CN115499774B - Vernier type positioning system and method based on forwarding beacon - Google Patents

Abstract

A vernier positioning method based on forwarding beacons includes the following steps: step 1. The interrogator periodically transmits a scheduling signal during movement to trigger the forwarding beacons that may exist in the surrounding area; step 2. The interrogator transmits a ranging signal to the triggered forwarding beacon; step 3. The triggered forwarding beacon forwards the ranging signal; step 4. The interrogator receives the forwarded ranging signal and calculates the ranging information; step 5. The interrogator position is calculated. The present invention also discloses a vernier positioning system based on forwarding beacons, characterized in that it includes at least three forwarding beacons that are not in co-linear positions, at least one interrogator that can communicate with each forwarding beacon, and a host computer that can communicate with the interrogator. The present invention uses the vernier method to calculate the signal flight time, which reduces the requirements for ranging pulse frequency, bandwidth and time synchronization in the system; at the same time, it uses a spread spectrum communication method to reduce the requirements for the signal-to-noise ratio of the interrogator receiving signal.

Description

A cursor positioning system and method based on forwarding beacon

Technical Field

The present invention belongs to the field of information technology, relates to positioning technology, and specifically to a cursor-type positioning system and method based on forwarding beacons.

Background Art

In recent years, my country's energy, chemical and other industries involving hazardous chemicals have developed rapidly, and the output of hazardous chemicals has also continued to increase. Article 3 of the "Regulations on the Safety Management of Hazardous Chemicals" stipulates that hazardous chemicals (hereinafter referred to as "hazardous chemicals") refer to highly toxic chemicals and other chemicals that have properties such as toxicity, corrosion, explosion, combustion, and combustion-supporting, and are harmful to the human body, facilities, and the environment. The hazardous chemical production environment is relatively special. To achieve high-precision positioning of personnel in hazardous chemical production environments requires special indoor and outdoor positioning system designs.

However, the existing hazardous chemical production environment has the following characteristics: First, there are a large number of production equipment and storage equipment in the hazardous chemical production environment, and the positioning environment is very complex; second, if industrial positioning facilities that require wiring are used, it is necessary to open the wall for wiring in the hazardous chemical production environment, which will not only require hazardous chemical production enterprises to stop production, increase the cost of positioning equipment deployment and maintenance, but also increase new safety hazards. Therefore, in the hazardous chemical production environment, a positioning device that does not require wiring, does not require frequent maintenance, and can operate stably for a long time is needed.

Existing wireless positioning devices in hazardous chemical production environments usually use Bluetooth positioning. Although it has low power consumption, no wiring required, and low maintenance frequency, the positioning accuracy of Bluetooth positioning is low, usually within the range of 3-5 meters. For industrial positioning environments, such positioning accuracy is poor and it is difficult to meet the high-precision positioning requirements in hazardous chemical production environments.

Summary of the invention

In order to overcome the defects of the prior art, the present invention discloses a cursor type positioning system and method based on forwarding beacons.

The cursor-type positioning method based on forwarding beacons described in the present invention comprises the following steps:

Step 1. During the movement of the interrogator, the interrogator periodically transmits a scheduling signal to trigger the forwarding beacons that may exist in the surrounding area. The scheduling signal includes trigger signals of multiple forwarding beacons. When the triggering conditions are met, the corresponding forwarding beacon is triggered; proceed to step 2, otherwise continue to step 1;

Step 2. The interrogator transmits a ranging signal to the triggered repeater beacon. The specific process is as follows:

Step 2.1. The clock generation unit inside the interrogator generates two rectangular wave clock signals with different frequencies, the master clock and the vernier clock; b(t) is counted at the moment when the edges of the master clock and the vernier clock coincide; _f1 is greater than _f2 , _f1 is the master clock frequency _f1 , and _f2 is the vernier clock frequency;

Step 2.2. Perform spread spectrum processing on the master clock a(t), and the spread spectrum signal after spread spectrum is c(t);

Step 2.3. After the spread spectrum signal c(t) is modulated by frequency modulation, the modulated signal is transmitted as the ranging signal d(t);

Step 3. The triggered forwarding beacon receives the ranging signal d(t) transmitted by the interrogator, and after filtering out the interference signal, forwards the ranging signal d(t) as the ranging signal;

Step 4. The interrogator receives the forwarded ranging signal and calculates the ranging information. The specific process is as follows:

Step 4.1. Demodulate the received ranging signal to obtain a demodulated signal c′(t);

Step 4.2. Despread the demodulated signal c′(t) to obtain a despread signal a′(t);

Step 4.3. Compare the edges of the despread signal a′(t) and the cursor signal b(t). Stop counting the cursor signal b(t) when the edges of the two coincide. The counting result is k.

Step 4.4. Calculate the flight time of the modulation signal d(t) as t=k(1/f ₂ -1/f ₁ ), where f ₁ and f ₂ are the master clock and vernier clock frequencies respectively;

Step 4.5. Calculate the distance from the interrogator to the repeater beacon: l = t*ν/2, where ν is the transmission speed of the electromagnetic signal in the transmission medium;

Step 5. When the distances of three or more non-collinear forwarding beacons are obtained at the same time, the position of the interrogator is calculated using the coordinates and distances of the three non-collinear forwarding beacons closest to the interrogator.

Preferably, the triggering process of step 1 is specifically as follows: the interrogator broadcasts an interrogation signal, and after receiving the interrogation signal, the forwarding beacon within the coverage of the interrogation signal transmits a response signal including the beacon's own coding information to the interrogator, and the interrogator obtains all forwarding beacon information within the coverage of the interrogation signal through the received response signal, and the forwarding beacon within the coverage of the interrogation signal is triggered.

Preferably, in step 2.3, the spread spectrum signal c(t) is modulated to the radio frequency segment by frequency modulation as the modulation signal d(t);

After receiving the modulated signal d(t) transmitted by the interrogator in step 3, the following processing is performed: the interference signal of the ranging signal d(t) is filtered out, the signal is converted to the intermediate frequency and then modulated to the radio frequency segment through a mixer for forwarding. The radio frequency segment signal frequencies in step 2.3 and step 3 are different.

Preferably, the scheduling signal is a time division multiple access scheduling signal.

The present invention also discloses a cursor-type positioning system based on forwarding beacons, comprising at least three forwarding beacons whose positions are not collinear, at least one interrogator capable of communicating with each forwarding beacon, and a host computer capable of communicating with the interrogator;

The forwarding beacon includes a beacon receiving unit, a frequency difference unit, a beacon transmitting unit and a forwarding beacon control unit. The frequency difference unit is used to process the signal received by the beacon receiving unit and transmit it through the beacon transmitting unit; the forwarding beacon control unit is used to detect the received scheduling signal and determine whether it is triggered;

The interrogator comprises a clock generating unit, a spectrum spreading unit, an interrogator transmitting unit, an interrogator receiving unit, a despreading unit, a timing unit, and an interrogator control unit;

The clock generation unit is used to generate a master clock, a vernier clock and a spread spectrum clock;

The spread spectrum unit is used to perform spread spectrum processing on the main clock signal for transmission;

The despreading unit is used to despread the signal received by the interrogator receiving unit;

The timing unit is used to perform edge coincidence detection on the main clock and the vernier clock, and the vernier clock and the despread signal, and record the coincidence moment;

The interrogator control unit is used to transmit a dispatch signal;

The host computer is used to calculate the location of the interrogator according to the information sent by the interrogator.

Preferably, the difference frequency unit comprises a first mixer, a signal processing module and a second mixer which are sequentially connected between the beacon receiving unit and the beacon transmitting unit, wherein the signal processing module comprises a bandpass filter and an amplifier connected to the bandpass filter. The first mixer and the second mixer are respectively connected to the first oscillator and the second oscillator.

Preferably, the despreading unit comprises a sampling decision device, a sequence matching filter and a comparator which are connected in sequence, wherein the comparator is connected to the timing unit, and the sampling decision device is connected to the inquiry receiving unit.

Preferably, the spectrum spreading unit comprises a PN code generator and a multiplier, two input ends of the multiplier are respectively connected to the PN code generator and the clock generating unit, and the output end of the multiplier is connected to the interrogation transmitting unit.

Preferably, the timing unit includes a first rising edge coincidence detection module connected to the clock generating unit, a second rising edge coincidence detection module connected to the clock generating unit and the despreading unit, and the output ends of the two rising edge coincidence detection modules are connected to the counter.

Preferably, the rising edge coincidence detection module includes two detection input terminals, the two detection input terminals are respectively connected to a detection branch, each detection branch includes a delay module, an XOR gate and an AND gate, the delay module is connected between the detection input terminal and an input terminal of the XOR gate, the output terminal of the XOR gate is connected to an input terminal of the AND gate, the other input terminals of the XOR gate and the AND gate are both connected to the detection input terminal, the output terminal of the AND gate serves as the output terminal of the detection branch and is connected to the input terminal of the output AND gate, and the output terminal of the output AND gate serves as the output terminal of the rising edge coincidence detection module.

The beneficial effects of the present invention are:

1. The positioning method of the present invention does not use traditional digital transmission and reception, but uses the cursor method to calculate the signal flight time, which reduces the requirements for ranging pulse frequency, bandwidth and time synchronization in the system; at the same time, the spread spectrum communication method is used to reduce the requirements of the signal-to-noise ratio of the interrogator receiving signal, and the spread spectrum coding is used to realize code division multiple access between different interrogators, so that multiple interrogators will not interfere with each other.

2. The present invention obtains the ranging result by calculating the signal flight time; the forwarding beacon turns on the forwarding module to receive, beat and forward the signal only after receiving the dispatch signal of the interrogator. The standby power consumption is extremely low, and long-term stable operation with low power consumption can be achieved. Therefore, it can be completely powered by batteries. No wiring is required when arranging the positioning system, and the subsequent maintenance cost and frequency are also greatly reduced.

3. The transmitting and receiving units of the interrogator and the repeater beacon in the present invention all use full analog circuits to ensure that the signal flight time and the delay during the transmission and reception process are fully controllable, and accurate signal flight time information can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a positioning system architecture in Embodiment 1 of the present invention.

FIG. 2 is a structural diagram of the interrogation machine in Embodiment 1 of the present invention.

FIG. 3 is a structural diagram of the composition of the forwarding beacon in Embodiment 1 of the present invention.

FIG. 4 is a schematic diagram showing the principle of a rising edge coincidence detection module in Embodiment 1 of the present invention.

Figure 5 is a schematic diagram of the forwarding beacon setting for the positioning system in Embodiment 2 of the present invention. In Figure 5, reference numerals 1 to 6 represent different forwarding beacons;

FIG. 6 is a schematic diagram of a specific flow chart of the positioning method proposed by the present invention.

The reference numerals in the figure are: LNA-low noise amplifier, BPF-band pass filter, DELAY-delay module, AND2-AND gate, XOR2-exclusive OR gate.

DETAILED DESCRIPTION

The specific embodiments of the present invention are described in further detail below.

Example 1

A typical implementation of the structure of the cursor-type positioning system of the present invention is shown in FIG1 . The system is composed of the following core devices: an interrogator, multiple forwarding beacons and a host computer; wherein at least three positions in the forwarding beacons are not collinear.

The interrogator is used to transmit and receive ranging signals and is carried by the person to be located. The microprocessor inside the interrogator generates ranging pulses and transmits them after spread spectrum and modulation processing.

After receiving the ranging pulse, each forwarding beacon forwards the returned ranging signal to the interrogator. After receiving the ranging signal, the interrogator performs ranging calculation and sends the calculated ranging information to the host computer.

The forwarding beacon is used to detect whether the interrogator is approaching and forward the ranging signal sent by the interrogator. It is arranged at a fixed position. When the interrogator is detected approaching, the forwarding module of the forwarding beacon is turned on, and the received ranging pulse is processed by difference frequency and amplification, and then converted into a ranging signal for forwarding; after a period of time, if no interrogator is detected approaching, the forwarding module is turned off.

The host computer is used to calculate the position of the interrogator and interact with the human-computer interface. Specifically, after receiving the ranging information sent by the interrogator, the host computer calculates the coordinates of the interrogator through the positioning algorithm and can display the position of the interrogator on the human-computer interaction interface.

Among them, a specific implementation of the interrogator is shown in Figure 2; it includes a clock generating unit, a spread spectrum unit, an interrogator transmitting unit, an interrogator receiving unit, a despreading unit, a timing unit, and an interrogator control unit. A specific implementation of the forwarding beacon is shown in Figure 3, including a beacon receiving unit, a difference frequency unit, a beacon transmitting unit, and a beacon control unit.

The clock generation unit of the interrogator includes a digital frequency generation unit (DDS), which is used to generate three signals CLK1, CLK2, and CLK3 with different frequencies. Among them, CLK1 is 50kHz and CLK3 is 49.99kHz. CLK1 and CLK3 are respectively used as the master clock and cursor clock for measuring the time interval by the cursor method. CLK2 is a spread spectrum clock, which is used to enable the spread spectrum unit to generate a 32-bit spread spectrum code and perform spread spectrum processing on the main clock signal.

The spread spectrum unit includes a PN code generator and a multiplier, which are used to generate a PN code of a certain length and multiply the waveform with the main clock CLK1 to realize the spread spectrum processing of the main clock CLK1 signal. Spread spectrum is used to realize code division multiple access. In real applications, there are multiple interrogators in the scene at the same time. Since the spread spectrum codes between different interrogators are orthogonal to each other during spread spectrum, even if an interrogator A receives a signal transmitted by another interrogator B, since the spread spectrum codes are orthogonal to each other, when despreading, the signal transmitted by another interrogator B will not be despread by the interrogator A.

The interrogator transmitting unit includes: a frequency modulator and a 2.4 GHz radio frequency transmitting antenna, which are used to frequency modulate the spread spectrum signal generated by the spread spectrum unit, convert the modulated signal to a 2.4 GHz radio frequency, and then transmit it through the antenna.

The interrogator receiving unit includes: a frequency modulation demodulator and a 5.8 GHz radio frequency receiving antenna, which are used to receive the ranging signal forwarded back by the forwarding beacon, demodulate the received ranging signal, and restore the signal before frequency modulation.

The despreading unit includes a sampling decision device, a sequence matching filter and a comparator connected in sequence. The sampling decision device is connected to the interrogator receiving unit and is used to perform sampling decision on the signal demodulated by the interrogator receiving unit, restore the spread spectrum signal, and then use the sequence matching filter and the comparator to despread. The despread signal after despreading is output by the comparator to the timing unit.

The timing unit includes a counter, a first rising edge coincidence detection module and a second rising edge coincidence detection module, wherein the rising edge coincidence detection module is used to perform rising edge coincidence detection on two input signals, and output a trigger signal when the rising edges coincide. A specific circuit implementation of the rising edge coincidence detection module is shown in Figure 4, which shows the connection relationship of the gate-level circuit. The rising edge coincidence detection module includes two detection input terminals, and the two detection input terminals are respectively connected to a detection branch. Each detection branch includes a delay module, an XOR gate and an AND gate. The delay module is connected between the detection input terminal and an input terminal of the XOR gate, the output terminal of the XOR gate is connected to an input terminal of the AND gate, and the other input terminals of the XOR gate and the AND gate are both connected to the detection input terminal. The output terminal of the AND gate is connected to the input terminal of the output AND gate as the output terminal of the detection branch, and the output terminal of the output AND gate is used as the output terminal of the rising edge coincidence detection module.

A person skilled in the art can derive a specific circuit and implement rising edge coincidence detection based on FIG. 4 . When the rising edges of two input terminals coincide, the output terminal of the specific circuit shown in FIG. 4 outputs a pulse signal.

The first rising edge coincidence detection module and the second rising edge coincidence detection module are respectively used to perform rising edge coincidence detection on the main clock CLK1 and the vernier clock CLK3, as well as the vernier clock CLK3 and the despread signal. When the rising edges of the main clock CLK1 and the vernier clock CLK3 coincide, the vernier clock CLK3 starts to be counted, and when the rising edges of the vernier clock CLK3 and the despread signal coincide, the counting is stopped. According to the principle of the vernier timing method, the flight time of the signal transmitted by the interrogator transmitting unit can be calculated through the obtained count value.

Different forwarding beacons can open the forwarding module at different times to realize the time division multiple access scheduling of each forwarding beacon; at the same time, it is used to send the ranging information to the host computer.

The triggering process of step 1 is specifically as follows: the interrogator broadcasts an inquiry signal, and after receiving the inquiry signal, the forwarding beacon within the coverage range of the inquiry signal transmits a response signal including the beacon's own coding information to the interrogator. The interrogator obtains all the forwarding beacon information within the coverage range of the inquiry signal through the received response signal, and the forwarding beacon within the coverage range of the inquiry signal is triggered.

For example, before positioning begins, the scheduling module based on the Bluetooth communication protocol built into the interrogator control unit first broadcasts an inquiry signal. The forwarding beacon control unit within the Bluetooth coverage receives the inquiry signal and then transmits a response signal to the interrogator. The response signal includes the coding information of the beacon. The interrogator control unit obtains the beacon information within the surrounding Bluetooth coverage through the received response signal. The inquiry signal can be a Bluetooth signal or other short-range wireless signal. The advantage of using short-range wireless signals such as Bluetooth is that only forwarding beacons within a closer range are triggered, and forwarding beacons farther away are not triggered to save energy.

During the positioning process, the scheduling module based on the Bluetooth communication protocol built into the interrogator control unit performs time division multiple access scheduling on each beacon, so that each beacon turns on the beacon receiving unit, difference frequency unit, beacon transmitting unit and other modules in different time intervals, and turns off the above modules after the time slot ends.

The beacon receiving unit in the forwarding beacon includes a 2.4GHz RF receiving antenna and a signal processing module, wherein the signal processing module includes a bandpass filter BPF and a low noise amplifier LNA. The beacon receiving unit is used to receive the RF signal sent by the interrogator transmitting unit and perform preliminary signal processing. The bandpass filter filters out clutter and the low noise amplifier amplifies the useful signal.

The difference frequency unit of the forwarding beacon is used to process the difference frequency, and includes a first oscillator, a first mixer, a second oscillator, a second mixer and a signal processing module, wherein the signal processing module includes a bandpass filter and an amplifier. The signal preliminarily processed by the receiving unit is converted to a 433MHz intermediate frequency by the first mixer using the first oscillator of 1.967GHz, and the clutter is filtered out and the signal is amplified by the signal processing module, and then the signal is converted to a 5.8GHz radio frequency by the second oscillator of 5.367GHz and the second mixer to realize the difference frequency processing of the signal.

The beacon transmitting unit includes: a signal processing module and a 5.8GHz radio frequency transmitting antenna, wherein the signal processing module includes a bandpass filter and an amplifier. The beacon transmitting unit is used to process the difference frequency signal, filter out clutter again, amplify the signal, and transmit the signal through the 5.8GHz radio frequency transmitting antenna.

The beacon control unit includes: a microprocessor and other control modules, which are used to receive the scheduling signal sent by the interrogation machine control unit, switch the forwarding module of the forwarding beacon, and minimize the power consumption of the forwarding beacon.

Example 2

This embodiment provides a positioning method, including the following steps: step 1. surrounding environment detection; step 2: ranging signal transmission; step 3: ranging signal forwarding; step 4: ranging signal reception; step 5: ranging information calculation; step 6: ranging information display.

First, install the positioning equipment and set the parameters.

The positioning equipment mainly includes positioning beacons and interrogators. The interrogator parameters are set as follows:

A specific industrial positioning environment is shown in Figure 5. For example, a rectangular factory building has multiple large equipment as obstacles. Six positioning beacons are arranged around the factory building, preferably evenly distributed at the boundary of the factory building. An XY plane coordinate system is established as shown in Figure 5. The beacon of the interrogator is (x ₀ , y ₀ ), the coordinates of beacon No. 1 are (x ₁ , y ₁ )=(0,0), the coordinates of beacon No. 2 are (x ₂ , y ₂ )=(5,0), the coordinates of beacon No. 3 are (x ₃ , y ₃ )=(10,0), the coordinates of beacon No. 4 are (x ₄ , y ₄ )=(10,5), the coordinates of beacon No. 5 are (x ₅ , y ₅ )=(5,5), and the coordinates of beacon No. 6 are (x ₆ , y ₆ )=(0,5), in meters.

Step 1: Surrounding environment detection. The interrogator detects the surrounding environment by interrogating the control unit, obtains the information of the surrounding forwarding beacons No. 1-6, and transmits a scheduling signal to perform time division multiple access scheduling on the beacons.

Step 2: Ranging signal transmission.

Specifically:

Step 2.1. The clock generation unit inside the interrogator generates two rectangular wave clock signals with similar frequencies. The frequency of the master clock a(t) is f ₁ = 50kHz, and the frequency of the cursor clock b(t) is f ₂ = 49.99kHz. At the moment when the rising edge of the master clock a(t) coincides with the rising edge of the cursor clock b(t), the cycle counting of b(t) begins.

Step 2.2. Perform spread spectrum processing on the master clock a(t), the spread spectrum code is a 32-bit m-sequence, and the spread spectrum signal after spread spectrum is c(t).

Step 2.3. Modulate the spread spectrum signal c(t) onto a 2.4 GHz RF carrier through frequency modulation, and transmit the modulated signal in the RF band as the ranging signal d(t) from the transmitting antenna of the interrogator transmitting unit.

Step 3: Ranging signal forwarding.

The forwarding beacon detects the scheduling signal and turns on the forwarding module, which includes a beacon receiving unit, a difference frequency unit and a beacon transmitting unit. The antenna of the beacon receiving unit receives the ranging signal d(t) transmitted by the interrogator, filters out the interference signal on the radio frequency through the filter in the difference frequency unit, transfers the signal to the 433MHz intermediate frequency, and then transfers the signal to the 5.8GHz radio frequency through the mixer, and forwards the ranging signal through the antenna of the beacon transmitting unit.

In steps 2.3 and 3, the reason for modulating the signal to the RF band and then transmitting it is that the antenna required for transmitting the RF band signal is small, the RF frequency of the forwarding beacon transmission signal and the RF of the interrogator transmission signal are different and the interval is large. Usually the frequency interval includes multiple channels to avoid mutual interference between the RF band frequencies.

Step 4. The interrogator receiving unit receives the ranging signal d(t) transmitted by the forwarding beacon and calculates the ranging information. Specifically:

Step 4.1. The receiving unit demodulates the received ranging signal to obtain a demodulated signal c′(t).

Step 4.2. Despread the demodulated signal c′(t) using a sequence matching filter. The sequence matching filter is a prior art in the art. Ideally, when the input sequence is exactly the spread spectrum code sequence of the sequence matching filter, the value output by the sequence matching filter is 32. If the input sequence is not the spread spectrum code sequence, the value output by the sequence matching filter is 0. Due to noise interference, the signal demodulation result is inaccurate. Therefore, the threshold of the sequence matching filter is set to 16. When the value output by the sequence matching filter is higher than the threshold, it is determined to be a despread. After despreading, the despread signal a′(t) is obtained.

Step 4.3. Compare the despread signal a′(t) with the cursor signal b(t), and stop counting b(t) at the moment when the rising edges coincide. The counting result is k.

Step 4.4. Calculate the flight time of the ranging signal d(t) as t=k(1/f ₂ -1/f ₁ ), where f ₁ and f ₂ are the master clock and vernier clock frequencies, respectively.

The round trip time of the ranging signal between the interrogator and the beacon is TA, and the main clock period is T1, so the period of the ranging signal transmitted by the interrogator and the signal received from the beacon is also T1. The cursor clock period is T2, and T2 is slightly larger than T1.

Take ΔT=T2-T1; the interrogator continues to transmit pulses at the master clock frequency f1, and continues to receive the receiving pulses returned by the beacon at the master clock frequency f1.

At the moment when the rising edge of the master clock coincides with the rising edge of the vernier clock, the vernier clock starts to count. After several T1 cycles, the rising edge of the received pulse coincides with the rising edge of the vernier clock again. At this time, the vernier clock has gone through k cycles. According to the vernier ranging method, the round-trip time of the ranging signal between the interrogator and the beacon can be obtained.

t=k(T2-T1)= k(1/f2-1/f1).

Step 4.5. Calculate the distance from the interrogator to the beacon: l = t*ν/2, where ν is the transmission speed of the electromagnetic signal in the medium, which is generally the speed of light or close to the speed of light.

Step 5. Distance measurement information is displayed. The interrogator sends the distance measurement result information to the host computer. The specific distance measurement results are as follows:

The host computer compares the distance information between the interrogator and each forwarding beacon, and selects the three beacons closest to the interrogator, namely beacons 1, 2, and 5, for positioning. Solve the equation group:

s ₁ , s ₂ , s ₅ represent the positions of beacons 1, 2, and 5 to the interrogator respectively, x ₁ , x ₂ , x ₅ represent the horizontal coordinates of beacons 1, 2, and 5 respectively, and y ₁ , y ₂ , y ₅ represent the vertical coordinates of beacons 1, 2, and 5 respectively.

The solution is that the coordinates of the interrogator are (x ₀ ,y ₀ )=(4,2).

The interrogation machine positioning coordinate information is displayed on the human-computer interaction page.

The foregoing describes various preferred embodiments of the present invention. Unless the preferred implementation modes in various preferred embodiments are obviously self-contradictory or based on a certain preferred implementation mode, various preferred implementation modes can be arbitrarily superimposed and used in combination. The embodiments and specific parameters in the embodiments are only for clearly describing the invention verification process of the inventor, and are not used to limit the patent protection scope of the present invention. The patent protection scope of the present invention shall still be based on its claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The vernier positioning method based on the forwarding beacon is characterized by comprising the following steps:

Step 1, periodically transmitting a scheduling signal in the moving process of the interrogator, and triggering forwarding beacons possibly existing around the scheduling signal, wherein the scheduling signal comprises triggering signals of a plurality of forwarding beacons, and when the triggering conditions are met, the corresponding forwarding beacons are triggered; step 2 is entered, otherwise step 1 is continuously carried out;

step 2, the interrogator transmits ranging signals to the triggered forwarding beacons, and the specific process is as follows:

Step 2.1, a clock generating unit in the interrogator generates two rectangular wave clock signal main clocks and vernier clocks with different frequencies; counting b (t) at the moment when the main clock coincides with the edge of the vernier clock; f ₁ is greater than f ₂,f₁ and the frequency of the main clock frequency f ₁,f₂ is the frequency of the vernier clock;

Step 2.2, performing spread spectrum processing on the master clock a (t), wherein spread spectrum signals after spread spectrum are c (t);

step 2.3, after the spread spectrum signal c (t) is modulated by frequency modulation, the modulated signal is used as a ranging signal d (t) to be transmitted;

step 3, the triggered forwarding beacon receives the ranging signal d (t) transmitted by the interrogator, filters the interference signal and forwards the ranging signal d (t) as the ranging signal;

Step 4, the interrogator receives the forwarded ranging signal and calculates ranging information, and the specific process is as follows:

step 4.1, demodulating the received ranging signal to obtain a demodulation signal c' (t);

step 4.2, despreading the demodulation signal c '(t), and obtaining a despreading signal a' (t) after despreading;

Step 4.3, comparing the edge of the despread signal a '(t) with that of the vernier signal b (t), and stopping counting the vernier signal b (t) at the moment that the edges of the despread signal a' (t) and the vernier signal b (t) coincide, wherein the counting result is k;

Step 4.4. Calculating the time of flight t=k of the ranging signal d (t) (1/f ₂-1/f₁),f₁ and f ₂ are the master and vernier clock frequencies, respectively;

Step 4.5, calculating the distance l=t×v/2 from the interrogator to the forwarding beacon, wherein v is the transmission speed of the electromagnetic signal in the transmission medium;

And 5, when the distances of the forwarding beacons with more than three non-collinear positions are obtained at the same time, calculating the position of the interrogator by using the coordinates and the distances of the forwarding beacons with the three nearest non-collinear positions to the interrogator.

2. The cursor positioning method based on forwarding beacons of claim 1, wherein the triggering process of step 1 specifically comprises: the interrogator broadcasts an inquiry signal, after receiving the inquiry signal, the forwarding beacon in the coverage area of the inquiry signal transmits a response signal comprising the coding information of the beacon itself to the interrogator, and the interrogator acquires all the forwarding beacon information in the coverage area of the inquiry signal through the received response signal, and the forwarding beacon in the coverage area of the inquiry signal is triggered.

3. The vernier positioning method based on a forwarding beacon according to claim 1, wherein the step 2.3 modulates the spread spectrum signal c (t) to a radio frequency section through frequency modulation as a ranging signal d (t);

after receiving the ranging signal d (t) transmitted by the interrogator in the step 3, the following processing is performed: filtering the interference signal of the ranging signal d (t), converting to an intermediate frequency, modulating the signal to a radio frequency section through a mixer, and forwarding, wherein the signal frequencies of the radio frequency section in the step 2.3 are different from those of the signal frequencies of the radio frequency section in the step 3.

4. The cursor positioning method based on forwarding beacons of claim 1, wherein the scheduling signals are time division multiple access scheduling signals.

5. A vernier positioning system based on forwarding beacons, which is used for realizing the positioning method as claimed in any one of claims 1 to 4, and comprises at least 3 forwarding beacons with non-collinear positions, at least 1 interrogator capable of communicating with each forwarding beacon, and an upper computer capable of communicating with the interrogator;

the transmitting beacon comprises a beacon receiving unit, a difference frequency unit, a beacon transmitting unit and a transmitting beacon control unit, wherein the difference frequency unit is used for processing signals received by the beacon receiving unit and transmitting the signals through the beacon transmitting unit; the forwarding beacon control unit is used for detecting the received scheduling signal and judging whether triggering is carried out;

The interrogator comprises a clock generation unit, a spread spectrum unit, an interrogator transmitting unit, an interrogator receiving unit, a despreading unit, a timing unit and an interrogator control unit;

The clock generation unit is used for generating a main clock, a vernier clock and a spread spectrum clock;

the spread spectrum unit is used for performing spread spectrum processing on the main clock signal so as to transmit;

the despreading unit is used for despreading the signals received by the interrogator receiving unit;

The timing unit is used for carrying out edge superposition detection on the main clock, the vernier clock and the signals after despreading and recording superposition time;

the interrogator control unit is used for transmitting a scheduling signal;

The upper computer is used for calculating the position of the interrogator according to the information sent by the interrogator.

6. The cursor positioning system based on forwarding beacons of claim 5, wherein the difference frequency unit comprises a first mixer, a signal processing module and a second mixer connected in sequence between the beacon receiving unit and the beacon transmitting unit, wherein the signal processing module comprises a bandpass filter and an amplifier connected to the bandpass filter; the first mixer and the second mixer are respectively connected with the first oscillator and the second oscillator.

7. The vernier positioning system based on a forwarding beacon of claim 5, wherein the despreading unit includes a sampling decision device, a sequence matching filter and a comparator connected in sequence, wherein the comparator is connected to the timing unit, and the sampling decision device is connected to the interrogation receiving unit.

8. The cursor positioning system based on forwarding beacons of claim 5, wherein the spread spectrum unit comprises a PN code generator and a multiplier, two input ends of the multiplier are respectively connected with the PN code generator and the clock generating unit, and an output end of the multiplier is connected with the inquiry transmitting unit.

9. The cursor positioning system based on forwarding beacons of claim 5, wherein the timing unit comprises a first rising edge coincidence detection module connected with the clock generation unit, a second rising edge coincidence detection module connected with the clock generation unit and the despreading unit, and the output ends of the two rising edge coincidence detection modules are connected with the counter.

10. The cursor positioning system based on forwarding beacons of claim 9, wherein the rising edge coincidence detection module comprises two detection input ends, the two detection input ends are respectively connected with one detection branch, each detection branch comprises a delay module, an exclusive-or gate and an and gate, the delay module is connected between the detection input end and one input end of the exclusive-or gate, the output end of the exclusive-or gate is connected with one input end of the and gate, the other input ends of the exclusive-or gate and the and gate are both connected with the detection input ends, the output end of the and gate is used as the output end of the detection branch to be connected with the input end of the output and gate, and the output end of the output and gate is used as the output end of the rising edge coincidence detection module.