kindly go through the following

http://www.sciencedirect.com/science/article/pii/S157087050800125X

http://www.sciencedirect.com/science/article/pii/S0045790617307085

http://www.sciencedirect.com/science/article/pii/S1877705815031860

Dear Khaoula, 

You can follow the closest related previous research trends to your topic, thus, you may follow same sensors or might be there is a new technology you can apply... 

Thank you for your answers. For outdoor localization using beacons, there are few existing technologies limited by the LOS and range. However, for longer range I did not find a WIFI beacon system ready for using.

Hi Khaoula,

Accuracy and reliability and range are key questions.

UWB systems are good but may have limited range and reliability.

WiFi may have accuracy issues (depending on your target) but comparable to generic GPS.

RFID is not very accurate or reliable unless in a highly controlled environment.

O and the company I work for is solving these issues.

http://minetec.com.au/

The underling system is based on WASP from CSIRO.  However we have commercialised it for use in the Mining sector. 

This system uses the same Band as 5.8GHz WiFi but is a dedicated tracking solution so has sub meter accuracy with high update rates.  It has been used in the past to tack athletes performance. 

http://minetec.com.au/

Thank you for your answer Craig!

Regards,

Khaoula Lassoued.

Khaoula, there are also solutions that integrate GNSS with two way radio for location sharing in remove environments. A number of dedicated radios exist that include GNSS chips. These are generally for military uses and are quite expensive. However, the technology is also used in some GNSS devices designed and sold - at least in the US - for recreational purposes, and especially hunting. For example, see the Garmin Alpha unit that can track 20 dog collars with one location transmitted from each collar to the handheld every 2.5 s. The newest version of the GNSS-RF approach that we are currently researching for a variety of forestry and wildland firefighting applications are radio devices that augment smart phones, making use of the phone GNSS chip. Examples are the goTenna and Beartooth products being marketed in the US. These use bluetooth or a cable to pair a small radio with the phone, and then transmit GNSS coordinates regularly to other devices. This approach is perfect for forestry, where we are generally far removed from cell service or WIFI. Some examples:

http://www.mdpi.com/1999-4907/8/2/44

http://www.mdpi.com/1424-8220/17/4/822

Hope that helps! Rob 

Just to follow up: in environments where GNSS positioning accuracy is poor, e.g. due to mature forest conditions, we might use these technologies in conjunction with other localization methods like, e.g. inertial navigation. Rob 

Thank you Robert, sure it is helpful!

Good Answer