Koninklijke Philips Corporation N.V.

Koninklijke Philips Electronics N.v.

Martin S Wilcox

Andrew Thomas Yule

Saul Robin Dooley

Adam Leitch

Paul Richard Simons

Frank Boeh

Paul M Fulton

Bryan D Young

Amites Sarkar

Adam S Leitch

First and second devices having clocks which may have different clock rates. Obtaining a measure of the distance of propagation of a signal passing between the devices involves transmitting a first signalfrom the first device to the second device. After a turnaround time TAT, a second signalis transmitted from the second device to the first device. Any error in the clocks may lead to an error in the measurement of the turnaround time TAT. One device contains circuitry to calculate the ratio of the clock rates of the first and second devices, either by adjusting frequency divider ratios until there is LO frequency match, or by determining the offset frequency of an envelope of a mixed signal. The ratio of the clock rates is used to compensate the turnaround time TAT, to mitigate error. The accurate distance measurement can be used to determine if a relay attack has taken place in a vehicle security system.

Measuring the distance between devices

A device measures distance using a wireless signal that has two simultaneously transmitted components. Each of the two components includes a respective repeated code, the two codes having different durations. On receipt of the signal, the propagation distance is calculated separately for each code and compared. The calculated distance is considered to be valid only if the two calculations yield the same result. The durations of the two codes may be proportional to numbers having a relative prime relationship. The signal is generated and transmitted by the same device that performs the distance calculation, with the signal being retransmitted back to the device by a remote device, or may be generated and transmitted by the remote device.

Method and apparatus for measuring distance

First and second devices () are configured to transmit and receive signals wirelessly and have first and second clocks respectively for determining signal transmission and arrival times. The first device transmits first and second signals () and the second device transmits a third signal (). By introducing a delay into the first signal, a thief may be able to fool the devices into thinking that they are closer than they really are. To help identify if a delay has been introduced into the first signal, the first device calculates a ratio of clock rates for the first and second clocks and determines whether the calculated ratio falls within a predefined range.

Arrangement and method for ascertaining whether a set of measurements is acceptable for use in determining a time of flight of signals

A wireless activation system, such as a keyless car entry system, uses repeated code sequences for communication between a transmitter device and a receiver device. By varying the sequence duration in a synchronism at the transmitter device and receiver device, either by varying the number of symbols or chips in the sequence, or by varying the symbol or chip rate, it is made more difficult for an unauthorised party to detect the code sequences and relay the code sequences to achieve unauthorised activation at the receive device.

Wireless activation system, method and device

A device measures distance using a wireless signal that has two simultaneously transmitted components. Each of the two components includes a respective repeated code, the two codes having different durations. On receipt of the signal, the propagation distance is calculated separately for each code and compared. The calculated distance is considered to be valid only if the two calculations yield the same result. Preferably, the durations of the two codes are proportional to numbers having a relative prime relationship. The signal is generated and transmitted by the same device that performs the distance calculation, with the signal being retransmitted back to the device by a remote device, or may be generated and transmitted by the remote device.

Method and apparatus for measuring distance using dual-component radar

Method for obtaining range and/or positional information of electronic devices typically rely on a device (A) re-questing that another device (B) supplies a reply message (), which contains some timing information (T, T) on the signals received and sent. Problems that arise in such networks comprise: firstly, some devices (C) may be out of range of the device (A) that initiates the ranging measurements, and secondly, some devices (B, C) may not be allowed to communicate with each other and thus, the distance between these devices cannot be found. This invention discloses that in these cases, eavesdropping on messages () passing between other devices (A, B, C) in the system can result in that distances between additional devices are found. Furthermore, by using eavesdropping the number of transmissions, and therefore the potential for collisions, is reduced. Thus, the power consumption of the nodes in the network can be lowered.

Making time-of-flight measurements in master/slave and ad hoc networks by eaves-dropping on messages

The invention provides a method for installing a positioning system, the positioning system comprising two or more base stations (BSto BS), and comprises the steps of; collocating the base stations (BSto BS); quantifying any lack of synchronization between the clocks of the base stations; relocating one or more of the base stations (BS' to BS&#x2032;) to their fixed, operational positions and measuring the time of flight of a signal from each of the relocated base stations; determining from the time of flight and quantified lack of synchronization data the relative separation of the base stations (BS, BS&#x2032; to BS&#x2032;) and hence the configuration of the installed positioning system, and recording the configuration of the installed positioning system. Data defining the configuration of the system can be relayed to a mobile transceiver in the vicinity of the installed positioning system and, along with time of flight measurements of signals emitted by the individual base stations, and data quantifying any real time lack of synchronization of the clocks of the base stations, can be used by the transceiver to position itself within the geographical area defined by the positioning system.

System and method for synchronizing base stations

A method of providing an estimate of the location of first and second devices MS, MScomprising the steps of obtaining at least one range measurement from the first device MSto a known reference point BS, GPS SVs; obtaining at least one range measurement from the second device MSto a known reference point BS, GPS SVs, the second device MSbeing located near to the first device MS; and calculating an estimate of the location of the devices MS, MSusing range measurements obtained with respect to both the first and second devices MS, MS

Method of providing an estimate of a location

A method and apparatus for receiving a spread spectrum signal at a mobile communications terminal, including the step of processing the signal for the purposes of signal acquisition and signal tracking, monitoring movement of the mobile terminal and deriving a signal indicative of a characteristic of movement of the mobile terminal, and further including changing the mode of the processing of the incoming spectrum signal in response to the signal indicating the said characteristic of movement of the mobile terminal.

Spread spectrum receiver and related method

A time shifted replica signal (SLS) is generated from a reference signal (SPS) including a series of samples (A to K) describing bits of a data message, the sampling rate being at least twice the data message bit rate. The phases of the reference signal samples are determined with respect to virtual epochs (41) of the data message bits of the reference signal (SPS). The time shifted replica signal (SLS) is composed from the reference signal samples as a function of the phases of the reference signal samples. In another embodiment, the time shifted replica signal (SLS) is composed from the reference signal samples (A to K), the sampling rate of the replica signal (SLS) being the same as that of the reference signal (SPS), at least one reference signal sample (A to K) not being present in the time shifted replica signal (SLS).

Method of generating a time shifted signal

A method of providing an estimate of the location of first and second devices (MS , MS ) comprising the steps of obtaining at least one range measurement from the first device (MS ) to a known reference point (BS , GPS SVs); obtaining at least one range measurement from the second device (MS ) to a known reference point (BS , GPS SVs), the second device (MS ) being located near to the first device (MS ); and calculating an estimate of the location of the devices (MS , MS ) using range measurements obtained in respect of both the first and second devices (MS , MS ).

A receiver for direct sequence spread spectrum code division multiple access signals (DS-CDMA) particularly for GPS signals includes a plurality of correlators. Each correlator includes variable level threshold circuits ( ) which follow integrate and dump registers ( ). The threshold level is set using the correlation noise level and predicted signal strength.

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Redhill, United Kingdom

Martin S Wilcox