CN111722181A - A method for indoor positioning and speed measurement using the speed difference between radio waves and sound waves - Google Patents

Abstract

The invention discloses a method for indoor positioning and speed measurement by utilizing the speed difference between radio waves and sound waves. It includes three or more reference points, and is mainly used to transmit radio waves and sound waves. The radio waves and sound waves contain the ID and ID of the reference points. Time information, the receiver can receive the wireless signal and sound wave signal emitted by the reference point, and can analyze the signal emitted by the reference point, use the three-point positioning principle to locate, and accurately calculate the position of the receiver; at the same time, it can effectively measure the indoor position of the item. Accurate position and measurement of the moving speed of objects indoors, the present invention will have a very wide application in the field of Internet of Things, and will have great practical and economic value, especially for the field of future IOT, there will be an earth-shaking effect.

Description

A method for indoor positioning and speed measurement using the speed difference between radio waves and sound waves

technical field

The invention belongs to the technical field of indoor positioning and speed measurement, in particular to a method for indoor positioning and speed measurement by utilizing the speed difference between radio waves and sound waves.

Background technique

Positioning technology has been widely used, especially satellite positioning technology, which uses satellites in the sky to transmit signals for positioning; however, the wireless signals emitted by satellites are very weak and due to the satellite radio waves themselves, they cannot penetrate buildings, so indoors Positioning has always been a difficult problem. There are many indoor positioning solutions on the market, such as positioning through WIFI signals, but the positioning accuracy is not high and can only locate a general orientation, so there is not much practical value.

In the prior art, GPS, Beidou and other positioning satellite signals cannot penetrate indoors and cannot be positioned. Other indoor positioning technologies: WIFI, ultra-wideband technology, Bluetooth radio wave positioning technology, because radio waves are circular wave propagation technology, It cannot be accurately determined; the reflective ultrasonic technology is easily affected by multipath effects and non-line-of-sight propagation, which reduces the positioning accuracy; at the same time, it also requires a lot of investment in the underlying hardware facilities, and the overall cost is high, so the practical value is not high.

As we all know, the speed of radio waves in space is 300,000 kilometers per second, while the speed of sound waves in the air is only 344 meters per second. Object A emits both radio waves and ultrasonic waves, and object B receives both radio waves and sound waves from object A. There is a is the time difference t, then the relative distance between object A and object B is: 344*t. Therefore, by using the relative distance of multiple points, the position, distance and speed of indoor and closed spaces can be measured.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the present invention provides a method for indoor positioning and speed measurement by utilizing the speed difference between radio waves and sound waves, which can be used in places that are not covered by positioning satellite signals, such as indoors, basements, tunnels, cabins, etc. to locate.

In order to achieve the above object, the technical scheme of the present invention is as follows:

A method for indoor positioning and speed measurement using the speed difference between radio waves and sound waves, comprising the following steps:

(1) In an indoor space or a closed environment, three or more reference devices are installed; the object to be positioned has a receiver, and the receiver can receive the wireless signal and sound wave signal of the reference point;

(2) Each reference device uses radio waves and sound waves to send out a signal with its own ID at the same time;

(3) The receiver can receive the signal of the reference device, and can receive the time difference between the wireless signal time and the acoustic signal time of a certain reference device; calculate the distance from the receiver to the reference device; also obtain the receiver to each the specific distance of a reference device;

(4) Test out the relative position of the receiver relative to each reference device through these specific distances, and know the indoor position of the receiver;

(5) Through the position change of the receiver in unit time, the moving speed of the receiver in the room can be measured.

Beneficial effects: the present invention can calculate the relative distance between the reference device and the receiver through the speed difference between the radio wave and the sound wave, and determine the position of the object through algorithms such as triangulation; the overall positioning accuracy is high, and the system structure is simple. For the change in the position of the receiver, the change in the speed of the receiver can be calculated. The invention can be widely used for positioning of equipment in indoor or closed space, speed measurement, and application of Internet of Things.

Description of drawings

FIG. 1 is a two-dimensional schematic diagram of positioning using the difference between the propagation speed of radio waves and the propagation speed of sound waves according to the present invention.

Detailed ways

The present invention will be described below with reference to specific examples. Those skilled in the art can understand that these examples are only for illustrating the present invention, and they do not limit the scope of the present invention in any way.

Embodiments of the present invention include:

1. The speed difference between radio waves and sound waves is used for indoor positioning;

2. The speed difference between radio waves and sound waves is used for indoor speed measurement.

A method for indoor positioning and speed measurement using the speed difference between radio waves and sound waves, comprising the following steps:

(1) In an indoor space or a closed space, three reference devices are installed, and the IDs of the reference devices are: A, B, and C; the object to be positioned has a receiver D, and the receiver can accept the reference point. wireless and acoustic signals;

(2) The reference device uses radio waves and sound waves to simultaneously send out a signal with its own ID at the same time; A (A1, RA1, USA1); B (B1, RB1, USB1); C (C1, RC1, USC1) );

(3) Receiver D can receive the signals of reference devices A, B, and C, and the time difference t=t2-t1 between the time t1 of the wireless signal RA1 and the time t2 of the acoustic signal USA1 can be received by the receiver D; it can be calculated from D to A Distance L; Similarly, the distance from D to B and the distance from D to C can be calculated;

(4) The relative position of the receiver relative to the reference devices A, B, and C can be tested through the distances of AD, BD, and CD, and the indoor position of the receiver D can be known.

Further, through the above steps (1) to (4), the receiver D measures the position (x ₁ , y ₁ ) at the time point T1 and the position (x ₂ , y ₂ ) at the time point T2; The distance is l and the time difference: t, the speed v=l/t can be calculated.

As shown in Figure 1, the above method is simplified to a plane, and the transmitters are placed at points A and B to transmit radio wave signals and acoustic wave signals. Using the time difference between receiving radio wave signals and acoustic wave signals, r ₁ and r ₂ can be calculated. Therefore, the coordinates of the receiver at point C can be calculated; the calculation process

The time difference between the radio wave and the sound wave from point A to point C is T ₁ ;

The time difference between the radio wave and the sound wave from point B to C is T ₂ ;

The distance between two points AB is L (known)

The speed of sound in air is known to be 344m/s; distance:

R ₁ =T ₁ ×344;

R ₂ =T ₂ ×344.

For spatial positioning, the mathematical model is that three spheres meet at a point! It can be simplified to two circles intersecting a point; because the intersection of two spheres is a circle, so it can become the intersection of two circles; the calculation formula simplified to a two-dimensional flat graph is obtained as follows: the distance of AB is L, the slope of AB is, CD The slope of is

EB ² =(L-AE) ²

CE ² =CF ² +EF ²

CF=EF·K ₂

x _c =x ₀ -EF

y _c =y _o +CF

x _d = x ₀ +EF

y _d =y _o -CF

y _c =y ₀ +K ₂ (x _c −.

The above descriptions are only the embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied to other related technologies Fields are similarly included in the scope of patent protection of the present invention.

Claims (2)

1. a method utilizing the speed difference of radio wave and sound wave to carry out indoor positioning, speed measurement, is characterized in that: comprise the following steps: (1) In an indoor space or a closed environment, three or more reference devices are installed; the object to be positioned has a receiver, and the receiver can receive the wireless signal and sound wave signal of the reference point; (2) Each reference device uses radio waves and sound waves to simultaneously send out a signal with its own ID and time at the same time; (3) The receiver receives the signal of the reference device, and can receive the time difference between the wireless signal time and the acoustic signal time of a certain reference device; calculate the distance from the receiver to the reference device; also obtain the receiver to each The specific distance of the reference device; (4) Test out the relative position of the receiver relative to each reference device through these specific distances, and know the indoor position of the receiver; (5) Through the position change of the receiver in unit time, the moving speed of the receiver in the room can be measured. 2. the method that utilizes the speed difference of radio wave and sound wave to carry out indoor positioning, speed measurement as claimed in claim 1, it is characterized in that: the position of the receiver in the room is informed by the precise coordinate signal of each preset reference equipment, mention its precise latitude and longitude information.

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