TECHNICAL FIELD

[0001] The present subject matter relates generally to automobiles. More particularly but not exclusively, the present invention relates to a vehicle location detection system and a method thereof.
BACKGROUND

[0002] Generally, automobiles parked in a parking lot are difficult to locate midst a huge number of automobiles. There may be a number of automobiles resembling the user vehicle when parked in a parking lot. The user will end up spending a lot of time searching for the automobile in the parking lot.
[0003] Generally, a vehicle location detection system that can assist the user to locate his / her vehicle in a parking pool by means of a key fob is known in the art. The key fob has a switch and a RF (Radio Frequency) transmitter, which can be used to transmit modulated radio waves at a particular frequency. The vehicle user carries the key fob and presses the switch to locate his / her vehicle. The
vehicle has an RF receiver and a control unit that can sense and identify that the key fob switch is pressed and hence activate lamps or buzzers in the vehicle to indicate the presence of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The detailed description is described with reference to the accompanying 20 figures. The same numbers are used throughout the drawings to reference like features and components.

[0005] Fig, 1 shows a block diagram illustrating the vehicle location detection system.

[0006] Fig. 2 illustrates a flowchart describing a method in accordance with a first embodiment.

[0007] Fig. 3 illustrates a flowchart describing a method in accordance with a second embodiment.

DETAILED DESCRIPTION

[0008] However, such a vehicle location detection system has a drawback in that the ECU continuously draws current from an auxiliary power source to sense if 10 the key fob is transmitting RF signal. If the vehicle is in a parked state for several days then the ECU drains the auxiliary power source energy and can lead to malfunction of vehicular electrical systems. For engine driven vehicles with an electric start system, electric start functionality will be affected, that may cause discomfort to the user.

[0009] A smart key system and apparatus to control a vehicle is also know in the art, wherein a sensor detects a change in state of a vehicle and only upon change in state of a vehicle an ECU delivers a wake up signal to the smart key. However, such a system requires additional sensor to monitor vehicle state.

[00010] Hence, an objective of the present invention is to have a system and a
method to prevent the draining of the auxiliary power source for a vehiclelocation
detection system. It is another objective of the present invention to have a vehicle
location detection system without usage of additional sensors. It is yet another

objective of the present invention to reduce power consumption utilized by the vehicle location detection system.

[00011] The auxiliary power source drainage is prevented by reducing the auxiliary power source consumption by a vehicle location detection system according to embodiments proposed in the present invention. The vehicle location detection system is applicable to any vehicle in general. The working of the vehicle location detection system can be understood in detail by the following description and the accompanying figures.

[00012] According to an embodiment of the present invention, the vehicle location detection system includes an authenticating device and a receiver control unit. The authenticating unit includes an authenticating switch and an RF transmitter. According to an embodiment, the RF transmitter includes a transmitting antenna. The driver circuit includes a RF receiver and a driver circuit to drive one or more loads.

[00013] The RF transmitter is capable of transmitting RF signals upon activation of the authenticating device and the RF receiver including a receiving antenna is capable of receiving transmitted RF signals.

[00014] Further, according to an embodiment of the present subject matter, the receiver control unit includes a microcontroller unit configured to control the detecting of RF signals by the RF receiver.

[00015] According to an embodiment of the present invention, the detection of RF signals is carried out for a predetermined duration and until the state of charge

of the auxiliary power source becomes less than a predetermined value. Upon completion of the aforementioned conditions, the microcontroller disables the scanning for RF signals by the vehicle location detection system. Hence, the auxiliary power source state of charge is conserved and is available for the user. Therefore, the user whenever reaches the vehicle is available with a minimum SOC of the auxiliary power source to start the vehicle.

[00016] Fig.l illustrates a block diagram of a vehicle location detection system. The vehicle location detection system comprises of a receiver control unit 210 connected to a vehicle and a portable authenticating device 201 carried by the vehicle user. The authenticating device 201 has an authenticating switch 203 capable of activating an RF (Radio Frequency) transmitter 202 when pressed by the user, to generate modulated radio waves at a specific frequency, for example, at 433.92MHz in the preferred embodiment.

[00017] According to an embodiment of the present invention, the receiver control unit 210 has an in-built RF receiver 205 for receiving the radio signal by means of a receiver antenna 204b. A microcontroller unit 206 present in the receiver control unit 210 decodes the input from the RF receiver 205 to identify the authenticating device 201. An auxiliary power supply 207 receives an auxiliary power supply input and supplies conditioned voltage supply to the microcontroller unit 206 and an enabling unit 211. The enabling unit 211 enables one or more loads including indicators on the vehicle based on the microcontroller unit 206 output to indicate the vehicle location to the user. In the preferred embodiment, the enabling unit 211 is comprised of a driving transistor 209 and a

relay unit 208. The relay unit 208 receives an input supply 208a. Additionally, blocking diodes are used to connect with one or more front indicator lamps of the vehicle. The one or more loads 212a, 212b include audio indicators and visual indicators. In addition to the auxiliary power supply 207, the receiver control unit 210 also receives an ignition switch input. The ignition switch input provides a signal indicative of vehicle operation state and the microcontroller unit 206 can understand if the ignition switch is OFF from this signal.

[00018] The working of the circuit diagram indicates that the one or more indicators on the vehicle are activated only when the ignition switch state is in OFF condition as detected by the microcontroller unit 206 and if the corresponding RF signals transmitted by the RF transmitter 202 from the authenticating device 201 are detected by the RF receiver 205. The working of the vehicle detection system dependent on various conditions can be understood in greater detail by the following flow chart.

00019] Fig. 2 illustrates a flow diagram depicting a method for detection of a vehicle location according to an embodiment. A step 301 shows a condition if an ignition switch of the user vehicle is ON. If the ignition switch of the corresponding user vehicle is ON, then the microcontroller unit 206 will not detect any RF signals as shown in step 302. Further, in step 303, the ignition switch status is again detected by the microcontroller unit 206. If the ignition switch is OFF, the microcontroller unit 206 activates RF receiver 205 to scan for the RF signals as shown in 304, transmitted from the RF transmitter 202 present in the authenticating device 201. After scanning for the RF signals, the

microcontroller unit 206 activates the RF receiver 205 to scan for the matching RF signals of the corresponding user vehicle only if the ignition switch is OFF. If the ignition switch is OFF and if the corresponding RF signals matching the vehicle user is identified, the microcontroller unit 206 will activate the enabling unit 211 which in turn will activate one or more loads 212a, 212b in the vehicle as shown in step 306. If the corresponding RF signals are not identified in step 305, then further the ignition switch status is monitored by the microcontroller unit 206. The microcontroller unit 307 checks if the ignition switch status is OFF for pre-determined time duration, for 48 hrs. According to the embodiment, after 48 hrs, the vehicle location detection system shuts down as indicated by step 308. After reaching step 308, the vehicle location detection system stops working and is re-activated only when the ignition switch is turned ON again by the user. In the preferred embodiment, the one or more indicator lamps of the vehicle will be activated at a predetermined flashing rate to indicate the vehicle location.

[00020] If the RF signal from the authenticating device 201 is not received for predetermined time duration, 48hrs in the preferred embodiment, the scanning function is stopped. The scanning function is reactivated only if the ignition switch is turned ON again. By stopping the scanning function, energy consumed by the RF receiver 205 is minimized, which in turn reduces the auxiliary power source energy consumption and ensures satisfactory performance of the vehicle even when used after a prolonged period of storage in ignition OFF condition.

[00021] Fig. 3 illustrates a flow diagram for vehicle location detection system in accordance with another embodiment. The ignition switch status is checked in a

step 401. If the ignition switch status is detected as ON, then there will be no scanning conducted to detect the RF signals by the RF receiver 205 as indicated by step 402. The microcontroller unit 206 activates the RF receiver 205 only if the ignition switch input is OFF as indicated in step 403. The RF receiver 205 continuously scans for matching RF signals of the corresponding user vehicle as indicated in step 404. If the matching RF signals are identified as indicated in step 405, then one or more indicators in the vehicle are activated as indicated in step 406 to identify the corresponding user vehicle. The time duration for allowing the RF signal scanning by the RF receiver 205 is not a constant in the present embodiment. The time duration available for scanning is a variable based on the auxiliary power source state of charge (SOC). The microcontroller unit 206 continuously monitors the auxiliary power source voltage and the auxiliary power source SOC is estimated from the available auxiliary power source voltage. The scanning for RF signals by the RF receiver 205 is permitted only until the auxiliary power source SOC drops below a predetermined value and the scanning for the RF signals by the RF receiver 205 is not carried out if the auxiliary power source SOC is below a predetermined value as indicated in step 407. The vehicle location detection system will stop functioning once the auxiliary power source SOC has reached below a predetermined value as indicated in step 408.

[00022] Hence, the vehicle location detection system will carry out functioning of scanning for matching RF signals transmitted from the authenticating device 201 only if the auxiliary power source SOC is above a predetermined value. If the auxiliary power source SOC is below a predetermined value, the system power

goes OFF and the scanning functionality is not performed. Hence, drainage of auxiliary power source present in the vehicle is avoided. This ensures maximum utilization of the vehicle location detection system without compromising on auxiliary power source life and vehicle performance.
[00023] Although the subject matter has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. It is to be understood that the aspects of the embodiments are not necessarily limited to the features described herein. Rather, the features are disclosed as embodiments of the vehicle location detection system 100 of the vehicle.

I/We claim:

1. A vehicle location detection system (100) for a vehicle, said vehicle
location detection system comprising:
an authenticating device (201) including an authenticating switch (203) and a RF transmitter (202) capable of transmitting RF signals upon enabling said authenticating device (201);
a receiver control unit (210) including a RF receiver (205) capable of receiving RF signals from said authenticating device (201), and an enabling unit (211) to enable one or more loads (212a, 212b); and an auxiliary power source (207) to supply power to said receiver control unit (210), wherein,
said receiver control unit (210) includes a microcontroller unit
(206) adapted to scan for said RF signals by means of said RF
receiver (205) and to monitor state of charge (SOC) of said auxiliary
power source (207); and
wherein, said scanning of said RF signals is disabled upon earliest occurring of at least one of events including completion of a predetermined duration and the SOC of said auxiliary power source
(207) reaching below a predetermined SOC.

2. A method to detect the location of a vehicle, said method comprising steps
of:
monitoring an ignition switch state by a receiver control unit (210);

detecting RF signals by a RF receiver (205) to communicate location
of the vehicle;
enabling one or more loads (212a, 212b) by a microcontroller unit
(206) if said ignition switch state is detected as OFF and if corresponding RF signals are detected; and disabling said detecting of RF signals by said microcontroller unit
(206) if said ignition switch state is detected as OFF for a
predetermined duration and if corresponding RF signals are not
detected.
A method to detect the location of a vehicle, said method comprising steps of:
monitoring an ignition switch state by a receiver control unit (210);
monitoring a state of charge (SOC) of an auxiliary power source
(207) by a microcontroller unit (206);
detecting RF signals by a RF receiver (205) to communicate location of the vehicle;
enabling one or more loads by a microcontroller unit (206) if the ignition switch state is detected as OFF, if said RF signals of corresponding vehicle are detected and, if said SOC of said auxiliary power source (207) is above a predetermined value; and disabling said detecting of RF signals by said microcontroller unit (206) if said SOC of said auxiliary power source (207) is less than a
predetermined value.

4. The vehicle location detection system (100) as claimed in claim 1, wherein said one or more loads (212a, 212b) include audio indicators and visual indicators.
5. The vehicle location detection system (100) as claimed in claim 1, wherein, said auxiliary power source includes a battery or a fuel cell.
6. The vehicle location detection system (100) as claimed in claim 1, wherein said RF transmitter (202) includes a transmitting antenna (204a).
7. The vehicle location detection system (100) as claimed in claim 1, wherein said RF receiver (205) includes a receiving antenna (204b).
8. The vehicle location detection system (100) as claimed in claim 1, wherein said predetermined SOC is 25% of initial SOC of said auxiliary power source (207).
9. The vehicle location detection system (100) as claimed in claim 1, wherein said predetermined duration is 48 hours.
10. A vehicle comprising a vehicle location detection system (100) and a method to detect the vehicle as claimed in any one of the preceding claims.