CN209372076U - Electronic compass and electronic compass bracelet based on magnetoresistance - Google Patents

Abstract

The utility model discloses a kind of electronic compass based on magnetoresistance and electronic compass bracelet, electronic compass includes Wheatstone bridge, GPS device, magnetoresistance device, data processor, interpretation of result and the sensing device of repacking；Wheatstone bridge, GPS device and the magnetoresistance device of repacking are connect with data processor respectively, and data processor is connect with interpretation of result and sensing device；In electronic compass bracelet, electronic compass is fixedly connected with wrist strap.A variety of methods for distinguishing north and south are combined together by electronic compass described in the utility model by the way of probability theory, and geographic area is not limited when taking one's bearings, is not influenced by region, and structure is simple, reliable, easy for installation, easy to use, applied widely.

Description

Electronic compass and electronic compass bracelet based on magnetoresistance

Technical field

The utility model relates to compass field, especially a kind of electronic compass and electronic guide based on magnetoresistance Needle bracelet.

Background technique

Compass is the instrument for differentiating orientation.Because there are natural magnetic fields and magnet to have same sex phase for earth interior Reprimand, the property that there is a natural attraction between the sexes, the needle of compass are directed toward the tangential direction of magnetic meridian under geomagnetic field action.Therefore compass The geographical South Pole is directed toward in the arctic of needle when static, can accurately be taken one's bearings using this characteristic.But traditional pointer Formula compass is because all there is certain limitations in portability, sensitivity, precision and service life for mechanical innate factor.And With the development of Magnetic Sensor and special chip, there is the electronic compass of precise treatment, precision is high, stability is good, is navigating Extensive use has been arrived in sea, measurement, travelling and military affairs etc., becomes a kind of important navigational tool.It is existing most of Electronic compass is all based on magnetoresistance, Wheatstone bridge or GPS positioning technology and carries out orientation detection and judgement.

However, being highly prone to external interference, especially since existing electronic compass is only with a kind of method for distinguishing orientation It is in part mountain area and depopulated zone, and the precision taken one's bearings is lower, this just greatly limits the application model of electronic compass It encloses, makes troubles to user.

Utility model content

Goal of the invention: the purpose of the utility model is to provide a kind of electronic compass and electronic guide based on magnetoresistance Needle bracelet, the compass do not limit geographic area, are not influenced by region when taking one's bearings, a variety of methods for distinguishing north and south are adopted It being combined together with the mode of probability theory, structure is simple, reliable, and it is easy for installation, it is easy to use, it is applied widely.

Technical solution: in order to achieve the above object, the electronic compass described in the utility model based on magnetoresistance includes: The Wheatstone bridge 1 of repacking, the first GPS device 2, the second GPS device 3, data processor 4, interpretation of result and sensing device 5； The Wheatstone bridge 1 of repacking, the first GPS device 2, the second GPS device 3 are connect with data processor 4 respectively, data processor 4 It is connect with interpretation of result and sensing device 5.

Further, the Wheatstone bridge of repacking includes four fixed value resistance R₁、R_S、R₅、R₆, R₅With R₁Series connection, R_SWith R₆String Connection, R₁、R₅Place branch and R_S、R₆Place branch circuit parallel connection, R₁、R₅Between electric wire midpoint pass through galvanometer and R_S、R₆Between electricity Line midpoint is connected.

Further, in the Wheatstone bridge of repacking, R₅=R₆, R₁=Rs, and resistance R₁With R_SMaterial it is identical.

Further, R₁In earth's magnetic field, Rs is arranged in the controlling magnetic field case in a shielding earth's magnetic field.

Further, GPS device is equipped with receiving end, and receiving end includes processor and receiving antenna.

Further, receiving antenna selects active microstrip antenna, built-in low-noise amplifier (LNA)；Processor includes low Noise amplifier, filter, low-converter, automatic gain controller, analog-digital converter.

Electronic compass bracelet described in the utility model, including wrist strap and above-mentioned electronic compass, electronic compass It is fixedly connected with wrist strap.

The utility model has the advantages that compared with prior art, the utility model has following remarkable advantage:

1) by a variety of methods for distinguishing north and south such as Wheatstone bridge, GPS positioning technology, magnetoresistance using probability theory Mode is combined together, and is commonly applied in electronic compass, and geographic area is not limited when taking one's bearings, not by the shadow in region It rings, it is applied widely；

2) it is directed to the concrete condition of different regions, weight is assigned to each result, by probability theory and real data phase In conjunction with the accuracy taken one's bearings is high；

3) electronic compass being combined with bracelet, structure is simple, reliable, and it is easy for installation, it is easy to use.

Detailed description of the invention

Fig. 1 is the utility model electronic compass structural schematic diagram；

Fig. 2 is improved wheatstone bridge circuits figure；

Fig. 3 is magnetoresistance device schematic diagram；

Fig. 4 is GPS satellite schematic illustration；

Fig. 5 is GPS receiver end schematic illustration.

Specific embodiment

The technical solution of the utility model is described further with reference to the accompanying drawing.

As shown in Figure 1, the electronic compass based on magnetoresistance includes: the Wheatstone bridge 1 of repacking, the first GPS device 2, the second GPS device 3, data processor 4, interpretation of result and inductor 5.The Wheatstone bridge 1 of repacking, the first GPS device 2 tool There is the function of distinguishing earth magnetism field direction, the second GPS device 3 has the function of positioning；Three connect with data processor 4, and Detected result is transferred to data processor 4；Data processor 4 is according to diverse geographic location and height above sea level using not Same weight carries out calculation processing to data.

Position result measured by Wheatstone bridge 1 is T₁, the obtained Position result of the first GPS device 2 is T₂, second Location information detected by GPS device 3 is T₃；The information T according to detected by the second GPS device 3 first₃Obtain the electronics Geographical location locating for compass and height above sea level, data processor are somebody's turn to do according to the geographical location and altitude info ination Weight W corresponding to position₁、W₂、W₃；The final Position result being calculated is T=W₁T₁+W₂T₂+W₃T₃, T be it is identified most Whole Position result.

Data processor calculates the W of different zones in simulation₁、W₂、W₃When value, known direction Y can be pre-entered, so thatWherein σ is dimensionless, obtains optimal solution by using gradient optimizing alternative manner, simulates each longitude and latitude Corresponding W₁、W₂、W₃Value, and it is stored in database；Bring determining W into automatically after GPS positioning₁、W₂、W₃Value, obtains most Excellent solution.When region can not determine specific W₁、W₂、W₃When value, it can be idealized according to gradient Continuation theorem and obtain this region Orientation judging result.

Wheatstone bridge is designed according to magnetoresistance principle.Metal can generate magnetoresistance in magnetic field, Formula are as follows: ρ=ρ₁+(ρ₂-ρ₁)cos²θ.Wherein: θ is the angle of resistance and magnetic field, and ρ represents all-in resistance rate, ρ₁And ρ₂It is respectively electric Hinder the resistivity of vertical and horizontal.

As shown in Fig. 2, the wheatstone bridge circuits of repacking employed in present embodiment include four fixed value resistance R1, R_S、R₅、R₆, R₅With R₁Series connection, R_SWith R₆Series connection, R₁、R₅Place branch and R_S、R₆Place branch circuit parallel connection, R₁、R₅Between electric wire in Point passes through galvanometer and R_s、R₆Between electric wire midpoint be connected.Wherein, resistance R₅=R₆, R₁And R_SMaterial is identical, resistance value phase Together.R₁In earth's magnetic field, R_SIn the controlling magnetic field of shielding external magnetic field.

Since the electromagnetic field of variation can generate Lorentz force effect, magnetoresistance is produced；Usually with resistivity Relative increment indicates the size of magnetic resistance, that is, uses Δ ρ/ρ₀It indicates；Wherein ρ₀Resistivity when being zero magnetic field, Δ ρ are resistivity Variable quantity.If magneto-resistor resistivity in the magnetic field that magnetic induction intensity is B is ρ_B, then Δ ρ=ρ_B-ρ₀。

Due to relative change rate's Δ R/R of magnetoresistive sensor resistance₀It is proportional to Δ ρ/ρ₀(wherein Δ R=R_B-R₀), R₀It is zero Resistance per unit length value when magnetic field, R_BMagnetic induction intensity is resistance per unit length value in the magnetic field of B.Therefore magnetic resistance can also be used The relative increment Δ R/R of sensor resistance₀To indicate the size of magnetoresistance.Resistance R becomes (ρ at this time_B-ρ₀)/ρ₀*R₀+R₀, So when R₁Resistance value becomes R₃；R₃For R₁Resistance value after changing in the magnetic field that magnetic induction intensity is B.R_SIn a shielding earth magnetism In the adjustable magnetic fields of field, adjusting controlling magnetic field case makes R_SResistance changes, until galvanometer pointer nulling stops adjusting Section records the reading of magnetic field measuring apparatus at this time.R at this time_SResistance value becomes R₄, R₄For R_SChange in the magnetic field that magnetic induction intensity is B Resistance value afterwards.According to Wheatstone bridge principle: as the electric current I in bridge_gWhen=0, i.e., galvanometer pointer nulling is (galvanometric Zero point is in the centre of dial), electric bridge is in equilibrium state at this time, has following relational expression to set up: R₅*R₄=R_S*R₁.To To R₄=R₃.The size and Orientation of adjustable magnetic fields is identical as earth's magnetic field at this time, therefore obtains the walking direction result in earth's magnetic field T₂。

As shown in figure 4, GPS needs four satellites 6,7,8,9 in positioning, GPS satellite 6,7,8,9 emits to the ground respectively Signal, then user equipment 10 obtains the running track information of satellite, really by receiving, measuring each satellite-signal from signal Determine the spatial position of receiver user itself.Form 4 equations, it may be assumed that

(x₁, y₁, z₁), (x₂, y₂, z₂), (x₃, y₃, z₃), (x₄, y₄, z₄), (X, Y, Z) is respectively satellite 6,7,8,9 and connects The coordinate of receipts machine 10, Δ t₁, Δ t₂, Δ t₃, Δ t₄(Δt_iFor receiver time-satellite time) be respectively signal from satellite 6,7, 8,9 ideal time for being sent to receiver 10, c are the light velocity, and T is clock deviation (comprising receiver clock-offsets and satellite clock correction), wherein (Δ t_i- T) be [(receiver time-receiver clock-offsets)-(satellite time-satellite clock correction)] simplification.

User equipment can simply be interpreted as GPS receiver, it is mainly by receiver hardware, data processing software, micro- Processor and terminal device composition.The main task of user equipment is the visible GPS satellite of tracking, to the satelline radio received Measured value and navigation information needed for signal obtains positioning after data processing are finally completed to the positions calculations of user and can The navigation task of energy.GPS positioning method utilizes one in conventional terrestrial coordinate system using absolute fix (One-Point Location) method Platform receiver measures position of this relative to the heart of the agreement earth, and the conventional terrestrial coordinate system that the method uses is WGS-84 Coordinate system.

As shown in figure 5,11 represent radiofrequency signal, 12 represent microstrip antenna of having chance with, 13 representative antennas preamplifiers, 14 generations List processing device, 15 represent power supply, and 16 represent transmission outside data storage.Receiving end includes processor and receiving antenna, due to Active microstrip antenna have the advantages that it is small in size, light-weight, be simple to manufacture, easily realize conformal, therefore received using active microstrip antenna The noise coefficient of system can be effectively reduced in GPS signal, built-in LNA (>=26dB), have stronger integration capability, can be with active device Part, circuit integration are unified component.Processor include low-noise amplifier, filter, low-converter, automatic growth control, The functions such as analog-to-digital conversion.The radiofrequency signal for the GPS that active microstrip antenna receives is transferred in processor after the amplification of outside, is passed through Down coversion, Channel Modulation, bandpass filtering, available analog intermediate frequency digital signal are crossed, then 2 are carried out to signal with sample frequency Sampling exports digital intermediate frequency signal, then according to the positioning of GPS, different weights is determined, so that it is guaranteed that final T is more smart Really.After receiver receives the signal of all visible GPS satellites by antenna, data processing is carried out to these signals and is accurately surveyed The launch time for measuring each satellite-signal by its signal reception time shown by the clock and measures resulting signal and emits Time subtract each other after multiplied by the light velocity, to obtain the distance between receiver and satellite p.Relative zero is provided by the 4th satellite The referential for making the time calculates clock deviation, and calculates by clock deviation bring error d, and the space bit of satellite is accurately calculated with this Set T₃.And calculate latitude, longitude.According to the movement of user whithin a period of time it is rough obtain direction of relative movement T₂, according to T₃ Determine W₁、W₂、W₃。

The above results are substituted into formula: T=W₁T₁+W₂T₂+W₃T₃In, obtain final result.

In order to improve user it is movable outdoors when ease of use, the utility model is also disclosed a kind of portable electronic and refers to Electronic compass and the wrist strap on bracelet are fixedly linked by compass bracelet, and the portability and user for substantially increasing compass make Convenience.

Claims (7)

1. a kind of electronic compass based on magnetoresistance, it is characterised in that: the electronic compass includes the favour stone of repacking Electric bridge (1), the first GPS device (2), the second GPS device (3), data processor (4), interpretation of result and sensing device (5)；Change Wheatstone bridge (1), the first GPS device (2) and the second GPS device (3) of dress are connect with data processor (4) respectively, data Processor (4) is connect with interpretation of result and sensing device (5).

2. electronic compass according to claim 1, it is characterised in that: the Wheatstone bridge of repacking includes four definite value electricity Hinder R₁、R_s、R₅、R₆, R₅With R₁Series connection, R_SWith R₆Series connection, R₁、R₅Place branch and R_s、R₆Place branch circuit parallel connection, R₁、R₅Between electricity Line midpoint passes through galvanometer and R_S、R₆Between electric wire midpoint be connected.

3. electronic compass according to claim 2, it is characterised in that: in the Wheatstone bridge of repacking, R₅=R₆, R₁ =R_s, and resistance R₁With R_SMaterial it is identical.

4. electronic compass according to claim 3, it is characterised in that: R₁In earth's magnetic field, R_SSetting is shielded at one In the controlling magnetic field case in earth's magnetic field.

5. electronic compass according to claim 1, it is characterised in that: GPS device is equipped with receiving end, and receiving end includes place Manage device and receiving antenna.

6. electronic compass according to claim 5, it is characterised in that: receiving antenna selects active microstrip antenna, built-in Low-noise amplifier (LNA)；Processor includes low-noise amplifier, filter, low-converter, automatic gain controller, modulus Converter.

7. a kind of electronic compass bracelet, it is characterised in that: including wrist strap and such as electronics of any of claims 1-6 Compass, electronic compass are fixedly connected with wrist strap.