CN205139365U - Novel indoor positioning system - Google Patents

Abstract

A novel indoor positioning system, comprising a tag and a reader for data transmission with the tag; the tag includes a processing unit and a first radio frequency module for mutual data transmission; the reader includes a second radio frequency module for mutual data transmission and a PC machine; the tag is an active tag; the working frequency bands of the first radio frequency module and the second radio frequency module are both 433MHz. The utility model is novel in design, and realizes fast indoor positioning through the reader and the label; by selecting the label as an active label, the positioning accuracy is improved, and the working stability of the whole system is reduced; the first radio frequency module and the second radio frequency module The working frequency band of the second radio frequency module is selected as 433MHz, which improves the coverage of the signal, thereby improving the accuracy of positioning.

Description

A New Indoor Positioning System

technical field

The utility model belongs to the field of wireless positioning systems, in particular to a novel indoor positioning system.

Background technique

Location-based services have important applications in common commercial activities, scientific research, and even emergency search and rescue industries. The existing outdoor identification is realized through the global positioning system based on satellite communication, which has high positioning accuracy and solves many practical problems in military and civilian use. However, due to the particularity of the indoor environment, there are serious problems such as indoor occlusion and non-line-of-sight noise interference, the positioning accuracy of the satellite positioning system is significantly reduced, and the cost is high.

In the prior art, in order to solve the problem of indoor positioning, infrared rays, wireless local area networks, ultrasonic waves, radio frequency identification, bluetooth, mobile communication networks, multimedia technologies and the like have been used.

Among them, radio frequency identification technology has become one of the preferred indoor positioning methods because of its non-contact and non-line-of-sight characteristics.

In the existing radio frequency identification indoor positioning system, the selected chip consumes a lot of power, and the signal is affected by indoor obstructions, and the positioning accuracy is low.

Utility model content

The utility model aims to provide a novel indoor positioning system with low power consumption and high positioning accuracy.

In order to solve the above technical problems, the utility model provides the following technical solutions: a new type of indoor positioning system, including a tag and a reader; the reader transmits signals to the tag, and the tag replies data to the reader according to the received signal;

The tag includes a processing unit and a first radio frequency module; the reader includes a second radio frequency module and a PC;

The processing unit sends a control signal to the first radio frequency module, and controls the first radio frequency module to be in a receiving mode or a sending mode;

The PC transmits signals to the processing unit through the second radio frequency module and the first radio frequency module; the processing unit returns data to the PC through the first radio frequency module and the second radio frequency module in turn according to the received signals;

The tag is an active tag;

The operating frequency bands of the first radio frequency module and the second radio frequency module are both 433MHz.

The reader also includes a level conversion chip, the serial port pin of the second radio frequency module and the serial port pin of the PC transmit data through the level conversion chip, and the transmission/control pin of the second radio frequency module The level conversion chip is connected to the serial port of the PC.

The serial port pin of the processing unit is connected to the serial port pin of the first radio frequency module, and the control pin of the processing unit is connected to the working mode control pin of the first radio frequency module.

The low power consumption control pin of the second radio frequency module is connected to a high level; the channel selection pin is connected to a low level.

The processing unit is a single-chip microcomputer, the model is AT89C52.

Both the first radio frequency module and the second radio frequency module are radio frequency chips, and the model is PTR2000.

Through the above technical scheme, the beneficial effects of the utility model are:

1. Through the cooperation of readers and tags, indoor positioning is realized, with simple structure and low cost;

2. The operating frequencies of the first radio frequency module and the second radio frequency module are both in the 433MHz frequency band, which ensures the coverage of the signal and avoids signal blind spots in the signal coverage;

3. The active tags are selected for the tags, which lowers the requirements for the receiving sensitivity of the readers and ensures the stable operation of the system for a long time. In addition, the data storage space of the active tag is large, which is suitable for storing a large amount of data required for indoor positioning.

4. The AT89C52 single-chip microcomputer is selected, with fewer peripheral components and low power consumption, and can run stably for a long time.

Description of drawings

Fig. 1 is a block diagram of the utility model;

Figure 2 is a schematic diagram of the tag circuit;

Figure 3 is a schematic diagram of the reader circuit.

detailed description

The new indoor positioning system shown in Figure 1 includes a tag and a reader for data transmission with the tag. The tag is an active tag and is set at an indoor reference point. The reason why the active tag is selected here: the signal strength of the active tag transmitted by its own power supply is relatively high, and the requirements for the receiving sensitivity of the reader are relatively low, and at the same time, it can ensure the stable operation of the system for a long time. In addition, the data storage space of the active tag is large, which is suitable for storing a large amount of data required for indoor positioning.

The reader transmits a signal to the tag, and the tag replies to the reader according to the received signal, and the reader receives the data returned by the tag, and obtains the distance between the tag and the reader according to the intensity of the received data, thereby obtaining the tag’s Position, complete indoor positioning through the Landmarc algorithm.

Among them, the reader sends data to the tag, and according to the signal strength of the data returned by the tag, it is a mature existing technology to realize indoor positioning through the mature Landmarc algorithm.

As shown in Figure 2, the label includes single-chip microcomputer U1 (model AT89C52) and the first radio frequency module U2 (model is PTR2000); Pins (DO, DI pins) are connected to realize the transmission of serial data. The control pins (P2.0, P2.1, P2.2) of the single-chip microcomputer U1 are respectively connected to the working mode control pins (TXEN, CS, PWR pins) of the first radio frequency module U2, so as to control the first radio frequency module to receive mode is still launch mode.

MCU U1 chooses AT89C52 model because: AT89C52 chip has fewer peripheral components, lower power consumption, and can run stably for a long time.

In order to ensure the normal operation of the single-chip microcomputer U1, a clock circuit and a reset circuit are also connected to the single-chip microcomputer U1.

The clock circuit includes a first clock capacitor C1, a second clock capacitor C2 and a crystal oscillator Y1, the first clock capacitor C1 and the second clock capacitor C2 are connected in parallel and grounded, and the other pin of the first clock capacitor C1 is connected to The first pin of the crystal oscillator Y1, the other pin of the second clock capacitor C2 is connected to the second pin of the crystal oscillator Y1, and the first pin of the crystal oscillator Y1 is connected to a clock pin of the microcontroller U1 (the pin is XTAL1) , the second pin of the crystal oscillator Y1 is connected to another clock pin of the microcontroller U1 (the pin is XTAL0).

The reset circuit includes a reset capacitor C3, a reset button S1 and a reset resistor R1, one end of the reset capacitor C3 and the reset button S1 is connected to a DC power supply, and the other end is respectively connected to a reset resistor R1 and a reset pin connected to the microcontroller U1 (the pin is RESET ).

The single-chip microcomputer sends a signal to the first radio frequency module to control the working mode of the first radio frequency module; then, the single-chip microcomputer receives the signal sent by the reader through the first radio frequency module; and returns data to the reader through the first radio frequency module.

As shown in Figure 3, the reader includes a level conversion chip U4 (model MAX202), a second radio frequency module U3 (model PTR2000), a data interface connector U5 (DB9) and a PC. The serial port pins (DO, DI pins) of the second radio frequency module U3 are connected to the data interface connector U5 through the level conversion chip U4, and the data interface connector U5 is connected to the PC.

The low power consumption control pin (PWR pin) of the second radio frequency module U3 is connected to the high-level VCC, so that the second radio frequency module U3 is fixed to work in the normal working state; the channel selection pin (CS pin) of the second radio frequency module U3 Pin) is connected to the low level of GND, so that the second radio frequency module U3 adopts the fixed communication channel 1, so that the working frequency is fixed at 433MHz. The transmit/control pin (TXEN pin) of the second radio frequency module is connected to the serial port of the PC through the level conversion chip U4, thereby controlling the second radio frequency module U3 to be in the receiving mode or in the sending mode.

During implementation, the operating frequencies of the first radio frequency module U2 and the second radio frequency module U3 are both 433 MHz. This frequency band is selected because the signal wavelength of 433MHz is close to 1 meter, so that the signal can bypass large obstacles through diffraction, thereby ensuring the coverage of the signal. When the signal frequency is too high, such as 2.4GHz, at this time the wavelength is too short to bypass indoor obstacles through diffraction, resulting in signal blind spots within the signal coverage.

The PC sends a signal to the level conversion chip U4 through the data interface connector U5, and the level conversion chip transmits the level conversion of the signal to the second radio frequency module U3, and the second radio frequency module U3 transmits the signal to the first radio frequency module after modulation. The radio frequency module U2, the first radio frequency module U2 transmits the signal to the single-chip microcomputer for analysis and storage, after analyzing and confirming that the signal is sent by the PC, the single-chip microcomputer outputs a control signal to the first radio frequency module U2 so that the first radio frequency module U2 sends data to The second radio frequency module U3, the data reaches the PC after passing through the level conversion chip U4, and the PC calculates the position of the label according to the received signal strength.

It is a mature existing technology to control the radio frequency module to send and receive data through a single-chip computer; it is a mature existing technology for the single-chip computer to determine whether the signal sent by the PC is based on the received signal through the communication protocol; the PC calculates the label according to the received signal strength The position is mature prior art.

The utility model has a novel design, and realizes fast indoor positioning through the reader and the label; by selecting the label as an active label, the power consumption is reduced and the working stability of the whole system is improved; the first radio frequency module and the second radio frequency module The selected working frequency band is 433MHz, which improves the coverage of the signal, thereby improving the accuracy of positioning.

Claims (6)

1. A new type of indoor positioning system, characterized in that: it includes a tag and a reader; the reader transmits signals to the tag, and the tag replies data to the reader according to the received signal; The tag includes a processing unit and a first radio frequency module; the reader includes a second radio frequency module and a PC; The processing unit sends a control signal to the first radio frequency module, and controls the first radio frequency module to be in a receiving mode or a sending mode; The PC transmits signals to the processing unit through the second radio frequency module and the first radio frequency module; the processing unit returns data to the PC through the first radio frequency module and the second radio frequency module in turn according to the received signals; The tag is an active tag; The operating frequency bands of the first radio frequency module and the second radio frequency module are both 433MHz. 2. The novel indoor positioning system as claimed in claim 1, characterized in that: the reader also includes a level conversion chip, and the serial port pin of the second radio frequency module and the serial port pin of the PC are transmitted through the level conversion chip For data, the transmitting/control pin of the second radio frequency module is connected to the serial port of the PC through a level conversion chip. 3. The novel indoor positioning system according to claim 1 or 2, characterized in that: the serial port pin of the processing unit is connected to the serial port pin of the first radio frequency module, and the control pin of the processing unit is connected to the first radio frequency module. Operating mode control pin. 4. The novel indoor positioning system according to claim 2, characterized in that: the low power consumption control pin of the second radio frequency module is connected to a high level; the channel selection pin is connected to a low level. 5. The novel indoor positioning system according to claim 3, characterized in that: the processing unit is a single-chip microcomputer, the model of which is AT89C52. 6. The novel indoor positioning system according to claim 5, characterized in that: the first radio frequency module and the second radio frequency module are both radio frequency chips, and the model is PTR2000.