초록 ▼

A terrestrial C/A code GPS receiver system derives along-track position information while tracking as few as two GPS satellites by use of conventional altitude hold and a cross-track hold mode in which the maximum expected deviation of the vehicle from the expected track is estimated by, for example

A terrestrial C/A code GPS receiver system derives along-track position information while tracking as few as two GPS satellites by use of conventional altitude hold and a cross-track hold mode in which the maximum expected deviation of the vehicle from the expected track is estimated by, for example, knowledge or prediction of the width of the roadway or other track. To maintain accuracy, cross-track hold is alternated with clock hold to update the cross-track estimate when changes in vehicle direction are detected or when a predetermined period has elapsed.

대표청구항 ▼

A terrestrial C/A code GPS receiver system derives along-track position information while tracking as few as two GPS satellites by use of conventional altitude hold and a cross-track hold mode in which the maximum expected deviation of the vehicle from the expected track is estimated by, for example

A terrestrial C/A code GPS receiver system derives along-track position information while tracking as few as two GPS satellites by use of conventional altitude hold and a cross-track hold mode in which the maximum expected deviation of the vehicle from the expected track is estimated by, for example, knowledge or prediction of the width of the roadway or other track. To maintain accuracy, cross-track hold is alternated with clock hold to update the cross-track estimate when changes in vehicle direction are detected or when a predetermined period has elapsed. rmined that the vehicle is in a critical situation. 6. The operational condition recording apparatus according to claim 5, wherein the risk detector detects that the vehicle is in a dynamic critical condition. 7. The operational condition recording apparatus according to claim 6, wherein the dynamic critical condition is detected when a driver of the vehicle suddenly treads a brake pedal. 8. The operational condition recording apparatus according to claim 6, wherein the dynamic critical condition of the vehicle is detected when ABS detects a locking of the wheels. 9. The operational condition recording apparatus according to claim 6, wherein the dynamic critical condition is detected when a periphery monitoring device detects access to another vehicle. 10. The operational condition recording apparatus according to claim 6, wherein the dynamic critical condition is detected when the running speed exceeds predetermined speed and a handle steering angle exceeds a predetermined angle. 11. The operational condition recording apparatus according to claim 1, wherein the vehicle traveling in the dangerous region is detected when the vehicle travels along a sharp curve. 12. The operational condition recording apparatus according to claim 1, wherein the vehicle traveling in the dangerous region is detected when the vehicle travels on a road during construction. 13. The operational condition recording apparatus according to claim 1, wherein the vehicle traveling in the dangerous region is detected when the vehicle travels on a road not open. 14. The operational condition recording apparatus according to claim 1, wherein the vehicle traveling in the dangerous region is detected when the vehicle travels in an intersection not open. 15. The operational condition recording apparatus according to claim 1, wherein the vehicle traveling in the dangerous region is detected when the vehicle travels on a road with a downward steep slope. 16. The operational condition recording apparatus according to claim 1, wherein the vehicle traveling in the dangerous region is detected when the vehicle travels on a road where many accidents occurred. 17. The operational condition recording apparatus according to claim 1, wherein the vehicle traveling in the dangerous region is detected when the vehicle travels on a road the surface of which is frozen. 18. The operational condition recording apparatus according to claim 1, wherein the vehicle traveling in the dangerous region is detected when the vehicle travels on a road while snow falls. 19. The operational condition recording apparatus according to claim 1, wherein the vehicle traveling in the dangerous region is detected when the vehicle travels on a road on which dense fog is caused. 20. An operational condition recording apparatus which can record vehicular operational condition information of a vehicle including at least one of running speed, rotational speed of wheels, engine revolving speed, position of a shift, handle steering angle, brake tread power, operational condition of ABS, result of peripheral monitoring and distance between another vehicle, the operational condition recording apparatus comprising: a first mode as a recording mode in which the operational condition recording apparatus always records the vehicular operational condition information; and a second mode as the recording mode in which the operation condition recording apparatus records the vehicular operational condition information in more detail compared with that in the first mode, the first and second mode can be switched, wherein the recording mode is switched from the first mode to the second mode when a predetermined determination condition is met, wherein the predetermined determination condition is met when a risk detector determines that the vehicle is in a critical situation, wherein the risk detector detects that the vehicle is in a dynamic critical condition, wherein the dynamic critical condition is detected w