Method for assisting in determining the position of an identifier in relation to a vehicle

• US 10,279,778 B2
• Filed: 09/16/2016
• Issued: 05/07/2019
• Est. Priority Date: 09/18/2015
• Status: Active Grant

• Current Assignee: Valeo Comfort And Driving Assistance
• Original Assignee: Valeo Comfort And Driving Assistance
• Inventors: Leconte, Eric
• Primary Examiner(s): Nguyen, Tan Q
• Application Number:
  US15/760,002
• Publication Number:
  US 20180257607A1
• Time in Patent Office: 963 Days
• Field of Search: 701 2
• CPC Class Codes: B60R 25/04 operating on the propulsion system, e.g. engine or drive motor
• CPC Class Codes: B60R 25/209 Remote starting of engine
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: B60R 25/246 characterised by the challenge triggering
• CPC Class Codes: G07C 2209/61 Signal comprising different frequencies, e.g. frequency hopping
• CPC Class Codes: G07C 2209/63 Comprising locating means for detecting the position of the data carrier, i.e. within the vehicle or within a certain distance from the vehicle
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks

Abstract

The invention relates to a method (METH) for assisting in determining the position of an identifier (I) for accessing and starting a vehicle (V), relative to the vehicle (V), comprising: transmission (Em_TS_vp), from a first device, either the vehicle (V) or the identifier (I) to a second device, different from the first, either the vehicle (V) or the identifier (I), at a transmission time t0, of an initial train (TS_vp) of N sinusoidal signals, having identical amplitudes and respective frequencies f_p, pϵ[1;N], for any p between 1 and N−1; reception (Rec_TS_vp′) by the second device of an image train (TS_vp′) corresponding to the initial train (TS_vp, TS_ip) altered by the transmission (Em_TS_vp); construction (Cons_Sp_v) of a frequency spectrum (Sp_v) for the image train (TS_vp′); inverse Fourier transformation (TFI_Sp_v) of the spectrum (Sp_v), allowing a time signature (Sg_v) to be obtained; first integration (Int1_Sg_v) of the time signature (Sg_v), between the transmission time t₀ and a pre-determined intermediate time t_int, producing a first result (Rlt1); second integration (Int2_Sg v) of the time signature (Sg_v) between the intermediate time t_int and a pre-determined end time t_f, producing a second result (Rlt2); comparison (Comp_1/2) of a ratio (R) of the first result (Rlt1) to the second result (Rlt2) with a threshold value (S), so that it is possible to determine if the identifier (I) is positioned inside the vehicle (V).

Claims

1. A method for assisting in determining a position of an identifier for accessing and starting a vehicle, in relation to said vehicle, the method comprising:

transmission, from a first device from among the vehicle and the identifier, to a second device, separate from the first, from among the vehicle and the identifier, at a transmission time t₀, of an initial train of N sinusoidal signals, with identical amplitudes and with respective frequencies f_p, pϵ

[1;

N], such that, for all values of p between 1 and N−

1;

reception, by the second device, of an image train corresponding to the initial train altered by the transmission,

construction of a frequency spectrum of the image train,

an inverse Fourier transform of the spectrum to obtain a temporal signature

a first integration of the temporal signature, between the transmission time and a predetermined intermediate time t_int, to obtain a first result

a second integration of the temporal signature, between the intermediate time and a predetermined final time t_f, to obtain a second result, and

comparison of a ratio of the first result to the second result with a threshold value, to determine whether the identifier is positioned inside the vehicle.

2. The method as claimed in claim 1, wherein the intermediate time t_int is such that the temporal signature, between the transmission time and the intermediate time, comprises a first reception lobe corresponding to a direct path between the identifier and the vehicle.

3. The method as claimed in claim 1, wherein the final time is such that the temporal signature, between the intermediate time and the final time, comprises secondary reception lobes corresponding to reflected and/or refracted paths between the identifier and the vehicle.

4. The method as claimed in claim 1, further comprising a step of multiplying the ratio by (t_f−

t_int)/(t_int−

t₀), and a step of comparing the result of the multiplication with the threshold value.

5. The method as claimed in claim 1, wherein the threshold value is greater than 10.

6. The method as claimed in claim 1, wherein the frequencies f_p are such that N=80, f1=2400 MHz and, for all values of p between 1 and 79, f_p+1−

f_p=1 MHz.