Method for drawing WIFI signal intensity distribution diagram

Abstract

The invention discloses a WIFI signal intensity distribution diagram drawing method, and belongs to the field of communication. On the basis of the rotary laser range finder, the house type image is automatically generated on site, and pre-input or manual drawing is not needed. In the construction process of the plane house type image, WIFI signal intensity collection is carried out in real time on a test motion track path, the position of a test point does not need to be limited, and meanwhile the true accuracy of the position of the test point in the house type is guaranteed. In the testing process, a gradually improved visual WIFI signal intensity distribution diagram can be visually displayed in real time. According to the method, the drawing complexity of the WIFI signal intensity distribution diagram is simplified, and the real accuracy of the WIFI signal sampling points is ensured. The complexity of obtaining the house type image is reduced, and the WIFI signal intensity distribution diagram and the house type image are accurately superposed, so that the display of the WIFI signal intensity distribution diagram is more visual and fits the actual situation.

Description

Technical Field

[0001] The present invention relates to the field of communications, and in particular to a method for drawing a WIFI signal strength distribution diagram. Background Art

[0002] Regarding the drawing of indoor WIFI (Wireless Fidelity) signal strength distribution map, the existing technology generally includes three steps: first, manually drawing or obtaining the indoor floor plan from the developer or property management agency; second, performing a WIFI signal strength test at a designated location indoors according to the indoor floor plan; finally, generating a WIFI signal strength distribution map according to the obtained WIFI signal strength, and then overlaying it with the floor plan for display.

[0003] In the process of drawing the WiFi signal strength distribution map, it is difficult to ensure the feasibility of obtaining the floor plan from the developer or property management company, and there is usually no ready-made floor plan available during the collection. If it is drawn according to the on-site environment, it is difficult to ensure the accuracy of the data, and it also brings extra workload to the testers.

[0004] The existing testing methods cannot determine the true coordinates of the test points on the floor plan, which results in errors or lack of authenticity in the final drawing results. At the same time, the limited test point collection method also makes the work of testers more complicated. Summary of the invention

[0005] The present invention provides a method for drawing a WIFI signal strength distribution diagram, which simplifies the drawing complexity of the WIFI signal strength distribution diagram and ensures the true accuracy of the WIFI signal sampling points.

[0006] The present invention provides the following technical solutions:

[0007] A method for drawing a WIFI signal strength distribution diagram, the method comprising:

[0008] S10: Move the test device steadily;

[0009] The test device includes a processor, a rotating laser rangefinder, a WIFI module, an IMU inertial measurement unit and a display device. The moving trajectory of the test device should pass through the entire space, and the rotating laser rangefinder should illuminate each wall of the entire space.

[0010] S20: During the movement of the test device, the straight-line distance data from each test point on the moving trajectory to the wall is collected in real time by the rotating laser rangefinder, the three-axis attitude angle data of each test point of the test device on the moving trajectory is collected in real time by the IMU inertial measurement unit, and the signal strength of each test point on the moving trajectory of all WIFI hotspots in the environment is scanned in real time by the WIFI module;

[0011] S30: the processor generates a floor plan and a moving trajectory in real time according to the straight-line distance data and the three-axis attitude angle data, and displays them on the display device in real time;

[0012] S40: After the test device is moved, information of all WIFI hotspots scanned this time is displayed on the display device, the WIFI hotspot used in the apartment is selected, and the placement position of the WIFI router on the apartment map is marked;

[0013] S50: generating a signal strength distribution map of the WIFI hotspots used in the apartment type according to the placement position of the WIFI router on the apartment type diagram and the signal strength of each test point of the WIFI hotspots used in the apartment type on the moving trajectory.

[0014] Furthermore, the rotary laser rangefinder can automatically rotate 360°; the testing device is moved by hand-held means, or the testing device is moved by a mobile platform.

[0015] Furthermore, when the testing device is moved by hand, the testing device is provided with a handheld stabilizer.

[0016] Furthermore, the floor plan is generated by the following method:

[0017] S31: Calculate the position data of each point on the wall according to the position of each test point on the moving trajectory and the straight-line distance data to the wall and the three-axis attitude angle data;

[0018] S32: performing a straight line fitting operation to obtain line segments according to the position data of each point on the wall, and performing a straight line drawing operation to obtain the floor plan.

[0019] Furthermore, a straight line fitting operation is performed through a straight line fitting function in the OpenCV library, and a straight line drawing operation is performed through a straight line drawing function in the OpenCV library.

[0020] Further, the S50 includes:

[0021] S51: With the WIFI router as the center, a series of radial lines are drawn in all directions, and two intersection points of any radial line and the moving track are taken, and the intersection point closer to the WIFI router is recorded as the second intersection point, and the intersection point farther from the WIFI router is recorded as the first intersection point;

[0022] S52: Calculate the signal attenuation S from the second intersection point to the first intersection point;

[0023] S=(p2-p1) / (d1-d2)

[0024] Wherein, d1 and d2 are the distances between the WIFI router and the first intersection and the second intersection respectively, and p1 and p2 are the signal strengths of the first intersection and the second intersection respectively;

[0025] S53: The signal attenuation from the WIFI router to the first intersection is approximately considered to be equal to S, and the signal strength distribution from the WIFI router to the first intersection on any radial line is plotted; the same operation is performed on all radial lines to obtain the signal attenuation around the WIFI router, thereby forming a signal strength distribution diagram of the WIFI hotspot.

[0026] Furthermore, the testing device also includes a magnetic field sensor. When generating a signal strength distribution diagram of a WIFI hotspot, the drawing direction of the signal strength distribution diagram is adjusted according to the magnetic field strength value collected by the magnetic field sensor.

[0027] The present invention has the following beneficial effects:

[0028] The present invention simplifies the drawing complexity of the WIFI signal strength distribution map, ensures the true accuracy of the WIFI signal sampling points, reduces the complexity of obtaining the house type map, and accurately superimposes the WIFI signal strength distribution map with the house type map, making the display of the WIFI signal strength distribution map more intuitive and in line with the actual situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart of the method for drawing a WIFI signal strength distribution map of the present invention;

[0030] Figure 2 Schematic diagram of the intersection of the radiation line and the moving trajectory. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0032] The embodiment of the present invention provides a method for drawing a WIFI signal strength distribution diagram, such as Figure 1 As shown, the method includes:

[0033] S10: Move the test device steadily.

[0034] The test device includes a processor, a sensor device and a display device. The processor is used to receive control signals, collect data information measured by the sensor device for processing, build a floor plan and record the signal strength of the WIFI hotspot in the environment measured at the current location in real time, and display the processed data to the display device in real time. The display device can receive the image data processed by the processing device for real-time display.

[0035] The sensor device includes a rotating laser rangefinder, a WIFI module, and an IMU (Inertial Measurement Unit). The rotating laser rangefinder can automatically rotate 360° and is used to measure the straight-line distance from the current position to the wall. The IMU inertial measurement unit is used to obtain the three-axis attitude angle. The positions of the rotating laser rangefinder and the IMU inertial measurement unit should be relatively fixed and the distance between the two modules should be as close as possible, and their positions in space can be considered the same. The positive direction of the display screen is specified to be north, and it will be aligned with the positive direction of the screen when drawing the floor plan. The WIFI module supports the IEEE802.11a / b / n / g / ac / ax standards and can be connected to various WIFI routers and APs on the market.

[0036] The testing device may further include a control module, which may be a button or a touch screen, and may respond to button events with the processor.

[0037] The present invention can be applied to the WIFI signal strength test limited to closed places such as residential indoors and open-air places such as stadiums. When moving, it should be as stable as possible, the moving trajectory should pass through the entire space (for example, each room in the entire apartment of a residential room, the entire space of a stadium, etc.), and the rotating laser rangefinder should illuminate each wall of the entire space.

[0038] In the present invention, the test device can be moved by hand, and in this case, the test device can be provided with a handheld stabilizer. The function of the handheld stabilizer is to increase the stability of the device during the test, and it is a preferred solution, but it can also be omitted. Without using a handheld stabilizer, a stable posture can be calculated using the posture data collected by the IMU unit. In addition, the test device can also be set on a simple mobile platform and moved by the mobile platform.

[0039] S20: During the movement of the test device, each sensor works simultaneously to obtain data of the current test point, and transmits the obtained data to the data processor for calculation. Specifically:

[0040] The straight-line distance data from each test point on the moving trajectory to the wall is collected in real time by a rotating laser rangefinder. The three-axis attitude angle data of each test point on the moving trajectory of the test device is collected in real time by an IMU inertial measurement unit. The signal strength RSSI (Received Signal Strength Indication) of all WIFI hotspots in the environment at each test point on the moving trajectory is scanned in real time by a WIFI module.

[0041] S30: The processor generates a floor plan and a moving trajectory in real time according to the straight-line distance data and the three-axis attitude angle data, and displays them on the display device in real time. In this process, a gradually improved floor plan and a moving trajectory of the person can be intuitively seen on the display screen.

[0042] In one of the examples, the floor plan can be generated as follows:

[0043] S31: Calculate the position data of each point on the wall according to the position of each test point on the moving trajectory and the straight-line distance data to the wall and the three-axis attitude angle data.

[0044] This embodiment uses the Gmapping or Hector SLAM algorithm in the two-dimensional SLAM (Simultaneous Localization and Mapping) technology to generate a raster map, and refers to the ros-kinetic-hector-slam library in the ROS open source system. After calculation, the raster map layer and the motion trajectory layer can be obtained.

[0045] S32: performing a straight line fitting operation to obtain line segments according to the position data of each point on the wall, and performing a straight line drawing operation to obtain a floor plan.

[0046] In the process of drawing the floor plan, it is necessary to perform a straight line fitting operation on the points to obtain line segments, and then draw the line segments to obtain the floor plan layer. The algorithm library used in this step is the OpenCV library (Open Computer Vision Library, open source cross-platform visual library). The point set in the raster map layer obtained in step S31 is passed into the fitting straight line function in the OpenCV library to obtain line segments. Then, the straight line drawing function is used to draw the floor plan on the line segment floor plan layer.

[0047] Specifically, the straight line fitting function is: void fitLine(InputArray points, OutputArrayline, int distType, double param, double reps, double aeps); the straight line drawing function is: line(img, pt1, pt2, color[, thickness[, lineType[, shift]]]).

[0048] S40: After the test device is moved, the information of all WIFI hotspots scanned this time is displayed on the display device, the WIFI hotspot used in the current apartment is selected, and the placement position of the WIFI router on the apartment map is marked.

[0049] In this step, after collecting all the space layout information, the tester clicks Stop Test. At this time, the information of all the WIFI hotspots scanned this time is listed in descending order according to the signal strength. The tester selects the WIFI hotspot used in this layout and marks the location.

[0050] S50: generating a signal strength distribution map of the WIFI hotspots used in the apartment type according to the placement position of the WIFI router on the apartment type and the signal strength of each test point on the moving trajectory of the WIFI hotspots used in the apartment type.

[0051] Specifically, S50 may include:

[0052] S51: With the WIFI router as the center, draw a series of radial lines in all directions. Take two intersection points of any radial line and the moving trajectory. The intersection point closer to the WIFI router is recorded as the second intersection point, and the intersection point farther from the WIFI router is recorded as the first intersection point. Figure 2 shown.

[0053] S52: Calculate the signal attenuation S from the second intersection point to the first intersection point.

[0054] S=(p2-p1) / (d1-d2)

[0055] Where, d1 and d2 are the distances between the WIFI router and the first and second intersections (in meters), and p1 and p2 are the signal strengths of the first and second intersections (in dBm). When a signal propagates in a transmission medium, part of the energy will be converted into heat or absorbed by the transmission medium, causing the signal strength to weaken continuously. This phenomenon is called attenuation.

[0056] S53: The signal attenuation from the WIFI router to the first intersection is approximately considered to be equal to S, and the signal strength distribution from the WIFI router to the first intersection on any radial line is plotted; the same operation is performed on all radial lines to obtain the signal attenuation around the WIFI router, thereby forming a signal strength distribution diagram of the WIFI hotspot.

[0057] Since the distance in the entire space is short, it can be assumed that the attenuation on the straight line from the first intersection to the router is also S, so the signal heat map from the first intersection to the router can be drawn. According to the above algorithm, the signal attenuation around the router can be calculated respectively, and finally the RSSI strength layer of the WIFI hotspot is formed. The RSSI strength layer is superimposed on the layer of the above-mentioned floor plan to form a complete WIFI hotspot signal strength distribution map.

[0058] The present invention is based on a rotating laser rangefinder, and automatically generates a floor plan on site without the need for advance entry or manual drawing. During the construction of the floor plan, the WIFI signal strength is collected in real time on the test motion trajectory path, without limiting the position of the measuring point, while also ensuring the true accuracy of the position of the measuring point in the floor plan. During the test, a gradually improved visual WIFI signal strength distribution map can be displayed in real time.

[0059] As an improvement, the test device may further include a magnetic field sensor for obtaining the magnetic field strength in three-axis directions. When generating a signal strength distribution map of a WIFI hotspot, the drawing direction of the signal strength distribution map may be adjusted according to the magnetic field strength value collected by the magnetic field sensor to make it consistent with the conventional map drawing direction ("up north, down south, left west, right east").

[0060] In summary, the present invention simplifies the drawing complexity of the WIFI signal strength distribution map, ensures the true accuracy of the WIFI signal sampling points, reduces the complexity of obtaining the house type map, and accurately superimposes the WIFI signal strength distribution map with the house type map, making the display of the WIFI signal strength distribution map more intuitive and in line with the actual situation.

[0061] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for drawing a WIFI signal strength distribution diagram, characterized in that: The method comprises: S10: Move the test device steadily; The test device includes a processor, a rotating laser rangefinder, a WIFI module, an IMU inertial measurement unit and a display device. The moving trajectory of the test device should pass through the entire space, and the rotating laser rangefinder should illuminate each wall of the entire space. S20: During the movement of the test device, the straight-line distance data from each test point on the moving trajectory to the wall is collected in real time by the rotating laser rangefinder, the three-axis attitude angle data of each test point of the test device on the moving trajectory is collected in real time by the IMU inertial measurement unit, and the signal strength of each test point on the moving trajectory of all WIFI hotspots in the environment is scanned in real time by the WIFI module; S30: the processor generates a floor plan and a moving trajectory in real time according to the straight-line distance data and the three-axis attitude angle data, and displays them on the display device in real time; S40: After the test device is moved, information of all WIFI hotspots scanned this time is displayed on the display device, the WIFI hotspot used in the apartment is selected, and the placement position of the WIFI router on the apartment map is marked; S50: generating a signal strength distribution map of the WIFI hotspots used in the apartment type according to the placement position of the WIFI router on the apartment type diagram and the signal strength of each test point of the WIFI hotspots used in the apartment type on the moving trajectory.

2. The method for drawing a WIFI signal strength distribution diagram according to claim 1, characterized in that: The rotary laser rangefinder can automatically rotate 360 ​​degrees; the testing device is moved by hand-held means, or the testing device is moved by a mobile platform.

3. According to the method for drawing a WIFI signal strength distribution diagram according to claim 2, when the test device is moved by hand, the test device is provided with a handheld stabilizer.

4. The method for drawing a WIFI signal strength distribution diagram according to claim 1, characterized in that: The floor plan is generated by the following method: S31: Calculate the position data of each point on the wall according to the position of each test point on the moving trajectory and the straight-line distance data to the wall and the three-axis attitude angle data; S32: performing a straight line fitting operation to obtain line segments according to the position data of each point on the wall, and performing a straight line drawing operation to obtain the floor plan.

5. The method for drawing a WIFI signal strength distribution diagram according to claim 4, characterized in that: The straight line fitting operation is performed through the fitting straight line function in the OpenCV library, and the straight line drawing operation is performed through the straight line drawing function in the OpenCV library.

6. The method for drawing a WIFI signal strength distribution diagram according to any one of claims 1 to 5, characterized in that: The S50 includes: S51: With the WIFI router as the center, a series of radial lines are drawn in all directions, and two intersection points of any radial line and the moving track are taken, and the intersection point closer to the WIFI router is recorded as the second intersection point, and the intersection point farther from the WIFI router is recorded as the first intersection point; S52: Calculate the signal attenuation S from the second intersection point to the first intersection point; S=(p2-p1) / (d1-d2) Wherein, d1 and d2 are the distances between the WIFI router and the first intersection and the second intersection respectively, and p1 and p2 are the signal strengths of the first intersection and the second intersection respectively; S53: The signal attenuation from the WIFI router to the first intersection is approximately considered to be equal to S, and the signal strength distribution from the WIFI router to the first intersection on any radial line is plotted; the same operation is performed on all radial lines to obtain the signal attenuation around the WIFI router, thereby forming a signal strength distribution diagram of the WIFI hotspot.

7. The method for drawing a WIFI signal strength distribution diagram according to claim 6, characterized in that: The testing device also includes a magnetic field sensor. When generating a signal strength distribution diagram of a WIFI hotspot, the drawing direction of the signal strength distribution diagram is adjusted according to the magnetic field strength value collected by the magnetic field sensor.

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