An apparatus to track a mobile subject based on Global Navigation Satellite Systems, GNSS, data, wherein the GNSS data comprises GNSS position, velocity, time, PVT, signals, wherein the apparatus is configured to be attached to or worn by the mobile subject, the apparatus comprising: a motion detector configured to detect motion of the mobile subject independently of the GNSS data; a signal reception and corrections unit configured to receive the GNSS data; a PVT engine configured to generate a GNSS position and GNSS speed from the received GNSS data; an actionable position and speed determination unit configured to determine an actionable position and speed of the mobile subject, wherein the actionable position and speed are quantities derived from the GNSS position and GNSS speed, confirmation of movement of the apparatus by detection results of the motion detector, GNSS solution metrics, GNSS signal metrics, and a prior actionable position and speed, wherein the GNSS solution metrics include an horizontal dilution of precision, estimated horizontal position error, estimated speed error, the horizontal dilution of precision times the estimated horizontal position error, the horizontal dilution of precision times the estimated speed error, or any combination thereof, wherein the GNSS signal metrics include a quantity representative of the aggregate observable GNSS signal to noise ratio and/or a quantity representative of the aggregate eligible GNSS signal to noise ratio, observable indicating all GNSS signals used to determine the GNSS position and speed, and eligible indicating all decodable GNSS signals emanating from satellites above a predetermined elevation threshold, wherein the prior actionable position and speed are maintained in response to the motion detector detecting no motion of the mobile subject, such that the actionable position and speed tracks the GNSS position and GNSS speed very closely under favorable GNSS signal conditions and GNSS speed, ceases tracking the GNSS position and speed if GNSS signal conditions and/or GNSS speed are below acceptable levels; and a boundary test unit configured to evaluate the actionable position and speed of the mobile subject relative to a predetermined boundary defining a containment area. a motion detector configured to detect motion of the mobile subject independently of the GNSS data; a signal reception and corrections unit configured to receive the GNSS data; a PVT engine configured to generate a GNSS position and GNSS speed from the received GNSS data; an actionable position and speed determination unit configured to determine an actionable position and speed of the mobile subject, wherein the actionable position and speed are quantities derived from the GNSS position and GNSS speed, confirmation of movement of the apparatus by detection results of the motion detector, GNSS solution metrics, GNSS signal metrics, and a prior actionable position and speed, wherein the GNSS solution metrics include an horizontal dilution of precision, estimated horizontal position error, estimated speed error, the horizontal dilution of precision times the estimated horizontal position error, the horizontal dilution of precision times the estimated speed error, or any combination thereof, wherein the GNSS signal metrics include a quantity representative of the aggregate observable GNSS signal to noise ratio and/or a quantity representative of the aggregate eligible GNSS signal to noise ratio, observable indicating all GNSS signals used to determine the GNSS position and speed, and eligible indicating all decodable GNSS signals emanating from satellites above a predetermined elevation threshold, wherein the prior actionable position and speed are maintained in response to the motion detector detecting no motion of the mobile subject, such that the actionable position and speed tracks the GNSS position and GNSS speed very closely under favorable GNSS signal conditions and GNSS speed, ceases tracking the GNSS position and speed if GNSS signal conditions and/or GNSS speed are below acceptable levels; and the GNSS position and GNSS speed, confirmation of movement of the apparatus by detection results of the motion detector, GNSS solution metrics, GNSS signal metrics, and a prior actionable position and speed, wherein the GNSS solution metrics include an horizontal dilution of precision, estimated horizontal position error, estimated speed error, the horizontal dilution of precision times the estimated horizontal position error, the horizontal dilution of precision times the estimated speed error, or any combination thereof, wherein the GNSS signal metrics include a quantity representative of the aggregate observable GNSS signal to noise ratio and/or a quantity representative of the aggregate eligible GNSS signal to noise ratio, observable indicating all GNSS signals used to determine the GNSS position and speed, and eligible indicating all decodable GNSS signals emanating from satellites above a predetermined elevation threshold, wherein the prior actionable position and speed are maintained in response to the motion detector detecting no motion of the mobile subject, such that the actionable position and speed tracks the GNSS position and GNSS speed very closely under favorable GNSS signal conditions and GNSS speed, ceases tracking the GNSS position and speed if GNSS signal conditions and/or GNSS speed are below acceptable levels; and a boundary test unit configured to evaluate the actionable position and speed of the mobile subject relative to a predetermined boundary defining a containment area.