Jostling for global positioning

| Transport

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Four global satellite constellations are positioned on the world arena for domination in the stakes for future transport applications.

Satellite navigation systems in Europe are almost invariably associated with GPS (Global Positioning System), the US constellation of 32 satellites that has been dominating the commercial market internationally for the last 20 years. But will it continue to dominate so unequivocally in the future?

GPS is just one Global Navigational Satellite System (GNSS) out of four that are emerging rapidly and will be competing with each other by the end of the decade. Russia’s GLONASS system is already fully operational with BeiDou and Galileo from China and the EU respectively expected to be commercially operational by 2020.

Compatible or Contradictory?

All four constellations provide the same information but do it at different frequencies and with varying levels of accuracy. For rough positioning, GPS and GLONASS provide adequate accuracy of under 10 metres but it’ll be down to Galileo to provide greater precision with positional accuracies of 1 metre or less, adequate for most civilian applications.

Of more concern to developers of systems based on GNSS signals are the frequency band crossovers between the different constellations. With the frequency allocations provided by the International Telecommunications Union (ITU), there will inevitably be some leakage between signals from different constellations that share the same band. In such a busy RF environment, the separation of valid signals from interference is an important function of the receiver.

Accurate and constantly available signals will become of prime concern in the near future for automotive applications relating to international automatic emergency calling in the event of a collision on the roads. It is in this respect that three of the main GNSS providers are vying for dominance.

Automatic emergency call systems

There are currently two major projects underway to introduce automatic emergency call systems, the pan-European eCall system and ERA-GLONASS covering the customs union of Russia, Belarus and Kazakhstan. The former makes use of GPS initially, later incorporating more accurate Galileo signals. The latter uses the Russian GLONASS constellation.

Both systems operate in similar ways, detecting a collision based on parameters such as air-bag deployment then placing an automatic call to national Public Safety Answering Points (PSAP) using the international standard 112 emergency call number. Once the call has been established, information is passed to the PSAP including positional coordinates and a voice channel is initiated to enable conscious occupants of the vehicle to communicate directly with call centre operators.

Real time satellite position chartSuch systems will reduce the deployment time of emergency services and is expected to save thousands of lives annually across both of the regions in which they operate.

Apart from the different signals used between eCall and ERA-GLONASS, there are other platform differences that make it difficult for suppliers to produce a single platform that covers both sets of requirements. eCall is based on EU-wide cooperation between governments and other agencies and was developed for the single purpose of emergency call operation whereas ERA-GLONASS was created with a slightly different aim and incorporates a general platform on which telematics applications can be built, such as fleet management software.

Harmonisation

The underlying principle of the harmonisation of eCall and ERA-GLONASS is one of cross-border continuous operation. eCall will operate in all of the participating EU countries as well as Switzerland and Turkey seamlessly. This means that if a driver has an accident in any of these countries, the automatic emergency platform will operate in the specified way.

Since Russia has been undergoing a largely parallel development of its own system, it seemed sensible to extend the harmonisation across common borders between the eCall participating countries and the countries that fall under the ERA-GLONASS project.

The fact that different positional signals are used in these projects makes no difference to the harmonisation scheme, the key lies in the data that’s transmitted to the PSAP and the telecommunications element which places the voice call using the standard 112 emergency call number.

When a crash is detected, an automated data and full duplex voice call is initiated over the mobile communications network. For harmonisation to work fully, this has to be supported by mobile and PSAP operators in all the affected territories.

For Russia, this is a challenge. Without considering Kazakhstan and Belarus, there are 83 regions across the Russian Federation alone, all of which have been operating separate emergency call numbers for fire, police and ambulance services. For the ERA-GLONASS system to work, these have to be brought together into the single 112 call centre number and operators have to be re-educated to handle emergency calls in a different way. The Russian government has set the highly ambitious target of having this complete by 2017.

Once that has happened, whether a vehicle is fitted with the eCall or ERA-GLONASS platform should be transparent to the driver and will operate regardless of which country the vehicle is travelling in.

In addition, the eCall system will be operable using more accurate Galileo signals when the constellation is commissioned. According to Carlo des Dorides, Executive Director of the European Global Navigation Satellite Systems Agency, Galileo will play a key role in the eCall initiative. He went on to say that not only would eCall devices be compatible with Galileo, but manufacturers will also be able to ensure compatibility with other navigation systems.

Implementation time-frame

Time is running out for the automotive industry and their platform suppliers and integrators as both schemes have tight implementation schedules and some remaining churn in specifications.

According to the latest information from the European Council released on 2nd March 2015, the timeframe for vehicle suppliers to meet the eCall requirements is March 2018. After then, all new vehicle registered within the participating countries must be equipped with the eCall emergency call platform.

The Russian Federation’s “GLONASS Union” stalwartly refused to acknowledge the objections of some of the largest car manufacturers in the world and went ahead with its planned implementation date of January 2015 for all new vehicles to be fitted with ERA-GLONASS equipment. The next ERA-GLONASS milestone is 1st January 2017, when the regulations will be extended to all vehicles entering the customs union, whether new or previously-owned.

U-Blox concurrent GNSS receiver chipTo meet these dates, component manufacturers and test equipment suppliers are gearing up for the expected rapid ramp in demand. Through its Cinterion brand, Gemalto supplies modules for vehicle communication with the PSAPs and companies such as u-blox and Telit are supplying satellite receivers for both GPS and GLONASS signals.

Preparing for volume production

Meeting the specifications for eCall and ERA-GLONASS is a challenging task. The Russian GOST R standard alone contains a list of at least 17 tests that need to be successfully conducted in order to receive certification including L1 band signal accuracy, signal restoration capability and interference handling.

Some test equipment suppliers are now able to supply complete testing rigs that meet either the eCall or ERA-GlONASS requirements, including equipment from Rohde & Schwarz.

In order to meet the high volume demand for equipment in time for the deadlines in 2017 for ERA-GLONASS and 2018 for eCall, there is little time to lose in developing and modelling systems that are likely to be in every new car delivered to Europe and Eurasia by the end of the decade.

Rohde test rig for eCall in-vehicle systems

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