Kirsten L. Strandjord's research while affiliated with University of Colorado Boulder and other places

Publications (6)

Article
As the dependence of Global Navigation Systems (GNSS) increases, so does a growing demand for GNSS accuracy in urban environments. This research aims to improve navigation in these environments by integrating non‐line‐of‐sight signals, building models, and measured signal to noise ratios in ways not typically used in GNSS positioning. We propose a...
Article
Full-text available
High-precision estimates of GPS satellite clock errors reveal systematic sub-daily clock bias variations on the order of 1 ns. The low noise levels in the Rubidium Atomic Frequency Standards onboard GPS IIR, IIR-M, and IIF satellites provide visibility of these small, but systematic behaviors. Prior studies have reported on this phenomenon and soug...

Citations

... Various studies have utilized 3D building models with or without ray tracing to overcome the unfavorable GNSS signal reception conditions in urban environments [14], [15], [20]- [22]. Shadow matching [20], specular matching [21], and urban trench modeling [22] were developed to decrease the positioning error by predicting the NLOS conditions of GNSS satellites using a 3D building map. In [14] and [15], 3D building models along with ray-tracing techniques were utilized to predict pseudoranges at a given location in an urban multipath environment. ...
... Several recent newspaper and magazine articles report jamming events [19][20][21] and spoofing attacks [22,23]. In this context, the need of creating a 'situational awareness' around the receiver is more than ever required [24,25]. In this regard, the crowd-sourcing paradigm, i.e., aggregating and sharing information from multiple receivers, is an highly effective means for detecting and even locating interference sources, as shown in [26] for the detection of spoofing attacks in the aviation domain and in [25] for creating situational awareness for vessels sailing the Baltic Sea. ...
... With the advantages of simple physical operation, small size, light weight, and high reliability, the rubidium (Rb) vapor cell atomic clock has wide applications in radio navigation, space exploration, satellite position, and telecommunication [1][2][3].The best frequency stability performance in vapor cell atomic clock has been demonstrated based on pulsed optically pumped (POP) scheme [3][4][5][6][7][8], in which the pumping, interrogation, and detection phases are separated in time. In this manner, the light shift is strongly reduced, and the smaller light-induced instability contributions have been experimentally demonstrated [4,9]. ...