Method and system for secure access to a vehicle

A transportation vehicle comprising:

• an arrangement of a first antenna and a second antenna;
• a controller communicatively coupled to the first antenna and the second antenna, wherein the controller determines a reliability of a determination of the relative position of the transportation vehicle with respect to a device for accessing the transportation vehicle;
• and
• a magnetic field detection system to measure a magnetic field;
• wherein the reliability determination comprises:
• transmitting, under the control of the controller, a first radio signal from the first antenna;
• transmitting, under the control of the controller, a second radio signal from the second antenna;
• receiving, via at least one of the first antenna and the second antenna, a first signal intensity from the device, the first signal intensity being the signal intensity of the first radio signal at the device;
• receiving, via at least one of the first antenna and the second antenna, a second radio signal intensity from the device, the second signal intensity being the signal intensity of the second radio signal at the device;
• determining, under the control of the controller, a relative position of the device and the transportation vehicle relative to each other based on the received first signal intensity and the received second signal intensity;
• comparing, under control of the controller, the determined relative position of the device and the transportation vehicle relative to each other with the arrangement of the first antenna and the second antenna, to assess reliability of the determined relative position of the device and the transportation vehicle relative to each other;
• measuring, by the magnetic field detection system, a magnetic field direction at the transportation vehicle;
• receiving from the device, via at least one of the first antenna and the second antenna, a magnetic field direction at the device;
• and
• comparing, under control of the controller, the measured magnetic field direction at the transportation vehicle and received magnetic field direction at the device to further assess the reliability of the determined relative position of the device and the transportation vehicle relative to each other.

A method for assessing, at a device for accessing a transportation vehicle, a reliability of a determination of the relative position of the device with respect to the transportation vehicle, the method comprising:

• receiving a first radio signal from a first antenna of the transportation vehicle;
• receiving a second radio signal from a second antenna of the transportation vehicle;
• receiving from the transportation vehicle information about an arrangement of the first antenna and the second antenna at the transportation vehicle;
• determining a first signal intensity of the received first radio signal at the device;
• determining a second signal intensity of the received second radio signal at the device;
• determining a relative position of the device and the transportation vehicle relative to each other and/or signal directions from which the first and second radio signals have arrived at the device, based on the determined first signal intensity and the determined second signal intensity;
• comparing the determined relative position of the device and the transportation vehicle relative to each other and/or the signal directions from which the first and second radio signals arrived at the device with the information about the arrangement of the first antenna and the second antenna at the transportation vehicle, to assess reliability of the determined relative position of the device and the transportation vehicle relative to each other;
• measuring a magnetic field direction at the device;
• receiving from the transportation vehicle a measured magnetic field direction at the transportation vehicle;
• and
• comparing the received magnetic field direction at the transportation vehicle and the measured magnetic field direction at the device to further assess the reliability of the determined relative position of the device and the transportation vehicle relative to each other.

A device for accessing a transportation vehicle, the device comprising:

• an antenna configured to transmit and receive radio signals;
• a controller communicatively coupled to the antenna, wherein the controller determines a reliability of a determination of the relative position of the device with respect to the transportation vehicle;
• and
• a magnetic field detection system configured to measure a magnetic field;
• wherein the reliability determination comprises:
• receiving, via the antenna, a first radio signal from a first antenna of the transportation vehicle;
• receiving, via the antenna, a second radio signal from a second antenna of the transportation vehicle;
• receiving, via the antenna from the transportation vehicle, information about an arrangement of the first antenna and the second antenna at the transportation vehicle;
• determining, under control of the controller, a first signal intensity of the received first radio signal at the device;
• determining, under control of the controller, a second signal intensity of the received second radio signal at the device;
• determining, under control of the controller, a relative position of the device and the transportation vehicle relative to each other and/or signal directions from which the first and second radio signals have arrived at the device, based on the determined first signal intensity and the determined second signal intensity;
• comparing, under control of the controller, the determined relative position of the device and the transportation vehicle relative to each other and/or the signal directions from which the first and second radio signals arrived at the device with the information about the arrangement of the first antenna and the second antenna at the transportation vehicle, to assess reliability of the determined relative position of the device and the transportation vehicle relative to each other;
• measuring, by the magnetic field detection system, a magnetic field direction at the device;
• receiving, via the antenna from the transportation vehicle, a measured magnetic field direction at the transportation vehicle;
• and
• comparing, under control of the controller, the received magnetic field direction at the transportation vehicle and the measured magnetic field direction at the device to further assess the reliability of the determined relative position of the device and the transportation vehicle relative to each other.