An indoor positioning solution for new manufacturing in Industry 4.0

• An overview of the

Since GPS/ Beidou satellite signals are difficult to penetrate building walls in indoor environment, the traditional GPS positioning terminal positioning system cannot be used in indoor environment such as factories, and a series of indoor positioning technologies are spawned. With the progress of science and technology, these technologies tend to mature in their own evolution. Current high-precision indoor UWB/BLE + AOA location technology, its average position precision can reach 0.3 meters, the highest accuracy of 0.1 m, compared with the traditional positioning technology based on signal intensity has great accuracy improvement, make the application scenario is more and more widely, especially in the factory environment, can realize accurate positioning device to the factory, Promote the further development of industrial automation and intelligence.

The Internet of Things department of Ali Cloud launched the factory indoor positioning system based on UWB technology and Alios-Things uLocation component, which integrates a series of processes such as device/personnel positioning, data aggregation and cloud deployment of location-based applications, providing solutions for digital factories to further perceive device positioning data.

Application Scenarios:

1. Plant equipment/personnel positioning, scheduling, optimize production resources arrangement
2. Real-time electronic fence, security monitoring

• case

The system has been deployed in a garment factory and has realized high-precision positioning of production equipment in the factory. The positioning accuracy is up to 10cm, and the normal accuracy is 30-50cm. It effectively supports garment factories’ activities of equipment audit, scheduling and production arrangement. In the future, it can further improve the production efficiency of factories by docking with industrial MES system.

• System principle and construction

• UWB base station and tag

UWB (Ultra Wideband) is an ultra-wideband wireless communication technology that transmits data using narrow pulses of non-sinusoidal waves ranging from nanosecond to subtle. Due to its narrow signal time domain width, which is less than the difference between the direct diameter and the reflection diameter in general indoor wireless environment, the arrival time of the direct diameter and the reflection diameter can be distinguished. The distance between the locating tag and the base station is determined by the transmission time of the direct path of the wireless signal. The location of the tag can be determined by the distance between the tag and the three base stations. Since the time-domain interval of UWB pulse is about 1 nanosecond, and the transmission distance of 1ns wireless signal is 30cm, the average accuracy of positioning accuracy based on UWB positioning can reach about 30cm in the environment with reflection path.

The positioning target of the system is the positioning tag. The following figure is a common UWB positioning tag:

The positioning label must be physically fixed to the device to be located. The installation principles are as follows:

1. Try to avoid metal objects, metal material has a shielding effect on electromagnetic waves.
2. Try to install the label on the high place of the device to be located, so that other components of the device do not block the wireless transmission path of the label to the base station.
3. A motion sensor is embedded in the label. UWB packets are frequently reported when the label motion is detected to improve real-time positioning, which reduces battery life. You can determine the device installation position based on site requirements.

The positioning base station is responsible for processing THE UWB signal, calculating the arrival time of the signal, and transmitting the calculation results to the positioning server for final calculation. The following figure shows the positioning base station:

The positioning base station shall be installed on the ceiling of the factory. The installation principle is as follows:

1. It should be installed above the location area and 5 meters above the ground.
2. Base stations are spaced between 10 to 15 meters.
3. Locate the base station through a wired network. Poe-hub network can be used, and the base station provides power at the same time.
4. Configure an independent subnet for the base station. The internal network segment 192.168.x. x is generally used.

• Locating server

The location server is responsible for label management, location calculation, data cloud, local location service interface and system operation and maintenance interface, etc. The schematic diagram of the installed software stack is as follows:



Installation steps:

1. The underlying operating system of the server is Linux.
2. The UWB Engine runs on a Windows operating system (OS). Therefore, deploy a VM on the SERVER and install the Windows OS. Install the UWB software package, including the UWB Engine and SDK, on Windows.
3. Map two network ports to the VM. Configure the same subnet IP address for one network port as that of the base station, and connect this network port to the POE-hub connected to the base station using a network cable. The other network port is configured as an internal IP accessible to the uLocation component’s Positioning Adapting Layer (PAL) Layer.
4. Install uLocation component and upper cloud component, upper cloud suite can choose LinkEdge. To facilitate dependency management of packages, uLocation and LinkEdge are deployed on Docker. Configure the Docker network, and another VIRTUAL machine for uLocation access IP network segment, and set the connection parameters through the configuration management of uLocation.

In 5.Ali Cloud industrial Internet platformLocate gateway devices and label products from creating indoor, as shown in figure:



6. Install LinkEdge and import the TSL file for the product created in Step 5. 6. Install LinkEdge and import the TSL file for the product created in Step 5.

7. Create a tag device on the cloud, the device name format is srvName + TagID, and import the created device triplet information into LinkEdge. Because the number of tags is large, you can create them using the page for adding devices in batches on the cloud.



8. After installation, start location services, uLocation and LinkEdge to provide location services locally and in the cloud.

After the system is up, real-time positioning data can be seen in the cloud and console:

1. After the cloud data system is started, you can open the cloud console to see the real-time positioning data of labels. The displayed label position is represented by three-dimensional spatial coordinates (X, Y, Z), with the origin of coordinates being a point in the edge corner of the factory. X and y represent the distance between the label and the coordinate origin in two vertical directions, in meters. The actual accuracy is one decimal point. The z value is the height between the label and the ground.

2. Background data

• Appendix: Comparison of several positioning techniques

• Conclusion:

Ali Cloud Iot will always track and promote the development of new positioning technology, and will provide customers with better positioning solutions in the future.