Method and apparatus for identifying, locating, tracking, or communicating with remote objects

Apparatus for determining an azimuth of a remote object from a base platform using broadband signals, the remote object being spaced from the base platform, the apparatus comprising:

• a transmitter device, located at the remote object, said transmitter device including
• a first waveform storage device that stores information characterizing a plurality of first broadband signals, such characterization including a prescribed signal transmission time for each first broadband signal,
• a plurality of broadband transmitter antennas arranged in an array of a prescribed geometry, and
• a broadband transmitter element configured to simultaneously radiate a one of the plurality of first broadband signals over each of said plurality of broadband transmitter antennas, in accordance with said stored information;
• a receiver device located at the base platform, the receiver device including
• a second waveform storage device that stores information characterizing one or more of a plurality of second broadband signals, including the prescribed signal transmission time for each of the one or more of the plurality of second broadband signal,
• a broadband receiver antenna that is capable of receiving electromagnetic radiation corresponding to the one or more of the plurality of first broadband signals radiated over said plurality of broadband transmitter antennas,
• a broadband receiver element configured to receive and process the electromagnetic radiation from said broadband receiver antenna, thereby producing a first output signal, and
• a digital signal processing correlator configured to correlate the output signal with the one or more of the plurality of second broadband signals characterized by the information stored within the second waveform storage device, the digital signal processing correlator outputs a correlation output that is used to derive a time of arrival of each of the one or more of the plurality of first broadband signals that is radiated by the plurality of broadband transmitter antennas;
• and
• a processing device that computes said azimuth based upon the prescribed geometry and the time of arrival differences of each of the one or more of the plurality of first broadband signals as determined by said correlation detector.

Apparatus for determining the azimuth of a remote object from a base platform using broadband signals, the remote object being spaced from the base platform, the apparatus comprising:

• a transmitter device, located at the remote object, said transmitter device including
• a first waveform storage device that stores information characterizing a broadband signal, such characterization including a prescribed signal transmission time,
• a broadband transmitter antenna, and
• a broadband transmitter element configured to radiate the broadband signal over said broadband transmitter antenna, in accordance with said stored information,
• a receiver device located at the base platform, the first receiver device including
• a second waveform storage device that stores information characterizing the broadband signal, including the prescribed signal transmission time,
• a plurality of broadband receiver antennas, arranged in an array of a prescribed geometry, that are capable of receiving electromagnetic radiation corresponding to the broadband signal radiated from said broadband transmitter antenna,
• a broadband receiver element configured to receive and process the electromagnetic radiation from each of said plurality of broadband receiver antennas, thereby producing a conditioned signal, and
• a multi-channel correlation detector configured to synchronously correlate the conditioned signal with the broadband signal characterized by the information stored within the second waveform storage device, the multi-channel correlation detector outputs a correlation output that is used to derive a time of arrival of the radiated broadband signal at each of the plurality of broadband receiver antennas;
• and
• a processing device that computes said azimuth based upon the prescribed geometry and the time of arrival differences of the broadband signal being received at each of the plurality of broadband receiver antennas as determined by said multi-channel correlation detector.

Apparatus for determining a location and a clock error of a remote object from a plurality of base platforms using broadband signals, the remote object being spaced from the plurality of base platforms, the apparatus comprising:

• a transmitter device, located at the remote object, said transmitter device including
• a first waveform storage device that stores information characterizing a broadband signal, such characterization including a prescribed signal transmission time,
• a broadband transmitter antenna, and
• a broadband transmitter element configured to radiate the broadband signal over said broadband transmitter antenna, in accordance with said stored information,
• a receiver device located at each of the plurality of base platforms, each receiver device including,
• a second waveform storage device that stores information characterizing the broadband signal, including the prescribed signal transmission time,
• a broadband receiver antenna that receives electromagnetic radiation corresponding to the broadband signal radiated from said broadband transmitter antenna, and
• a broadband receiver element that receives and processes the electromagnetic radiation from the broadband receiver antenna, thereby producing a conditioned signal;
• a correlation detector configured to synchronously correlate the conditioned signal with the broadband signal characterized by the information stored within the second waveform storage device, the correlation detector outputs a correlation output,
• a first processing device, responsive to the correlation output, for deriving a time of arrival of the radiated broadband signal at the broadband receiver antenna and a location of the broadband receiver antenna at the time of arrival;
• and
• a communication device for sending the time of arrival and the location of the broadband receiver antenna at the time of arrival;
• and
• a second processing device that computes said location and said clock error based upon the locations of the broadband receiver antenna and the time of arrival of the broadband signal being received at the plurality of broadband receiver antennas.

A method for communicating a prescribed broadband signal from a remote object to a first base platform, the remote object being spaced from the first base platform, the method comprising:

• transmitting the prescribed broadband signal from the remote object by
• storing information that characterizes the prescribed broadband signal, including a prescribed signal transmission time,
• maintaining a first settable time reference, and
• radiating the prescribed broadband signal in accordance with the stored information and the first time reference;
• receiving the transmitted, prescribed broadband signal at the first base platform by
• storing information characterizing the prescribed broadband signal, including the prescribed signal transmission time,
• receiving and processing electromagnetic radiation, to produce a first output signal,
• maintaining a second settable time reference, and
• correlating the first output signal with the prescribed broadband signal characterized by the information stored at the first base platform, and producing a first correlation output;
• and
• computing, based upon the first correlation output, a first apparent arrival time of the transmitted, prescribed broadband signal relative to the second time reference.

A method for determining an azimuth of a remote object from a base platform using broadband signals, the remote object being spaced from the base platform, the method comprising:

• transmitting multiple copies of a prescribed broadband signal at the remote object, including
• storing information in a first waveform storage device that characterizes the prescribed broadband signal, including a prescribed signal transmission time,
• providing a plurality of broadband transmitter antennas arranged in an array of a prescribed geometry,
• radiating the multiple copies of the prescribed broadband signal simultaneously over said plurality of broadband transmitter antennas;
• receiving the radiated multiple copies of the prescribed broadband signal at the base platform, including
• storing information in a second waveform storage device that characterizes the prescribed broadband signal, including the prescribed signal transmission time,
• providing a broadband receiver antenna that receives electromagnetic radiation from the plurality of broadband transmission antennas,
• receiving and processing the electromagnetic radiation from said broadband receiver antenna, to produce a conditioned signal for each of said radiated multiple copies of the prescribed broadband signal, and
• correlating the conditioned signal with the prescribed broadband signal characterized by the information stored within the second waveform storage device, to produce a correlation output that can be used to compute the time of arrival for each of the multiple copies of the prescribed broadband signal with respect to said second time reference;
• and
• computing the azimuth based upon the prescribed geometry and the time difference of arrival of the multiple copies of the prescribed broadband signal transmitted from the plurality of broadband transmitter antennas.

A method for determining the azimuth of a remote object from a base platform using a prescribed broadband signal, the remote object being spaced from the base platform, the method comprising:

• transmitting the prescribed broadband signal at the remote object by
• storing information in a first waveform storage device that characterizes the prescribed broadband signal, including a prescribed signal transmission time,
• providing a broadband transmitter antenna, and
• radiating the prescribed broadband signal over said broadband transmitter antenna;
• receiving the transmitted prescribed broadband signal at the base platform by
• storing information in a second waveform storage device that characterizes the prescribed broadband signal, including the prescribed signal transmission time,
• providing a plurality of broadband receiver antennas, arranged in an array of a prescribed geometry, that receive and filter electromagnetic radiation,
• receiving and processing the electromagnetic radiation received from each of said broadband receiver antennas, to produce a separate conditioned signal for each broadband receiver antenna, and
• correlating each conditioned signal with the prescribed broadband signal characterized by the information stored in the second waveform storage device, to produce a plurality of correlation outputs;
• computing, based upon the plurality of correlation outputs, the arrival time of the transmitted, prescribed broadband signal at each of the plurality of broadband receiver antennas;
• and
• calculating the azimuth based upon the prescribed geometry and the computed arrival time of the transmitted, prescribed broadband signal at each of the plurality of broadband receiver antennas.

A method for determining an estimated position of a remote object and a time error between a first time reference at a remote object and a second time reference at a base platform, using a prescribed broadband signal, the remote object being spaced from the base platform, the method comprising:

• transmitting the prescribed broadband signal from the remote object by
• storing information characterizing the prescribed broadband signal in a first waveform storage device, the stored information including a prescribed signal transmission time,
• producing the prescribed broadband signal in accordance with the stored information in the first waveform storage device, and
• providing a broadband transmitter antenna to radiate the produced, prescribed broadband signal;
• receiving the transmitted prescribed broadband signal at the base platform by
• storing information characterizing the prescribed broadband signal in a second waveform storage device, the stored information including the prescribed signal transmission time,
• providing a plurality of broadband receiver antennas, arranged in an array of a prescribed geometry, each configured to receive electromagnetic radiation from said broadband transmitter antenna, to produce a plurality of receiver antenna signals,
• receiving and filtering the plurality of receiver antenna signals, to produce a corresponding plurality of conditioned signals, and
• correlating the conditioned signal corresponding to each broadband receiver antenna with the prescribed broadband signal as characterized by the information stored in the second waveform storage device, to produce a plurality of correlation outputs based upon each correlation;
• computing, based upon the plurality of correlation outputs, a plurality of arrival times of the transmitted broadband signal relative to the second time reference;
• and
• deriving an estimated position of the remote object and the time error based upon the prescribed geometry and the plurality of arrival times.

A method for communicating a prescribed broadband signal from a remote object to a base platform, the remote object being spaced from the base platform, the method comprising:

• transmitting the prescribed broadband signal, formed from a plurality of fundamental pulses, at the remote object by
• deriving a first set of pseudo-random information characterizing the plurality of fundamental pulses, including the number of fundamental pulses and the timing between each successive fundamental pulse, and
• radiating from a broadband transmitter element the prescribed broadband signal in accordance with the derived information;
• and
• receiving the transmitted, prescribed broadband signal at the base platform by
• deriving a second set of pseudo-random information, identical to the first set of pseudo-random information, characterizing the prescribed broadband signal,
• receiving and filtering electromagnetic radiation, to produce a conditioned signal, and
• correlating the conditioned signal with the prescribed broadband signal characterized by the second set of pseudo-random information, to produce a correlation output.

A method for communicating a prescribed broadband signal from a remote object to a base platform, the remote object being spaced from the base platform, the method comprising:

• transmitting the prescribed broadband signal from the base receiver device by
• storing information characterizing the prescribed broadband signal, and
• radiating the prescribed broadband signal in accordance with the stored information;
• receiving the transmitted, prescribed broadband signal at the base platform by
• storing information characterizing the prescribed broadband signal,
• receiving and filtering electromagnetic radiation, to produce a conditioned signal, and
• correlating the conditioned signal with the prescribed broadband signal characterized by the information stored at the base platform, to produce a correlation output;
• and
• protecting the transmitted, prescribed broadband signal from interference.

Apparatus for deriving an estimated position of a remote object and a time error between a first synchronizable clock positioned at the remote object, and a second synchronizable clock positioned at a base platform, the remote object being spaced from the base platform, the apparatus comprising:

• a transmitter device, located at the remote object, said transmitter device including
• a first waveform storage device that stores information characterizing a prescribed broadband signal, such characterization including a prescribed signal transmission time,
• the first sychronizable clock maintains a first time reference,
• a broadband transmitter element configured to produce the prescribed broadband signal in accordance with said stored information and said first time reference, and
• a broadband transmitter antenna configured to radiate the prescribed broadband signal produced by said broadband transmitter element;
• a receiver device, located at the base platform, the receiver device including
• a second waveform storage device that stores information characterizing the prescribed broadband signal, including the prescribed signal transmission time,
• a plurality of broadband receiver antennas, arranged in an array of a prescribed geometry, each broadband receiver antenna being configured to receive electromagnetic radiation from said broadband transmitter antenna, thereby producing a plurality of receiver antenna signals,
• a broadband receiver element configured to receive and filter the plurality of receiver antenna signals and to produce a conditioned signal for each receiver antenna signal,
• the second synchronizable clock maintains a second time reference, and
• a digital signal processing correlator configured to correlate each conditioned signal with the prescribed broadband signal characterized by the information stored within the second waveform storage device, the correlation detector outputting a plurality of correlation outputs;
• and
• a processing device, responsive to the plurality of correlation outputs and the prescribed array geometry, that computes the arrival time of the radiated, prescribed broadband signal received at each broadband receiver antenna element relative to the second time reference, wherein the processing device additionally computes an estimated position of the remote object and time error between the first time reference and the second time reference.