The principle of operation of the digital compass
In connection with a wide spread of android and the gps chips in the composition of end products in particular, I became interested in the idea of digital compass, around which there is so many questions.
So, before us the object is a compass, which is based on the principle of building on the determination of the coordinates using satellite navigation systems. However, in practice there are cases when the compass is composed as a receiver unit magnetoresistors(the principle of change of resistance from the position of an object in absolute space) or elements of the Hall. Elements of the Hall are being built on the basis of micromechanical systems, highly sensitive to the change of the magnetic field in the specific case of change of the charge distribution on a silicon wafer under the influence of Earth's magnetic field. Devices on magnetoresistor and elements of the Hall represent the compass in its classical form, as a stand-alone measuring instrument, in contrast to systems of "collective" type, the input information which is supplied directly to a satellite signal. In the end system tied to an external source of information in essence are instruments with indication of track angle in the form of a compass.br>
because in practice we deal most often with the location and directions using navigation systems, an example of this at least android with its google maps app, then prividitsya the principle of the algorithm for exactly this use case:
1. The signals from the satellites shoot the readings of the coordinates of the receiver satellite navigation system (and therefore object)
2. Note the time in which it was the determination of the coordinates.
3. Wait a period of time, short enough for better results.
4. Re-determines the location of the object.
5. Solved simple navigation problem of computing the movement velocity vector obtained from coordinates of two points and the size of the time interval, and then, knowing the vector, we easily obtain:
a) the direction of the movement
b) the speed
6. Transition to step 2.
As you can see, the algorithm is provided in cycles and the starting point for the next vector will be the end of a direction vector in the last time interval.
The disadvantages of this method, in the use of digital kompasiana:
if the object is stationary in absolute space, the direction of learn does not work, the point of fixation of coordinates coincide in this case.
As an exception to quite large objects (for example, large ships), where it is possible to install 2 receivers (e.g. on bow and stern). Thus, coordinates of two points directly, even if the object is stationary, and go to item 5.
It is also necessary to take into account the positioning accuracy, satellite positioning systems and its effect on slow moving objects, because of the spread of errors of the positioning.
Article based on information from habrahabr.ru
So, before us the object is a compass, which is based on the principle of building on the determination of the coordinates using satellite navigation systems. However, in practice there are cases when the compass is composed as a receiver unit magnetoresistors(the principle of change of resistance from the position of an object in absolute space) or elements of the Hall. Elements of the Hall are being built on the basis of micromechanical systems, highly sensitive to the change of the magnetic field in the specific case of change of the charge distribution on a silicon wafer under the influence of Earth's magnetic field. Devices on magnetoresistor and elements of the Hall represent the compass in its classical form, as a stand-alone measuring instrument, in contrast to systems of "collective" type, the input information which is supplied directly to a satellite signal. In the end system tied to an external source of information in essence are instruments with indication of track angle in the form of a compass.br>
because in practice we deal most often with the location and directions using navigation systems, an example of this at least android with its google maps app, then prividitsya the principle of the algorithm for exactly this use case:
1. The signals from the satellites shoot the readings of the coordinates of the receiver satellite navigation system (and therefore object)
2. Note the time in which it was the determination of the coordinates.
3. Wait a period of time, short enough for better results.
4. Re-determines the location of the object.
5. Solved simple navigation problem of computing the movement velocity vector obtained from coordinates of two points and the size of the time interval, and then, knowing the vector, we easily obtain:
a) the direction of the movement
b) the speed
6. Transition to step 2.
As you can see, the algorithm is provided in cycles and the starting point for the next vector will be the end of a direction vector in the last time interval.
The disadvantages of this method, in the use of digital kompasiana:
if the object is stationary in absolute space, the direction of learn does not work, the point of fixation of coordinates coincide in this case.
As an exception to quite large objects (for example, large ships), where it is possible to install 2 receivers (e.g. on bow and stern). Thus, coordinates of two points directly, even if the object is stationary, and go to item 5.
It is also necessary to take into account the positioning accuracy, satellite positioning systems and its effect on slow moving objects, because of the spread of errors of the positioning.
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