Vehicle positioning using radio ranging

Abstract

Vehicle positioning using radio ranging. The invention relates to a method for continuously determining the position of one or more moving vehicles in a fleet of vehicles, comprising: providing, at a host vehicle, an anchor module comprising at least three radio frequency sensors; providing a tag module on each slave vehicle; at least a first ranging procedure for continuously determining a position of the first slave vehicle, the at least first ranging procedure comprising: determining a position of the radio frequency sensor in the reference coordinate system; exchanging a set of radio signals between a first tag module on the first slave vehicle and each of the radio frequency sensors; calculating the flight time of each group of radio signals; calculating a distance between the first tag module and each respective radio frequency sensor based on the determined time of flight; deriving a position of the first tag module and / or the first slave vehicle in the reference coordinate system based on the calculated distance; a reporting signal indicative of the derived location of the first slave vehicle is provided.

Description

Technical Field

[0001] This invention relates to a method and system for locating multiple vehicles working together as a fleet. More specifically, only the main vehicle of the fleet is equipped with a positioning system (e.g., a GNSS or TPS positioning system), and the positions of the other vehicles are determined using radio signals and time-of-flight measurements relative to a global coordinate system provided by the positioning system. Background Technology

[0002] An example of multiple vehicles working together as a convoy is a paving unit, in which two or more mobile machines travel in formation to lay concrete or asphalt material and create a continuous surface layer with a desired surface profile along a predetermined path. In particular, such paving units are used for the construction and maintenance of roads, runways, etc. The machines used in a paving unit include, for example, at least one paver and at least one finisher, such as a slipform paver or asphalt paver. It is also known to use two or more finishers in a paving unit. The finisher is typically followed by a spray vehicle that sprays chemicals onto the surface, preventing the material from drying too quickly. During paving, the material to be laid is typically transported by a loader unit (e.g., a truck or mixer) and unloaded along a predetermined path. The paver is equipped to distribute the material and perform lateral distribution and initial grading of the material. Coarse grading is achieved by the paver's traction device in a manner that approximates the desired height of the surface layer. The grader follows the paver at a predetermined distance and then draws the material using its characteristic beams (e.g., a screeding beam or a contour beam) to achieve the desired height of the surface layer. Preferably, each machine in the paving unit should have access to its current GNSS location to perform its tasks accurately and efficiently. Current systems for locating machines working together in a swarm typically require each machine to be equipped with a GNSS positioning system. Using such a system, each machine knows its location in the world, allowing them to coordinate their activities relative to a single global map. This can be expensive because GNSS receivers are costly devices with high computing power. This results in a high investment in the entire swarm.

[0003] An alternative to the traditional approach is to mount a single GNSS positioning system on the main machine and determine the positions of other machines relative to the main machine. EP 2 155 968 B1 discloses a paving unit for generating a surface layer, comprising multiple individually movable units, each configured to perform processing steps in the generation of the surface layer. Only the first unit includes a GNSS receiver to determine its position, and an optical guidance system is used to determine the positions of the other units. This involves emitting an optical reference beam to the photosensitive receivers of the other units. This solution disadvantageously requires several optical transmitters and receivers, all of which must be aligned and aimed at each other, making it difficult to integrate a large number of machines.

[0004] EP 3 477 335 B1 discloses a proximity warning system using radio frequency-based time-of-flight ranging between an anchor and a tag. The anchor is placed on a mobile machine (heavy mining equipment), and a person (pedestrian) wears a tag. The anchor and tag are used to measure the distance between the machine and the person, and a proximity alarm is issued if the distance exceeds a threshold. However, the system is not used to calculate a complete positional solution for the person relative to the machine or between the two machines. Summary of the Invention

[0005] The object of this invention is to provide an improved method and system that allows for determining the location of a moving vehicle.

[0006] The specific objective is to provide methods and systems in which multiple vehicles work together as a fleet, particularly where the vehicles are mobile construction machines.

[0007] Another objective is to provide methods and systems in which location can be determined with less effort, more reliably, and over greater distances, particularly in a GNSS coordinate system, without requiring a GNSS antenna on each vehicle.

[0008] According to the proposed solution, in a fleet of vehicles (or “machines”), a single GNSS or TPS positioning system (reference positioning system) is installed on the first (“master”) machine, and peer radio rangefinder systems are installed on multiple other (“slave”) machines. The distances measured by the peer systems can then be used to determine the network geometry, and the time rate of change of the distances can be used to determine the direction of travel of the various machines in the fleet. The ground speeds and directions of the slave vehicles can also be determined by further utilizing the ground speeds and headings of the master vehicle.

[0009] A first aspect of the invention relates to a method for continuously determining the position of one or more moving vehicles in a vehicle group. The vehicle group includes a master vehicle and one or more slave vehicles, the master vehicle being equipped with one or more components of a reference positioning system that provides reference position information about the position of the one or more components in a reference coordinate system.

[0010] For example, the reference positioning system may be a GNSS positioning system, in which one or more components are one or more GNSS antennas configured to receive GNSS signals, and the GNSS positioning system provides GNSS position information about the location of one or more GNSS antennas in a GNSS coordinate system. Alternatively, the reference positioning system may be a TPS, in which one or more components are at least two reflecting targets (such as prisms) tracked by an odometer or total station, and the TPS provides TPS position information about the location of the reflecting targets in a TPS coordinate system.

[0011] According to this aspect of the invention, the method includes:

[0012] - An anchor module is provided at the main vehicle, the anchor module comprising at least three radio frequency (RF) sensors positioned on the main vehicle in a known spatial relationship to each other and to the one or more components, each of the RF sensors being configured to transmit and receive radio signals;

[0013] - A tag module is provided on each of the subordinate vehicles, each tag module being configured to transmit and receive radio signals; and

[0014] - Perform one or more ranging procedures for continuously determining the position of each of the subordinate vehicles, the one or more ranging procedures including at least a first ranging procedure for determining the position of the first subordinate vehicle.

[0015] The first distance measurement process includes:

[0016] - Use the reference position information and the known spatial relationship to determine the position of the RF sensor in the reference coordinate system;

[0017] - A set of radio signals is exchanged between the first tag module on the first subordinate vehicle and each of the RF sensors;

[0018] - Calculate the flight time of each group of radio signals;

[0019] - Calculate the distance between the first tag module and each of the corresponding RF sensors based on the determined flight time of the corresponding set of radio signals;

[0020] - Derive the positions of the first tag module and / or the first subordinate vehicle in the reference coordinate system based on the calculated distance; and

[0021] - Provide a reporting signal indicating the exported location of the first subordinate vehicle.

[0022] According to some implementations of this method, the frequency of the group of signals is in the ultra-wideband range.

[0023] According to some embodiments of the method, the set of signals includes a distance signal and a response signal, wherein the distance signal is emitted by the RF sensor of the anchor module, and in response to receiving the distance signal, the first tag module emits a response signal, particularly wherein the RF sensor simultaneously emits the distance signal. Alternatively, the distance signal may also be emitted by the first tag module, and the response signal may be emitted by the RF sensor of the anchor module.

[0024] In some implementations, the response signal is transmitted after a known response time (e.g., less than 1 ms), and the distance between the first tag module and each radio frequency sensor is also calculated based on the response time. Alternatively, the distance signal can be transmitted at a first time point, and the response signal can be received at a second time point, wherein the time of flight of the set of radio signals is calculated based on the following equation:

[0025]

[0026] Where ToF is the time of flight. It is the first point in time. It is the second time point, and The response time is known. For example, each flight time can be calculated at the anchor module.

[0027] In some implementations, an initialization signal is emitted by the first tag module, and a distance signal is emitted upon receiving the initialization signal. In particular, the initialization signal includes information that allows identification of the first tag module and / or the first subordinate vehicle.

[0028] According to some embodiments of the method, a reporting signal is provided to a first slave vehicle, wherein the position of the first slave vehicle is displayed to the operator of the first slave vehicle and / or provided to a machine control unit of the first slave vehicle for at least partial control of the operation of the first slave vehicle. Optionally, providing the reporting signal includes transmitting a reporting signal by at least one of the RF sensors and receiving the reporting signal by a first tag module.

[0029] If the signal from the anchor radio to the tag includes the anchor's GNSS location, the tag can fully calculate the network geometry as well as its own GNSS location. For example, this could include the following steps:

[0030] - Once all the GNSS antennas are mounted on the host machine, calibrate the GNSS antennas relative to the anchor RF radio;

[0031] - The system uses the measured GNSS position and calibration data to calculate the GNSS position of the anchor RF radio;

[0032] - The anchor RF radio transmits its GNSS location when sending messages to the tag; and

[0033] The tags use the measured distance and the GNSS position of the RF radio to calculate their GNSS position.

[0034] According to some implementations of the method, the anchor module includes:

[0035] - Position at least three RF sensors of the anchor module in a common plane (e.g., a common horizontal plane);

[0036] - Determine the geometry of the RF sensor and the one or more components; and

[0037] - Determine the orientation of the RF sensor relative to the direction of travel of the host vehicle.

[0038] Optionally, to align the RF sensors of the anchor modules at the same height, the main vehicle can be placed on a horizontal surface. Providing tag modules may include positioning each tag module in a common plane.

[0039] According to some embodiments of the method, the anchor module includes at least four RF sensors, and the derived position of the first tag module and / or the first subordinate vehicle is a 3D position derived based on the calculated distance between the first tag module and the at least four RF sensors.

[0040] For example, the 3D position of the first subordinate vehicle relative to the master vehicle can be derived.

[0041] Optionally, providing an anchor module includes positioning at least three RF sensors of the anchor module in a common plane and positioning at least one RF sensor of the anchor module outside the common plane.

[0042] According to some implementations of the method, the set of signals is exchanged iteratively (e.g., at least every 500 ms), wherein each iteration of exchanging the set of signals enables the calculation of distance, the derivation of the position of the first subordinate vehicle, and the provision of a report signal.

[0043] In some implementations, the method further includes receiving speed information about the current speed of the master vehicle at the anchor module, and calculating the current or recent speed of the first slave vehicle based on the speed information and multiple calculated distances and / or derived locations. The reporting signal then also indicates the current or recent speed of the first slave vehicle, and optionally also indicates the current speed of the master vehicle.

[0044] The speed of the master vehicle can be determined based on GNSS data or a combination of GNSS and IMU data. The speed of the tag relative to the anchor radio can also be directly measured using the Doppler shift in the ranging message. Optionally, slave vehicles can also use IMU data or odometer data to help measure their own local or global speed.

[0045] According to some embodiments of the method, the fleet includes at least two subordinate vehicles, and the method includes at least a second ranging process for continuously determining the position of a second subordinate vehicle. In particular, the fleet may include multiple subordinate vehicles, such that the method includes multiple simultaneously executed ranging processes for continuously determining the positions of multiple subordinate vehicles.

[0046] A second aspect of the invention relates to a vehicle positioning system configured to continuously determine (particularly according to the method of the first aspect) the positions of one or more moving vehicles in a vehicle group, the group comprising a master vehicle and one or more subordinate vehicles, the master vehicle being equipped with a reference positioning system comprising one or more components that provides reference position information regarding its position in a reference coordinate system. According to this aspect of the invention, the vehicle positioning system includes:

[0047] An anchor module, disposed at the host vehicle, comprising at least three RF sensors positioned on the host vehicle in a known spatial relationship relative to each other and relative to one or more components, each RF sensor configured to transmit and receive radio signals, and

[0048] - A tag module is installed on each of the subordinate vehicles, and each tag module is configured to transmit and receive radio signals.

[0049] - The vehicle positioning system is configured to perform at least a first ranging process for continuously determining the position of a first subordinate vehicle, the first ranging process including:

[0050] - Use the reference position information and the known spatial relationship to determine the position of the RF sensor in the reference coordinate system;

[0051] - A set of radio signals is exchanged between the first tag module on the first subordinate vehicle and each of the radio frequency sensors;

[0052] - Calculate the flight time of each group of radio signals;

[0053] - Calculate the distance between the first tag module and each of the corresponding radio frequency sensors based on the determined flight time of the corresponding set of radio signals;

[0054] - Derive the positions of the first tag module and / or the first subordinate vehicle in the reference coordinate system based on the calculated distance; and

[0055] - Provide a reporting signal indicating the exported location of the first subordinate vehicle.

[0056] As mentioned above, the reference positioning system can be a GNSS positioning system or a TPS.

[0057] A third aspect of the invention relates to a computer program product for performing one or more ranging processes according to the method of the first aspect of the invention. Attached Figure Description

[0058] The invention will now be described in detail with reference to exemplary embodiments accompanied by the accompanying drawings, wherein:

[0059] Figure 1 An example of a vehicle fleet equipped with an exemplary embodiment of the system according to the present invention is shown;

[0060] Figure 2 The working principle of an exemplary embodiment of the system according to the present invention is shown;

[0061] Figure 3 A flowchart illustrating an exemplary embodiment of the method according to the present invention is shown;

[0062] Figure 4 The description is shown as Figure 3 A flowchart of the steps for positioning the anchor module on the master vehicle as part of the method; and

[0063] Figure 5 A ranging protocol according to an exemplary embodiment of the system based on the present invention is shown. Detailed Implementation

[0064] Figure 1An example of a paving machine group is shown, consisting of multiple vehicles working together as a fleet 1. The vehicles of the paving machine group are mobile machines comprising an asphalt paver (combined as a master vehicle 10) and multiple rollers (as slave vehicles 11, 12, 13). The master vehicle 10 includes a positioning system 5 with one or more GNSS antennas (e.g., a pair of GNSS antennas) and an anchor module 2 including three radio frequency (RF) ranging sensors (collectively referred to as "anchor sensors"). Each of the slave machines 11, 12, 13 is equipped with tag modules 3, 3', 3'', each including a single RF ranging sensor ("tag sensor"). The combination of the positioning system 5 and the anchor module 2 on the master machine 10 serves as a globally positioned localpositioning network (GP-LPN). The anchor module 2 and / or tag modules 3, 3', 3'' may include computing units (e.g., including processors, data storage devices, and communication devices) for calculating distance and / or location based on sensor data.

[0065] Instead of using a positioning system with a GNSS antenna (GNSS positioning system), a pair of prisms (or similar target objects) set on the main vehicle and the odometer or total station (total positioning system, TPS) can be used to globally track the main vehicle.

[0066] Another example of multiple machines working together as a group 1 is an excavator or wheel loader operating as the master vehicle and a group of dump trucks operating as slave vehicles.

[0067] An additional advantage of the proposed solution is that the radio link can be used not only for ranging but also for information transmission. Therefore, any communication between the master vehicle and the fleet of slave vehicles can be carried over to ranging communication without requiring an additional communication link. Similarly, if an existing radio link exists, the carrier signal can be modified based on existing components to perform ranging.

[0068] Figure 2 The operating principle of an exemplary embodiment of the system according to the invention is illustrated. In this example, the vehicle fleet consists of only one master vehicle 10 and one slave vehicle 11. The master vehicle 10 is equipped with a GPS-LPN (i.e., a combination of a GNSS positioning system and an anchor module), and the slave vehicle 11 is equipped with a tag module 3. In the illustrated embodiment, the GP-LPN includes a GNSS positioning system having two GNSS antennas 51 and 52 and an anchor module 2, the anchor module 2 including three anchor sensors 21, 22, and 23.

[0069] The three anchor sensors 21, 22, and 23, and the tag module 3, are located in the same reference plane, i.e., at the same height. The distances between the three anchor sensors 21, 22, and 23 and the tag 3 are determined by... , , The 2D position of tag module 3 relative to anchor module 2 can be determined. Since anchor sensors 21, 22, 23 and GNSS antennas 51, 52 have known positions relative to each other, the position of tag module 3 relative to the "global" position in the coordinate system provided by the GNSS positioning system can be determined. Since anchor sensors 21, 22, 23 and GNSS antennas 51, 52 have known positions on the master vehicle 10 (i.e., relative to the master vehicle 10), and tag module 3 has a known position on the slave vehicle 11 (i.e., relative to the slave vehicle 11), the 2D position of slave vehicle 11 relative to master vehicle 10 can also be determined.

[0070] Alternatively, GNSS antennas 51 and 52 can be used as anchor sensors for the GP-LPN. Alternatively, a single housing may include both the GNSS antenna and the anchor sensor, wherein the antenna and sensor are positioned close enough that the gap is negligible. In this case, the location of the GNSS antenna will coincide with the location of one or more anchor sensors.

[0071] Figure 3 A flowchart illustrating an exemplary embodiment of a method 100 for continuously determining the positions of one or more moving vehicles according to the present invention is shown. The method begins with positioning an anchor module 110 on a master vehicle and a tag module 115 on a slave vehicle. In order to use the anchor module as part of a GP-LPN, its internal geometry needs to be calibrated. This will refer to... Figure 4 Provide a detailed description.

[0072] After the anchor module has been properly positioned on the main vehicle, its GNSS position can be continuously determined, and the ranging process can be initiated, which will refer to... Figure 5 Detailed Description. The ranging process involves exchanging radio signals between the anchor module and the tag module, specifically in the ultra-wideband frequency range. The time of flight (ToF) of the signals is determined, and the distance between the anchor sensor and the tag module is calculated. The position of the slave vehicle can be derived from these distances. A reporting signal indicating the position can then be provided to, for example, a supervisor of the vehicle fleet or the operator of the respective slave vehicle. Furthermore, the signal can be provided to the machine control unit of the slave vehicle for at least partial control of the vehicle.

[0073] In the case of numerous subordinate vehicles, "leapfrog" positioning is possible, where a subordinate vehicle unable to communicate with the anchor due to distance or line-of-sight loss can be positioned relative to other subordinate vehicles with valid positions relative to the anchor. In this way, subordinate vehicles can also form a mesh network for positioning themselves, provided each tag can communicate with at least three other tags with valid positions. That is, for a tag unable to communicate with the anchor, a group of three or more tags with valid positions can act as a "moving anchor."

[0074] Alternatively, in addition to the radio distance positioning system, slave vehicles can also incorporate IMU data and run an onboard INS (inertial navigation system) to track their positions. This increases the accuracy of their positions between radio messages, reduces the rate at which radio ranging must be reproduced, thereby reducing the computational and communication load on the network, increases the knowledge of slave vehicle speeds, and results in a more robust system to partial or complete radio communication disruptions.

[0075] Figure 4 A flowchart illustrating an exemplary process for positioning the anchor module 110 on the host vehicle is shown. In the illustrated embodiment, to calibrate the GP-LPN, the process includes leveling all sensors to the same height and then determining the geometry of the ranging sensor network and the GNSS antenna. While any suitable method can be used to level the sensors, in the illustrated embodiment, the method includes placing the host unit 10 111 on a horizontal surface, placing a spirit level across one of the anchor sensors and on top of the GNSS receiver, and adjusting the height of sensor 112 until both are level. This can be repeated on subsequent sensors until all sensors are at the same height. Alternatively, a planar laser can be used to project a laser line that enables all sensors to be leveled. The sensors can be equipped with electronic actuators that enable them to self-level, or they can be manually leveled. The leveling process ends with the sensors in a single sensing plane.

[0076] Next, the geometry of the 113 anchor sensors and the GNSS receiver must be determined. The anchor sensors can determine their own geometry in the sensing plane by measuring the distance between each pair of sensors. This then defines the size of the triangle with vertices at the anchor sensors. However, there are still two solutions for the geometry because the system cannot detect the vertical direction. The anchor sensors must be calibrated against the GNSS antenna to merge the local and global coordinate systems. The most convenient method for this is to juxtapose the GNSS antenna and the anchor sensors so that the positions of both GNSS antennas are also used for the RF positioning network. This can also be achieved using the geometry of the antenna housing and a fixed offset from the leveling point on the antenna, allowing the GNSS antenna and the anchor sensors to share a common housing that enables precise calibration of the GNSS measurement frame and the RF positioning network. Alternatively, a fourth anchor sensor can be mounted on a GNSS rover pole. By moving this rover pole to several locations near the machine, the position of the GNSS antenna on the vehicle relative to the rover antenna can be combined with the anchor sensors on the pole to simultaneously determine the position of the GNSS antenna within the RF ranging network and solve for the geometry of the anchor sensors. For this step, it is not necessary to place the GNSS antenna or anchor sensor on the mobile pole within the sensing plane.

[0077] Next, the yaw rotation of the local positioning network relative to the vehicle's longitudinal axis needs to be calibrated. Typically, this can be handled using existing calibration routines for mounting GNSS antennas to construction equipment. However, the system according to the invention allows for an alternative method. While the combined GNSS / RF mobile pole remains stationary, the vehicle must be started and driven straight forward. This allows the system to determine the orientation of the sensor network on the main vehicle relative to the direction of travel. In this case, it is assumed that the direction of motion of the GNSS antennas is along the vehicle's longitudinal axis. For a main vehicle equipped with a pair of GNSS antennas, this motion also allows the system to calculate the yaw offset between the vector between the GNSS antennas and the vehicle's longitudinal axis. This process simply determines all mounting geometry entirely by driving the machine past the stationary mobile pole.

[0078] A single GNSS antenna can also be used instead of a pair of GNSS antennas. In this case, the heading of the master vehicle can only be determined as the master vehicle moves, i.e., the heading is determined using the trajectory heading of the GNSS position. In this case, the global velocity is measured by obtaining the finite difference between two subsequent position measurements, and it is assumed that the global velocity is along the longitudinal axis of the master vehicle. In the case of a master vehicle with dual GNSS antennas, the global heading can be determined from that pair of antennas, as can the angle between the global velocity and the vehicle heading. Regardless of the number of GNSS antennas on the master vehicle, the use of an RF ranging network allows the global position to be extended from the master vehicle to all slave vehicles, and also allows for the estimation of the travel speed and direction of the slave vehicles.

[0079] Alternatively, the Doppler of the ranging message can be used to calculate the relative velocity between the tag and the anchor. This involves an IMU with the tag, running an inertial navigation system on the tag, and using knowledge of the wheel speeds on the dependent vehicle along with its current estimate of the heading to determine the relative velocity.

[0080] After the GP-LPS is installed and calibrated on the master vehicle, a single RF ranging sensor (tag) can now be placed on the slave vehicle. Figure 3 (Step 115 in the original text). If a planar simplification is used, the sensor should be located in the sensing plane of the anchor module. It can be calibrated to this plane using any reasonable method. The position of the slave vehicle can then be tracked in a local positioning system consisting of an RF ranging network. This can be correlated with a global network that uses the GNSS measurement position on the master vehicle and the orientation of the master vehicle in a global reference frame.

[0081] This solution can be simplified by mounting the radio ranging equipment on the end of a pole that includes a laser catcher and a linear actuator. All transmitters can then be moved (i.e., raised) to the same height using a planar laser. By ensuring all transmitters are at the same height, a planar positioning solution can be used instead of a spatial solution. This additional simplification may be desirable under certain conditions.

[0082] Figure 5 A ranging protocol according to an exemplary embodiment of a system based on the present invention is illustrated. The protocol includes a two-way ranging (“ping-pong”) topology. The tag module (or “tag”) 3 of the slave vehicle requests ranging information by sending (broadcasting) an initialization signal 31, which is received by the anchor module (or “anchor”) 2 of the master vehicle (i.e., each of its anchor sensors). For example, such an initialization signal 31 may be sent every 250 ms (milliseconds). Upon receiving the initialization signal 31, the anchor 2... The distance signal 32 is sent back to tag 3. Preferably, It should be within 60ms after receiving the initialization signal. Distance signal 32 arrives at tag 3 after the first time of flight (ToF), depending on the distance d between anchor 2 and tag 3. Tag 3 quickly sends a response signal 33 to anchor 2, which arrives after the second time of flight. Anchor 2 is reached.

[0083] Response time (That is, the time between receiving the distance signal 32 and transmitting the response signal 33) is known. Preferably, the response time should be less than 1 ms, for example, about 400 μs. If the response time... If it is short enough, then advantageously, the response time can be ignored. Any relative movement between anchor 2 and tag 3 that occurs during this period allows it to be assumed that distance signal 32 and response signal 33 have the same Time of Flight (ToF). Therefore, tag 3 can be configured to have a response time. The response time It depends on the maximum expected speed (relative or absolute) of the vehicles involved—the higher their speed, the faster the response time. The smaller. Then it can be based on and The delay between and the known response time To calculate the Time-of-Flight (ToF) and therefore the current distance d between anchor 2 (i.e., each of its anchor sensors) and tag 3:

[0084]

[0085] Multiplying the calculated flight time by the speed of light, each nanosecond equals approximately 30 cm of distance between anchor 2 and tag 3. The relative position can be derived from the distance from the anchor's sensor to the tag. Adding the known GNSS coordinates of anchor 2, the tag's position in GNSS coordinates can be determined. This position is included as a report signal 34 in the payload and sent to tag 3.

[0086] Distance calculation can occur on a radio, an anchor, or a mobile radio. For example, the anchor sends a signal, the mobile radio responds, and the anchor calculates the distance to the radio and sends it back to the mobile radio along with its positioning information. Alternatively, this can be reversed: the mobile radio sends a message, and the anchor then sends a response message appending the anchor's current global location to the response message. The mobile radio then calculates its own distance to the anchor. Due to necessary timing, these systems can be configured to send messages absolutely not simultaneously. For example, they can include patterns that pre-schedule each message to avoid message collisions and cycle slips.

[0087] Alternatively, the anchors on the main vehicle can provide the IDs and network geometry of all anchors. This allows mobile radio tags to calculate their own positions relative to the anchors' global GNSS coordinates. This reduces the computational and communication load on the anchors, as they only need to send their current position and the possible distance to the mobile radio. The mobile radio tags then include their latest global position to the anchor as part of a distance message initiated by the mobile radio tag. This minimizes crosstalk between anchors while maintaining an updated central list of tag positions. In an alternative implementation where one or more anchors calculate the mobile radio positions, the anchors must communicate with each other. In this case, the anchor network must determine which anchor will calculate the position of each mobile radio tag. The anchors must then share distance calculations so that the anchors can calculate the positions of the mobile radio tags. The anchors must then combine these list of tag positions to have a complete central list. The choice between these two alternatives depends on network bandwidth and processing and power constraints. In systems where tags are battery-powered and very simple, it may be advantageous to have the anchors attached to the vehicle's power supply provide as much computation as possible. In bandwidth-constrained situations, it may be preferable to minimize radio traffic and therefore have the tags calculate their own position solutions.

[0088] All signals 31, 33, 34 can be transmitted in the ultra-wideband (UWB) frequency range. In particular, the initialization signal 31 and the reporting signal 34 can also include payloads containing information about the respective module or vehicle. For example, the information included in the initialization signal 31 may include the identifier of the tag module 3 and / or the slave vehicle, current speed, or other status information. The information included in the reporting signal 34 may include the identifier of the anchor module 2 and / or the master vehicle (especially if more than one vehicle includes an anchor module), current speed, or direction of travel, or other status information. Furthermore, the reporting signal 34 can be used to provide software updates or similar data to the tag module 3.

[0089] Data can also be included in the ranging message, allowing tags to report their current global location and their ID to the anchor when they request distance from it. The anchor can include its global location, master vehicle orientation, and anchor network geometry, and may include the distance to the tag when responding to the tag's distance request. This data exchange can be identical regardless of which sensor calculates the distance. If the anchor calculates the distance, the tags can still calculate their own location.

[0090] By bridging their global position and velocity from the master vehicle to the slave vehicle, the slave vehicle can be automated or controlled within the global framework without requiring its own GNSS antenna or receiver.

[0091] Some implementations of this system allow for different ranging protocols by which subordinate vehicles can calculate their own (absolute) positions. In this case, the system utilizes the following:

[0092] 1. The RF ranging sensor (tag) on ​​the slave machine sends messages to each RF ranging sensor (anchor sensor) on the master machine.

[0093] 2. Each anchor sensor responds to a message from the tag. The data packet includes the anchor sensor ID, the main vehicle's GNSS position, heading, and speed, as well as the processing time (response time) between receiving the message and sending the response.

[0094] 3. When the tag receives a response from each anchor sensor, it can use the two-way time of flight of the message to calculate the distance between the sensors.

[0095] 4. The updated distance from the master vehicle to the slave vehicle from the ranging network can be used with information about the global position and motion of the master vehicle to locate the slave vehicle within the ranging network and the global reference frame, including position, heading, and speed.

[0096] Using this architecture, ranging can be achieved without slave machines communicating with each other, and without the master machine needing computing power to perform positioning calculations for each slave machine. In this type of network, additional messages defined for communication between RF ranging sensors are useful. Sensors on the master machine can be configured to act as the base network, and sensors on slave machines can be configured to act as mobile sensors. Upon startup, the mobile sensors can broadcast a wake-up message (similar to...). Figure 5 The initialization signal 31) and wake-up message include their sensor IDs. Upon receiving such a broadcast wake-up message, the sensors configured as base network sensors will respond with their own IDs and information about the network geometry, i.e., which other sensor IDs correspond to the geometry of the base network RF ranging sensors and GNSS antennas and base network sensors in the master vehicle coordinate system.

[0097] If the slave vehicle has surface data associated with its GNSS position, it can also use its own position, the master vehicle's position, and the GNSS map to compensate for its positional solution for non-planar surfaces. That is, each slave vehicle can compensate for the movement of its RF sensors within or outside the sensing plane due to the shape of the surface it is driving over.

[0098] In a vehicle fleet comprising excavators or wheel loaders operating as primary machines and dump trucks operating as secondary machines, a local positioning system is used to locate trucks near the loaders or excavators. This can be used to provide instructions to truck operators on where to park. It can also be used to provide excavator or loader operators with information about where the trucks are parked, or as input to an automated system that operates to automatically load trucks using excavators or wheel loaders. In this example, the tag's peer-to-peer communication capability can provide additional functionality. For example, if the excavator or wheel loader is equipped with a load metering system, the tag can be used to automatically associate each batch of material load with the truck receiving the material. If the truck then passes through a scale or is equipped with an onboard load metering system, the weight measured by the truck can be cross-checked with the wheel loader or excavator's system.

[0099] The accuracy of the proposed positioning solution can be improved by including additional RF ranging sensors in the network. Utilizing a fourth RF ranging sensor on the master machine allows for the use of a best-fit algorithm to perform the positional solution for the slave machine, which is less sensitive to measurement noise than a direct solution. Similarly, the use of the best-fit solution can be extended to the calculation of the global velocity of the slave machine.

[0100] In cases where planar simplification is insufficient, for example, if the RF ranging sensors on the slave vehicle cannot be placed within the sensing plane, the above workflow can be extended to a 3D system. This requires a set of four RF ranging sensors (anchor sensors) on the master vehicle to determine the 3D position of the slave vehicle. These four sensors must be arranged in a non-planar network. That is, for any plane consisting of three RF ranging sensors, the fourth sensor must not be located in or near the plane. It is desirable to have the widest possible offset from the physically possible plane on the vehicle to provide the best possible geometry for the positioning solution. As in the 2D case, additional RF ranging sensors can be included on the master vehicle to allow the use of a best-fit solution to calculate the position of the slave vehicle.

[0101] While solutions described above may have a single slave vehicle or an architecture configured only for communication between the master vehicle and each of the multiple slave vehicles, alternatively, additional RF ranging measurements between various slave vehicles can be included to obtain a better solution for network geometry. In the case of peer-to-peer slave vehicles, rules can be set such that a first subset of slave vehicles communicates with the master vehicle, and then they themselves act as the localization network for the other subsets of slave vehicles. Advantageously, this allows the system to dynamically assign multiple groups of vehicles to different subnets to optimize the communication load on all RF ranging sensors and prevent any particular sensor from exceeding its communication bandwidth.

[0102] Although the invention has been described above with reference to some preferred embodiments, it should be understood that many modifications and combinations of different features of the embodiments can be made. All such modifications are within the scope of the appended claims.

Claims

1. A method (100) for continuously determining the position of one or more moving vehicles in a vehicle group (1), the vehicle group comprising a master vehicle (10) and one or more subordinate vehicles (11, 12, 13), the master vehicle being equipped with one or more components (51, 52) of a reference positioning system (5), the reference positioning system providing reference position information about the position of the one or more components (51, 52) in a reference coordinate system, the method comprising: An anchor module (2) is provided at the main vehicle (10), the anchor module comprising at least three radio frequency sensors (21, 22, 23) positioned on the main vehicle (10) in a known spatial relationship with each other and with respect to one or more components (51, 52), each of the radio frequency sensors (21, 22, 23) being configured to transmit and receive radio signals; A tag module (3, 3', 3'') is provided on each of the subordinate vehicles (11, 12, 13), each tag module being configured to transmit and receive radio signals; as well as Perform one or more ranging procedures to continuously determine the position of each of the subordinate vehicles (11, 12, 13), wherein the one or more ranging procedures include at least a first ranging procedure for determining the position of the first subordinate vehicle (11). The first ranging process includes: The position of the radio frequency sensor (21, 22, 23) in the reference coordinate system is determined using the reference position information and the known spatial relationship (120); A set of radio signals (32, 33) is exchanged (130) between the first tag module (3) on the first subordinate vehicle (11) and each of the radio frequency sensors (21, 22, 23). Calculate the flight time of each group of radio signals (32, 33) (140); Based on the determined flight times of the corresponding set of radio signals (32, 33), the distance between the first tag module (3) and each of the corresponding radio frequency sensors (21, 22, 23) is calculated (150). , , ); Based on the calculated distance ( , , ) Export (160) the position of the first tag module (3) and / or the first subordinate vehicle (11) in the reference coordinate system; and Provide (170) a report signal (34) indicating the outgoing position of the first subordinate vehicle (11).

2. The method (100) according to claim 1, wherein, The reference positioning system (5) is a GNSS positioning system (5), and the one or more components (51, 52) are one or more GNSS antennas configured to receive GNSS signals. The GNSS positioning system (5) provides GNSS location information about the position of the one or more GNSS antennas in the GNSS coordinate system.

3. The method (100) according to claim 1 or 2, wherein, The frequencies of the set of radio signals (32, 33) are in the ultra-wideband range.

4. The method (100) according to any one of the preceding claims, wherein, The set of radio signals includes a distance signal (32) and a response signal (33), wherein The distance signal (32) is emitted by the radio frequency sensors (21, 22, 23) of the anchor module (2), and the response signal (33) is emitted by the first tag module (3) in response to receiving the distance signal (32), particularly wherein the radio frequency sensors (21, 22, 23) simultaneously emit the distance signal (32); or The distance signal (32) is emitted by the first tag module (3), and the response signal (33) is emitted by the radio frequency sensor (21, 22, 23) of the anchor module (2) in response to receiving the distance signal (32), wherein the radio frequency sensor (21, 22, 23) simultaneously emits the response signal (33).

5. The method (100) according to claim 4, wherein The response signal (33) is emitted after a known response time, and in particular, The response time is less than 1ms; as well as Calculate (150) the distance between the first tag module (3) and each of the radio frequency sensors (21, 22, 23). , , Also based on the aforementioned response time, Specifically, the distance signal (32) is transmitted at a first time point and the response signal is received at a second time point, wherein the flight time of the set of radio signals (32, 33) is calculated (140) based on the following equation: Where ToF is the time of flight. It is the first point in time. It is the second time point, and The response time is known, and in particular, each flight time is calculated at the anchor module (2).

6. The method (100) according to claim 4 or 5, wherein, The first tag module (3) transmits an initialization signal (31) and transmits the distance signal (32) upon receiving the initialization signal (31), wherein the initialization signal (31) includes information that allows identification of the first tag module (3) and / or the first subordinate vehicle (11).

7. The method (100) according to any one of the preceding claims, wherein, The reporting signal (34) is provided (170) to the first subordinate vehicle (11), wherein the position of the first subordinate vehicle (11) is... Displayed to the operator of the first subordinate vehicle (11); and / or A machine control unit provided to the first subordinate vehicle (11) is used to at least partially control the operation of the first subordinate vehicle (11). In particular, providing the report signal (34) (170) includes transmitting the report signal (34) by at least one of the radio frequency sensors (21, 22, 23) and receiving the report signal (34) by the first tag module (3).

8. The method (100) according to any one of the preceding claims, wherein, Provided (110) the anchor module (2) includes Position (112) at least three radio frequency sensors (21, 22, 23) of the anchor module (2) in a common plane, particularly wherein the common plane is a horizontal plane; Determine (113) the geometry of the radio frequency sensor (21, 22, 23) and the one or more components (51, 52); and Determine (114) the orientation of the radio frequency sensors (21, 22, 23) relative to the forward direction of the main vehicle (10). Especially among them In order to adjust (112) the radio frequency sensor of the anchor module (2) to be at the same height, the main vehicle (10) is placed (111) on a horizontal surface; and / or Providing (115) the label modules (3, 3', 3'') includes positioning each label module (3, 3', 3'') in the common plane.

9. The method (100) according to any one of the preceding claims, wherein, The anchor module (2) includes at least four radio frequency sensors, wherein the derived position of the first tag module (3) and / or the first subordinate vehicle (11) is a 3D position, which is derived based on the calculated distance between the first tag module (3) and the at least four radio frequency sensors, particularly wherein - The 3D position of the first subordinate vehicle (11) is derived relative to the master vehicle (10); and / or Providing (110) the anchor module (2) includes positioning (112) at least three radio frequency sensors (21, 22, 23) of the anchor module (2) in a common plane and positioning at least one radio frequency sensor (21, 22, 23) of the anchor module (2) outside the common plane.

10. The method (100) according to any one of the preceding claims, wherein, The set of radio signals (32, 33) is exchanged iteratively, particularly at least every 500 ms, wherein each iteration of exchanging the set of radio signals (32, 33) enables the calculation (150) of the distance, the derivation (160) of the position of the first subordinate vehicle (11), and the provision (170) of the reporting signal (34).

11. The method (100) according to claim 10, wherein the method comprises: The anchor module (2) receives speed information about the current speed of the main vehicle (10); as well as Based on the speed information and multiple calculated distances and / or derived locations, the current or most recent speed of the first subordinate vehicle (11) is calculated. The reporting signal (34) also indicates the current or recent speed of the first subordinate vehicle (11), and in particular, the reporting signal (34) also indicates the current speed of the master vehicle (10).

12. The method (100) according to any one of the preceding claims, wherein, The fleet (1) includes at least two subordinate vehicles (11, 12), and the method includes at least a second ranging process for continuously determining the position of the second subordinate vehicle (12), in particular, wherein the fleet (1) includes a plurality of subordinate vehicles (11, 12, 13), and the method includes a plurality of simultaneously executed ranging processes for continuously determining the positions of the plurality of subordinate vehicles (11, 12, 13).

13. A vehicle positioning system configured to continuously determine the positions of one or more moving vehicles in a vehicle group (1) based, particularly on the method (100) according to any one of claims 1 to 13, the vehicle group comprising a master vehicle (10) and one or more subordinate vehicles (11, 12, 13), the master vehicle being equipped with a reference positioning system (5) comprising one or more components (51, 52), the reference positioning system (5) providing reference position information regarding the position in a reference coordinate system. Its features An anchor module (2) is disposed at the main vehicle (10), the anchor module comprising at least three radio frequency sensors (21, 22, 23) positioned on the main vehicle (10) in a known spatial relationship with each other and with respect to one or more components (51, 52), each of the radio frequency sensors (21, 22, 23) being configured to transmit and receive radio signals; as well as Tag modules (3, 3', 3'') are installed on each of the subordinate vehicles (11, 12, 13), and each tag module is configured to transmit and receive radio signals. The positioning system is configured to perform at least a first ranging process for continuously determining the position of a first subordinate vehicle (11), the first ranging process including: The position of the radio frequency sensor (21, 22, 23) in the reference coordinate system is determined using the reference position information and the known spatial relationship (120); A set of radio signals (32, 33) is exchanged (130) between the first tag module (3) on the first subordinate vehicle (11) and each of the radio frequency sensors (21, 22, 23). Calculate the flight time of each group of radio signals (32, 33) (140); Based on the determined flight times of the corresponding set of radio signals (32, 33), the distance between the first tag module (3) and each of the corresponding radio frequency sensors (21, 22, 23) is calculated (150). , , ); Based on the calculated distance ( , , ) Export (160) the position of the first tag module (3) and / or the first subordinate vehicle (11) in the reference coordinate system; and Provide (170) a report signal (34) indicating the outgoing position of the first subordinate vehicle (11).

14. The vehicle positioning system according to claim 13, wherein, The reference positioning system (5) is a GNSS positioning system (5), and the one or more components (51, 52) are one or more GNSS antennas configured to receive GNSS signals. The GNSS positioning system (5) provides GNSS location information about the position of the one or more GNSS antennas in the GNSS coordinate system.

15. A computer program product for performing one or more ranging processes of the method (100) according to any one of claims 1 to 12.

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