Location system
AssigneeSonitor Technologies AS
InventorsWilfred Edwin Booij, Øystein Haug Olsen
Life of this patent
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Abstract
Static transmitter stations are used to determine the position of a mobile receiver unit. Each transmitter station transmits an ultrasonic signal including a transmitter-specific phase-shifting signature. The receiver unit receives a signal and identifies a transmitter station by its signature. It uses the received signal and the identity of the source transmitter station to determine the position of the mobile receiver unit. The signature may include two patterns phase-shift-key (PSK)-encoded on respective carrier signals of the same frequency but different phase, with the patterns being offset from each other by a transmitter-specific offset. The signal from the transmitter station may also include a PSK-encoded message.
Claims28
A system for determining the position of a mobile receiver unit comprising:
- a plurality of static transmitter stations each configured to transmit an ultrasonic signal comprising a phase-shifting signature specific to the static transmitter station, wherein each signature comprises a first pattern, binary-phase-shift-key (BPSK)-encoded on a first carrier, and a second pattern, BPSK-encoded on a second carrier, wherein the first and second carriers are at the same frequency, and wherein the first carrier is 90 degrees out of phase with the second carrier;
- a mobile receiver unit configured to receive an ultrasonic signal from one of the transmitter stations;
- a processor configured to use the received signature to identify the source transmitter station;
- and
- a processor configured to use the received signal and the identity of the source transmitter station to determine information relating to the position of the mobile receiver unit.
(canceled)
4-6. (canceled)
A system as claimed in claim 41, wherein the first pattern is a Barker code and wherein the second pattern is the same Barker code.
A system as claimed claim 41, wherein a single pattern is used as the first and second patterns in the signatures of all the transmitter stations.
A system as claimed in claim 41, wherein the beginning of the second pattern is offset in time from the beginning of the first pattern by a predetermined offset that is less than the length of the first pattern.
A method of determining the position of a mobile receiver unit comprising:
- transmitting a respective ultrasonic signal from each of a plurality of static transmitter stations, each signal comprising a phase-shifting signature specific to the static transmitter station, wherein each signature comprises a first pattern, binary-phase-shift-key (BPSK)-encoded on a first carrier, and a second patter, BPSK-encoded on a second carrier, wherein the first and second carriers are at the same frequency, and wherein the first carrier is 90 degrees out of phase with the second carrier;
- receiving an ultrasonic signal from one of the transmitter stations at a mobile receiver unit;
- using the received signature to identify the source transmitter station;
- and
- using the received signal and the identity of the source transmitter station to determine information relating to the position of the mobile receiver unit.
A static transmitter station configured to transmit an ultrasonic signal comprising a phase-shifting signature specific to the static transmitter station, wherein the signature comprises a first pattern, binary-phase-shift-key (BPSK)-encoded on a first carrier, and a second pattern, BPSK-encoded on a second carrier, wherein the first and second carriers are at the same frequency, and wherein the first carrier is 90 degrees out of phase with the second carrier.
A mobile receiver unit configured to receive an ultrasonic signal comprising a phase-shifting signature from a transmitter station, wherein the signature comprises a first pattern, binary-phase-shift-key (BPSK)-encoded on a first carrier, and a second pattern, BPSK-encoded on a second carrier, wherein the first and second carriers are at the same frequency, and wherein the first carrier is 90 degrees out of phase with the second carrier, wherein the mobile receiver unit comprises a processor configured to use the received signature to identify the source transmitter station and/or comprises a processor configured to use the received signal and the identity of the source transmitter station to determine information relating to the position of the mobile receiver unit.
25-62. (canceled)
Dependencies are inferred from the claim text.