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5 X-ray Pulsar-Based Navigation: Theories and Experiments
orientation of the detector by adjusting the pitch and yaw angles. The orbit
tracking demonstration device is responsible for simulating the spacecraft’s
orbits, verifying the turntable pointing and tracking and detecting the single
photon. The projection display equipment is responsible for displaying the test
results on the large screens, such as the orbital data generation, pulse profile
extraction and navigation parameter estimation.
5.7.4 Design of Operating Modes
There are six operating modes designed in the ground test system: pure mathematical
simulation, laser detection simulation, short-range X-ray photon detection simulation, pure electronics access simulation, remote X-ray photon detection simulation
and actual X-ray data processing.
(1) The pure mathematical simulation mode is with the mathematical simulation segment as the core, and under the unified scheduling of the network
control computer, to test the correctness of orbital data generation, photon
arrival-time simulation, navigation database updating and calling, large-scale
space-time and dynamic effect simulation, pulse profile extraction, as well
as autonomous navigation and fault-tolerant processing algorithm, and to
quantitatively analyze and demonstrate the principle feasibility of the XPNAV.
(2) The laser detection simulation mode is on the basis of the pure mathematical
simulation mode, and by connecting with the high-precision time synchronization devices, laser signal sources, photoelectric converters, two-dimensional
control turntable and orbit tracking demonstration device, to test the hardware performance of light-source driven and modulated circuit, light intensity
attenuation device, photoelectric converter, two-dimensional control turntable
and orbit tracking demonstration device, so as to simulate and demonstrate
the two-dimensional control turntable pointing and orbital-dynamic tracking
process, and to carry out the closed-loop tests of the pulse signal detection
and processing as well as the autonomous navigation process under the local
coordinate system and large-scale space-time frame.
(3) The short-range X-ray photon detection simulating-mode is on the basis of
the pure mathematical simulation mode, and by connecting with the highprecision time synchronization device, adjustable micro X-ray generator, and
Silicon Drift Detector (SDD), to verify the X-ray photon intensity modulation technology, and to test the hardware performances of the X-ray generator
and SDD, so as to achieve the simulation confirmation for the autonomous
navigation process with distribution, full-path, semi-physics and short-range
closed-loop.
(4) The electronic access simulation mode is on the basis of the pure mathematical
simulation mode, and by connecting with the high-precision time synchronization device, signal control device and multi-channel electronic readout device,
to test the performances of multi-channel pulse profile generators and electronic
5 X-ray Pulsar-Based Navigation: Theories and Experiments
orientation of the detector by adjusting the pitch and yaw angles. The orbit
tracking demonstration device is responsible for simulating the spacecraft’s
orbits, verifying the turntable pointing and tracking and detecting the single
photon. The projection display equipment is responsible for displaying the test
results on the large screens, such as the orbital data generation, pulse profile
extraction and navigation parameter estimation.
5.7.4 Design of Operating Modes
There are six operating modes designed in the ground test system: pure mathematical
simulation, laser detection simulation, short-range X-ray photon detection simulation, pure electronics access simulation, remote X-ray photon detection simulation
and actual X-ray data processing.
(1) The pure mathematical simulation mode is with the mathematical simulation segment as the core, and under the unified scheduling of the network
control computer, to test the correctness of orbital data generation, photon
arrival-time simulation, navigation database updating and calling, large-scale
space-time and dynamic effect simulation, pulse profile extraction, as well
as autonomous navigation and fault-tolerant processing algorithm, and to
quantitatively analyze and demonstrate the principle feasibility of the XPNAV.
(2) The laser detection simulation mode is on the basis of the pure mathematical
simulation mode, and by connecting with the high-precision time synchronization devices, laser signal sources, photoelectric converters, two-dimensional
control turntable and orbit tracking demonstration device, to test the hardware performance of light-source driven and modulated circuit, light intensity
attenuation device, photoelectric converter, two-dimensional control turntable
and orbit tracking demonstration device, so as to simulate and demonstrate
the two-dimensional control turntable pointing and orbital-dynamic tracking
process, and to carry out the closed-loop tests of the pulse signal detection
and processing as well as the autonomous navigation process under the local
coordinate system and large-scale space-time frame.
(3) The short-range X-ray photon detection simulating-mode is on the basis of
the pure mathematical simulation mode, and by connecting with the highprecision time synchronization device, adjustable micro X-ray generator, and
Silicon Drift Detector (SDD), to verify the X-ray photon intensity modulation technology, and to test the hardware performances of the X-ray generator
and SDD, so as to achieve the simulation confirmation for the autonomous
navigation process with distribution, full-path, semi-physics and short-range
closed-loop.
(4) The electronic access simulation mode is on the basis of the pure mathematical
simulation mode, and by connecting with the high-precision time synchronization device, signal control device and multi-channel electronic readout device,
to test the performances of multi-channel pulse profile generators and electronic