A device and method for positioning based on WIA-FA network

Abstract

This invention also discloses a device and method for positioning based on a WIA-FA network, relating to the field of positioning technology. The device includes: a gateway device (GW), at least three wireless access devices (ADs), and a field device (FD) to be located. The gateway device is connected to each wireless access device via a wired connection to implement WIA-FA protocol control. The wireless access devices convert the wired signal from the gateway device into radio electromagnetic wave signals and transmit them to the field device through the wireless WIA-FA network. During positioning, the output power of the wireless access devices is acquired in real time, and the location information of the field device is calculated based on the acquired output power. This invention improves the positioning accuracy of the RSSI algorithm by real-time acquisition of the signal strength of the output positioning power devices to compensate for their dynamic changes.

Description

Technical Field

[0001] This invention relates to the field of positioning technology, and in particular to a device and method for positioning based on WIA-FA network. Background Technology

[0002] Currently, there are many indoor positioning technologies, such as infrared, Bluetooth, Zigbee, and WIFI wireless technologies. They all basically use RSSI (Received Signal Strength Indication), which measures the distance between the signal point and the receiving point by the strength of the received signal, and then performs positioning calculations based on the corresponding data.

[0003] The RSSI method assumes that the output power of the device is a fixed value during design. However, in actual operation, the output power varies slightly, resulting in a relatively large positioning accuracy error for RSSI, particularly for moving objects, which can easily deviate from the designed path.

[0004] To compensate for the uncertainties caused by dynamic changes in output power and improve the safe and reliable operation of moving objects indoors, there is an urgent need for a solution that can eliminate or reduce the impact of dynamic changes in output power on RSSI positioning accuracy. Summary of the Invention

[0005] In view of this, the present invention provides a device and method for positioning based on WIA-FA network, which can achieve dynamic and efficient capture of the device's output power and improve RSSI positioning accuracy.

[0006] Therefore, the present invention provides the following technical solution:

[0007] This invention discloses a WIA-FA network-based positioning device, comprising: a gateway device, at least three wireless access devices, and a field device to be located; the field device to be located is located within the signal coverage area of ​​a plane defined by the coordinate points of the at least three wireless access devices;

[0008] The gateway device is connected to each of the wireless access devices via a wired connection to achieve WIA-FA protocol control;

[0009] The wireless access device converts the wired signal of the gateway device into a radio electromagnetic wave signal and transmits it to the field device through the wireless WIA-FA network.

[0010] During positioning, the output power of the wireless access device is acquired in real time, and the location information of the field device is calculated based on the acquired output power.

[0011] Furthermore, the gateway device is used to configure the output power, operating frequency, and operating mode of the wireless access device and the field device.

[0012] Furthermore, the field device is a mobile device.

[0013] This invention also discloses a WIA-FA network-based positioning method, applied to the aforementioned WIA-FA network-based positioning device, comprising:

[0014] Obtain the path loss index of the space where the field equipment is located;

[0015] Each wireless access device transmits wireless signals through the WIA-FA network at different times and sends the output power and coordinate points to the field devices.

[0016] The field equipment acquires the received strength of the output power of each wireless access device at each transmission time;

[0017] The distance is calculated using the strength calculation formula based on the default output power of the wireless access device.

[0018] By comparing the calculated distance with the coordinates sent by the WIA-FA network, the real-time output power of the same wireless access device is obtained by solving the different coordinates corresponding to each wireless access device sent each time.

[0019] The average value of the real-time output power collected from multiple acquisitions is taken, and the location information of the field device is calculated based on the average value of the real-time output power.

[0020] The strength calculation formula is as follows:

[0021] Prad = 10^(Pt - 10*log10(SP*(C / F)^2 / ((4*π)^2)) + 10*n*log10(D / SP) / 10); where Prad is the received signal strength, Pt is the output power, D is the distance, SP is the standard parameter with a value of 1, C is the electromagnetic velocity, F is obtained from the channel table, and n is the path loss exponent.

[0022] Further, calculating the location information of the field device based on the output power includes:

[0023] Substitute the real-time output power into the intensity calculation formula to calculate the spherical distance from the field device to each wireless access device, and calculate the dynamic position of the field device based on the spherical distance from the field device to each wireless access device.

[0024] Further, calculating the dynamic position of the field device based on the spherical distance from the field device to each wireless access device includes:

[0025] The dynamic position of the field device is calculated using a position calculation formula based on the spherical distance from the field device to each wireless access device; wherein the position calculation formula is:

[0026] (x1–x)^2+(y1-y)^2+(z1-z)^2=r1^2;

[0027] (x2–x)^2+(y2-y)^2+(z2-z)^2=r2^2;

[0028] (x3–x)^2+(y3-y)^2+(z3-z)^2=r3^2;

[0029] Where (x, y, z) are the coordinates of the field device in the coordinate system established with the gateway device as the origin, (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3) are the coordinates of the first, second, and third wireless access devices in the coordinate system established with the gateway device as the origin, respectively; r1, r2, and r3 are the spherical distances from the field device to the first, second, and third wireless access devices, respectively.

[0030] Furthermore, when using three wireless access devices for positioning, the coordinate point error is accurate to the centimeter level.

[0031] Furthermore, the path loss index of the space where the field equipment is located is obtained, including:

[0032] Query the path loss index of the space where the field equipment is located from the path loss index table.

[0033] Furthermore, the path loss index table includes:

[0034] Free space, urban cellular, urban cellular shadow, line-of-sight propagation within buildings, path loss index due to building obstruction, and complex spaces.

[0035] Furthermore, the path loss exponent of the complex space is calculated as follows:

[0036] In complex spaces, a standard constant signal source outputs constant power, and multiple distances are collected. The constant power, received strength, and distance are then substituted into the strength calculation formula to calculate the path loss index in complex spaces.

[0037] Advantages and positive effects of the present invention: In the present invention, by acquiring the signal strength of the output positioning power device in real time, the dynamic changes of the signal are compensated for, thereby improving the accuracy of Pt in the RSSI algorithm.

[0038] Furthermore, this invention also improves the distance measured from the RSSI algorithm, thereby improving the positioning accuracy of moving objects. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the structure of a WIA-FA network-based positioning device according to an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the basic location information of the device based on WIA-FA network positioning in an embodiment of the present invention. Detailed Implementation

[0042] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0043] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0044] In indoor private network positioning, the RSSI algorithm is generally used to calculate the location information of moving objects. This algorithm assumes that the output power of the device is constant. However, the output power of wireless devices varies dynamically during operation, resulting in relatively large accuracy errors when using infrared, Bluetooth, Zigbee, and WIFI for positioning. To compensate for the uncertainty caused by the dynamic changes in output power and improve the reliability and safety of moving objects indoors, this invention provides a device and method based on WIA-FA network positioning. This method can achieve highly efficient dynamic capture of the device's output power, that is, to obtain the device's output power in real time and accurately, thereby improving RSSI positioning accuracy.

[0045] like Figure 1 As shown, an embodiment of the present invention provides a WIA-FA network-based positioning device, comprising: a gateway device (GW), a wireless access device (AD), and field devices (FDs) to be located. Mirror locations have the same physical characteristics; therefore, n FDs should be within the signal coverage area of ​​a plane established by at least three AD coordinate points to avoid positioning errors caused by differences in physical characteristics. Wherein:

[0046] The gateway device (GW) manages the entire wireless network. It connects to the wireless access devices (ADs) via a wired connection to implement WIA-FA protocol control. The gateway device (GW) is used to configure the operating parameters of the entire network, specifically the output power, operating frequency, and operating mode of the wireless access devices (ADs) and field devices (FDs).

[0047] The wireless access device (AD) transmits and receives wired data from the gateway using wireless WIA-FA technology.

[0048] The field device (FD) can communicate with the wireless access device (AD) via a wireless WIA-FA network.

[0049] During positioning, the gateway device (GW) transmits data to the wireless access devices (ADs) via the network interface. The ADs convert the input wired signal into a radio electromagnetic wave signal for output. The field device (FD) receives the radio electromagnetic wave signal and converts it back into a wired signal for output. Simultaneously, when the ADs output radio electromagnetic wave signals, other ADs also receive them. To enable the positioning of moving objects, the design uses at least three ADs as the output of the wireless WIA-FA signal. The output power of the wireless access devices is acquired in real time based on the signal transmission and reception of the WIA-FA network, and the location information of the field devices is calculated based on the real-time acquired output power.

[0050] A WIA-FA network-based positioning method according to an embodiment of the present invention, applied to the aforementioned WIA-FA network-based positioning device, includes:

[0051] The path loss index in complex spaces is collected, and a constant power is output through a standard constant signal source. The data is collected at more than three distances. The collected distance D, output power Pt, and received strength Pr are substituted into the strength calculation formula to calculate n, which is used as the basic data source.

[0052] The equipment collects accurate basic location information at the work site: such as Figure 2 As shown, the distances between the three ADs are D12, D13, and D23. Using GW as the origin, the coordinates of the ADs in their respective coordinate systems—AD1(x1, y1, z1), AD2(x2, y2, z2), and AD3(x3, y3, z3)—are obtained through surveying. This forms the basic information, which provides the basis for calculating the location information. When using the three ADs for positioning, the coordinate point error is accurate to the centimeter level.

[0053] When AD1 transmits a radio electromagnetic signal (frequency F), the other two ADs receive it with strengths of Prad12 and Prad13 respectively. Substituting the distance and received strength Prad into the strength calculation formula, the relationship between AD1's output power and its corresponding point is calculated. In the WIA-FA network calculation process, since the WIA-FA network outputs radio signals time-based, when AD1 transmits at time t1, AD2 receives AD1's output power and distance data, and the output power and distance {Ptad12, D12} corresponding to AD1's output are calculated for AD2, and the output power and distance {Ptad13, D13} corresponding to AD3's output are calculated for AD3.

[0054] At time t2, device AD2 is transmitting, AD1 receives the output power and distance data of AD2 {Ptad21, D12}, and AD3 receives the output power and distance data of AD2 {Ptad23, D23}.

[0055] At time t3, the AD3 device is transmitting, AD1 receives the AD3 output power and distance data {Ptad31, D13}, and AD2 receives the AD3 received power and distance data {Ptad32, D23}.

[0056] The output power and coordinate points are sent to the field device FD via the WIA-FA technical protocol. At times t1, t2, and t3, FD obtains the corresponding received power Pr1, Pr2, and Pr3 of AD1, AD2, and AD3. Then, the intensity calculation formula is used to calculate the distance D using the default AD device output power. The calculated distance D is compared with the position Dxx sent by the protocol. For each output device sent, the output power of the same device corresponding to different positions is calculated, and the most recent received power is obtained for calculation. The final output power Ptadxx is substituted into the intensity calculation formula to calculate the three spherical distances Dfd1(r1), Dfd2(r2), and Dfd3(r3) from FD to AD1, AD2, and AD3. Finally, the dynamic position (x, y, z) of coordinate FD is calculated using the position calculation formula.

[0057] In practice, the output power can be collected and determined multiple times, and the average value of multiple output power values ​​can be taken. The distance can then be calculated based on the average value, which can eliminate random interference and improve positioning accuracy.

[0058] Strength calculation formula:

[0059] Prad=10^(Pt-10*log10(SP*(C / F)^2 / ((4*pi)^2))+10*n*log10(D / SP) / 10);

[0060] The standard parameter SP = 1, electromagnetic wave velocity C = 3 * 10^8, F is obtained from the channel table, pi = 3.1415926, and n is the path loss exponent. The environment in which the setting is performed is a complex space, which is obtained or calculated from the path loss exponent table.

[0061] Location calculation formula:

[0062] (x1–x)^2+(y1-y)^2+(z1-z)^2=r1^2;

[0063] (x2–x)^2+(y2-y)^2+(z2-z)^2=r2^2;

[0064] (x3–x)^2+(y3-y)^2+(z3-z)^2=r3^2;

[0065] Where (x, y, z) are the coordinates of the field device in the coordinate system established with the gateway device as the origin, (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3) are the coordinates of the first, second, and third wireless access devices in the coordinate system established with the gateway device as the origin, respectively; r1, r2, and r3 are the spherical distances from the field device to the first, second, and third wireless access devices, respectively.

[0066] The channel correspondence tables are shown in Table 1 and Table 2.

[0067] Table 1

[0068] environment Path loss index Free space 2 Urban honeycomb 2.6～3.5 Urban honeycomb shadow 3～5 Line-of-sight propagation within buildings 1.6～1.8 Blocked by buildings 4～6 Complex Space calculate

[0069] Table 2

[0070]

[0071]

[0072] To facilitate understanding, a specific example is provided below to illustrate the above-mentioned WIA-FA network-based positioning method.

[0073] A WIA-FA network is set up in the production unit workshop, which has a floor area of ​​20×50 meters. The design adopts 1 WG, 3 AD and 2 FD, and the FD is installed on a moving vehicle.

[0074] Because the production workshop is relatively complex, the path loss index is obtained by measurement. First, the standard constant signal source is fixed and the output signal channel is adjusted. Channel 1 is used in this case. By adjusting the distance D between the receiving unit and the signal source, the received power Pr is collected. In this case, D is the maximum distance divided into 5 equal parts, i.e., D = {10, 20, 30, 40, 50}, corresponding to Pr. The data is substituted into the strength calculation formula to obtain the value of n, and then averaged to obtain the final value of n as the basic data. The working channel of the device in the network is channel 1, i.e., F = 2412MHz.

[0075] Since the workshop uses only require the vehicle's planar position information, the design places the coordinates of the WG at a point (x0, y0) on the plane corresponding to one AD coordinate point, which is the origin of the AD coordinates. The other two ADs are perpendicular to the origin. This facilitates the calculation of position information. By obtaining the coordinates (x1, y1), (x2, y2) and the relative distances D12, D13, and D23 of the three ADs, the basic data processing is completed. At the same time, the initial output power of the three ADs is obtained as references Ptad1, Ptad2, and Ptad3. The FD is installed at the center point of the vehicle to facilitate the calculation of the vehicle's position. This completes the basic data and the installation and deployment of the equipment.

[0076] When the vehicle moves within the production unit's workshop, once the WIA-FA network initialization is complete and the AD and FD begin data transmission, the AD acquires real-time data from other AD devices via the network, simultaneously obtaining the power output of other AD devices and calculating the real-time output power Pt of the corresponding AD. It then synchronizes the output power and distance data to other devices in the network (FD and AD). When the FD acquires real-time data via the WIA-FA network, including the corresponding AD device's output power and distance data, the FD calculates the distance sphere D between the real-time AD output signal strength and the received signal strength using the strength calculation formula (where F = 2.412 * 10^9). By substituting the distances D of the three AD devices into the position calculation formula, and since only planar coordinates need to be calculated, the z-axis calculation can be omitted, reducing the computational difficulty, thus obtaining the vehicle's position information (x, y) on a planar map composed of basic data.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device based on WIA-FA network positioning, characterized in that, include: The system includes a gateway device, at least three wireless access devices, and a field device to be located; the field device to be located is located within a planar signal coverage area defined by the coordinates of the at least three wireless access devices. The gateway device is connected to each of the wireless access devices via a wired connection to achieve WIA-FA protocol control; The wireless access device converts the wired signal of the gateway device into a radio electromagnetic wave signal and transmits it to the field device through the wireless WIA-FA network. During positioning, the output power of the wireless access device is acquired in real time, and the location information of the field device is calculated based on the acquired output power. The device performs WIA-FA network-based positioning according to the following method, including: Obtain the path loss index of the space where the field equipment is located; Each wireless access device transmits wireless signals through the WIA-FA network at different times and sends the output power and coordinate points to the field devices. The field equipment acquires the received strength of the output power of each wireless access device at each transmission time; The distance is calculated using the strength calculation formula based on the default output power of the wireless access device. By comparing the calculated distance with the coordinates sent by the WIA-FA network, the real-time output power of the same wireless access device is obtained by solving the different coordinates corresponding to each wireless access device sent each time. The average value of the real-time output power collected from multiple acquisitions is taken, and the location information of the field device is calculated based on the average value of the real-time output power. The strength calculation formula is as follows: Prad = 10^(Pt - 10 * log10(SP * (C / F)^2 / ((4 * π)^2)) + 10 * n * log10(D / SP) / 10); where Prad is the received signal strength, Pt is the output power, D is the distance, SP is the standard parameter with a value of 1, C is the electromagnetic velocity, F is obtained from the channel table, and n is the path loss exponent.

2. The device based on WIA-FA network positioning according to claim 1, wherein, The gateway device is used to configure the output power, operating frequency, and operating mode of wireless access devices and field devices.

3. The device for positioning based on a WIA-FA network according to claim 1, characterized in that, The field device is a mobile device.

4. The device for positioning based on a WIA-FA network according to claim 1, characterized in that, Calculating the location information of the field device based on the output power includes: Substitute the real-time output power into the intensity calculation formula to calculate the spherical distance from the field device to each wireless access device, and calculate the dynamic position of the field device based on the spherical distance from the field device to each wireless access device.

5. A device for positioning based on a WIA-FA network according to claim 1, characterized in that, Calculating the dynamic position of the field device based on the spherical distance from the field device to each wireless access device includes: The dynamic position of the field device is calculated using a position calculation formula based on the spherical distance from the field device to each wireless access device; wherein the position calculation formula is: (x1–x)^2 + (y1-y)^2+ (z1-z)^2 = r1^2; (x2–x)^2 + (y2-y)^2+ (z2-z)^2= r2^2; (x3–x)^2 + (y3-y)^2+ (z3-z)^2= r3^2; Where (x, y, z) are the coordinates of the field device in the coordinate system established with the gateway device as the origin, (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3) are the coordinates of the first, second, and third wireless access devices in the coordinate system established with the gateway device as the origin, respectively; r1, r2, and r3 are the spherical distances from the field device to the first, second, and third wireless access devices, respectively.

6. The device for positioning based on a WIA-FA network according to claim 1, characterized in that, When using three wireless access devices for positioning, the coordinate point error is accurate to the centimeter level.

7. The device for positioning based on a WIA-FA network according to claim 1, characterized in that, Obtain the path loss index of the space where the field equipment is located, including: Query the path loss index of the space where the field equipment is located from the path loss index table.

8. A device for positioning based on a WIA-FA network according to claim 7, characterized in that, The path loss index table includes: Free space, urban cellular, urban cellular shadow, line-of-sight propagation within buildings, path loss index due to building obstruction, and complex spaces.

9. A device for positioning based on a WIA-FA network according to claim 8, characterized in that, The path loss index of the complex space is calculated as follows: In complex spaces, a standard constant signal source outputs constant power, and multiple distances are collected. The constant power, received strength, and distance are then substituted into the strength calculation formula to calculate the path loss index in complex spaces.

Images