Method for operating a motor vehicle accident data memory and accident data memory system

Abstract

In a motor vehicle accident data memory and method of operating it, a reference time is determined by a satellite navigation system, and a system time is synchronized with the reference time. When an accident is detected, accident data and the system time are recorded in a non-volatile memory.

Claims

1. A method of operating an accident data memory for a motor vehicle, comprising: establishing a system time of the accident data memory; obtaining raw data and a reference time from a satellite navigation system; generating integrity data indicating reliability or integrity of the reference time from the satellite navigation system; synchronizing the system time of the accident data memory with the reference time when the reference time is available; receiving an accident signal indicating detection of an accident of the motor vehicle; when the reference time becomes unavailable, calculating an integrity level of the reference time based on the integrity data existing prior to the unavailability of the reference time, and recording the integrity level of the reference time in response to the accident signal; receiving accident data regarding the accident; in response to the accident signal: recording the raw data from the satellite navigation system, the accident data regarding the accident, and the system time in a non-volatile memory of the accident data memory, and recording the integrity data in the non-volatile memory; and providing the raw data, the accident data, the system time, and the integrity data from the non-volatile memory for use in an evaluation or a reconstruction of the accident.

2. The method according to claim 1, wherein the integrity data are wholly or partially based on a satellite-based augmentation system.

3. The method according to claim 1, further comprising managing the system time in a clock of a unit containing the accident data memory.

4. The method according to claim 1, further comprising managing the system time in a clock of the accident data memory.

5. The method according to claim 1, further comprising updating the system time by a number of decaying storage elements when the reference time becomes unavailable.

6. The method according to claim 5, further comprising calibrating the storage elements when the reference time is available.

7. The method according to claim 6, wherein the calibrating of the storage elements is carried out taking account of one or more of the following influence variables: temperature, air humidity, radiation, air pressure, voltage level of a voltage supply, age.

8. The method according to claim 6, further comprising recording calibration data relating to the calibrating in the non-volatile memory.

9. The method according to claim 5, wherein the storage elements include different storage elements respectively having different time constants and/or different storage element types.

10. An accident data memory system for a motor vehicle, comprising: a non-volatile memory; a clock for managing a system time of the accident data memory system; and an electronic control apparatus configured: to establish the system time of the accident data memory system; to obtain raw data and a reference time from a satellite navigation system; to generate integrity data indicating reliability or integrity of the reference time from the satellite navigation system; to synchronize the system time of the accident data memory system with the reference time when the reference time is available; when the reference time becomes unavailable, to calculate an integrity level of the reference time based on the integrity data existing prior to the unavailability of the reference time, and record the integrity level of the reference time in response to the accident signal; to receive an accident signal indicating detection of an accident of the motor vehicle; to receive accident data regarding the accident; in response to the accident signal, to record the raw data from the satellite navigation system, the accident data regarding the accident, the system time in the non-volatile memory of the accident data memory system, and the integrity data in the non-volatile memory; and to provide the raw data, the accident data, and the system time from the non-volatile memory for use in an evaluation or a reconstruction of the accident.

11. The accident data memory system according to claim 10, further comprising a satellite navigation module that comprises the satellite navigation system and that is configured to generate the reference time.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The person skilled in the art will infer further features and advantages from the embodiment example described below with reference to the appended FIGURE, wherein:

(2) FIG. 1: shows a vehicle having an accident data memory system.

(3) FIG. 1 shows a vehicle 10 in a purely schematic form.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

(4) The vehicle 10 has an accident data memory system 20 which is likewise represented purely schematically.

(5) The accident data memory system 20 has a satellite navigation module 30. An outside antenna 35 is mounted thereon. The outside antenna 35 is designed to receive signals from satellites 31, 32, 33, 34 which are merely represented schematically. A location of the vehicle 10 can in particular be established therewith. Furthermore, a time of day can be determined as the reference time by the satellite navigation module 30 based on the satellite signals.

(6) The accident data memory system 20 further has a clock 40. This is used for managing a system time. The system time is continually synchronized with the reference time determined by the satellite navigation module 30 for as long as the reference time is available.

(7) Furthermore, the clock 40 has a number of decaying storage elements (not represented) in the form of multiple different capacitors. These are continually calibrated for as long as the reference time 30 is available. Should the reference time 30 not be available, for example because the vehicle 10 is located in a tunnel or in a garage and, correspondingly, no signals can be received from the satellites 31, 32, 33, 34, the system time is updated in the clock 40 with the aid of the storage elements. To this end, recourse can be had to the known decay behavior, in each case, and in particular the respective time constant of the respective storage element.

(8) Furthermore, the accident data memory system 20 has a non-volatile memory 50. Data can thus be recorded in this non-volatile memory 50 such that they are read out again independently of a power supply.

(9) Furthermore, the accident data memory system 20 has an electronic control apparatus 60. This is configured to execute a method according to an embodiment example of the invention.

(10) The non-volatile memory 50 and the control device 60 can be considered jointly as an accident data memory 25.

(11) If an accident is detected, which will not be dealt with in greater detail here, accident data are recorded in the non-volatile memory 50. These data are, for example, data from acceleration sensors, steering wheel angle sensors or other data which can be helpful for reconstructing the sequence of events leading to an accident. Such data relate to a period of time of 10 s prior to the accident up to 10 s following the accident. For example, an accident can be detected as a result of a control device triggering an airbag.

(12) In the event of a detected accident, the system time from the clock 40 is stored in the non-volatile memory 50. Consequently, an accurate value for the time at which the accident happened can be recorded in the non-volatile memory 50.

(13) Integrity data, which relate to the integrity of the respective reference time, are additionally constantly generated by the satellite navigation module 30. These data are also recorded in the non-volatile memory 50 such that the integrity of the respective time can be reconstructed. The integrity data are in particular based on a satellite-based augmentation system.

(14) The sequence of events leading to the accident can be reconstructed particularly well by means of the accident data memory system 20 according to the invention in the vehicle 10, in the event of the vehicle 10 having an accident, since very accurate information regarding the accident time are available and a comparison, for example, with accident data memories of other vehicles, which are likewise involved in the accident, can be carried out very accurately. As a result, malfunctions of technical systems in autonomous vehicles can, for example, also be detected.

(15) The aforementioned steps of the method according to the invention can be executed in the indicated order. They can, however, also be executed in another order. The method according to the invention can be executed in one of its embodiments, for example with a specific combination of steps, such that no further steps are executed. However, further steps can essentially also be executed, including those which are not indicated.

(16) The claims which form part of the application do not constitute a waiver of the attainment of more extensive protection.

(17) If in the course of the proceedings it transpires that a feature or a group of features is not absolutely necessary, then the applicant here and now seeks a wording of at least one independent claim, no longer comprising the feature or the group of features. This may, for example, involve a sub-combination of a claim existing as at the application date or a sub-combination of a claim existing as at the application date restricted by further features. Such claims or combinations of features, which are to be newly worded, are understood to also be covered by the disclosure of this application.

(18) It is further pointed out that configurations, features and variants of the invention, which are described in the various embodiments or embodiment examples and/or shown in the FIGURES, can be combined with one another as desired. Individual or multiple features are interchangeable as desired. Resulting combinations of features are understood to also be covered by the disclosure of this application.

(19) Back references in dependent claims should not be construed as a waiver of the right to independent, objective protection for the features of the subclaims referred back to. These features can also be used in any combination with other features.

(20) Features which are only disclosed in the description or features which are disclosed in the description or a claim only in conjunction with other features can, in principle, be of independent inventive relevance. They can therefore also be included separately in claims to distinguish from the prior art.