Position detector with satellite signal receiver

IS 2 174 307 T3

DESCRIPTION

Location sensor with a satellite receiver for position determination. State of the art

The invention starts from a location sensor with a satellite receiver for the determination of the position of the type of the main claim. It is already known to use a location and navigation system for determining the location, especially of a car. Sensors are frequently connected to the navigation system to determine the direction of travel and the distance traveled. For the determination of an absolute position of the automobile, a satellite receiver can also be used, as known, for example, by the GPS system (Global Positioning System).

However, mounting the steering and travel sensors in the car is relatively expensive. On the other hand, the determination of the position with the help of the GPS receiver is relatively inaccurate, so that in densely built urban regions the GPS satellites cannot be received to a sufficient extent, so that the determination of the location on the basis of the reception by satellite is not always satisfactory. Furthermore, the signals from the satellite receiver as well as those from the direction and path sensor must be conditioned with corresponding filters, so that the location determination is not only unreliable, but also expensive.

Described in the article "Aided Inertial Land Navigation System with a Minimum Set of Inertial Sensors", Peter Daum et al. IEEE 11.04.1994, XP 000489353 a navigation unit, which has a locating module, a voltage supply and a GPS receiver. The locating module can have, for example, a gyroscope and two acceleration meters. To determine the position, a mixture of the different sensor data is carried out. It is known from the publication of Mark Sturza et al. “Embedded GPS Solves The Installation Dilemma”, IEEE 29.11.1988, XP 000043850 a navigation system for vehicles, in which a position determination by means of GPS and by means of sensors was integrated in a system. The data from the GPS receiver is transmitted over a Kalman filter. Advantages of the invention

The location sensor according to the invention with the characteristic features of the main claim has, on the other hand, the advantage that by means of the arrangement of the sensors in the same housing, the location sensor can be built very compactly. In this way, not only the assembly cost is advantageously reduced, but also the manufacturing cost. It is particularly advantageous that, due to the compact design, the individual components can be used several times for signal evaluation, for example filters, so that the manufacturing cost for the location sensor is further reduced. Due to the compatible data format at the location sensor output, a replacement for conventional satellite receivers is also possible.

Through the interconnection of the individual sensors on a common position filter, other structural groups are saved, which would otherwise be necessary for each individual sensor. Especially favorable in this case is that the sensor signals are weighted with a priority factor, so that, for example, the determination of the position with the GPS receiver has the highest priority, so that signals from satellites can be received. for a long enough time. On the other hand, if signals from satellites can no longer be received, for example in a tunnel, the travel sensor and the steering sensor receive the highest priority. These priorities are then maintained until satellite signals can be received again with sufficient quality.

By means of the measures indicated in the dependent claims, advantageous developments and improvements of the location sensor indicated in the main claim are possible. It is especially advantageous that a GPS and / or GLONASS system is used as a satellite receiver, since these systems are already installed and are partially released for civil use.

The use of one or more acceleration sensors and / or a rotational speed sensor (gyro sensor) as a path sensor and a steering sensor, respectively, seems therefore favorable, because these sensors can be installed in one independently of the car's signal generators in the location sensor housing. In this way, additional installations and connections on the outside of the vehicle can be saved.

By means of the additional use of a baromometric altimeter or a temperature sensor, the accuracy of the position determination can be monitored and improved. Since in the case of insufficient reception from GPS satellites, an altitude determination is also possible, the position determination can be calibrated by means of a comparison with the measurement values ​​of the baromometric altimeter. Since the working accuracy of the components used also depends on the ambient temperature, these errors can be advantageously compensated with the help of the temperature sensor.

In order to enable a position determination also in the case of very unfavorable reception conditions or also for the calibration of the sensors, for example the acceleration sensor, the connection of a tachoometer is advantageous. The tachoometer can in this case be a signal transmitter, present in the vehicle, for a traveled route, the signals of which can be used additionally for the calibration of the acceleration sensor.

It is particularly advantageous if a Kalman filter is provided as the position filter. In this filter, the errors of the individual sensors are compensated in the opposite direction, thereby improving the localization result.

IS 2 174 307 T3

He drew

An example of embodiment of the invention is represented in the drawing and is described in detail in the following description. In this case:

Figure 1 shows a block diagram of a known navigation location system, and

Figure 2 shows an exemplary embodiment according to the invention.

Description of the realization example

Figure 1 shows a known location system, which is configured with a GPS receiver 1, a magnetic compass 3 as a steering sensor and a path sensor 4, for example with wheel sensors in a car. The GPS receiver 1 in this case has a position filter 6 for determining the location from the signals received from the satellites. The signals from these sensors are connected to a computer 5, at the output 9 of which the position and the location data can be taken, respectively.

The GPS receiver 1 as well as the individual sensors 3, 4 and the computer 5 are in this case mounted in different housings, the individual housings being fixed in respective suitable places of the automobile.

FIG. 2 shows an embodiment following the invention of a location sensor 10, in which housing 11 is arranged the satellite receiver 1 with the direction sensor 3, the direction sensor 4 as a compact unit. The path sensor is configured, for example, as a rotational speed integrating sensor (gyroscope sensor). The gyro sensor is known to sai and therefore does not need to be explained in detail. A speed meter is provided as the path sensor 4, from which signals a traveled path can be calculated by integration. The outputs of these sensors are connected to a position filter 6. The position filter 6 is preferably configured as a Kalman filter.

To further improve the availability of position data, a temperature sensor 12 and / or a barometric altimeter can be provided.

7. Their outputs are also connected to the position filter 6. In another configuration of the invention, a tachometer 14 is provided as a path sensor, the signals of which are conducted through an external connection also on the position filter 6. To complete, this An antenna 2 is still planned for the satellite receiver 1. The position filter 6 calculates from the signals of the individual sensors the momentary position of the vehicle, the direction of travel and the distance traveled and makes this data available in a compatible data format on an output 9.

The Kalman filter is an optimal filter, which feeds, from the dynamics of the system, the stochastic characteristic data of the process noise and the measurement noise and from an initial information, an estimate of the state of the system with an estimation error. minimal. A detailed description can be found in "Introduction to Random Signals and Applied Filtering"; Robert Grover Brown, Patrick YC

Hwang; John Wiley & Sons, INC .; New York

1992.

The following explains in detail how this arrangement works. The position filter 6 is designed in such a way that it processes the signals from all connected sensors and signal generators. It is configured as a Kalman filter and can compensate for individual signals affected by error from connected sensors, so that a real location position is output with the highest possible probability.

Since both the signals from the satellite receiver 1 as well as the signals from the steering sensor and the path sensor 3, 4 are affected by error, in this case in particular the errors of the steering sensor and the path sensor 3, 4 accumulate An attempt is made to minimize errors with the help of the arrangement according to the invention, in order to determine a location position that is as reliable as possible. In this regard, an essential idea of ​​the invention is that the signals of the individual components are weighted with a priority factor. The weighted signals can then be evaluated according to the rules of the docking navigation. If, for example, GPS satellites can be received to a sufficient extent, then the position determination of satellite receiver 1 receives the highest priority, for example factor 1, while direction sensor 3 and path sensor 4 receive the factor 0. In case the reception conditions are bad, for example if the reception of satellites is prevented in densely built urban regions or in a tunnel, then the GPS receiver 1 receives the lowest priority factor, for example 0. Since the position filter 6 is continuously parallel to the position data of the satellite receiver 1, which feeds back and compares the position data obtained through the gyro sensor 3 and the acceleration sensor 4, the They will position the vehicle also when GPS signals are not available. In this case, the gyro sensor 3 and the acceleration meter 4 receive the highest priority, for example the value 1. As soon as the satellites can be received again to a sufficient extent, the last position is compared with the position determined by the satellite receiver 1 and corrected, if necessary. By means of this weighting of the priority factor dependent on the reception quality, a high accuracy of the location position is achieved. The individual sensors 3, 4 monitor each other in this way, so that the accuracy of the individual sensor in particular is not very important. Since the gyro sensor 3 and the acceleration sensor 4 are only used for a limited path, advantageously the accumulated errors of these sensors are also limited. Therefore, as a gyro sensor, a slightly inaccurate consumption gyro sensor can be used and therefore cheaper, since its data is only weighted when the most accurate measurement data from the GPS receiver 1 is not available for the calculation. of the position data.

Through the use of the temperature sensor3

ES 2 174 307 T3 temperature 12 and / or barometric altimeter 7 further optimization can be performed for the location position.

In another configuration of the invention it is envisaged to also use the signal from the tachometer 14 as a path sensor. In the case of using an acceleration sensor 4, it is foreseen to detect the acceleration in the three spatial axes perpendicular to each other, in order to obtain the information of the path and direction directly from the complex acceleration vector. In this case, the use of a gyroscopic sensor for generating the address information can be dispensed with.

If the gyroscopic sensor 3 and the acceleration sensor 4 are realized as a micromecaine component preferably on a semiconductor chip, then they can be realized as an integrated circuit or as a module on a plate in a space-saving embodiment.

Through the compatible data output format, the advantage is achieved that an existing GPS receiver 1 can be replaced with excess cost by a location sensor 10 according to the invention.