In outdoor scenarios, GNSS positioning technologies such as Beidou and GPS are continuously evolving, with higher precision and wider application. With the advent of the new infrastructure boom, with the help of 5G+ new infrastructure, unmanned driving, autonomous driving and other technologies are gradually improving. The demand for positioning is not just a rough trajectory, but high-precision positioning to improve user experience and expand business model to improve social efficiency .
Ordinary GPS positioning modules and Beidou positioning modules will be affected by the errors of the satellite terminal, the transmission terminal, and the user terminal, resulting in the positioning accuracy of the feedback position information can only reach the meter level. And other application scenarios increasingly require higher precision for outdoor positioning, such as about 1 meter, sub-meter level, decimeter level, and centimeter level. For smart-driving cars, the lanes are narrow and the distances between roadside obstacles are shorter. This means that the car requires a positioning accuracy of 10 to 30 centimeters. Ordinary positioning modules cannot achieve centimeter-level positioning accuracy. This article will introduce you to high-precision positioning based on RTK technology.
RTK positioning
RTK (Real-time kinematic, real-time dynamic) carrier phase difference technology is a difference method for real-time processing of carrier phase observations of two measurement stations, and sends the carrier phase collected by the base station to the user receiver for difference calculation and coordinates.
This is a new and commonly used satellite positioning measurement method. Previous static, fast static, and dynamic measurements required subsequent calculations to obtain centimeter-level accuracy, while RTK is a measurement that can obtain centimeter-level RTK positioning accuracy in real time in the field. method.
RTK high-precision positioning technology is an important means for GNSS system to obtain high-precision real-time dynamic positioning. RTK positioning is mainly composed of three parts, namely the base station receiver, the mobile station receiver and the data transmission link between the two stations. The RTK reference station sends the corrected data or the collected carrier phase observation value to the mobile station built within its data transmission range through the data transmission link, and the satellite observation data received by the mobile station receiver is phased differently from the data sent by the reference station The positioning process is the RTK positioning process.
The working principle of high-precision RTK positioning is to use the power phase difference test technology of GPS signals. When the GPS data signal reaches the signal receiver, the phase of the data signal will change when it is affected by various factors such as the earth's atmosphere and road surface behind the communication satellite. In the absence of any influence, the power phase change of the GPS signal can be detected, but due to various factors such as influence, a single signal receiver does not obtain high-performance phase difference information content.
The precise positioning of high-precision RTK is to place the GPS signal receiver on the reference station in the known area, measure the phase change between the reference station and the communication satellite, and obtain the position information content compared with the reference station. At the same time, when a GPS signal receiver is placed on the mobile website that needs positioning and navigation, the GPS signal receiver in the mobile website communicates with the base station, and communicates the overall phase difference data obtained by the accurate measurement of the base station to the GPS signal in the mobile website. receiver.
The GPS signal receiver in the mobile station can distinguish the phase angle between the base station and the communication satellite and the phase angle between the mobile station and the communication satellite, so as to obtain the phase angle of the mobile station compared with the reference station, thereby obtaining High-performance positioning information. Through the calculation of various difference signals, the precise positioning of high-precision RTK can achieve high precision, and generally centimeter-level precision can be achieved.
RTK positioning accuracy
Compared with traditional GPS positioning technology, high-precision RTK positioning can achieve centimeter-level accuracy, and is suitable for industries that require high-precision positioning information, such as land area measurement, building measurement, and intelligent agriculture. RTK is a new and commonly used satellite positioning measurement method. Previous static, fast static, and dynamic measurements required subsequent calculations to obtain centimeter-level accuracy. RTK technology can obtain centimeter-level RTK positioning accuracy in a very short period of time. , widely used in map root control survey, construction stakeout, engineering survey and topographic survey and other fields.
The original complex RTK technical details are reasonably encapsulated, and users can use it directly like using ordinary single-point positioning GPS products, but what they get is centimeter-level positioning accuracy. The centimeter-level precision outdoor positioning solution based on the RTK positioning module uses high-precision positioning technology, and the high-precision positioning module built in the terminal product/equipment combines the actual view to quickly and accurately locate its location. The administrator can use the management platform View the real-time location and historical trajectory of end products/equipment.
High-precision RTK positioning solution
The high-precision RTK positioning system adopts dual-frequency RTK high-precision positioning modules SKG122GR and SKG123NR that fully support the Beidou-3 satellite signal system. This module supports BDS B1I+B1C+B2a, GPS/QZSS L1+L5, Galileo E1+E5a multi-system at the same time Multi-frequency points, internally integrated dual-frequency RTK high-precision positioning algorithm, can provide centimeter-level high-precision location services. The module can be turned into a mobile station through configuration. Can meet the strict requirements of professional positioning and personal consumption needs. The system integrates functions such as personnel information management, historical track playback, electronic fence, intelligent patrol inspection, electronic work ticket, intelligent early warning, emergency rescue, etc., which can meet the multiple needs of enterprise safety production management and help enterprises maintain safety protection lines.
RTK positioning module
1. RTK high precision GNSS G-Mouse SKM2102ER
SKM2102ER is an industrial-grade, L1 single-frequency RTK high-precision positioning antenna integrated multi-system GNSS G-Mouse. The terminal has a built-in high-precision GNSS antenna; the module can simultaneously support satellite receiving modules of GPS, Beidou, GLONASS, GALILEO, QZSS and SBAS; the RTK calculation algorithm is integrated inside, and combined with RTK services, centimeter-level positioning can be achieved. The module can be turned into a mobile station through configuration. Can meet the strict requirements of professional positioning and personal consumption needs. The positioning accuracy of SKM2102ER open sky can reach 2.5m horizontal positioning accuracy in autonomous positioning mode, 2.5cm+1ppm(H) positioning accuracy in RTK mode, and 0.1m/s speed accuracy. The cold start time of 28s and the tracking sensitivity of -162dBm extend the positioning coverage to urban canyons and dense foliage environments.
SKM2102ER adopts IP67 waterproof shell, with 6-level dustproof and 7-level waterproof ability, which can meet the waterproof and dustproof requirements of vehicle navigation system, security monitoring and positioning, and personal navigation equipment.
SKYLAB SKM2102ER supports serial output position information, supports the following NMEA-0183 messages: GGA, GSA, GSV, RMC, ZDA, GST, the default baud rate is 115200bps. The communication interface is a 4PIN Micro-Fit 3.0 connector, and the cable length can be customized. Currently, 3 meters, 5 meters, and 8 meters are available.
2. Dual-frequency high-precision positioning module SKG122GR
SKG122GR is a satellite receiving module that can support L1+L5 frequency bands, GPS, Beidou, GALILEO, QZSS and SBAS at the same time. It can track up to 40 satellites at the same time, and supports receiving Beidou No. 3 signals. It integrates RTK calculation algorithms and combines RTK services It can realize centimeter-level positioning, and the module can be turned into a mobile station through configuration.
SKG122GR is an industrial-grade positioning module with a cold start time of <28s. It has superior satellite search and positioning performance. It supports PPS timing with an accuracy of ±20ns. PPS is associated with NMEA. The module has antenna detection functions. The maximum data update rate in PVT mode is 10Hz, and the maximum data update rate in RTK mode is 5Hz.
The positioning accuracy of SKG122GR in the open sky is 2.5m, the positioning accuracy in SBAS mode is 2m, the positioning accuracy in D-GNSS mode is less than 1m, the positioning accuracy in RTK mode is 1.5cm+1ppm(H), 6.5cm+1ppm(V ).
3. Dual-frequency high-precision positioning module SKG123NR/SKG123NRD
SKG123NR is a high-performance, multi-system dual-frequency RTK navigation and positioning module, which can provide RTK phase difference high-precision positioning, and the positioning accuracy can reach 10cm, achieving centimeter-level positioning.
SKG123NRD is a high-performance, multi-system dual-frequency RTK inertial navigation positioning module, which can provide RTK phase difference high-precision positioning and inertial navigation positioning services, and realize centimeter-level and inertial navigation positioning.
SKG123NR and SKG123NRD can support GPS, Beidou, GLONASS, GALILEO, QZSS and SBAS satellite receiving modules at the same time, and have the advantages of fast positioning, high precision and reliable product performance.
The module integrates an internal RTK calculation algorithm, and combined with RTK services, centimeter-level positioning can be achieved. The module can be turned into a mobile station through configuration. Can meet the strict requirements of professional positioning and personal consumption needs.
The module has compact dimensions and is compatible with international mainstream navigation and positioning modules on the market. It adopts SMD pads and supports standard pick-and-place and reflow soldering.
In addition to the traditional surveying and mapping field, the high-precision application market of high-precision location services in precision agriculture, intelligent driving test, unmanned aerial vehicles, general aviation, Internet of Vehicles, autonomous driving and other fields is showing huge growth potential. The high-precision positioning module supporting RTK algorithm is especially suitable for specific industries that require relatively high positioning accuracy.