are incorporated by reference herein.
To verify that the RUT is functioning properly, it is necessary that the target simulator equipment used to test it be accurately calibrated. Calibrating a radar target simulator requires knowing the gain and delay through the simulator, including all of its components such as the radar target generator and its associated antennas and transmission cables.
In many radar test configurations, the simulator will use antennas that are located a significant distance from its accompanying radar target generator
16
. These antennas, shown as elements
18
and
20
in
FIG. 1
, and the associated cables, elements
24
and
26
, may even be in locations that are difficult to physically access, such as on towers or rooftops.
Traditionally, calibration of the simulator for gain and delay are performed in two distinct operations.
While it is easy to measure the gain of the radar target generator itself (from its input to output), ascertaining the gain associated with the transmission cables running from the target generator to its antennas can be problematic. This is particularly true when sections of the receive and transmit cables running to and from the antennas are changed over the course of time, requiring ideally that separate gain measurements be made for the target generator and for the cables. An even greater challenge is measurement of the receive and transmit antennas gains themselves. Vendor-provided specifications of antenna gain are frequently subject to significant errors. Though archived measurements can be useful, they often must be fitted/interpolated for the particular frequency of each RUT. Additionally, archived values can change over time as an antenna degrades. Thus the over-all determination of the parameters which enter into the gain calibration of a radar target simulator is a fragmented process, not integrated into a single measurement.
Determining the over-all delay through a radar target simulator is also desirable in order to properly calibrate the simulator. Traditional measurements of over-all delay are subject to some of the same problems as gain measurement such as the inaccessibility of cables and use of a fragmented measurement process.
SUMMARY OF THE INVENTION
An apparatus and process makes it possible to quickly and accurately determine an equivalent for the RCS and range delay of a signal provided by a radar target simulator system. This calibration process considers the gain and delays associated with a radar target generator, the receive and transmit antennas associated with the generator, and the receive and transmit cables going to and from the generator to the receive and transmit antennas, respectively. Accurately determining gain and delay through the radar target simulator system permits the simulator to provide a well-calibrated RCS and range for radars it is testing and calibrating.
An object of this invention is to provide a calibrator for a radar target simulator that permits the over-all gain of the simulator to be determined.
Another object of this invention is to provide a calibrator for a radar target simulator that permits the RCS of a simulator signal as received by a RUT to be determined.
A further object of this invention is to provide a calibrator for a radar target simulator that permits the over-all delay through the simulator to be determined.
REFERENCES:
patent: 3169244 (1965-02-01), Scribner et al.
patent: 3323123 (1967-05-01), Hegarty et al.
patent: 3641574 (1972-02-01), Douglas
patent: 3683381 (1972-08-01), Strenglein
patent: 3792475 (1974-02-01), Smetana
patent: 3898662 (1975-08-01), Hom et al.
patent: 3903521 (1975-09-01), Jensen et al.
patent: 4168502 (1979-09-01), Susie
patent: 4195300 (1980-03-01), Gouley
patent: 4644357 (1987-02-01), Schaaf et al.
patent: 4982196 (1991-01-01), Thomas et al.
patent: 5164734 (1992-11-01), Fredericks et al.
patent: 5223840 (1993-06-01), Cronyn
patent: 5351054 (1994-09-01), Fredericks et al.
patent: 5359331 (1994-10-01), Adler
patent: 5457463 (1995-10-01), Vencel et al.
patent: 5493304 (1996-02-01), Lee et al.
patent: 5818384 (1998-10-01), Nishri
patent: 5870055 (1999-02-01), Kim
“A new direct millimeter wave six-port receiver”, Tatu, S.O.; Moldovan, E.; Ke Wu; Bosisio, R.G.; Microwave Symposium Diges 2001 IEEE MTT-S International, Vol: 3, May 20-25, 2001 Page(s): 1809-1812.*
“Universal eight-port RC network”, Vrba, K.; Cajka, J.; Lattenberg, I.; Electronics, Circuits and Systems, 1999. Proceedings of ICECS '99. The 6th IEEEInt'l Conf. on, Vol: 3, Sep. 5-8, 1999 Ps: 1317-1320.*
“A mature mixed-mode simulator”, Sullivan, S.K.; Circuits and Systems, 1989., IEEE International Symposium on, May 8-11, 1989 Page(s): 689-692 vol. 1.*
Cronyn, Will et al.; Universal Radar Moving Target Transponder; I.E.E.E, 1996, USA.
Cameron Andrew J.
Kagan Michael A.
Lipovsky Peter A.
Sotomayor John B.
The United States of America as represented by the Secretary of
LandOfFree
Calibrator for radar target simulator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Calibrator for radar target simulator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Calibrator for radar target simulator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3261949