Active signalling systems
First Claim
1. A signalling system for detecting targets in a given medium, comprising:
- means for generating and transmitting in said given medium a time-frequency wave packet which is the complex (phase) conjugate of the impulse response of the combined medium and target, andmeans for solving the wave equation for transmissions through said medium, reflectance from said target and transmission back through said medium.
1 Assignment
0 Petitions
Accused Products
Abstract
A signalling system in time-frequency space for detecting targets in the presence of clutter and for penetrating media, includes a transmitter antenna system, receiver and processor system. The transmitter antenna system generates and launches into a medium containing the targets an energy pulse (wave packet) having a predetermined duration and frequency characteristic, and which energy pulse matches at least one of the following: 1) the time-frequency reflection characteristics of the target(s) but not the clutter, or 2) the penetration time-frequency dielectric window of the medium, or 3) the time-frequency characteristics of the window of the receiver. Preferably, the time-frequency wave packet is the complex conjugate of the impulse response of the combined medium and target.
The processor solves the wave equation for transmissions through the medium, reflectance from the target(s) and transmission back through the medium and causes a match of the generated wave packet signals to both the medium and target for maximum propagation through the medium and reflectance from the target, the wave packet match to the medium and the target being with respect to both time and frequency response characteristics.
125 Citations
22 Claims
-
1. A signalling system for detecting targets in a given medium, comprising:
-
means for generating and transmitting in said given medium a time-frequency wave packet which is the complex (phase) conjugate of the impulse response of the combined medium and target, and means for solving the wave equation for transmissions through said medium, reflectance from said target and transmission back through said medium. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 14)
-
-
10. A signalling method for detecting targets in a given medium, comprising:
-
generating and transmitting in said given medium a time-frequency wave packet which is the complex (phase) conjugate of the impulse response of the combined medium and target, and solving the wave equation for transmissions through said medium, reflectance from said target and transmission back through said medium. - View Dependent Claims (11, 12)
-
-
13. Signalling system in time-frequency space for detecting a target in the presence of clutter and for penetrating media, comprising:
-
transmitter antenna means, receiver and processor means, said transmitter antenna means having means for generating and launching into a medium containing said target an energy pulse (wave packet) having a predetermined duration and frequency characteristic, and which energy pulse matches one of the following; 1) the time-frequency reflection characteristics of said target but not said clutter, or 2) the penetration time-frequency dielectric window of said medium, or 3) the time-frequency characteristics of the window of said receiver.
-
-
15. A time-frequency space signalling method for and launching into a medium containing a target wave packets having a predetermined duration and frequency characteristic, and in which the wave packets match at east one of the following:
-
1) the time-frequency reflection characteristics of said target but not said clutter, or 2) the penetration time-frequency dielectric window of said medium, or 3) the time-frequency characteristics of the window of said receiver.
-
- 16. A method of analyzing wave packet transmissive solid media, comprising generating and launching a time frequency wave packet into said solid media and causing said wave packet to match the penetration time-frequency dielectric window of said solid media.
-
18. A method of enhancing the radar cross-section of a target when using an impulse radar system, said method comprising the steps of:
-
transmitting a pilot impulse radar pulse at a target, said pilot impulse radar pulse comprising a pulse of duration shorter than the target length and generated by an impulse radar system, receiving a return pulse from the target, which return pulse provides information indicative of scattering centers on the target, and wherein the return pulse is used as a calibration signal, processing the calibration signal corresponding to the return pulse to form a phase conjugated transmit pulse, and transmitting the phase conjugated transmit pulse at the target, processing a target return signal derived from the transmitted phase conjugated pulse, and wherein the target return signal derived from the transmitted phase conjugated pulse has an enhanced radar cross-section of the target since the waveform of the transmitted phase conjugated pulse is matched to the characteristics of the target. - View Dependent Claims (19)
-
-
20. An impulse radar system comprising:
-
a transmitter for transmitting a pilot impulse radar pulse at a target, which pilot pulse comprises a pulse of a duration shorter than the target length, a receiver for receiving a return impulse radar pulse from the target, which return pulse provides information indicative of scattering centers on the target, which return pulse provides a calibration signal, and processing means coupled to the transmitter and receiver for processing the calibration signal corresponding to the return impulse radar pulse to form a phase conjugate impulse radar pulse, wherein the transmitter is adapted to transmit the phase conjugate pulse at the target, and wherein the receiver is adapted to process a target return signal derived from the transmitted phase conjugate pulse, and wherein the target return signal derived from the transmitted phase conjugated pulse enhances the radar cross-section of the target since the waveform of the transmitted phase conjugated pulse is matched to the characteristics of the target. - View Dependent Claims (21)
-
-
22. An impulse radar system comprising:
-
a transmitter for transmitting impulse radar pulses at a target, wherein said transmitter comprises means for generating a search pulse having a duration shorter than the target length, a receiver for receiving return pulses from the target, which return pulses provide information indicative of scattering centers on the target, and processing means coupled to the transmitter and receiver for processing the return pulses and for adaptively adjusting the phase of the transmitted pulses that are transmitted at the target in response to the return pulses in such a manner as to cause the radar cross-section contributed by the backward traveling wave on the target to be made to add in phase in the received direction, and wherein the transmitter transmits the pulses having adaptively adjusted phases at the target, and wherein the receiver sums the spectral components comprising return pulses derived from the transmitted pulses having adjusted phases to increase the radar cross-section of the target.
-
Specification