# US 12,181,602 B2 · Systems and methods of calibrating a range measurement system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,181,602 B2 - Document ID: US12181602B2 - Status: Granted - Kind: B2 - Application number: 17/649,649 - Filed: 2022-02-01 - Published: 2022-08-04 - Granted: 2024-12-31 - Earliest claimed: 2021-02-01 - Assignees: Hitachi Rail GTS Canada Inc. - Applicants: Hitachi Rail GTS Canada Inc. - Inventors: Alon Green; Kevin Tobin; Marco De Thomasis - Web page: https://patentgrep.com/patent/US12181602B2 ## CPC - G01S 7/40: Means for monitoring or calibrating - B61K 13/00: Other auxiliaries or accessories for railways - G01S 7/4065: {involving a delay line} - G01S 7/4082: {using externally generated reference signals, e.g. via remote reflector or transponder} - G01S 7/4091: {during normal radar operation} - G01S 13/74: Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems - G01S 13/75: using transponders powered from received waves, e.g. using passive transponders {, or using passive reflectors} - G01S 13/931: of land vehicles - G01S 2013/9328: {Rail vehicles} - G01S 2013/9329: {cooperating with reflectors or transponders} - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - B61K: AUXILIARY EQUIPMENT SPECIALLY ADAPTED FOR RAILWAYS, NOT OTHERWISE PROVIDED FOR ## Abstract Systems and method of calibrating a range measurement system for a vehicle mounted on a guideway are disclosed. In some embodiments, a method includes: measuring a first time of transmission (TOT) between a first internal component of an on-board range measurement device and a second internal component of a wayside range measurement device. The first TOT is compared with a first pre-determined time. A health of the range measurement system is determined based on a difference between the first TOT and the first pre-determined time. ## Claims ### Claim 1 A method of calibrating a range measurement system for a vehicle mounted on a guideway, the method comprising: measuring a first time of transmission (TOT) between a first internal component of an on-board range measurement device and a second internal component of a wayside range measurement device; comparing the first TOT with a first pre-determined time; and determining a health of the range measurement system based on a difference between the first TOT and the first pre-determined time, wherein the first internal component is a first central processing unit (CPU) or first microcontroller unit (MCU) (first MCU/CPU) and the second internal component is a second CPU or second MCU (second MCU/CPU), wherein measuring the first TOT comprises: transmitting a first signal from the first MCU/CPU to a first antenna (first transmission); transmitting the first signal from the transmitting the first signal wirelessly from the first antenna to a second antenna (second transmission); transmitting the first signal from the second antenna to the second MCU/CPU (third transmission); transmitting a second signal from the second MCU/CPU to the second antenna (fourth transmission); transmitting the second signal wirelessly from the second antenna to the first antenna (fifth transmission); transmitting the second signal from the first antenna to the first MCU/CPU (sixth transmission); measuring a combined TOT of first transmission, the second transmission, the third transmission, the fourth transmission, the fifth transmission, and the sixth transmission as the first TOT. ### Claim 2 (depends on 1) The method of claim 1, wherein comparing the first TOT with the first pre-determined time, comprises: subtracting a total time of travel of first transmission, the third transmission, the fourth transmission, and the sixth transmission from the combined TOT to obtain a first time of flight (TOF); comparing the first TOF with the first pre-determined time. ### Claim 3 (depends on 2) The method of claim 2, wherein determining the health of the range measurement system based on the difference between the first TOT and the first pre-determined time comprises determining that the range measurement system is calibrated between the first MCU/CPU to the second MCU/CPU through the first and second antennas when the difference between the first TOF and the first pre-determined time is less than a threshold. ### Claim 4 (depends on 2) The method of claim 2, wherein determining the health of the range measurement system based on the difference between the first TOT and the first pre-determined time comprises determining that the range measurement system is not calibrated between the first MCU/CPU to the second MCU/CPU through the first and second antennas when the difference between the first TOF and the first pre-determined time is greater than a threshold, and wherein the method further comprises: determining a scaling factor, wherein the first TOF multiplied by the scaling factor is equal to the first pre-determined time. ### Claim 5 (depends on 1) The method of claim 1, further comprising: measuring a second TOT between the first internal component of the on-board range measurement device and the second internal component of the wayside range measurement device via a first signal route; measuring a third TOT between the first internal component of the on-board range measurement device and the second internal component of the wayside range measurement device via a second signal route that is different than the first signal route; comparing a difference between the second TOT and the third TOT with a threshold; and determining a health of the range measurement system based on the difference between and the second TOT and the third TOT and the threshold. ### Claim 6 (depends on 5) The method of claim 5, wherein the first signal route is through a first antenna and the second signal route is through a second antenna. ### Claim 7 (depends on 1) The method of claim 1, further comprising: measuring a second TOT between the first internal component of the on-board range measurement device and a third internal component of a second on-board range measurement device, wherein a coaxial cable is connected between the first internal component and the third internal component; comparing the second TOT with a second pre-determined time; and determining the health of the range measurement system based on a difference between the second TOT and the second pre-determined time. ### Claim 8 (depends on 7) The method of claim 7, wherein the second pre-determined time is an expected time of propagation for a coaxial cable having a same length as the coaxial cable and wherein determining the health of the range measurement system comprises comparing the second TOT with the expected time of propagation. ### Claim 9 (depends on 1) The method of claim 1, further comprising: raising an alarm in response to the difference between the TOT and the pre-determined time being greater than a threshold. ### Claim 10 (depends on 1) The method of claim 1, further comprising: calibrating the range measurement system in response to the difference between the first TOT and the first pre-determined time being greater than a threshold. ### Claim 11 A range measurement system for a guideway mounted device, comprising: a first antenna; a first wireless device operably associated with the first antenna and configured to generate a first signal; a non-transitory computer readable medium configured to store computer executable instructions; at least one microcontroller or central processing unit (MCU/CPU) operably associated with the first wireless device and the non-transitory computer readable medium, wherein, when the at least one MCU/CPU executes the computer executable instructions, the at least one MCU/CPU is configured to: measure a first time of transmission (TOT) between the at least one MCU/CPU and an internal component of a wayside range measurement device; compare the first TOT with a first pre-determined time; and determine a health of the range measurement system based on a difference between the first TOT and the first pre-determined time, wherein the internal component is a second CPU or second MCU (second MCU/CPU), wherein the at least one MCU/CPU is configured to measure the first TOT by: transmitting a first signal from the MCU/CPU to a first antenna (first transmission) transmitting the first signal from the transmitting the first signal wirelessly from the first antenna to a second antenna (second transmission); transmitting the first signal from the second antenna to the second MCU/CPU (third transmission); transmitting a second signal from the second MCU/CPU to the second antenna (fourth transmission); transmitting the second signal wirelessly from the second antenna to the first antenna (fifth transmission); transmitting the second signal from the first antenna to the MCU/CPU (sixth transmission); measuring a combined TOT of first transmission, the second transmission, the third transmission, the fourth transmission, the fifth transmission, and the sixth transmission as the first TOT. ### Claim 12 (depends on 6) The range measurement system of claim 6, wherein the at least one MCU/CPU is configured to compare the first TOT with the first pre-determined time by: subtracting at total time of travel of first transmission, the third transmission, the fourth transmission, and the sixth transmission from the combined TOT to obtain a first time of flight (TOF); comparing the first TOF with the first pre-determined time. ### Claim 13 (depends on 12) The range measurement system of claim 12, wherein the at least one MCU/CPU is configured to determine the health of the range measurement system based on the difference between the first TOT and the first pre-determined time by determining that the range measurement system is calibrated between the MCU/CPU to the second MCU/CPU through the first and second antennas when the difference between the first TOF and the first pre-determined time is less than a threshold. ### Claim 14 A method of calibrating a range measurement system for a vehicle mounted on a guideway, the method comprising: measuring a first time of transmission (TOT) between a first internal component of a first wayside range measurement device and a second internal component of a second wayside range measurement device; comparing the first TOT with a first pre-determined time; and determining a health of the range measurement system based on a difference between the first TOT and the first pre-determined time; measuring a second TOT between the first internal component of the first wayside range measurement device and a third internal component of a third wayside range measurement device; measuring a third TOT between the second internal component of the second wayside range measurement device and the third internal component of the third wayside range measurement device; comparing the second TOT with a second pre-determined time; comparing the third TOT with a third pre-determined time; and wherein the determining the health of the range measurement system is based on the difference between the first TOT and the first pre-determined time, a difference between the second TOT and the second pre-determined time, and a difference between the third TOT and the third pre-determined time.