1. How is the GPS positioning system positioning

The 24 GPS satellites run around the earth at a high altitude of 12,000 kilometers from the ground, so that at any moment at any time, any at all at the ground can be observed at the same time.

Because the position of the satellite is accurate, in the GPS observation, we can get the distance from the satellite to the receiver. Using the distance formula in the three -dimensional coordinates, the three satellites can be used to form three equations to solve the position of the observation point (x X, y, z).Considering the error between the clock of the satellite and the receiver clock, there are actually 4 unknown, X, Y, Z, and clock difference, so the 4th satellite needs to be introduced to form 4 squares to solve, so as to obtain the observation point of the observation pointLavels and heights.

In fact, the receiver can often lock more than 4 satellites. At this time, the receiver can be distributed into several groups according to the satellite constellation, and each group is 4, and then the group with the smallest error is selected by the algorithm for positioning, thereby positioning, so asImprove accuracy.

Due to the errors of satellite Running tracks and satellite clocks, the impact of atmosphere on the signal of the flow layer, the ionization layer on the signal, and the artificial SA protection policy, the positioning accuracy of the civil GPS is only 100 meters.In order to improve the positioning accuracy, the differential GPS (DGPS) technology is generally adopted to establish a reference station (differential table) for GPS observation. The accurate coordinates of the known benchmark station are used to compare the observation values to obtain a correction number and release it outside the outside world.EssenceAfter receiving the correction number, the receiver compares it with its own observation value, eliminates most of the errors, and obtains a more accurate position.Experiments show that the positioning accuracy can be increased to 5 meters by using differential GPS.

vehicle navigation system is mainly composed of navigation hosts and navigation display terminals.The built -in GPS antenna will receive at least 3 data information transmitted from 24 GPS satellites surrounding the earth, thereby determining the current location of the car.The navigation host is matched with the electronic map data determined by the GPS satellite signal to determine the accurate location of the car in the electronic map.

On this basis, various functions such as driving navigation, route recommendation, information query, and playback AV/TV will be realized.Drivers only need to watch the screens on the display and listen to voice prompts, and manipulate the remote control in the hand to achieve the above functions, so as to drive easily and freely.

Global Positioning System is the second -generation satellite navigation system in the United States.It was developed on the basis of the Ziwuyi satellite navigation system, and it adopted the successful experience of the Wuwuyi system.Like the Ziwuyi system, the global positioning system consists of three parts: space part, ground monitoring, and user receiving machines.

According to the current plan, the space part of the global positioning system uses 24 satellites with a height of about 20,200 kilometers to form a satellite constellation.21 3 satellites are near -circular orbit, and the operating cycle is about 11 hours and 58 minutes. It is distributed on the six orbit planes (four on the surface of the orbit), and the orbital inclination angle is 55 degrees.The distribution of satellites allows more than four satellites at any time around the world at any time, and can maintain a good positioning and solving geometric graphics (DOP).This provides continuous global navigation capabilities in time.

The ground monitoring section includes four monitoring stations, one upward injection station and a main control station.The monitoring station has a GPS user receiver, atomic clock, a sensor collected by local weather data, and a computer that processes preliminary data.The main task of the monitoring station is to obtain satellite observation data and send these data to the main control station.The main control station is located at the Vanden Fort Air Force Base.It implements comprehensive control of the ground monitoring department.The main task of the main control station is to collect all observation data of the GPS satellites in each monitoring station, and use these data to calculate the orbit and satellite clock of each GPS satellite.The upward injection station is also located at the Vanden Fort Air Force Base.Its task is mainly to inject such navigation data and the instructions of the main control station into the satellite when each satellite runs to the sky.This injection is performed once a day for each GPS satellite and the final injection before the satellite leaves.

The global positioning system has the characteristics of good performance, high accuracy, and wide application. It is by far the best navigation positioning system.With the continuous improvement of the global positioning system and the continuous improvement of software and software, the application fields are continuously developing. At present, the various departments of the national economy have begun to gradually penetrate people's daily life.

2. Positioning principle of GPS navigation

d1 = [(x1-x2)^2 (y1-y2)^2 (Z1-Z2)^2]^1/2 c (vt1-vt0)

d2 = [(x2-x)^2 (y2-y)^2 (Z2-Z)^2]^1/2 c (vt2-vt0)

d3 = [(x3-x)^2 (y3-y)^2 (Z3-Z)^2]^1/2 c (vt3-vt0)

d4 = [(x4-x)^2 (y4-y)^2 (Z4-Z)^2]^1/2 c (vt4-vt0)

In the above four equations, the coordinates of the measuring point X, Y, Z, and VTO are unknown parameters, where DI = C TI (i = 1, 2, 3, 4).

DI (i = 1, 2, 3, 4) is satellite 1. Satellite 2, satellite 3. Satellite 3. Satellite 3, satellite 4 to receiver.

TI (i = 1, 2, 3, 4) is satellite 1. Satellite 1. Satellite 2. Satellite 2, satellite 3, and satellite 4 signals to reach the time of the receiving machine.

C is the speed of transmission of GPS signal (ie, the speed of light).

The meaning of each parameter in the four equations is as follows:

X, Y, and Z is the spatial right -angle coordinates of the coordinates to be tested.

XI, Yi, Zi (i = 1, 2, 3, 4) are satellite 1. Satellite 1. Satellite 2. Satellite 2, Satellite 3, Satellite 4's spatial right -angle coordinates at the time of T, can be obtained by satellite navigation.

VT I (i = 1, 2, 3, 4) is satellite 1, satellite 2, satellite 3. Satellite 3, and satellite 4 satellite clocks, which are provided by the satellite star calendar.

VTO is the bell of the receiver.

From the above four equations, the clock vTO of the coordinates of X, Y, Z and the receiver at the above four equations.

The basic positioning principle of GPS is: satellite sends its own star parameters and time information uninterrupted. After receiving this information, the user receives the three -dimensional position, three -dimensional direction, and time information of the receiver.

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What are the functions of a car umbrella?

1. sunscreen and insulation

Sun protection and insulation is the most basic function. After all, the original intention of buying a car Parasol is to prevent the car from being exposed.The Parasol is mainly protected by car paint, and at the same time blocked the damage of ultraviolet rays to the interior of the car. It can also avoid the rising temperature of the car in direct sunlight, so that we can be more comfortable when we use the car next time.

2. Rain prevention

The car umbrella can not only allow us to use it in a sunny day, that is, we can also use it in severe weather, especially nowadays in the rainy season. If we don't want the car to be rained, we can protect the car before the rain.Not only can our cars be protected, but it also avoids the destruction of car paint on the wind.

3. Dust -proof bird dung

When there are more windy weather, there are naturally more dust. Although the dust cannot be corroded to our car, there will be more dust.The car paint will definitely have an impact, and many riders will stop the car under the tree in order not to let the car expose, but when we drive, we will find that there are many bird dung on the car. Bird dung will have the car paintWith corrosive, with a car Parasol, these problems can be solved.

4. Fireworks and firecrackers damage

The car is parked at the door of the hotel. Fireworks and firecrackers are often encountered. Fireworks in burning often fall on the car. Use fire -resistant materials to prevent the drops of fireworks and firecrackers damage to the body.

How to choose the right car sun umbrella

1. Look at the appearance

Although the appearance of the car umbrella does not affect our use, a more satisfied appearance of ourselves is also familiar when we use. If the appearance is not good, we are afraid of not so much confidence.

2. Look at the umbrella surface

The umbrella surface and appearance of the Parasol are very different concepts. When choosing an umbrella surface, we must choose the kind of glossy umbrella surface. Such an umbrella surface is not only effective, but also has a certain amount of obstruction of ultraviolet rays.The role, of course, has also improved a certain improvement in the aesthetic perspective.

3, umbrella Bone

The umbrella Bone of the Parasol cannot be ignored. The umbrella Bone determines the storage of the Parasol.Life life is reduced.

4. Look at wind resistance

Skeleton umbrella resistance is relatively weak than that of round umbrellas and folding umbrellas. It is recommended that consumers choose products with good wind resistance.

5. Look at the brand

The quality of the product of large brands is often guaranteed, after -sales service is good, the production process technology is mature, the price is also reasonable, and the national supervision is relatively strict. Consumers can buy the appropriate car sun umbrella according to their actual needs.

[Hot and warm box safety] precautions for the operation of the warm and warm box

The characteristics of warm and warm box products:

The warm and warm box is very popular among developed countries in Europe and the United States.In the hot summer, it can bring you a touch of coolness. Regardless of Outdoor travel, or when you encounter traffic obstructions, you can be frozen drinks, fruits and fresh foods.

Because of its light weight, the warm and warm box is easy to carry, with DC power cord and AC power cord.It can also be used indoors, which is particularly convenient for students to store cold drinks in the apartment.If it is placed in a hotel, office and living room, its beautiful appearance and design, complete functions will bring you comfort, especially after your hard work will reduce your fatigue for a day.

The warm and warm box is an electronic refrigerator. It uses semiconductor refrigeration technology, energy saving and environmental protection, high safety, long service life, will not produce noise and pollution, and has the function of refrigeration and heating.

Instructions for the warm and warm box operation:

1. Set the HOT/COLD switch in "OFF" and turn off the power supply of the warm and warm box.

2. Put directly into the 12V cigarette heater socket in the car or directly connect to AC power in the room. Select the corresponding indicator light according to the cooling heat.

3. Refrigeration: The HOT/COLD switch is set in "COLD", the green indicator is on, indicating the refrigeration function.

4. Heating: The HOT/COLD switch is set in "HOT". The red indicator light is on, indicating the heating function.

Safety precautions for car warm and warm box:

1. To prevent the ventilation outlet and heat dissipation holes, the blocking will accelerate the heat and warm box, which will cause fire.

2. Do not enter the water inlet, otherwise the warm and warm box will stop working.

3. Please do not plug the items into the heat and warm box heat dissipation holes and inhale holes, and stay away from the heat source.

4. Do not put magnetic objects in the warm and warm box to prevent the internal chip from being affected.

5. Do not place overheated or corrosive objects to avoid damage to the inner biliary of the warm and warm box.

6. Stay away from flammable and humid places to prevent the hot and cold box explosion and fire.

7. The plug of the DC power cord or the AC power cord should be tightly inserted, otherwise it will cause the heat and damage of the wire and the plug, and even the fire.

8. Do not invert, collide, vibrate and warm and warm box.

9. Do not disassemble and modify the warm and warm box.

10. When the cooling and heating box is converted from the heating function to the refrigeration function or transform from the refrigeration function to the thermal function, it is recommended to turn off the power supply and start it after 30 minutes.

11. When cleaning the warm and warm box, turn off the power, do not use a powerful cleaner.

12. When using the car, turn off the power supply of the warm and cold box after turning off the engine.

13. Do not continue to work for 24 hours, otherwise it will shorten the service life of the warm and warm box.

1. Features of Bluetooth GPS wireless module

Although the Bluetooth GPS receiver is more expensive, the advantage is self -evident. The biggest feature is to get rid of the restraint of the data cable.smart phone of the operating system.Another feature is that you can place the range of no more than 10 meters between the smartphone and the Bluetooth GPS between the two. This advantage is that the GPS receiver can be placed to the place where the satellite model is favored.In the location of the viewing, for example, NOKIA's latest GPS module provides lane, which can be hung on the chest for easy carrying.In addition, it is used for car navigation to use an external antenna. At this time, you should consider whether the GPS receiver provides an external antenna interface.

2. Disadvantages and advantages

1. Bluetooth GPS is very small, easy to carry, simple use.

2. Bluetooth GPS can be used with smartphones, laptops, and PDA palm computers.It's not troublesome to use!It is best to use genuine navigation maps. If you temporarily use pirated maps, there are currently intercity pirated maps, pirated map 3.05 pirated maps, Kailid navigation maps (intelligent use on mobile phones), Route 66 test version map, ozi, mapking......wait.For details, please go to the navigation map column to view.

3. Bluetooth GPS price is not expensive.The cheapest is only about 500 in China, and the best imported from Taiwan is about 880 yuan.There are nearly 20 types of Bluetooth GPS in the market for you to choose.

4. Choose Bluetooth GPS. When using smartphones and PDAs, it will no longer occupy the battery resources of the mobile phone or PDA alone, because the Bluetooth GPS is equipped with a battery, both equipped with vehicle chargers and 220V battery chargers.

Bluetooth GPS wireless template

1) Quick search: 32 XXX search at the same time, 20 channels.

2) High -tech GPS chip: Sirf Star III chip.

3) Quick TTFF: 200,000 valid decoders, which can ensure that fast TTFF can still operate when low signals.

4) Built -in Waas/EgNOS (optional hidden WAAS/EGNOS device) and DGPS high -precision positioning.

5) Quick heat start: built -in charging lithium batteries can provide sufficient power for fast heat start.

6) Support protocol NMEA-0183 v3. Data protocol.

7) Strengthening the computing method provides super navigation performance, which can be located in environments such as cities, canyons or trees.

8) No user initialization settings are required.

9) LED light number display status: LED's light display status allows users to judge the power status. When the power supply is connected, the LED light is on. When the GPS-6036 is located, the indicator light "On" is shining, no need to use it no longer need to use it.Other devices to distinguish.

Disclaimer: The above method stems from the index of the program system or the sharing of netizens. It is for your reference only and does not represent the research perspective of this website. It proves that it is valid. Please pay attention to the authenticity and authority of the source of the content of the content.Apply to delete & gt; & gt; error correction & gt; & gt;

[Refrigeration Box] The functional characteristics of the category of refrigerated boxes and use drug refrigerated boxes and blood refrigerated boxes

What are the types of refrigerated boxes in my country?

1) Portable refrigerator: It is mainly suitable for short -distance transportation of a small amount of medicine/blood/vaccine/reagent/specimen.For example, the township health officer is applicable to the grassroots, and the short -distance transportation of a small amount of blood/specimen between the Hospital and the Hospital.The main size of the portable refrigerator is usually 3L in the refrigerator box, 5L of refrigerated box, 6L of refrigerated boxes, refrigerated box 8L (QB0408), and refrigerated box 12L (QB7003).

2) Specimen receiving package: It is mainly suitable for testing centers, universities, scientific research institutions, etc.Suitable for Outdoor work such as samples and samples.The main feature of the specimen receiving package is that it is relatively stable, not easy to shake, the bag is relatively strong, and it is also very light. It is suitable for the use of temperature recorder and embedded thermometer.At present, our company has provided multiple styles for major research institutions, universities, and testing centers across the country.

3) Large -volume refrigerated box: It is mainly suitable for short -distance transportation of low -temperature refrigerated products such as drugs/reagents/vaccines/specimens/seafood.If the vaccine/medicine/reagent is transported out of the cold storage, it is distributed to the dealers/Hospital/blood station/pharmacy.Qi Bing Da Rong accumulate refrigerated boxes Special internal and external seals to ensure that air conditioning is not lost.At present, our company can customize various specifications of large -scale refrigerated boxes such as tie rod refrigerator 25L, refrigerated box 30L, refrigerated box 40L, refrigerated box 60L, refrigerated box 80L, refrigerated box 100L, etc.

Classification and use of refrigerated boxes

The drug preservation box is a professional equipment for refrigerated drugs in the medical industry and can also be used to store biological products.It is suitable for pharmacy, pharmaceutical factories, hospitals, disease prevention and control centers, and health centers.

Pharmaceutical refrigerated box function characteristics:

Wing -type evaporator to improve the speed of cooling;

Humanized design, reliable and convenient temperature control;

Micro -computer control, digital temperature display, adjustment increase to 0.1 C;

The air -cooled system, the temperature fluctuation range of the box in the box is 2 C, the set temperature can be controlled at 2 ~ 8 C by adjusting the setting temperature;

Built -in circular fan, ultra -mute design;

Double -layer hollow glass insulation design;

The professional refrigerated equipment of the blood refrigerated box medical industry can also be used for refrigerated drugs, biological products, and is suitable for heavy blood stations, hospitals and epidemic prevention stations.

Blood refrigerated box function characteristics:

Temperature control

Accurate microcomputer control system, the temperature in the box is constant controlled in the range of 4 ;

Digital temperature display, the average temperature display accuracy is 0.1 C and the resolution is 0.1 C, which is convenient to accurately observe the temperature in the monitoring box;

Intelligent control fan forced air conditioning system to ensure the internal temperature of the box;

Ultra -mute design, solve the troubles brought by noise;

Safety system

Double display Running parameters (digital display), real -time monitoring to ensure the safety and qualitative equipment;

Built -in battery, continuously displaying the temperature and sound and light alarm for 24 hours after power off;

Dual system power disconnection record temperature data, (optional number display record);

Fluorofluor refrigerant Hard polyurethane insulation; insulation;

Unique power -off memory function, large amount of information, high time to save temperature data;

Special -designed sensor failure and digital disorders: two types of safe automatic transportation strokes (select electronic temperature recorder, real -time monitoring, with USB interface or optional printer).

Full transparent program

The application of external door anti -condensation technology, 85 % humidity has no gel, ensuring the observation of the in -box conditions;

Transparent hollow tempered glass door;

Double -layer hollow glass thermal insulation design of electric heating and dew glass door design;

Pharmaceutical refrigeration boxes and blood refrigerated boxes can be used for regular storage of products in laboratories such as medical clinical, life sciences, pharmaceutical companies, biotechnology, etc., and are suitable for medical institutions, pharmaceutical factories, biological product manufacturers, research institutions, etc.