Method for measuring speed of vehicle using RFID, RFID reader for measuring speed of vehicle, and system for collecting vehicle information using the same

An RFID reader comprising:

• a transmitting unit that has a transmitting antenna configured to radiate an RF signal, generate an RF signal to be transmitted to an RFID tag attached to a vehicle, transmit the generated RF signal via the transmitting antenna, and transfer the frequency of the transmitted RF signal to a Doppler shift extracting unit;
• a receiving unit that has a receiving antenna configured to receive a reflected wave from the RFID tag, extract reception data included in the received reflected wave, transfer the extracted reception data to a controller, and transfer the frequency of the received reflected wave to the Doppler shift extracting unit;
• a frequency synthesizing unit configured to synthesize the frequency of a band to be used for RFID communication between the RFID tag and the RFID reader and supply the synthesized frequency to the transmitting unit and the receiving unit under the control of the controller;
• the Doppler shift extracting unit configured to compare the frequency of the transmitted RF signal transferred from the transmitting unit and the frequency of the reflected wave transferred from the receiving unit to extract a Doppler shift value;
• a vehicle speed calculating unit configured to calculate a vehicle speed by using the frequency of the transmitted RF signal and angle information transferred from the controller and the Doppler shift value transferred from the Doppler shift extracting unit;
• and
• the controller configured to control the respective elements of the RFID reader to perform communication with the RFID tag and calculate the vehicle speed,
• wherein the vehicle speed calculating unit calculates the vehicle speed by Equation shown below:
• v
• 0
• =
• c
• 2
• ⁢
• f
• 0
• ·
• r
• r
• 2
• -
• h
• 2
• ·
• Δ
• ⁢
• ⁢
• f
• wherein v0 is a vehicle speed, ‘c’ is a signal propagation speed, f0 is the transmission frequency of the RFID reader, ‘r’ is the distance in straight line between the RFID reader and the RFID tag, ‘h’ is the height of the RFID reader, and Δf is the Doppler shift value.

A system for collecting vehicle information, the system comprising:

• an RFID reader configured to perform RFID communication with an RFID tag attached to a running vehicle to acquire information about the vehicle embedded in the RFID tag, calculate a vehicle speed by using a Doppler shift value, generate a vehicle information package including information about the vehicle and vehicle speed information, and transmit the vehicle information package to a central control server;
• and
• the central control server configured to receive the vehicle information package from the RFID reader, and collect, process, and analyze the received data,
• wherein the RFID reader calculates the vehicle speed by using Equation shown below:
• v
• 0
• =
• c
• 2
• ⁢
• f
• 0
• ·
• r
• r
• 2
• -
• h
• 2
• ·
• Δ
• ⁢
• ⁢
• f
• wherein v0 is a vehicle speed, ‘c’ is a signal propagation speed, f0 is the transmission frequency of the RFID reader, ‘r’ is the distance in straight line between the RFID reader and the RFID tag, ‘h’ is the height of the RFID reader, and Δf is the Doppler shift value.