DSC-RX100M3
ƒ/1.8
8.8 mm
1/30
500
the only GPS satellite on display.
The circular sensors on top detect nuclear explosions (x-ray sensor and radiometer).
2 responses to “First Generation GPS Satellite”
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details
"The Nuclear Detection System (NDS) sensors are:• GBD (Global Burst Detection suite of instruments)
• BDY (Bhangmeter) – non-imaging radiometer that detects the optical flash generated by a nuclear explosion fireball. It consists of a lens with a 30 degree field of view, a conical sunshade, a three-segment photodiode sensor and an electronics subsystem.
• BDX – an X-ray sensor that monitors four different bands in the X-ray spectrum. This detector is important in discriminating between atmospheric and exoatmospheric (space) detonations.
• BDW – electromagnetic receiver and processor. This monitors two bands in the radio spectrum (BDW-lo [VLF] and BDW-hi [VHF]) for the electromagnetic pulse (EMP) generated by an atmospheric nuclear explosion. Because there are many sources of interference (RFI) in the bands monitored, the BDW reports a signal only when there is a coincidence with a BDY detection. Lightning in particular is a confounding signal with this detector.
• BDP – Burst Detector Processor – this is the interface between the various detectors and the satellite. It provides power for the sensors, timing, command signals, data processing and transfer of data to the satellite communications system.
• The BDD is a dosimeter to provide an indication of the ionising particulate and gamma radiation in the environment of the satellite.
Although none of these sensors has imaging capability, they have access to the high precision on-board atomic clocks. These are used to time tag any events detected. Comparison of these times with the times recorded by other GPS satellites allow positional determination of the event source to high accuracy (as with the similar determination of position by the navigation system).
The GPS satellites are situated in a Medium Earth Orbit (MEO) within the van Allen radiation belts. This requires that their systems and electronics be hardened to withstand the high radiation environment. As such, they are uniquely suited to survive in the case of an exoatmospheric nuclear detonation.’:"
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