A rail transport company uses a global positioning system (GPS) to determine a train's position.
The GPS data is used to provide real-time arrival data on video displays in train stations.
The GPS data is made publicly available so that software developers can use it to build apps.
The mobile application ATrainAway uses the real-time train GPS data as well as the GPS data from the user's smartphone.
State one data item concerning the arrival of a train that may be provided on the video display.
Method #1
\text{Award} \boxed{1 \text{ max}} $
- Train number/route/direction
- Status (on time/delayed/cancelled)
- Time train/
next train are due
Explain how GPS works.
Explain how GPS works
- The GPS receiver in a train takes the information from the satellite/ picks up the signals from (at least) 3 satellites
1 mark - The signals transmitted are: time of transmission, coordinates of the satellite
1 mark - The difference between the (atomic) time of transmission and (atomic) time of receiving the signal is used to calculate the distance
1 mark - The method of trilateration is used to determine position from the distance to satellites/ is used to determine the train's exact position/ is used to calculate position of the train through equation resolution on a sphere
1 mark
Outline two pieces of information that the ATrainAway application could provide to the user.
Outline two pieces of information that the ATrainAway application could provide to the user
-
Real-time information (train number/ route / direction and status (on time / delayed / cancelled))
2 marks relating to the arrival / departure of a particular train -
The time next train is due (the next 2/3 times a train will arrive at the station)
2 marks helps passenger to spend less time waiting on trains -
Should save user's (passenger) most frequented stops and routes for quick access to get the next rail trip
-
Alerts (set) to let you know when a train is nearing the station
-
Trip planning (conducted) through Google trip planner within the app
-
Information on the nearest station, distance to station/ next train arrival/ next train departure to help passenger to spend less time travelling/ save time
Outline how sensors can be used in combination with GPS to provide more accurate arrival data.
Method #1
Motion sensors/vibration sensors (can be placed on track rail);
(Sensing devices are placed) at a distance from each side of a train station/junction OR at some fixed points where obstacles (like tunnels) prevent GPS from working properly;
Data from each sensor can be logged continuously and used in calculations/determinations (of expected arrival times/ delays / rerouting during disruption, etc.);
Discuss the advantages and disadvantages of using GPS in transportation systems.
Advantages
- Safer transit
1 mark - Trains are tracked and in case of emergency the location can be reached at the earliest and emergency services provided
- More favorable view of transit/helps passenger to get punctuality status of the train/
1 mark - GPS can provide worldwide three-dimensional positions (24 hours a day) (in any type of weather)
Disadvantages
- Sometimes it is too difficult to ensure reliable positioning
1 mark - Objects, such as buildings, overpasses, and other obstructions (that shield the antenna from a satellite) can potentially weaken a satellite's signal
- Privacy issues
1 mark - Knowing the absolute position of anything, anytime, anywhere
