GPS FILTER ALGORITHM

• US 20110018760A1
• Filed: 02/28/2008
• Published: 01/27/2011
• Est. Priority Date: 02/28/2008
• Status: Active Grant

• Current Assignee: Volvo Truck Corporation (AB Volvo)
• Original Assignee: Volvo Group North America LLC (AB Volvo)
• Inventors: Gwynn, James R., Gardea, Raymond A., Bate, John G.
• Granted Patent: US 8,626,435 B2
• Time in Patent Office: Days
• US Class Current: 342/357.25
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: G01S 5/0018 Transmission from mobile station to base station

Abstract

A method for determining location such as vehicle location receives data at a predetermined frequency, validates the received data, stores the received data based on the validation and computes a location based on the stored data. The validation includes verifying a presence of particular data substrings within the received data, verifying a presence of a plurality of data fields within each data substring, computing a parameter based on information contained in two of the plurality of data fields and comparing the computer parameter with a pre-defined threshold.

Claims

1. A method for determining location comprising:

receiving data at a predetermined frequency;

validating the received data;

storing the received data based on the validation; and

computing a location based on the stored data, wherein the validation further comprises;

verifying a presence of particular data substrings within the received data;

verifying a presence of a plurality of data fields within each data substring;

computing a parameter based on information contained in two of the plurality of data fields; and

comparing the computed parameter with a pre-defined parameter threshold.

2. The method of claim 1, further comprising receiving the data from a vehicle.

3. The method of claim 2, further comprising receiving the data at a central station remote from the vehicle.

4. The method of claim 1, wherein the received data represents location information for a vehicle.

5. The method of claim 1, wherein the received data is a NMEA-1803 data string.

6. The method of claim 5, wherein the substrings represent at least one of a GSA substring and a RMC substring.

7. The method of claim 6, wherein the GSA substring includes fields representing at least horizontal dilution of precision and vertical dilution of precision.

8. The method of claim 7, wherein the parameter is computed based on the horizontal dilution of precision and the vertical dilution of precision.

9. The method of claim 8, further comprising:

designating the received data as invalid data if the computed parameter is greater than or equal to the pre-defined parameter threshold.

10. The method of claim 9, further comprising:

measuring a time lapse since a storage of a last data; and

overwriting the last stored data with the last stored data if the time lapse is less than a pre-defined time threshold.

11. The method of claim 10, further comprising:

triggering a notification that a signal is not being received if the time lapse is equal to or greater than the pre-defined time threshold.

12. The method of claim 6, wherein the RMC substring includes fields representing at least latitude, longitude and time.

13. The method of claim 1, wherein storing the received data comprises storing sixteen discrete data strings.

14. The method of claim 13, further comprising receiving the data strings at one second intervals.

15. A system for determining vehicle location, the system comprising:

a communication means for receiving data representing vehicle location;

a processing means for determining validity of the received data and determining the vehicle location; and

a storage means for storing validated data, wherein the processing means

verifies a presence of a particular data substrings within the received data;

verifies a presence of a plurality of data fields within each data substring;

computes a parameter based on information contained in two of the plurality of data fields; and

compares the computed parameter with a pre-defined parameter threshold.

16. The system of claim 15, wherein the processing means verifies receipt of data corresponding to a NMEA standard including a complete RMC substring and a complete GSA substring.

17. The system of claim 16, wherein the processing means computes the parameter based on data within the GSA substring.

18. The system of claim 17, wherein the processing means compares the computed parameter with a pre-defined parameter threshold stored in the memory means.

19. The system of claim 18, wherein the communication means is a modem.

20. The system of claim 19, wherein the modem receives data from an electronic control unit of a vehicle.