8.4.2 Ionospheric Function and Cycle Slips

Dual-frequency observations can eliminate the first-order ionospheric effects by forming the popular dual-frequency ionospheric-free functions. Consider the relevant terms of the ionospheric-free function (6.1.41)

and the ionospheric function (6.1.44)

8.4.25 equation

with c08-math-0363, c08-math-0364, and the squared ratio c08-math-0365 as already defined in (6.1.1). Analyzing these dual-frequency carrier phase functions requires extra attention because certain cycle slip combinations on L1 and L2 generate almost identical effects. For example, consider the ionosphere-free phase observable (8.4.24). The ambiguities enter this function not as integers but in the combination of c08-math-0366, causing noninteger change when cycle slips occur.

Table 8.4.1 lists in columns 1 and 2 small changes in the ambiguities and shows in columns 3 and 4 their effects on the ionospheric-free and the ionospheric phase ...

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