Synthetic-aperture communications receivers

A method of improving the performance of a receiver receiving a signaling stream on a carrier frequency from a transmitter in an environment wherein relative motion exists between the receiver and transmitter at a velocity and in a direction of movement, the method comprising the steps of:

• estimating a Doppler shift in the carrier frequency due to the relative motion;
• determining the apparent angle between the receiver and transmitter relative to the direction of movement as a function of the Doppler shift;
• using the apparent angle to produce time-delayed replicas of the received signaling stream;
• and
• coherently adding the time-delayed replicas of the signaling stream to synthesize an increased apparent receiver antenna aperture.

A method of improving the performance of a mobile cellular communications receiver receiving a signaling stream on a carrier frequency from a stationary transmitter, the method comprising the steps of:

• determining the apparent angle between the mobile cellular receiver and the stationary transmitter as a function of the direction of movement of the receiver;
• using the apparent angle to produce time-delayed replicas of the received signaling stream;
• and
• coherently adding the time-delayed replicas of the signaling stream to synthesize an increased apparent receiver antenna aperture.

A method of improving the performance of a mobile cellular communications receiver receiving a spread-spectrum signaling stream on a carrier frequency from a stationary transmitter, the method comprising the steps of:

• estimating a Doppler shift in the carrier frequency due to the relative motion of the receiver;
• determining the apparent angle between the receiver and transmitter relative to the direction of movement as a function of the Doppler shift;
• using the apparent angle to produce time-delayed replicas of the spread-spectrum signaling stream;
• and
• coherently adding the time-delayed replicas of the spread-spectrum signaling stream to synthesize an increased apparent receiver antenna aperture.

An improved communications receiver in an environment wherein relative motion exists between the receiver and a transmitter at a velocity and in a direction of movement, the improved communications receiver comprising:

• an antenna for receiving a signaling stream on a carrier frequency from the transmitter;
• and
• a processor operative to perform the following functions:
• a) determine the apparent angle between the receiver and the transmitter as a function of the direction of movement,
• b) generate time-delayed replicas of the received signaling stream based upon the apparent angle;
• and
• c) synthesize an increased apparent receiver antenna aperture by coherently summing the time-delayed replicas of the signaling stream.