The Global Positioning System is a constellation of 24 satellites which have the ability to calculate the position, time and velocity of any GPS receiver. Ethical concerns arise when a person carrying a receiver has their location transmitted to second party. This type of tracking has a wide variety of applications including tracking dementia sufferers, tracking parolees and law enforcement. A literature review found that the ethics of GPS tracking has not been thoroughly assessed. This paper investigates the ethical issues arising from the real time tracking of people using GPS-based location services. Usability context analysis and an observational study were the methodology used in this study. Usability context analysis provided insight into GPS tracking over the contexts of care, control and convenience. Its current applications could be seen in the tracking of Alzheimer’s patients, parents tracking children, law enforcement, parolee and sex offenders, terrorist tracking, employee monitoring and commercial uses. A participant observational study was also used to develop an ethical discussion. It found five issues prevalent to GPS tracking: accuracy, editing track data, user travel behaviour, detail of GIS and user awareness. The results from the usability context analysis and participant observational study were used to form a discussion based on the issues of privacy, accuracy, property and accessibility.