Active geo-location range for WLAN devices
AssigneeSR Technologies, Inc.
InventorGraham K. Smith
Life of this patent
Estimating the term…
Abstract
A method and devices are disclosed that increase the range of active geo-location from the airborne measuring station as compared with known methods by increasing the effective receive sensitivity of the airborne measuring station. In one embodiment this may be accomplished by transmitting a predetermined ranging packet and correlating the raw received bit stream of the response packet with the predetermined bit stream. In one embodiment, the disclosed method applies to the reception of IEEE 802.11 direct sequence spread spectrum DSSS ACK and DSSS CTS packets in response to DSSS data null and DSSS RTS packets respectively, in the 2.4 GHz band.
Claims19
A method for a first wireless device (WD), the method comprising:
- transmitting a ranging signal;
- receiving a response signal transmitted from a second WD in response to the ranging signal;
- extracting a received sequence from the response signal;
- correlating the received sequence with an expected sequence to determine a correlation value;
- comparing the correlation value to a threshold;
- and
- when the correlation value exceeds the threshold, then determining a geo-location of the second WD based at least in part on a time of transmitting the ranging signal and a time of receiving the response signal.
A first wireless device (WD), comprising:
- a transceiver configured to:
- transmit a ranging signal;
- and
- receive a response signal transmitted from a second WD in response to the ranging signal;
- and
- processing circuitry in communication with the transceiver, the processing circuitry configured to:
- extract a received sequence from the response signal;
- correlate the received sequence with an expected sequence to determine a correlation value;
- compare the correlation value to a threshold;
- and
- when the correlation value exceeds the threshold, then determine a geo-location of the second WD based at least in part on a time of transmitting the ranging signal and a time of receiving the response signal.
A method for a first wireless device (WD), the method comprising:
- transmitting a ranging signal and recording a time of transmitting the ranging signal;
- receiving a response signal transmitted from a second WD in response to the ranging signal;
- extracting a received sequence from the response signal, extracting the received sequence from the response signal including de-spreading the response signal by a known sequence;
- correlating the received sequence with an expected sequence to determine a correlation value;
- comparing the correlation value to a threshold;
- and
- when the correlation value exceeds the threshold, then determining a geo-location of the second WD based at least in part on the time of transmitting the ranging signal and a time of receiving the response signal, determining the geolocation of the second WD including determining a time between an ending of the transmitted ranging signal and an ending of a reception of the transmitted ranging signal.
Dependencies are inferred from the claim text.