静脉，o​​mnet ++和相扑中车辆状态的速度和位置不一致

Question

Used: Omnet++4.6, Sumo0.21.0 and Veins-3.0
I tried to track a vehicle using RSU when a vehicle continuously send a beacon(WSM) contained Vx(velocity to x-axis),Vy(velocity to y-axis),position,speed in every second .I used open-street-map for this scenario. After recorded beacon message(WSM) trough RSU,I found followings:

t0=0.839078378444 id=0 x0=299.711 Vx0=-0.0273485 y0=542.695 Vy0=-1.58621 AngleRed0=1.58804 Speed=1.58645
t1=1.839078378444 id=0 x1=299.665 Vx1=-0.0607238 y2=540.03 Vy2=-3.52198 AngleRed1=1.58804 Speed=3.5225

I used following code to set the properties in WSM in vehicle node which has been retrieved from RSU's onBeacon method:
wsm->setSpeed(traci->getSpeed());
wsm->setAngleRad(traci->getAngleRad());
wsm->setvecX(traci->getCurrentSpeed().x);
wsm->setvecY(traci->getCurrentSpeed().y);
wsm->setSenderPos(traci->getCurrentPosition());
wsm->setCarId(getParentModule()->getIndex());

Now Calculation to check Vx and Vy are consistent:
At time t1 = 1.839078378444,(x1,y1) = (299.711,542.695),(x2,y2)=(299.665,540.03)
d=√(-0.046)²+(-2.665)² = 2.665396 So,1.588 = 91.032ᶿ, Cos(91.032)= -0.018008156, Speed=2.665396/1,Vx=Speed*Cosᶿ,Vx = 2.665396*Cos91.032=2.665396*(-0.018008156)= -0.0479 is not consistent with Vx0(-0.0273485)
Vy= 2.66496 is not consistent with Vy0(-1.58621) and same for the others records. Therefor, d/t=speed=2.665396 is not consistent with speed=3.5225. Any advise or solution or clarify the concept?

Answer 1

Your car seems to be speeding up.

If I understood you right, at the two time instants you measured, SUMO reports the car's speed first as 1.6 m/s, one second later as 3.5 m/s.

In my view, the distance you calculated (2.67 m) is reasonable. You would expect your car to travel somewhere in-between 1.6 m and 3.5 m, which it does.

Note that, when you calculated the speed, you flipped the sign in y direction: remember that OMNeT++ uses a coordinate system where (0,0) is the top left.