Delivery Of Precise Time Error And/Or Compensation To GPS Receivers In An On-Board Unit Over Dedicated Short Range Communications

A method of operating on-board equipment in a motor vehicle, the method comprising:

• providing the on-board equipment with an on-board unit including a radio and a GPS receiver;
• using the radio to receive a signal from road side equipment, the signal having an accurate frequency in accordance with GPS time;
• using the on-board unit to establish a frequency of the on-board unit in accordance with the signal;
• determining within the on-board equipment a GPS accurate time, the GPS accurate time being dependent upon the established frequency of the on-board unit;
• and
• providing GPS time error or compensation to the GPS receiver, the GPS receiver time base clock error or compensation being dependent upon the GPS accurate time.

An arrangement for providing GPS accurate time in a motor vehicle, the arrangement comprising:

• road side equipment including a road side unit, the road side unit having:
• a first GPS receiver producing GPS accurate time;
• and
• a first radio communicatively coupled to the first GPS receiver, the road side unit being configured to establish a frequency of the road side unit in accordance with the GPS accurate time, the road side equipment being configured to transmit a signal including an accurate frequency, the accurate frequency being dependent upon the first GPS receiver;
• and
• on-board equipment, the on-board equipment comprising:
• a second radio configured to receive the signal from the road side equipment;
• and
• a second GPS receiver communicatively coupled to the second radio;
• the on-board equipment being configured to:
• determine the GPS accurate time, the determining of the GPS accurate time being dependent upon the accurate frequency in the signal;
• ascertain GPS receiver time base error or compensation based on the GPS accurate time;
• and
• provide the GPS receiver time base error or compensation to the second GPS receiver.