Detecting an abnormal driving condition

• US 8,781,646 B2
• Filed: 07/25/2013
• Issued: 07/15/2014
• Est. Priority Date: 07/31/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cheng, Xin Hao, Hu, Guoqiang, Mei, Li Jun, Yang, Bo, Yuan, Yu
• Primary Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US13/950,349
• Publication Number:
  US 20140035773A1
• Time in Patent Office: 355 Days
• Field of Search: 701/1, 701/46, 701/47, 701/90, 701/29.1, 701/424, 340/426.16, 340/438, 340/439
• US Class Current: 701/1
• CPC Class Codes: G01S 11/10 using Doppler effect
• CPC Class Codes: G08G 1/052 with provision for determining speed or overspeed speed measuring in general G01P
• CPC Class Codes: G08G 1/162 event-triggered
• CPC Class Codes: G08G 1/163 involving continuous checking
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes

Abstract

A method of detecting an abnormal driving includes receiving a RF signal transmitted from a vehicle in front; performing digital down conversion on the RF signal to obtain a baseband digital signal; performing frequency shift detection on the baseband digital signal to obtain frequency shift between the received RF signal and the RF signal transmitted from the vehicle in front; and determining that the abnormal driving condition in front exists response to determining that the frequency shift has reached a set threshold.

Claims

1. A method of detecting an abnormal driving condition, the method comprising:

receiving, by a first vehicle, an RF signal transmitted from a second vehicle located in front of the first vehicle;

performing digital down conversion on the RF signal to obtain a baseband digital signal;

performing frequency shift detection on the baseband digital signal to obtain a frequency shift between the received RF signal and the RF signal transmitted from the second vehicle; and

determining that the abnormal driving condition of the second vehicle exists responsive to determining that the frequency shift has reached a set threshold.

2. The method according to claim 1, wherein performing frequency shift detection on the baseband digital signal to obtain frequency shift between the received RF signal and the RF signal transmitted from the vehicle in front comprises:

obtaining adjacent first sample point and second sample point of the baseband digital signal;

representing the first sample point as a first complex vector;

representing the second sample point as a second complex vector;

computing phase difference between the first complex vector and the second complex vector;

computing frequency shift between the received RF signal and the RF signal transmitted from the vehicle in front based on the phase difference.

3. The method according to claim 1, wherein performing frequency shift detection on the baseband digital signal to obtain frequency shift between the received RF signal and the RF signal transmitted from the vehicle in front comprises:

obtaining a plurality of continuous sample points of the baseband digital signal;

representing the plurality of continuous sample points as complex vectors;

computing phase differences between complex vectors corresponding to adjacent sample points in the plurality of continuous sample points;

performing weighted averaging on the phase differences to obtain average phase difference;

computing frequency shift between the received RF signal and the RF signal transmitted from the second vehicle based on the average phase difference.

4. The method according to claim 1, wherein performing frequency shift detection on the baseband digital signal to obtain frequency shift between the received RF signal and the RF signal transmitted from the second vehicle comprises:

obtaining sample points of the baseband digital signal;

performing time frequency transformation on the sample points of the baseband digital signal to obtain a set of amplitudes corresponding to a set of frequency points;

comparing the amplitudes with a preset valid amplitude;

filtering out frequency points corresponding to amplitudes which are greater than the valid amplitude;

computing frequency difference for each of the filtered-out frequency points between the filtered-out frequency points and a reference modulation frequency of the baseband digital signal;

selecting a largest frequency difference as frequency shift between the received RF signal and the RF signal transmitted from the vehicle in front.

5. The method according to claim 1, wherein, before performing frequency shift detection on the baseband digital signal, the method further comprising:

performing low pass filtering on the baseband digital signal.

6. The method according to claim 5, further comprising:

transmitting another RF signal to a third vehicle behind the first vehicle via a directional antenna.