Derivation of 1PPS from GPS.
- Introduction
- The output of a GPS Rx consists of 2 data streams in RS422 form (1PPS and status infromation). There are 2 packaging forms of the same GPS Rx - 60742 and 60743, they are for different purposes
- 60742 GPS Ae/Rx.
- This unit is an integrated GPS Ae and GPS Rx under a small dome (approximately 150mm dia) - it uses the same GPS Rx engine as the 60743. Intended for light industrial use it should be positioned outside of the site building - possible on the roof, wall or on a local pole/mast. It is not necessary for the unit to be mounted high up as long as there is an uninterrupted view of the equatorial sky. It should not be used either where there is a likelyhood of severe RF interference (it is not possible to filter the RF side) or in locations where extreme physical abuse is probable - it will not withstand much physical attack. There have been several hundred in service for several years and they have proved to be effective and reliable, particularly if due diligence is taken of their positioning. Connection to the output data streams is via a multi-core cable (a component in the Distribution section of this publication).
- 60743 GPS Rx.
- This unit is a GPS Rx in a small box designed for mounting inside the site building on a wall or cabinet side - it uses the same GPS Rx as the 60742. It requires to be connected to a source of GPS RF signals (be aware that there is a 3V3 supply on the co-axial connector) and the 60744 GPS Ae is available for that purpose. The 60743 Rx is, in RF interference terms, more robust than the 60742 unit in that it can be fitted with RF filtering devices on its RF input. Careful positioning is not required - that is a problem associated with the actual Ae (60474). Connection to the output data streams is via a multi-core cable (a component in the Distribution section of this publication).
- 60744 GPS Ae.
- This unit is a GPS Ae of very robust construction - it is a Trimble product. I should be used in conjuction with the 60743 GPS Rx. It connects to the Rx via co-axial cable (not supplied).
- Rx Tech Pubs.
| Hand book | 2.0 | This information is common the 60742 and 60743 GPS Rx; it is a handbook in the form of that which would have been paper in a ring binder before the advent of 'the web'. |