Method and device for integrating a RF GPS emulator in a simulation environment
View Patent ↗A method for integration of a GPS emulator in a simulation environment includes operating a computer adapted for using a simulation timer and configured to receive a signal of x_PPS type. For each pulse detected on the x_PPS signal, a counter is updated with a number of detected pulses and a value of the simulation timer is stored. A given simulation time moment is evaluated according to the detected and counted number of pulses, a current value of the simulation timer, and the stored value of the simulation timer. A related device and computer readable medium are also disclosed.
1. A method for using a GPS emulator in a simulation environment including a computer adapted for using a simulation timer, the method comprising:
receiving an x_PPS signal having pulses regularly spaced apart by one or more seconds at the computer from the GPS emulator;
for each pulse detected by the computer on the x_PPS signal
updating a counter with a counted number of detected pulses on the x_PPS signal, and
storing a value of the simulation timer having a resolution of a fractional part of a second; and
evaluating a given simulation time moment according to the counted number of detected pulses, a current value of the simulation timer, and the stored value of the simulation timer.
2. The method according to claim 1 , further comprising:
initializing the counter at a time of detection of a first pulse following a beginning of a simulation.
3. The method according to claim 1 or claim 2 , wherein the evaluating the given simulation time moment is based on the following relationship:
t
k
=
(
n
-
1
)
x
+
(
t
k
′
-
t
i
′
)
where n is the counted number of pulses, t′ k is the current value of the simulation timer, and t′ i is the stored value of the simulation timer.
4. The method according to claim 1 , further comprising:
verifying validity of a detected pulse; and
preventing the updating the counter with the counted number of detected pulses and preventing the storing the value of the simulation timer if the detected pulse is not valid.
5. The method according to claim 4 , wherein the verifying the validity of the detected pulse includes comparing a time interval separating a moment of detection of the detected pulse and a moment represented by the stored value of the simulation timer with at least one predetermined threshold.
6. The method according to claim 1 , wherein the x_PPS signal is a 1_PPS signal having pulses regularly spaced apart by one second.
7. The method according to claim 1 , further comprising:
transmitting, to the emulator, data characteristic of a position; and
transmitting, to the emulator, the evaluated given simulation time moment corresponding to the position to allow the emulator to determine a GPS signal corresponding to the position and the evaluated given simulation time moment.
8. A non-transitory computer readable medium storing instructions, which, when executed by a computer in a simulation environment including a GPS emulator and having a simulation timer, cause the computer to perform a method comprising:
receiving an x_PPS signal having pulses regularly space apart by one or more seconds at the computer from the GPS emulator;
for each pulse detected by the computer on the x_PPS signal
updating a counter with a counted number of detected pulses on the x_PPS signal, and
storing a value of the simulation timer having a resolution of a fractional part of a second; and
evaluating a given simulation time moment according to the counted number of detected pulses, a current value of the simulation timer, and the stored value of the simulation timer.
9. A GPS simulation apparatus comprising:
a computer having a simulation timer and configured to receive an x_PPS signal having pulses regularly spaced apart by one or more seconds from a GPS emulator, the simulation timer having a resolution of a fractional part of a second;
a counter that is updated with a counted number of pulses detected by the computer when each pulse is detected by the computer;
a memory that stores a value of the simulation timer operating at a frequency greater than the x_PPS signal when each pulse is detected by the computer; and
the computer is further configured to evaluate a given simulation time moment according to the counted number of detected pulses, a current value of the simulation timer, and the stored value of the simulation timer.
10. The apparatus according to claim 9 , wherein the x_PPS signal is at least partially transmitted in optical form.
11. The apparatus according to claim 9 , further comprising:
an initialization section that initializes the counter at a time of detection of a first pulse following a beginning of a simulation.
12. The apparatus according to claim 9 , wherein:
the computer is further configured to evaluate the given simulation time moment based on the following relationship:
t
k
=
(
n
-
1
)
x
+
(
t
k
′
-
t
i
′
)
where n is the counted number of pulses, t′ k is the current value of the simulation timer, and t′ i is the stored value of the simulation timer.
13. The apparatus according to claim 9 , wherein:
the computer is further configured to verify validity of a detected pulse; and
the computer is further configured to prevent updating the counter with the counted number of detected pulses and preventing the storing the value of the simulation timer if the detected pulse is not valid.
14. The apparatus according to claim 13 , wherein:
the computer validates the validity of the detected pulse by comparing a time interval separating a moment of detection of the detected pulse and a moment represented by the stored value of the simulation timer with at least one predetermined threshold.
15. The apparatus according to claim 9 , wherein the x_PPS signal is a 1_PPS signal having pulses regularly spaced apart by one second.
16. The apparatus according to claim 9 , further comprising:
the computer is further configured to transmit, to the emulator, data characteristic of a position; and
the computer is further configured to transmit, to the emulator, the evaluated given simulation time moment corresponding to the position to allow the emulator to determine a GPS signal corresponding to the position and the evaluated given simulated time moment.