US 11,757,487 B2 · Systems and methods for long range, high-capacity multipoint distance and velocity measurement

Abstract

A round-trip, spread-spectrum navigation and locating system achieves high capacity and large processing gains in one-to-many and many-to-one configurations using round-trip signaling with frequency division based upon precise responding device carrier frequency offsets. Reduced cross-correlation is achieved by assigning these very small disparate frequency offsets to replies from interrogated devices so that the long-term correlation between disparate reply sequences is reduced almost to that of random noise of equivalent energy. The invention supports simultaneous interrogation of multiple responding devices, which responding devices respond essentially simultaneously at a fixed delay after receiving the query. The originating and/or responding devices may be fixed or mobile, permanently or temporarily deployed, terrestrial, airbourne or space-based with any source of power including batteries and solar without limitation. The signaling may be electromagnetic or acoustic with the potential for under-water use.

Claims19

Dependent claims

An enhanced, high-sensitivity round-trip distance measuring system, comprising:

an originating device including a wireless signal transmitter, a wireless receiver and a signal processor;
a plurality of responding devices, each including a wireless signal transmitter and receiver, each being assigned disparate reply frequency offsets, and each being assigned disparate spreading codes;
wherein CDMA-DSSS (Code Division Multiple Access-Direct Sequence Spread Spectrum) signaling is used between the originating device and the responding devices;
wherein the originating device is operative to send and capture signals from the responding devices to determine spatial or velocity relationships between the originating device and the plurality of responding devices;
and
wherein the originating device coherently accumulates and correlates a sequence using the spreading code of code of a selected responding device such that sequences using spreading codes for non-selected devices are nearly orthogonal to the sequence of the selected device due to the disparate reply frequency offsets, thereby substantially reducing cross-correlation.

3 more elements

An enhanced, high-sensitivity round-trip distance measuring system, comprising:

an originating device including a wireless signal transmitter, a wireless receiver and a signal processor;
a plurality of responding devices, each including a wireless signal transmitter and receiver;
wherein CDMA-DSSS (Code Division Multiple Access-Direct Sequence Spread Spectrum) signaling is used between the originating device and the responding devices;
wherein each of the plurality of responding devices is assigned a corresponding reply frequency offset and spreading code;
wherein the corresponding reply frequency offset and spreading code for each of the plurality of responding devices is different from one another;
and
wherein the originating device is operative to:
send and capture signals from the plurality of responding devices to determine spatial or velocity relationships between the originating device and the plurality of responding devices;
and
coherently accumulate and correlate sequences for each selected responding device by applying the corresponding frequency offset and spreading code, wherein the sequences for non-selected responding devices are nearly orthogonal to the sequence of the selected device due to the different reply frequency offsets, thereby substantially reducing cross-correlation.

7 more elements

Dependencies are inferred from the claim text.

Systems and methods for long range, high-capacity multipoint distance and velocity measurement

Life of this patent

Systems and methods for long range, high-capacity multipoint distance and velocity measurement

Life of this patent

Abstract

Claims19