GNSS Repeater Based Differential Indoor Positioning With Multi-Epoch Measurements

Global Navigation Satellite System (GNSS) based indoor positioning generally utilizes repeaters to amplify and retransmit the original GNSS signals to indoor receivers. To improve the positioning accuracy with GNSS repeaters in indoor environments such as an underground parking lot and an enclosed depot, in this paper, a carrier phase measurement based differential indoor positioning method is proposed. Without reference stations, the carrier phases measured by using the repeated signals are differenced between repeaters. Considering that upon carrier tracking loop locking the signals the carrier phase cycle integer ambiguity remains unchanged, the differenced phase measurements at two consecutive epochs are combined to find the receiver position. Receiver coordinates and phase cycle integer ambiguities are solved jointly with assistant Least-squares AMBiguity Decorrelation Adjustment (LAMBDA) algorithm. High positioning accuracy is achieved by the proposed technique, and this is verified by close-to-reality simulations.