EVALUATION METHOD FOR RADAR MEASUREMENT DATA OF A MOBILE RADAR MEASUREMENT SYSTEM

Abstract

An evaluation method for radar measurement data of a mobile radar measurement system includes the steps of preparing a multidimensional range-Doppler map from the radar measurement data. In this evaluation method, each multidimensional range-Doppler map is stored together with time information. Moreover, at least one multidimensional range-Doppler map with time information is propagated on the basis of known movement data of the radar measurement system to the current time. The multiple multidimensional range-Doppler maps may be combined to form a combined range-Doppler map.

Claims

1. An evaluation method for radar measurement data of a mobile radar measurement system comprising the step of: preparing a multidimensional range-Doppler map from the radar measurement data, wherein each multidimensional range-Doppler map prepared is stored together with time information, wherein at least one multidimensional range-Doppler map with time information is propagated on the basis of known movement data of the radar measurement system to the current time, and wherein multiple multidimensional range-Doppler maps are combined to form a combined range-Doppler map.

2. The evaluation method as defined in claim 1, wherein the combined range-Doppler map is evaluated with respect to objects.

3. The evaluation method as defined in claim 1, wherein the combined range-Doppler map is evaluated with the aid of the CFAR algorithm.

4. The evaluation method as defined in claim 1, wherein the combined range-Doppler map is averaged before the evaluation.

5. The evaluation method as defined in claim 1 wherein only those regions at the combined range-Doppler map that are relevant for static objects are evaluated.

6. (canceled)

7. The evaluation method as defined in claim 2, wherein the combined range-Doppler map is averaged before the evaluation.

8. The evaluation method as defined in claim 3, wherein the combined range-Doppler map is averaged before the evaluation.

9. The evaluation method as defined in claim 2, wherein the combined range-Doppler map is evaluated with the aid of the CFAR algorithm.

10. The evaluation method as defined in claim 2 wherein only those regions at the combined range-Doppler map that are relevant for static objects are evaluated.

11. The evaluation method as defined in claim 3 wherein only those regions at the combined range-Doppler map that are relevant for static objects are evaluated.

12. The evaluation method as defined in claim 4 wherein only those regions at the combined range-Doppler map that are relevant for static objects are evaluated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The evaluation method, and a radar measurement system suitable for it, are explained below by way of example and extensively with reference to a plurality of figures. Here:

[0031] FIG. 1 shows a schematic illustration of a plan view of a mobile radar measurement system and surroundings;

[0032] FIG. 2 shows an angle-dependent range-Doppler map of the radar measurement system;

[0033] FIG. 3 shows a multidimensional range-Doppler map of the radar measurement system;

[0034] FIG. 4 shows the addition of a plurality of multidimensional range-Doppler maps.

DETAILED DESCRIPTION

[0035] A radar measurement system 10 and surroundings are illustrated in plan view in FIG. 1. The radar measurement system 10 transmits radar waves 12 that can be reflected at objects and can be detected again by the radar measurement system 10. The radar waves 12 are illustrated in a simplified manner as lines. At least one transmitting antenna and at least one receiving antenna are designed for the purpose at the radar measurement system 10. The radar measurement system 10 further comprises a plurality of electronic components in order to enable a transmission and reception of the radar waves and also to be able to process the ascertained measurement data.

[0036] Two static objects 14, 16 that are permanently joined to a ground, or that are at least unable to move with respect to it, are located by way of example in the surroundings of the radar measurement system 10. The radar measurement system 10, on the other hand, itself moves with a speed of v.sub.r. The radar measurement system 10 is accordingly also referred to as a mobile radar measurement system 10. This can, for example, be arranged at a motor vehicle. In the further explanations, the movement is assumed to be constant and straight. In fact, however, the radar measurement system 10 can execute any arbitrary movement pattern.

[0037] This movement of the radar measurement system 10 is known, and is available for the further steps. The motor vehicle can, for example, supply this movement information.

[0038] FIG. 1 shows the objects 14, 16 at various time points t.sub.0, t.sub.1, t.sub.2 and t.sub.3. These time points correspond to the time points at which the radar measurement system 10 carries out measurements, and accordingly transmits and receives radar waves 12. The time point to corresponds to the time point of the current measurement, wherein the previous measurement was carried out at the time point etc.

[0039] The object 14 is located directly in front of the radar measurement system 10, wherein the location of the object 16 is offset laterally with respect to the object 14. For the purposes of the following explanations, both objects 14, 16 are located at the same height, which corresponds to an unchanging height angle for the radar measurement system 10. The radar waves 12 that are transmitted to the objects 14 and 16 form an angle . This angle increases with respect to the object 16 as time goes on.

[0040] After the transmission of a pulse sequence by the transmitting antennas, the reflection of these pulse sequences at the objects 14, 16, and a subsequent detection by the receiving antennas, range-Doppler maps, RDM, are prepared from the measurement data of the radar measurement system 10. Each RDM corresponds to a transmitting antennareceiving antenna pair, and comprises a distance and a radial speed of an object with respect to the radar measurement system.

[0041] For each angle , an angle-dependent range-Doppler map, wRDM is prepared from the ascertained RDM with the aid, for example, of the beam-forming method. Such a wRDM 18 is represented in FIG. 2 for an angle =0. The speed is plotted from v.sub.max to +v.sub.max on the X-axis. The radial distance from 0 to s.sub.max is also shown on the Y-axis. This range of distances and speeds results from the properties of the construction of the radar measurement system 10, and represents the system limits.

[0042] A measured value that corresponds to the object 14 is illustrated within this wRDM. Since the object 14 is static, it moves in the wRDM toward the radar measurement system 10 with the speed v.sub.r. The object 14 is illustrated with the reference signs 14a, 14b, 14c and 14d at the time points t.sub.0, t.sub.1, t.sub.2 and t.sub.3.

[0043] Each object 14a, 14b, 14c and 14d is part of its own wRDM 18 at the time points t.sub.0, t.sub.1, t.sub.2 and t.sub.3. To illustrate the movement of the object 14 these are, however, represented together, i.e. overlaid, in FIG. 2. Since the object 14 is located directly in front of the radar measurement system 10, the angle also does not change, so that it always remains within the same wRDM 18.

[0044] In addition to objects 14, 16, ghost objects 20 are also generated in the wRDM 18 by the measurement data. These ghost objects 20a, b, c, d are represented for the different time points. These can for example result from unwanted reflections from the side-lobes of the radar measurement system 10. These unwanted reflections can also result from multipath propagation, if a radar wave can propagate along different paths. Interference with other mobile or stationary radar measurement systems can thereby also be averaged out.

[0045] The majority of such wRDMs can be combined into a multidimensional range-Doppler map, mRDM. Such an mRDM 22 is illustrated in FIG. 3. This extends the wRDM by the angle from .sub.max to +.sub.max. The wRDM 18 of FIG. 2 is an element of the mRDM, being central at =0.

[0046] In addition to the object 14, the object 16 is also drawn in the mRDM for the time points t.sub.0, t.sub.1, t.sub.2 and t.sub.3. The object 16 here moves toward the radar measurement system 10, wherein the radial speed falls and the angle rises to .sub.max.

[0047] For the further evaluation according to FIG. 4, a propagation is now carried out for all time points apart from the current time point to. The propagation uses the known movement of the radar measurement system in order to propagate the mRDM, or the respective wRDM, to the time point to. Propagation means that a determination is made as to where an object 14 would be in the form of a measured value from the time point t.sub.1 to the current time point to. Each position within the mRDM is propagated here, wherein only a partial number of all possible positions can comprise static objects. The location at which a measured value must be is also calculated from the time point t.sub.2 to the current time point to, etc. This is here only a straight-line movement, for which reason a shift of the measured values is relatively simple. This method can, in principle, be used for any arbitrary movement pattern. The position of the measured value of the object 14d in the mRDM is thus propagated or shifted to the position of the measured value of the object 14a. The measured values of the objects 14c and 14b are also propagated to the position of the measured value of the object 14a.

[0048] Thus according to FIG. 4, a plurality of mRDMs for different time points are propagated to the current time point with the corresponding propagation, and then combined. These mRDMs are given reference signs 22a, 22b, 22c etc. A combined, multidimensional range-Doppler map 24, zRDM is thereby obtained. A mean value can also be determined if appropriate. The number of points beyond the time point t indicates how far the mRDM is propagated. Static objects are always propagated at the same location. Such unwanted reflections, however, behave differently, so that, on the basis of the time points t.sub.0, t.sub.1, t.sub.2 and t.sub.3, they are positioned at different locations in the combined range-Doppler map 24 after the propagation, and thereby average themselves out. Static objects that are submerged in the noise background in the evaluation of one mRDM can thereby nevertheless be ascertained.

[0049] The application can be extended to include a height angle in addition to the side angle . The way in which it functions is the same here. Due to the difficulty that a 4-dimensional mRDM would represent in a figure, a 3-dimensional mRDM has been used for the explanation.