“Is this knowledge not quite cold ” the develop that how chooses UWB for your application attacks structure?
[introduction]“This knowledge is not quite cold ” series, aim to help young associate people the memory that awakens knowledge, will choose one part Qorvo to delimit the knowledge of the key is nodded, combinative industry current situation is unscrambled, with this gain new insights through reviewing old material, fill a vacancy that check leakage. This piece will continue to discuss UWB.
“This knowledge is not quite cold ” series, aim to help young associate people the memory that awakens knowledge, will choose one part Qorvo to delimit the knowledge of the key is nodded, combinative industry current situation is unscrambled, with this gain new insights through reviewing old material, fill a vacancy that check leakage. This piece will continue to discuss UWB.
Anchorage dot and label
Want to understand UWB system, you need to understand anchorage dot and label these two term. Anchorage dot is fixed UWB equipment normally. Label is the UWB equipment that points to shift normally. Anchorage dot and label are exchangeable information, so that decide both the distance between. The exact position of label can correspond through be being nodded with many anchor will decide.
A few equipment can serve as anchorage dot, also can serve as label. For example, when two mobile mobile phones use UWB is calculated mutual when the distance between, they can change a part in computational process, alternant ground uses as label and anchorage dot.
Location and processing capability
Typical UWB equipment needs to have certain level to handle ability and specific function. To simple label, requirement processor is had a few shine put (but process designing blame breaks sexual memory easily) with data memory (lose a sex easily random access memory, or RAM) . Nod application to anchor, arrival time is for instance wrong (the anchorage site that uses in TDoA) , the likelihood needs to have the processor of RAM of more Shan Cunhe, still need data to answer below a lot of circumstances pass.
Graph 1 showed ticket (have motion to detect) or anchorage dot (have time pass interface, be like aether net or Wi-Fi interface) common framework. To anchorage dot, the likelihood needs the processor of different type, specific depend on systematic dimensions and working load / handling capacity demand.
Aerial
Element of another system consideration is aerial. Different application can need different antenna. For example, label uses antenna of small-sized complete tropism normally. Anchorage drop should use directional antenna possibly, specific depend on develop attacks structure.
Software inn
Between UWB communication component and application important interrelating is UWB software inn, if pursue,2 are shown. Software inn conduces to coordinate the each other with peripheral equipment to operate gender and coexistence. In addition, software can realize the communication between UWB communication component and in-house small controller. For example, when controlling the join between smartphone and car, software is in charge of coordinating communication.
Software still can manage at the same time many application and with exemple. For example, a certain solution may be control loudhailer, lighting installation, heat the component of the intelligent household ecosystem such as the system. It can be mixed with all UWB label UWB support facilities corresponds, use positional information operating ring at the same time door of condition, lock and open the door, enable and ban with call the police the system. UWB software inn can handle all cases that these differring at the same time.
Inn of use UWB software can ensure UWB communication component satisfies the requirement of different application. In addition, devise point of view from final user and whole system interconnected system for, a lot of functions that use this software can let a thing become simpler.
The function is preferential class sort
In a few application setting falls, different function needs to have first step sort. For example, it is suppose in a certain application, power source management and battery service life are very important, newer than the position rate or data handling capacity are more important. Below this kind of circumstance, can use software to optimize power comsumption, equipment the setting is need not when shut, need the open when communication.
Another kind of circumstance is, want or sensor LOS signal is paid no attention to is to come from different way. Right now, can use software general result average, in order to obtain accurate distance information; Software returns the signal with OK and flowing noisier than other signal processing. To achieve more accurate result (it is especially in fast and mobile application) , or the information that concerns equipment way to add, software is OK still the data that will come from UWB chip set and come from inertial measurement unit (include accelerometer, gyroscope and magnetometer to wait) data conformity is together.
UWB develop attacks to the structure is compared and choose
UWB uses the concept of ToF, this is one kind measures two radio to send and receive through multiplying the ToF of signal with velocity of light implement between the method of the distance. Be based on this fundamental, the requirement that can use according to the target implements technology of UWB fixed position with different kind.
Optimal develop attacks the structure basically is decided by application. This that is to say, design engineer wants to attack application and develop above all the structure matchs. The means that can offer an alternative has:
Two-way range finding (TWR) : If the graph is shown 3 times, TWR method can be passed determine the ToF of signal of UWB radio frequency, take this time next will calculate with velocity of light the distance between label and anchorage dot. The TWR of an application give typical examples that the car uses TWR method namely without system of key entrance guard can create a safe vacuum, be similar to a safe bleb, ensure at the same time when applying, this bleb retains the safe control of high accuracy.
If you implement TWR plan between two equipment, can obtain the distance information between equipment. On the foundation of TWR plan, you still can be between mobile label and mooring anchor dot implementation 2D even 3D position is measured; Call ” 3 edges measure a way ” .
Use TWR method, exchangeable 3 messages. Label nods the poll message of the address to start TWR through sending to contain foregone anchor. Anchorage dot records poll to receive time, reply answer a message. In receive after answering a message, label clock writes last word. Anchorage dot can use the information in last message to decide the ToF of UWB signal.
TWR method also can be used at the graph 4 with the graph 5 shown 2D/3D asset setting. Graph the 4 two-way range finding that show use monitor, and graph the TWR that label of 5 indication service data returns. If the graph is shown 5 times, data is answered pass can use a variety of methods (wait like Wi-Fi, NB-IoT, LTE-M) implementation, transmit data through these methods to the cloud.
Arrival time is wrong (TDoA) and retrorse TDoA: TDoA and retrorse TDoA method are similar to GPS. In foregone fixed place deploy many reference point, call ” anchorage dot ” , and these anchorage dots realized close together synchronism in time aspect. If be TDoA, mobile equipment will twinkle (send message regularly namely) , when anchorage dot receives beacon signal, will be based on jab of collective time of mark of synchronous time base. Next, the time stand sth on end that many anchor order reachs transmit engine of central fixed position, engine of central fixed position moves the beacon signal TDoA that nods according to every anchor many a little bit fixed position algorithm. Will get the 2D of mobile equipment or 3D seat finally, if pursue,6 are shown.
Retrorse TDoA more resemble GPS. In this system, anchorage dot sends synchronous beacon (have fixed / foregone deflection, produce collision in order to avoid) , mobile equipment uses TDoA and algorithm of many bits of fixed position to calculate its position, if pursue,7 are shown.
Arrive at phasic difference (PDoA) : Another UWB develop attacks is PDoA. PDoA but two equipment the distance between and both the azimuth between measures union to be together, if pursue,8 are shown. Use the assorted information of distance and azimuth, the opposite seat of two equipment can give in the computation below the circumstance that does not have any other infrastructure. For this, among them an equipment must deploy at least 2 antenna, and can gauge the phasic difference that every antenna place reachs signal carrier. Phasic and complete do not suffer aerial metabolic effect, and can realize excel the measurement of 10 ° precision, can leave the position of affirmatory emitter in the circumstance that is less than 5 ° thereby.
Attack to every kinds of develop structure, which kinds of application to suit most respectively? These use a field that basically emphasizes particularly on to differ at 3: Service of inductive type entrance guard, fixed position and equipment are right equipment (the place is bit righter) application. Graph 9 introduced TWR, TDoA, retrorse TDoA and PDoA develop to attack in detail optimal application of the structure.
Article origin: Qorvo semiconductor
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