Satellites to Satnavs – The back story
Satellites to Satnavs - The Allianz connection
Allianz SpaceCo are the Allianz experts in space and satellite insurance. Since 2004, they have specialised in satellite insurance and are now global leaders in this rapidly growing field. Allianz Spaceco’s clients include launch agencies, satellite operators and satellite users. As well as insuring satellites, Allianz also cover more than 50million cars around the world and for many the insurance policy covers their in-car satnav.
Space and satellite insurance
This has evolved from simple launch insurance coverage to a complex discipline combining contract analysis and advice, risk evaluation, alternative risk transfer concepts, insurance program design and claims negotiation. Risk consulting helps clients assess risks by conducting surveys, safety awareness consultations and other proactive steps to keep losses from occurring. With such high-value property at stake, risk guidance saves clients time and money.
What uses satellite technology?
Apart from your car’s satnav, many other vital components of our everyday life also use satellite technology:
- Communications satellites – example: HYLAS (Highly Adaptable Satellite)
These are used by mobile phones, TV and internet services; use of satellite enables mobile phone / broadband internet coverage even in remote areas and substantially wider choice of TV channels.
- Navigation satellites – example: GPS (Global Positioning Satellite) used by car satnavs.
Invented in 1973 and fully operational by 1994, GPS is maintained by the US government and is freely accessible to anyone with a GPS receiver. It works by taking signals from four satellites to plot your position and the satellite signal is then overlaid onto digital maps. GLONASS is an alternative system from Russia, the EU is developing Galileo; India and China are also developing their own systems.
- Weather satellites – example: NWP SAF (Numerical Weather Prediction Satellite Application Facility)
Use of satellites has substantially improved the accuracy of weather prediction.
- Geological Surveys – example: Landsat
These satellites can help geologists determine factors such as quantity of foliage, chemical composition of the air in different locales, changing height of the polar ice caps, shoreline erosion, or mapping of ocean currents and movements in the Earth’s outer layers.
- Search and Rescue – example: Cospas-Sarsat
This search and rescue (SAR) system detects and locates emergency beacons activated by aircraft, ships and remote explorers in distress.
- Reconnaissance – example: Big Bird
Satellites provide high quality intelligence – they can see objects on Earth that would otherwise be obscured by cloud cover and darkness.
- Astronomy satellites – example: Hubble Space Telescope
Because it is outside the earth’s atmosphere, the space telescope gets much clearer images of stars, planets, black holes and other celestial bodies. The Hubble space Telescope was launched by NASA in 1990. It has the smoothest large mirrors in the world, 2.4m in diameter. It is named after the American astronomer Edwin Powell Hubble (1889–1953) who established the field of extra-galactic astronomy.
How to spot a satellite in the night sky
Satellites are visible when the sky is dark and the satellite is reflecting sunlight back to the observer. These conditions generally occur up to about 45 minutes before sunrise and 45 minutes after sunset. Most satellites are not visible all night long. If the object is moving slowly across the sky then it may be one of the larger satellites. The light from the satellite may be steady or flashing.
- How they work
GPS, (Global Positioning System), works on a triangulation method used by map-makers for many centuries. Satnavs work by taking signals from four satellites to plot your position and the satellite signal is then overlaid onto digital maps. Your position is calculated by measuring how long a radio signal takes to reach your satnav from the four satellites. To do this, the satellite compares the time at which the signal was sent to your car and the time at which the return signal is received. This time is multiplied by the speed of light, and the distances are worked out. All GPS satellites are fitted with atomic clocks which means their time-keeping is permanently accurate to within 1 second per 300,000 years.
- In the beginning…
The first commercial satnavs for cars were marketed in the UK in the 1990s, after President Reagan had made the GPS technology commercially available in the 1980s. Initial reactions were mixed, with some drivers disliking the female voice that gave them instructions! One of the earliest satnav voices used in the UK was Susan Skipper, who appeared as Nigel Havers' posh girlfriend in the 1980s sitcom Don't Wait Up.
- The map angle
The satellite is only one side of the satnav system; the digital maps on which your position is calculated must be kept up-to-date and other information such as road width and suitability for large lorries needs to be overlaid for the system to be practical. Infamous examples of huge lorries getting stuck in narrow roads or under low bridges regularly hit the headlines. In March 2012, the UK government held a summit meeting with highway authorities, mapping companies and satnav manufacturers to ensure accuracy is improved. In the future, local councils will gain new powers to decide how their roads will appear on maps, aimed at directing traffic better.