The market research (mr) industry should deliver timely and reliable information to their clients based on surveys and marketplace and consumer knowledge. However, surveys are not done where the action is. Tracking location can be done by using the GSM /3G net or, on a phone with GPS. The location can be used to intercept and invite potential respondents to participate in surveys in the marketplace. The m-phones are more user-friendly and the use of other services than text-messaging and calling is growing. In the next years it is very likely that location based services (LBS) will grow significantly. For the market research industry, to meet the needs of their clients, this opportunity should be used and surveys that make use of location data should be offered. They key argument is that then there is not "I cannot remember what happened and why I decided to buy product X and not Y". On the other hand, the market research industry does not want to be accused for surveillance or for getting negative reactions from panel-members and respondents. The area of mobile-phone LBS has shown some recent developments in the implementation of privacy functions into the supporting infrastructure.

Privacy protection in location-aware, context based systems can be reached using privacy-enhancing technology (PET) and privacy-preserving identity management (IDM). Such technology provides basic building blocks and tools. IDM is used for concealing user identities against service providers, and for managing of pseudonyms, identifiers and credentials. PETs are configured for the creation of anonymity upon the creation of a LBS event, and the implementation of technically sound anonymity and pseudonymity in communications.

This article will emphasize the technical implementation of anonymity in LBS survey research. It will discuss an infrastructure that is inspired by research from the EU PRIME (Privacy and Identity Management for Europe) project, where researchers, vendors and T-Mobile developed and implemented a privacy-friendly way of connecting mobile user location contexts to 3rd-party services. In summary, this paper will show that technical solutions to the location-related privacy problems are sufficiently mature to implement a trustworthy mobile survey approach with location context.